Restoration of the Wilts & Berks Canal Feasibility Study 1998

WILTS& BERKSCANAI.TRUST

Restoration of the Wilts & BerksGanal Feasibility Study 1998 FinalReport January

WILTS& BERKSCANALTRUST

RESTORATION OFTHE WILTS& BERKSCANAL Feasibility Study FinalReport January 1998

Approled By

& Co l-td ScottWilsonKirkpatrick l6 Priestgatc Peterborough Calnbridgeshire PLlIJA

Wilts& BerksCanalTrustat No|thWiltshireDistrictCouncil MonktonPark Chippenham Wiltshire S N 1 5I E R

Resloration ofthe Wihs & BerksCanal FeasibilrtySrudy

SUMMARY OF PRINCIPAL FINDTNGS 1. INTRODUCTION This reporthasbeenpreparedin fulfilmentofa commissionawardedto ScottWilson by North WiltshireDistrictCouncilon behalfof the Wilts andBerksCanalTrusron 10 April 1997.The commissionwas for a FeasibilityStudyfor the restorationof the Wilts & Berks Canal,over the full route betweenthe Kennet & Avon Canal at Semingtonnear Melkshamin Wiltshire, and the River Thamesat Abingdon in Oxfordshire.Also includedrverethe North Wilts Canalfrom Swindonto Lattonnear Cricklade,andthe Calnebranch.The principalfindingsof the studyare summarised below. 2. ROUTE SI,LECTION The studyhasexaminedrouteoptionsfor restoration ofthe Wilts & BerksCanalwith particularemphasis wheretheoriginalroutehasbeenlost or obstructed on reaches by development.It concludesthat in generalthere appearto be feasibleengineering solutionsto satisfythe majorrestorationobjectivesand which may be supportedby parties. theprincipalinterested For the main urban centres (Melksham, Swindon, Cricklade and Abingdon) restorationon the original alignrnent,which would require significantproperty acquisition,andinfrastructure modifications, hasbeenfoundto be lessfavouredfor a numberofreasons.However,otherthanin Swindon,restorationon the originalroute may still be cost effective by comparisonwith the altemativeoptions and if achievablewouid maximisethe historic,fteritage value of the whole restorarion project. At Melksham,the preferredaltemativeto the originalroute makesuse of a short reachofthe Avon throughthecentreofthe town.This couldhavea significantimpact on the river, andconsiderably morework will be neededin the next phaseof studies to developthis optionbeforethe EnvironmentAgencyin particularcould offer their support.However,anotherviablebut lesspreferredalternativeroute to the eastof Melkshamhasbeenidentifiedandbothoptionsneedto be retainedfor thepresent. For the Calnebranch.shouldthe Conigretunnelproveto be impracticable to restore, thereis sufficientspaceto cut a newtunnelto the north. At WoottonBassettcurrentplansfor a new bypassallow for the 43102 to be closed offat this point to permitrestoration on theline andlevelofthe originalCanal. The major obstacleto reslorationin Swindon arises lrom development,most particularlyin rcspectofthe North Wilts Canal.The principalissuesidentifiedin this (i.e. makingnavigable)of naturalwatercourses, study are the necd for canaiisation which the EnvironmentAgencymav oppose(but which th€ preferredrouteavoids); and the proximity of building development,especially Sainsbury'sstore at

ScottWilsonKirkpatrick& Co Lrd

Restoration oflh€ Wilts & BerksCrnal Feas)bility Study

Bridgemead.Theseconstraintsmeanthat only one possiblysupportablealtemative routefor the North Wilts Canalhasbeendetcrmined. For the main line ofthe Wilts & BerksCanal,a preferednew routeto the southof Swindonhasbeenidentifiedwhich keepsthe Canalas far llom the M4 as possible. Crossingsof the M4 and A419 would requirethrust bored culverts,but there is adequate headroom.The routemay createa llew shortsummitpoundat a lev€l some 17mabovethe originalsummitalthoughit may be possible(andis desirable) to lower this new summitpoundat detaileddesignstage.Onceeastofthe A419, the route is relativelyconstrained;the preferredaltemativefollows (but doesnot canalise)the LidenStream,rejoiningtheoriginalCanalrouteat Acom Bridge. At East Challow, an option to dive( the Canal north of the village to avoid developmenton the originalline hasbeenexamined,althoughrestorationalong the originalrouteis preferred. The proposedThamesWaterReservoirto the southwestofAbingdonwould be sited directlyoverthe originalCanalline,requiringa divenion arcundthe northside.Such a diversionis likely to be includedin Thameswater'splansfor thereservoir. At Abingdon,a newroutealongtheOckcorridorappearsfeasiblealthoughgivingnse to environmental objections.However,an altemativenew rout€to the southof the town is likely to be lesscontroversial, andis stronglyfavouredby localinterests. At Cricklade,thereappearto be viable altemativel1ewrcutes for the North Wilts Canalto both eastandwestof the town. Giventhe desireto allow for restorationof the Swindon-Crickiade railwaythroughto Cirencester, whichwould needto sharethe samecorridorasthe CanalthroughHorseyDown,the westemrouteoptionhasbeen proposedastheprefenedaltemative. 3. ENGINEERING "standard"narowboat The study has been basedon the need to accommodate dimensions of up to 22.0mlength,2.13mbeamand l.0m draft. Broaderbeamcraft will not be accommodated. The total volume of excavatedmaterial(mainlv stiff clavs from the new canal is estimated sections) to be about1.4Mmr,of wlich only ierhaps0.1Mmrwill be requiredto form new embankments. Thereis potentialto useup to 0.5Mm' of surplus matedalin the formingofthe surfacewaterreserr"oirs requiredfor watersupplyto the restoredcanal.The most significantnew canalcut on the cunentlyprcfenedroutes u'ouldbe tkough the OxfordClay ofHorseyDown at Cricklade,wherea depthof up to 6m is anticipated. This cuttingwouldbe sharedwith a restoredrailway. Therewill be numerousstructures to be constructed or reconstrucied for a restoration to navigablestandards ofthe full 108kmofCanal. For lhe vast majority of these crossings, thc cngineering solutionis straightforward, scope andthereis considerable for standardisation with resultingeconomyof construction.

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Restoration ofthe Wilis & BerksCanal FeasibilityStudy

ln most casesat road crossings of the originalCanal,the originalstructuehasbeen removedand the channelinfilled and culverted.There is now often insufficient of a new bridgeover the restoredCanalwithout headroomto permitthe construction changes to theroadalignment.Theroadapproaches appropriate at eachcrossinghave beenexaminedto confirmthatraisingofthe roadlevelto achievesufficientheadroom (whilst maintainingacceptablestandardsof vertical and horizontalalignmentand sightlines)wouldappearto be practicable. For crossingsunderthe M4 and the A4l9 at Swindon,the A34 at Abingdon,and at it is proposedto usethetechnique leastoneandpossibleup to tkee railwaycrossings, jacking (commonly of structue knownasthrustboring)which enablesthe crossingto withoutdisturbance be undertaken to the traffic.In everycasethereis adequate room to allow this techniqueto be employed,and, whilsr the method is somewhat (estimated costrangingilom 31.75Mfor railwaycrossings specialised andexpensive up to !2.25M for the M4), it is well triedandt€sted,andthereforethesecrossjngsare not consideredlikely to be critical in engineeringtems to the feasibility of restomtion. The mostcriticalobstructionon thewholelengthofthe restoration is identifiedasthe crossingunder the car park of Sainsbury'sstore at Bridgemead,Swindon,on the firstly the enlargement North Wilts Canal.Two solutionshavebeendeveloped; ofthe existingElcombeBrook culvertfor useby the Canalandthe provisionof a new dry weatherflow culvert for the Brook, rvhich would involve minimum disruption; secondly(andprefened),theconstruction ofa newcut andcoverculvertfor the Canai throughthe carpark. A totalof 82 locksmay be requiredfor therestoredCanal,against54 for the original. The additionallocks are requiredprimarilyto crossthe highersummitlevel on the ne\r' route south of Swindon,and for the diversionsat Melksham,Crickladeand Abingdon. Each lock or lock flight is likely to requirebackpumpingfor water conservation. A total of 39 pumpingstationsis projected. Althoughlocks may be seenasan interestingfeatureby non-boating visitors,this increasein the total number is scenas undesirable by boatusersandattentionwill no doubtbe requiredat later stagesof the projectdcsignto reducethe numberwheneverpossible,as an aid to navlgatlonuse, 4. WATER RESOURCES Basedon the clay-dominatcdgeologyunderlyingthe original Canal route and a modelledhistoricalwaterbalance,a targettotalscepage/leakage lossof l0 mm d r has beenassumed.Usingthis rate,fu(her waterbalancemodellingfor the restoredCanal hasindicateda total waterresourcerequirement of about4200Ml y'', in additionto directrainfallon the Canalsurface.This supplywascalculated on thebasisof a need to naintain a mjnimum waterdepthofabout 1.4m, assumingthat,(a) backpumping is usedto minimiseJockage losses,and(b) ullimatelossesof by-passflows to waste u,eirsanddownstream el1dsofthe Canalareminimised.

ScottWilsonKirkparick & Co Lrd

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Restoration ofthc Wihs & BerksCanal FeasibilityStudy

An evaluationof water resourcesalong the full lengthof Cturalhas identifiedthe followingresources ashavingthepotentialto supplya totalofabout4800Ml ofwater annually,andthussatisfythecalculated deficitin supply: . surfacewater abstractionat high river flows, followed by storagein about l0 reseruoirs; e groundwaterabstraction,using about 20 bored wells at 14 locations;winter groundwater may requirestoragein surfacewaterreservoirs, abstracted for summer use. The surfacewaterreservoirswould supplyabout2030Ml y-r, while the wells would supplyabout2770Ml y'' . However,thereis uncertaintyconcemingthe availability e.g.theremay be problemswith groundwater andsuitabilityofthesewaterresources, qualitywhich couldreducethe total resourceidentifiedto dateto about4200 Ml y I. To ensurethat useof theseadditionalresources is optimised,strategiclining of the restor€dCanalis recommended: o puddling of in-situ clay where localisedfracturesand fissuresoccur, and/or preparingthechannelfloor by rollingor producinga cleanlycut surface; . lining of canal reacheswhich cross permeablefomations where lossesmay reasonably be suspected; currentestimates suggesta total lengthofjust over 3 km will berequired at a costofabout!l-l.5 million. The current,approximateconstructioncost estimateof developingadditionalwater resources to meetthesupplydeficitrLre!11 7 million (annualO&M costsoff82k) for surfacewater,and f2.5 million (amual O&M costsof f32k) for groundwater.This givesa total construction costestimateofjust over €14 million and an annualO&M However, the constmctioncostsfor developinggroundwater costoft114k. resources arecheaperthanfor surfacewater,thecomparative costsfor supplying1 Ml d r being f2.1 millionandf0.4 millionrespectively. 5. ENVIRONMENTALASSESSMENT The environmentaisludy has focusedon a wide range of envircnmentalissues including land use, ecology & naturc conservation,landscape,water quality, archaeology & culturalhcritage,noise,air quality and wastedisposal. Overall,the proposedrestorationof the Wilts & Berks Canaland the North Wilts Canaloffcrs considerable opportunityfor associated envi.onmental enhancement both in termsof the naturalenvironment andbenefitsto localcommunities.The extentto which this environmental enhancement can be realisedwill dependupon featuresbuilt into the restoredCanaland, the subscqucnt overallmanagement and associated recrcational aclivities. The restorationproposalswill raise a very large numberof environrnental issues, embracinga wide rangeof topics. The main disruptionis likely to be during the construction phasebut providingadequate mitigationand goodconstructionpractice

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Restorairon of theWilts & BerksCanal Feasibilitv Studv

is adoptedthe majorityof n€gativeimpactsarelikely to be reducedin magnitudeand be temporaryin nature. Thereis alsoscopefor the majodtyof potentiallynegative impactsor conflictswhich could ariseduringoperationof the Canalto be overcome andeffectivemaintenance ofthe waterway.Key or minimisedby goodmanagement issuesareoutlinedbelow. In termsof ecologythereis a wide rangeof habitatt)?es alongthe routesconidor. any formally designatednatue Although none of the examinedroutestrangresses conseryation sitesthereare a largenumberof valuablesitescloseto the alignments includingSitesof SpecialScientificInterestanda largenumberof Alert Sites. Some changesin habitat t]?e uill occur but there is potentiallyconsiderablescopeto enhancethe existingecologicalhabitatsalong and adjacentto the Canal and the suggestedwater storagereservoirs. The scopeof enlancementwill dependupon the availablewaterquality,and carefulplanningand integrationof designmeasures, The most sensjtiveareasare likely to activity. the level of boatingand recreational arise on thc route optionswhich make use of short sectionsof the River Avon throughMelksham,the Rivcr Ray (sometimesreferredto as the ElcombeBrook) throughSwindonand the River Ock though Abingdon. However,if the preferred optionswereadoptedonly the RiverAvon wouldbe affected. The restor€dCanalwill passthJoughor closeto a numberof townsand villagesof that therearepotentiallymorepositiveenvironrnental varyingsize. lt is considered particularlythe with a route runningcloseto such settlements, impactsassociated largerurbanareasof Meiksham,WoottonBassett,Swindon,Cricklade,Wantageand resourceandprovide Grove,wherethe Canalcouldadda significantlocalrecreational deeperlinks into the countryside. Althoughtherearelimited datacurently availableon the qua:ityofwater which may considered in this be suppliedto the restoredCanal,it is clearthatall the catchments at times of low study suffer from excessivelutrient loadingwhich is exacerbated flow. The main impactswhich follow, therefore,dre directly relatedto nutrient and,in the longerterm, enrichmentofthe Canaiu,aters,with localiseddeoxygenation eutrophication. recordsexistcloseto the ofiginalCanalrouteandwithin A numberol archaeological with the relevantauthoritiesand the collidor ofnew routeoptions.Closeconsultation interestgroupsu,ill be requiredprior to the commencement of the restorationor development of any individualrcachof the Canalin orderthat a full examinationof and mitigatedagainstwhere the possibleimpactof the restorationcan be assessed, practicable. The quantitiesof cxcavatedmaterialare cxpectcdto be largeand they representa significantcomponentof the total schemecost. A limited amountof excavat€d materialcouldbe re-uscdasfill but initial estimates suggest thatoff-sitedisposalcosts wastedisposal couldbe in theorderof!12 million. ln orderto minimise costsit will be importantto developorl-sitedisposaloptionsfurtherfor eachsectionofthe Canal to be restored.

Scoft Wilson Kirkpatnck & Co Lld

Resloration ofthe wilts & BerksCanal FeasibilityStudy

6. UTILITTES The utilities companieshavcbcencontactedto providecurent servicesinformation relatingto the prefenedalignmentsdevelopedfrom th€ routeoptjonsstudy.At the remaifloutstanding. time of writing this reportsomeresponses Although liom the infomation receivedto date there appearsto be a numberof importantcrossingsof the proposedCanalroute,andseveralsectionswhereservices we considerthat in all casesan effective arevery closeandmay affectconstruction, found to allow restoration ofthe Canal. solutioncanbe Ar allowanceof !1.19m in total has been made for servicesdiversionsfor the relativelyminor works requiredfor electricity,telecomsand gas and small piped seNicesfor waterandsewage.In thecaseofmajor pipelines(primarilyfor petrcleum products)acrossor alongsidethe route,it may be cheaperto adjustthe routeof the Canalto avoid interference.Clearlythis is a matterthat will needto be studiedin moredetailat laterstagesofthe project,on a caseby casebasis.

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Scofl Wilson Kirkpatrick & Co Ltd

R€storation of thewilts & BerksCanal FeaslbitltyStudy

7. COSTESTIMATE Theoverallsummary costestimate for restoration is pr€sent€d below

cosrs(r M)

Section

Length Locks Canal Struct Serv(kml Reach -ures ices

Total Cost

ENGINEERING Semingtonto Hay Lane

37.60

Hay Laneto Acom Bndge

17.05

Acom Bridgeto Abingdon

34.45

CalneBranch

4.85

North Wilts Canal

11.45

SUBTOTAL

108.4

29 5 . 9 5 t 6 5.87 20 7 . 3 8 2 0.59 15 5.18 82 24.97

8.97

t5.22 0 . 1 8 16.62 0.24 20.42 0.03 2 . 76 0.48 t4.63

43.49

1 . l 9 69.65

9.01 10.57 12.80 2.14

0.26

WATER RESOURCES SurfaceWaterRcsources Resources Groundwater

9.50 2.46 SUB TOTAI Contingencies @ 10% Engineering services@ 1l% TOTAL CONSTRUCTIONCOST Land, Legal and other costs

8 1. 6 1 8.16 8.98 98.'75 4.00

TOTAL PROJECT COST 102.75 ANNUAI OPERATING& MA]NTENANCECOSTS

0.45

NOTES: derelopmenl. marinas etc. L Coslscxcludean1cenelrelated lining option,costsof which are 2. Waterresourcecostsarebasedon recommended includedin the engineering costs. 3. Arrnualcostsfor operationand maintenance cover all recurrentcostsincluding maintenance andrepairwork, powersupply staff,contractwork, office overheads, andabstraction discharge licencecharges, but depreciation ofassetsis excluded.. 4. Engineeringsenicesincludestopographicsurveys,groundinvestigations, furth€r engineeringand cnvironmentalstudies,planning approvals,detailed designs, construction contactdocumentation andsitesuperisioncosts. 5. Othercostsincludesfor theestablishment ofa navigationauthority 6. 95yoconfidencelimits assessed at 67yoto 150%ofestimate

Scotl Wrlson Krrkpatnck & Co I-td

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Restorarion ofrhe Wilts & BerksCanal FeasibrluySludl,

8. USEAND BENEFITASSESSMENT It is estimatedthat the restoredWilts & BerksCanaland the North Wilts Canalwill generatesubstantialeconomicbenefitsfor both the immediateareasthroughwhich the Canalspass and for adjacentcentressuch as Chippenham. The leisure and tourismactivitiesthatwill takeplaceon andaroundthe Canalswill attractvisitorsto the area and provide recreationopportunitieslocally for peoplewho live in the vicinity. Thebenefitsaresummarised asfollows:

Grossvisitorexpenditure Incomeretained Pemanentjobs created employment Construction

WithoutCotswold Canalsrestoration

With Cotswold Canalsrestoration

!18 million f Tmillion 130 1,519man-years

f,20million I8million 790 1,519man-years

In addition,the schemewill leadto an cnhancement ofresidentialprop€rtyvaluesfor new housingalongsideor closeto the waterway.A 19%premiummight be expected for watersidehousing,while housingwithin the samedevelopmentbut without a watersidefrontagemight experience an 8% increase in value. Indirectly,the re-opening ofthe Canalswill raisetheprofileofthe areaandbe a factor in attractingnon-leisureandtouism relateddevelopments alongthe corridorbut not directly relatedto the Canalmarketssuch as office/retaildevelopmentand leisure e.g.pubshestaumnts. developments, The incomeretainedin the localeconomy(f8 million per year)canbe comparedwith the overall cost of the restorationproject (f,103 million). In simple terms, this suggests the pay-backcanbe achievedin around12 - 13 years. In reality,however, the pay-backperiodis likely to be lessthan this sinceat leastsomeof the capital involvedwill be raisedoutsidethe localarea.For example,HeritageLotteryFunding' might meetup to 75%ofthe costofa qualifyingproject. Thismeansthat 75% ofthe costwould be met fiom nationallyderivedsources, with local sourcesonly requiring to raise25o% ofthe capital. In this cascthe scheme(assumed fully qualifying)would generatean inflow of capital to the area of !75 million (althoughthis might be displacedftom olherprojeclsin the area). The restorationschemewill also generatesocialbenefitsfor the locality, including opportunitiesfor educationinitiatives;recreationand linls to other recreation resources in thc arca;integrationofrecreationwith the naturalenvironment; health& fitnessschemes; enhanced recreational facilitiesand inftastructurefor disadvantaged groups;a focusfor specialeventsandfestivals;communityinvolvementin restontion Note that this studysas not rcqu;edto investigate sourcesof fundng. Al the trmeofwrxing this reporl a review of amngemcntsfo. ali lottery fund orgamsatrons was bemg camed out by the Government andthe iuturealailabilityofmoney tiom the HenrageFundfor canalrestorallonprojects wasberngreconsLdered. Thjsmaherwill needto be properlymvestigated ln thenextsiageofstudres

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Restoraiionofth€ Wilts & Berks Canal Feasibility Study

and subsequent management; involvementby third partiesin specialprojectsand commuting; andemployment initiatives;off-road training.

9. RECOMMENDATIONS This study has examinedin somedctaii thc difficultiesto be overcomein order to achievethe goal ofrestorationofthe Wilts & BerksandNorth Wilts Canalsto a fully In engineering navigablestandard. termsthereappearto be practicable solutionsto all the major obstructions;there are some significant(but localised)environmental issues,but the overall environmentalenhancementarising from restorationis recognisedas a majorbenefit.Waterresources are seenas perhapsthe most critical uncertaintyremainsat the end of this study,but the initial issue,and considerable assessmentindicates that overall, sufficient water may be available from a An assessment of the costsand combinationof surfaceand groundwaterresources. soundeconomicbasisfor advancement benefitsof restorationsuggestsa reasonably ofthe scheme. To progressthe scheme,an overallStrategyStudyis now stronglyrecommended as a fust priority. This StrategyStudyshoulddraw upon the findingsof this Feasibility ofthe projectencompassing all Studyanddevelopa detailedplan for implementation elementsincluding:Planningandotherconsents; BusinessPlanandFunding essential Strategy;Land Ownershipand Acquisition Strategy;Design and Construction Management Strategy;and MarketingStrategy.We would Strategyand Programme; suggesta budgetoff50,000 be setasidefor this StrategyStudywhich overallis likely to takeabout5 - 6 monthsto complete. Given the critical natureof watersupplyto the viability of the restoration,and the with both resourceavailablityandresourcerequired(the largeuncertaintyassociated rates),furtherinvestigations latterprimarilydueto largeuncertaintyin likely seepage to addressthesematte$ must be regardedas the next pdority. An initial budgetof for thesestudieswhich couldtakeabout9 - 12 monthsto €160,000is recommended progmmmes. on field measurement completedep€nding to the StrategyStudy,and furtherinvestigations In addition,but subsequent of water supplies,fufiher rvork will be requiredin all the engineering topicscoveredin this FeasibilityStudyto confirmthe viability of the proposedrestorationoptionsand to incorporation achievethe milestoneof full andadequate of the final preferedroutes into all Local Plans. The primary requirementfor this will be good quality an initialbudgetfigureof!50,000 be setaside topographic survey.We would suggest for topographicsurveysprimarily for the new Canalroutes;f30,000 for preliminary geotechnicalinvestigationwork; and f300,000for the ensuingengineeringstudies designwork to achievethe standardsof information and preliminaryacceptance by the LocalAuthorities.A total time of 12 - 18 monthsmay requircdfor acceptance be requiredfor this phaseof work but much would dependon the programmefor LocalPlanreviewandtheearlyagreement ofa singleprefenedroutc. Further environmentalstudieswill then be rcquired relating to ecology, archaeology, \\,aterquality, noise and waste disposal. Somc initial work relating to thesematters

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Resloralionofthe Wihs & Berks Clanal FeasrbilityStudy

will alsobe requiredto assistwith protectionof the preferredroutesin Local Plans, however,particularlythose relating to ecology, archaeologyand water quality. Further work is also requiredwith regard to noise and waste disposalto help detemine costs and mcthods for restorationwork. To ensure that minimal environmental impactwill occurand that relevantlegislationis compliedwith, it is recommended that an Environmental Codeof ConstructionPracticeis drawnup and used in relation to constructionworks associatedwith the restoration.An initial for thesefurtherenvironmental budgetof€90,000is reconrnended studies,which will with the furtherengineering needto run concurrent studi€s. On completionof the StategyStudyand the furtherwater supplies,engineering and preferred environmental studies,and assumingadoptjonof a routein Local Plans,it shouldthenbe possiblcto considerthe development of individualprojectsaccording to the availabilityofsuitablefunding. No detailsoftheseprojectscanbe givenat this stage.

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Restorationof the Wilts & Berks Canal: Feasibility Study

CONTENTS 1.INTRODUCTION

1

I ,I CoMMTSSION L2 BACKGRoUND I .2.1 Wilts & Berks CanalTrust 1.2.2HistoricalContext I .2.3 The Current Stateof Restorationby the Amenity Croup 1.3 PRoJECT TEAM To STUDY 1.4 APPRoACH 1.5DATAFoRTHESTUDY ANDUNITS I.6 ABBREVIATIoNS 1.7AcKNowLEDGEMENTS

I 2 2 2 3 4 5 5 o 6

2. ROUTE SELECTION

7

2.1 INTRoDUCTIoN 2.2 APPRoAcll 2.2.1Identificationof PossibleRoutes 2.2.2WorkshopMeetings 2.2.3Resultsof WorkshopMeetings 2.3 WEsr WILTSHIRT 2.3.l Introduction 2.3.2 Development of Route Options for Melksham 2.3.3RouteDescription 2.3.4Discussionon MelkshamRoutes 2.3.5 Prefened Routes for Melksham 2.4 NoRTHwrLrsHIRE 2.4.I Introductron 2.4.2 Development of Route Options for Wilts & Berks Canal 2.4.3 Development of Route Options for North Wilts Canal at Cricklade 2.4.4Discussionon CrickladeRoutes 2.4.5 Preferred Routes for Cricklade 2,5 SWINDoN 2.5.1Introductron 2.5.2DevelopmentofRoute Optionsfor Swindon 2.5.3 Original Routes Through Swindon 2.5.4Northem RouteOptions 2.5.5WestemRouteOptions 2.5.6SouthemRouteOptions 2.5.7 Eastem Route Options 2.6 VALEoF WHIrE HoRsEDISTRICT 2.6.I Introduction 2.6.2EastChallow RouteOptions 2.6.3ThamesWater ReservoirRouteOptions 2.6.4AbingdonRouteOptions 2.7 CONCI-USIoNS

7 8 8 8 9 9 9 9 10 15 l6 l6 l6 l6 18 l8 19 19 l9 20 20 20 22 24 24 24 z) 26 30

3. ENGINEERJNG CONSIDER{TIONS

-t-t

3,1 INTRoDUCTIoN STANDARDS 3.2 REsroP-A.TIoN 3.2.I SpecihedCriteria 3.2.2DesignDimensions ANDGEoLocY 3.3 EARTHwoRKS 3 . J . 1E m b a n l m e nat n dM a t e r i a l s 3.3.2Cutlrngs r uRFs 3.,1STRUC 3.4.I Bridge Type Selection 3.4.2StandardMethodsof Bridge Construction 3.4.3AdditionalFactorsfor RarlwayCrossings

33 33 33

Scott WilsonKirkpatdck& Co Ltd

35 36 36 37 37 38 40

Restorationof the wilts & BerksCanal: Feasibrlity Study. 3.4.4AltemativeCrossingMethods 3.4.5Bridgesfor Footpathsand Bridleways 3.4.6Particularcrossings 3.5 PoUNDLEvELs,LocKSANDBACKPUMptNC 3.5.1PoundLevel and Lock Lifts 3.5.2 Locks and Backpumping 3.6 CoNCLUSTONS

40 42

4. WATER RESOURCES

5l

4,1 INTRoDUCTIoN ANDPREVTOUS STUDIES 4.2 BACKGRoUND 4.2.I Original Water Supply 4.2.2 Previousstudies 4.3 METHoDoLoGY 4.3.1 Data collectionand analysis 4.3.2 Water requirements oF ExtsrtNc wATERRESouRcEs 4.4 AssESSMENT 4.4.I HistoricalWater Services 4.4.2 OtherSources WATERBALANCE 4,5 HISToRICAL 4.5.I Model Assumptions 4.5.2 Model Results CANAL FoR A RESToRED 4.6 WATERBALANCE DEFICIT 4.7 PRoposALsTo MEETTIrERESOURCE 4.7.1 Developmentof HistoricalResources 4.7.2 DemandReductionOptions 4.7.3 ChannelLining 4.7.4New SurfaceWaterAbstractions 4.7.5 Groundwater Abstractions 4.7.6 Reactivation& PurchaseofAbstractionLicences 4.7.7Urban Runoff 4.7.8 SewageEffluent 4.7.9 Land Drainage 4.8 WATtsRQUALITYISSUES 4.9 STRATEGY TOMEETCANALWATERDEMANT) 4.10 CONCLUSIoNS

5l 51 51 52 53 53 54 55 55 56 58 58 58 60 62 62 62 64 67 72 80 80 8l 84 84 86 89

5. ENVIRONMENTAL

ASSESSMENT

5.I INTRODUCTION 5.1.1Aims 5.1.2Methodology 5.2 ExrsrNc LANDUsES 5.2.I AgriculturalLand 5.2.2Settlements 5.2.3Recreation& Leisure 5 . 2 . 4A n g l i n g 5 . 2 . 5W a l k i n g 5.2.6Cycling ECoLOGY 5.3 EXISTING 5.3.1HabitatsAlong the ExistingRoute 5.3.2HabitatsalongAltemativeRoutes 5.3.3 Statutory and Non StatutoryNature ConservationSites 5.4 EcoLocICALIMPACTS 5.4.1VegetatlonClearance 5.4.2Effect on River Sections 5.4.3Disnrrbanceat Riv€r Crossrngs 5.4.4Effectsof Boating 5.4.5Off- line StorageReservoirs 5 . 5L A N D S C A P T 5.5.1 ExistingLandscapeCharacter& Features 5.5.2 Impactsof the Canal

ii

45 45 48

93 93 93 93 94 94 95 9'/ 9'7 98 99 99 99 100 100 104 105 105 t08 108 lll 1t2 tt2 Il4

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Restorationof the Wilts & Berks Canal: Feasibility Study 5.5.3LandscapeMitigation 5.6 WArERQuALrrY 5.6.1Legislationand Regulation 5.6.2BaselineConditions 5.6.3GeneralQuality Assessment & WaterQuality Objectives 5.6.4SpecificCatchmentWaterQuality Issues 5.6.5Impact Prediction 5.6.6Mitigation 5.7 ARCHAEoLoGY 5.7.1Methods 5.7.2Results 5.7.3Impacts 5.7.4 Mitigation and Eniancement 5 . 8N O I S E 5.8.1Regulation 5.8.2Impact Identification 5.8.3Mitigation of ConstructionNoise 5.9 WASTEDrsPosAL 5.9.1Introduction 5.9.2Definitionsand Regulatrons 5.9.3 Material Excavatedfrom the Canal Route 5.9.4 Material Dredged from the Canal 5.9.5GreenWaste 5.9.6 MaterralArrsing from Construction 5.9.7CostsofDisposal 5 . 1 0A r RQ u A L r r Y 5.l0.l Regulation of ConstructionImpacts 5.10.2Assessment 5.10.3Mitigation 5.I 1 CoNCLUSIONS

t44 t4'7 148 148 148 149 149 151 153

6. USE & BENEFIT STUDY

r51

6.1 MARKETSETTING & PRoSPECTS 6.1.1 Inhoduction 6.1.2 Tourism 6. 1.3 PopulationCatchments 6.2 METItoDoLOGY 6.2.1GeneralApproach 6.2.2Multipliers 6.2.3AnalysisAssumptions 6.2.4Baseline 6.2.5 Assumptions for Prefened Route 6.3 ECoNoMICEvALUATIoN 6.3.1Boatson Passage 6.3.2 Private Boats: Waterway-based 6.3.3Hire Boats 6.3.4Trip Boats 6.3.5Day Boats 6.3.6Hotel Boats 6.3.7RestaurantBoats 6.3.8Canoeing[Inpowere d Boating 6.3.9Angling 6 . 3 . 1 0C y c l i n g 6.3.1I Informal Visitors 6.3. l2 Temporary ConstructionEmployment 6.3.l3 Impactson ExistingUsers 6.3.14Implicationsfor Boat Traffic 6.3.15 PropertyDevelopment 6 . 1 . l 6I n d i r e cE t c o n o m r Icm p r c t s 6.3.17Other EconomicImpacts

l5'7 | 5'7 t57 159 160 160 l6l l6l l6l t62 162 t62 163 164 165 166 166 166 166 t67 t67 168 t70 170 170 170 t7l t72

Scott Wilson Kirkpatrick & Co Ltd

tt4 ll5 116 1t'7 119 119 123 129 133 133 134 134 135 135 136 t37 138 140 140 141

lll

Restorationof the Wilts & BerksCanal: Feasibility Study. 6.4 CoMMUNtry& SoctALBENEFTTS oF RESToRATIoN 6.4.1 The ability to seeboats moving on the water 6.4.2Education 6.4.3Recreationopportunitiescloseto home 6.4.4 Links 6.4.5 Integration of recreationand environment 6.4.6 Health and fitness 6.4.7 Development of enianced recreationalfacilities and infrastructurefor local communities 6.4.8Eventsand festivals 6.4.9Community involvement 6.,{.10Third party involvement 6.4. I I Commuting 6.4.l2 Enhancedpropertyvalues 6.4.13A safeenvironment 6.4.14 EmploymentTraining 6.5 CoNcLUsroNS

t73 t74 174 r74 t74 174 t ' 75 175 t75 175 176

7. UTILITIES

179

7.I INTRODUCTTON 7.2 PTPELTNES 7.2.1PipelineManagement(EssoPipelines) 7.2.2SercoGulf EngineeringLtd (GovemmentOil Pipelines,GPSS) 7.2.3ICI Chemical& PolymersLtd 7.2.4 Fina plc 7.3 TtsLEcoMs 7 . 3 . 1B T p l c 7.3.2Mercury Communications Ltd 7.4 ELECTRICTTY 7.4.I NationalGrid 7.4.2 Southem Electric plc 7.5 GAS 7.5.I TranscoLtd 7.6 WArER 7.7 SEwERACE 7.8 CoNCLUSIoNS

t'79 1'79 t79

8. COST ESTIMATE

185

9. RECOMMENDATIONS

187

9.I INTRODUCTToN 9.2 STRATEGY STUDY 9.3 ENGINEERING STUDIES 9.4 WATERREsouRcES STTJDTES 9.5 ENvTRoNMENTAL STUDIES

187 187 188 189 l9l

10. REFER.ENCES

193

1I. APPENDICES

t97

172 l'72 tl.J

173 t t )

r80 180 180 180 180 181 l8l 181 181 183 183 184 184 t84

TABLES IN THE TEXT T a b l e3 . 1 Table 3.2

CanalDesignCriteria HistoricLock Lifts and PoundLevels

33 46

T a b l e4 . 1 Table4.2 Table4.3 Table4.4 Table4.5 Table4.6 Table4.7

OutcropGeologyAlong OriginalCanalRoute EstimatedWater Fluxes (betweenthe Canal and groundwaterin aquifeIS) HistoricalAnnual WaterBalance Lossesfrom BritishCanals Water Balancefor a RestoredCanal Costsfor Lining LeakingCanalReaches Costsfbr Lining All CanalReaches

54 57 59 60 61 66 6'7

IV

ScottWilsonKirkoatrick& Co Ltd

Restorationof the Wilts & Berks Canal: Feasibility Study

Table4.8 Table4.9 Table4.l0 Table4.11 T a b l e4 . 1 2 T a b l e4 . 1 3 T a b l e4 . l 4 T a b l e4 . l 5

CatchmentsWith Potential for SurfaceWater Abstraction and Storage Potential for Developing GroundwaterResources Benefits and DisbenefitsofRe-using Urban Runoff SewageWorks Consideredfor Supplying Treated Effluent Benefits and DisbenefitsofRe-using Effluent Average Water Qualify for RestoredCanal* Surface Water and Groundwater ResourcesAvailable Costsof DevelopingResources

Table5.1 Table5.2 Table5.3 Table5.4 Table5.5 Table5.6 Table5.7 Table5.8 Table5.9

PotentialGradesof Towpath Sites of Nature ConservationInterest Bank ProtectionOptions WatercoursesAffected by Canal Infrastructure Water Quality for Watercourses Box Jacking Locations Matedals Generation Quantities of ExcavatedMaterials Potential Contaminants

98 102 lll I t8 120 138 t4l 142 t45

Table6.1 Table6.2

Population Catchments Summary of Economic Benefits

159 t76

Table8.1

Overall Project Cost Estimate

186

Table9.1 Table9.2

Recommendationsfor Further Water RersourcesInvestigations Further Environmental StudiesRequired

190 l9l

7l 81 83 83 85 86 87

PLATESIN THE TEXT PlateI Plate2 Plate3 Plate4 Plate5 Plate6 Plate7

RestoredCanal at Wootton Bassett Original Canal, marsh./wetlandhabitat Typical woodland and scrub habitat Arable habitat Neutral grasslandhabitat River Avon below Melksham River Avon downstreamfrom Town Bridge, Melksham

Facing Page

100 100 100 100 100 106 106

Facing page

t0 t6 20 20 22

F i g u r e2 . I I

Possibleroute options: Melksham Possibleroute options: Cricklade Possibleroute options: North of Swindon Possibleroute options: West of Swindon West Swindon route option minimising canalisation Canalrouteavoidingcanalisation of the ElcombeBrooke,Swindon Possiblerouteoptions:Southof Swindon Possiblerouteoptions:eastof Swindon Possiblerouteoptions:EastChallow Possibleroute options in the vicinity of potentialreservoirsrteSW ofAbingdon Possrblerouteoptrons:Abrngdon

F i g u r e3 . 1 Figure3.2 Figure3.3 Figure3.,1

Typical CanalSectionsand Drmensrons Precastconcretebeamson conventionalabutments Concretebox structure Precastconcretearch

Facingpage

F i g u r e4 . I

Projectedcanal$,aterdemand as a function of seepagerate

Facingpage

FIGURES IN THE TEXT Figure2.1 Figure2.2 Figure2.3 Figure2.4 Fiorrre ) 5

Figure2.6 Figure2.7 Figure2.8 Figure2.9 F i g u r e2 . 1 0

Scon WilsonKirkpatrick& Co Ltd

22 22

26 zo

40 40 40 62

Restoration of thewilts & BerksCanal: Feasibility Study. DRAWINGS DBKEP/001 DBKEP/002 DBKEP/003

OverallRoutePlanSheetl/3 OverallRoutePlanSheet2/3 OverallRoutePlanSheet3/3

DBKEP/004/01

Definedsub-catchments andgeologyalong theWilts& BerksCanal Locationsfor potentialsurfacewaterabstraction abstraction andstorage,andpotentialareasfor groundwater

DBKEP/004/02

VI

At endofAppendixD

At end of Repon

Scott Wilson Kirkpatrick & Co Ltd

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Restoration of theWilts & BerksCanal: FeasibiliryStudy

1. INTRoDUCTTON

1.1 Commission This reporthasbeenpreparedin fulfillmentof a commissionawardedto ScottWilson by North WiltshireDistrict Councilon behalfof the Wilts andBerksCanalTrust (the Trust),on 10April 1997. The commissionwas for a FeasibilityStudyfor the restorationof the Wilts & Berks Canal,and coveredthe full route betweenthe Kennet& Avon Canalat Semington nearMelkshamin Wiltshire,andtheRiverThamesat Abingdonin Oxfordshire.Also includedwerethe NorthWilts Canalfrom Swindonto nearCricklade,andthe Calne branch.The studywasrequiredin particularto addressthe following: l.

reviewthe principaldifficultiesto be facedin restoringthe Canaland how thesemaybe overcome; consider

2.

of carryingout the restoration considerthe bestmeansand sequence anddeterminetheoptimumroute;

3.

review the water requirementsand the best meansof providing the resources; necessary

4.

assessthe benefitsof restorationto the local communitv.as well as regionallyandnationally;

5.

investigatethe environmentalimpacts of restoration,assessthe environmental enhancementsachievable, and suggest suitable wherenecessary; mitigationmeasures

o.

providesectional costestimates.

A copy of the full scopeof study is includedfor referencein Appendix A. This report presentsall the findings on our field work and desk studies,and makes recommendations for the continuation of the restoration process. Estimated construction, maintenanceand operating costs are given and a range of restoration optionsis proposedfor furlherevaluationand selection.

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Restorationof the Wilts & Berks Canal: FeasibilityStudy.

1.2 Background 1.2.1 Wilts & BerksCanalTrust The Wilts & Berks CanalTrust is a privatecompanylimited by guaranteeand not having a sharecapital. It has beenset up for the purposeof restoringthe Wilts & Berks Canaland the North Wilts Canallor the use and benefitof the public. The currentmembershipof the Trust is the District Councilsof North Wiltshire, West WiltshireandVale of WhiteHorse;SwindonBoroughCouncil;the CountyCouncils of Oxfordshire& Wiltshire;andthe Wilts & BerksCanalAmenityGroup. I .2.2 HistoricalContext The following is reproducedfiom theoriginalConsultant'sBrief lor the Study: The Wilts & BerksCanalextendedfrom SemingtonJunction,on the Kennet& Avon Canalin Wiltshire,to theRiverThamesat Abingdon,whichat thetime of theCanal's constructionwas in Berkshirealthoughit is now part of Oxfordshire. The route passesthroughor nearMelksham,Chippenham,Calne,Lyneham,WoottonBassett, Swindonand Wantage. The main line of the Canalwas built between1796 and in 1814-1819between 1810. A branch,the North Wilts Canal,was constructed A number of smallerbranches at Cricklade. Thames & Sevem Canal Swindonand Calne,LongcotandWantage. werebuilt fiom the mainline to Chippenham, boats with maximum The Canal was built as a "narrow canal" to accommodate (22 and hada depthof 4ft (2.13 m) length, m) and 72ft beam dimensions of 7ft Oin 6in (1.37m) excepton thesummitlevelwhichwasprobably7ft (2.1m) deep.'Useof the Canal declined in the secondhalf of the nineteenthcentury and navigation effectively ceasedearly in this century. The Canal was abandonedby Act of Parliamentin 1914with the land revertingto the riparianowners. Most of the originalbridgeshavebeendemolished The total route of the main line from Semingtonto Abingdonis 83.9 km; the North Wilts branchis 14.5 km and the other branchestotal 9.5 km. Therewere 23 locks whichclimbedthe62.1mfromtheKennet& Avonto theCanal'ssummitat Swindon, fromthe48.3m fromthereto theThames.ll lockson andi8locks whichdescended the 18.0 m to the Thames& Sevem. The average the North Wilts descended differencein level of the locks alongthe Canalvaries:on the main line it is on average 2.7m whilston theNorthWiltsit is 1.6 m. The Canalwas onginallysuppliedwith water from CoateWaterand Tockenham reservoirsand from a numberof small streams;the reservoirsare now used for recreationalpurposesand may not be availableto supplywater to a restoreCanal. The Wilts & BerksCanalAmenityGroupwasfoundedin 1976;its aim is to protect, for the conserveand improvethe routeof the Wilts & BerksCanal,and branches, goal of restoring a with the ultimate benefitof the communityandthe environment, '

Recent restorationwork undertakenby the Amenify Group has cast doubt on this depth holding over the full length of the sumrnrtpound

ScottWilsonKirkpatrick& Co Ltd

Restoration orthew\*,i.,.fi

:il:i

continuousnavigablewaterway. The Groupbelievesthat the Canalis largelystill in restorableconditionin rural areas,albeitsiltedup, overgrownandin placesobstructed by roadcrossings.Along the lengthspassingthroughtownsthe originalline hasbeen particularlyin Melksham,Swindon,Abingdon, subjectto much redevelopment, Wantageand part of Cricklade. The Group has shown that altemativeroutesare availableavoidingthesedevelopments. A totalof6.5 km ofrural lengthsof theCanal restored by the largely havebeen Group, usingvoluntarylabour,for amenitypurposes and to demonstratethe benefitsof restorationto the community. The Group has received increasingsupport for this work from the district councils, the former National Rivers Authority (now the EnvironmentAgency) and from a number of charitiesandotherfundingagencres. by theAmenityGroup 1.2.3 The CurrentStateof Restoration The following has beencontributedby Mr P A Smith, RestorationDirector of the Wilts & BerksCanalAmenityGroup: of the Canalin 1988, Sincethe AmenityGroupcommitteditselfto full restoration considerableprogresshas been made, using mainly volunteerlabour for labourintensivetaskssuchasbricklaying,andgenerallyemployingspecialistcontractorsfor taskssuchas largescaledredging. As the Canal is in multiple ownership,with approximately200 land owners,tasks havehadto be tackledonly whenthe landownerhasbeenwilling to allow access. At Foxham,nearChippenham,a mile of Canalhasbeenclearedand partly dredged. A lock has been rebuilt, and two lift bridgesconstructed,one of which is fully operational;the other will not be fitted with lifting beamsuntil the Canal is more has nearlyrestored.A major spillweirhas beenbuilt, and one of the landowners reinstated two accommodationbridges. This length requires one more bridge beforeit can be completedand put back into water; this is accommodation scheduled to bebuilt in 1999. At DauntseyLock, the Group has beenworking with the site owners,the Wilts & Berks Canal Company,a commercialorganisation.One lock and a spillweir have beenbuilt, andnearlya mile of Canalhasbeendredged.Onespillweiris neededto completethis section,and this is scheduled to be built during 1998. The Wilts & BerksCanalCompanyhaverestored a canal-side settlement comprising five cottages. At WoottonBassett, on thewestsideof Marlborough Road,the archof Dunnington Aqueducthasbeenrepairedand one portalrestored.On the eastsideof the road,a lengthof nearlyonemile hasbeendredgedandput backinto water,andis usedto give boattrips to the public at weekendsduringthe summer. A slipway,a footbridge and a spillweir havebeenrebuilt, and a temporaryfootbridgehasbeenbuilt on the foundationof an archbridge. Two archbridgesremainto be built; the designis nearlycomplete,andhasbeenpassed by the LocalAuthority,andwork will startin 1998.

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Restorationof the Wilts & Berks Canal: FeasibilityStudy.

Furtherto the east,the sectionof StudleyGrangeFarm,nearJunction16of the M4, is adjacentto a landfill site ownedby Barge WasteManagement, who also own this lengthofthe Canal.Theyareplanningto dredgeandreinstate it during1998. On the far sideof the M4, a lengthof abouthalf a mile at WestLeazeFarmhasbeen dredgedand filled, and is currentlyusedfor fishing. Plansarein handto dredgethe next field goingnorth eastduring 1998. This links with the sectionleadingup to Kingshill Road,Swindon,which will be clearedand dredgedin conjunctionwith SwindonBoroughCouncilin thenearfuture. On the North Wilts Canal,at Moredonto the northeastof Swindon,restorationof the for two yearsandis very nearly MoredonAqueducthasbeenprogressing three-arched complete. The Canalhasbeendredgedfor a quarterof a mile back towardsPurton Road,andthe remainsof MouldonLock havebeencleared.The Local Authority has plans to reinstatethe bridge under Purton Road once financesbecomeavailable. When plans for this are finalised,a decisioncan be made on whetherto restore MouldonLock. NearShrivenham, abouttwo milesofCanal havebeenclearedanddredgedfrom near junction the of ShrivenhamRoadwith the 4420, to StainswickLane. On the eastem by the Group,and in conjunction sideof StainswickLanea field hasbeenpurchased with Shrivenham ParishCouncil,it has beenlaid out as a park. Plansfor 1998 includethe installationof a slipway,dredgingof the Canalas lar as Tuckmill Brook, treeplantingon thepark. abouthalfa mile furthereast,anda large-scale In the Grove/Wantagearea,more than fwo miles of canal have been clearedof vegetationand the towpathreinstated.Two lengths,one of 300 yards and one ol abouthalf a mile, havebeendredgedand put back into water. The tail bridge of a lock,whichhasvirtuallycollapsed, hasbeenre-built. At Dral'ton,nearAbingdon,half a mile of Canalhasbeenclearedandclearanceofan infilledlock is nearlycomplete.This siteis in the areaofthe proposed new Thames Water Reservoir,and future work will dependon whether those proposalsare implemented. 1.3 ProjectTeam The studywas administered by a Management Groupon behalfof the Trust. The Management Groupcomprised : Mr A Harrison

Wilts andBerksCanalTrust (Chairmanof theManagement Group)

Mr J Dix Mr J Newton Mr P Hempstead Mr A Macdonald

No(h WiltshireDistrictCouncil OxlordshireCountyCouncil EnvironmentAgency,ThamesRegion Wilts andBerksCanalAmenitvGrouo

ScottWilsonKirkpatrick& Co Ltd

Restoration orthew'\*""r",1n:illi The ManagementGroup met for formal ProgressMeetingswith the Scott Wilson teamon five occasionsprior to the publicationof the draft report. Therewere many other informal meetingsand discussionsthroughoutthe progressof the study, in detailin Chapter2 of includinga seriesof routeselectionworkshops(described thisdocument). The ScottWilson teamincludedin-houseexpertsin civil engineering, hydrologyand bridges,railwaysand roads,and the environment.To water resources,geotechnics, of economicbenefits,the MarketResearch assistwith the evaluation Unit at British Waterways wasretained asa sub-consultant. 1.4 Approachto Study Althoughessentiallya deskstudy,a seriesof held visits weremadeto ensurethat the whole of the original Canal route and the alternativeroute optionswere seenand reportedon by Scott Wilson staff. Specialattentionwas paid to known areasof difficulty with the historicor altemativeroutes,suchas the North Wilts Canalroute west of Swindon,and all major road and rail crossingswere separatelyvisited and engineer. by a specialist evaluated to be approached for discussions The brief for the studyincludeda list of consultees and information for each elementof the study. All of theseorganisationswere contacted and they provided valuable information. We also approacheda numberof otherorganisations and individualsfor informationor advice considerable andwe list all theconsultees in Appendix B. duringthe investigations, 1.5 Data for the Study Notwithstandingthe numberof previousstudiesthat havebeenundertakenand the to obtainsome extentof otherinformationthat alreadyexistedwe foundit necessary further data in order to completethe study brief tasks. Generallythesedata were obtained from our own resources,from, publishedinformation or fiom specific investigationscarriedout as a part of the studywork, and the referenceshavebeen incorporated into this report. In some instanceshoweverthe data had to be purchasedand/orwill be of greater interestfor later stagesof the project. Thesedatahavebeencollectedtogetherfor retentionby the Trust. list ofall thedatacollected andtheprincipalreference A comprehensive documents is givenin AppendixC.

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Restoration of theWilts& BerksCanal: FeasibilityStudy.

1.6 Abbreviationsand Units throughoutthis report, Abbreviationshave beenusedfor well known organisations althoughfull titleshavebeengivenon thefirstmention. aregivenasfollows: Abbreviationsusedfor unitsof measurements mm m or lin.m 2 m or sq.m I m or cu.m Mmr km kg t ha no. dia or DN % mmo I I S

mg/l ppt 3,^. cumecsor m Ml d-r

millimetre metre squaremetre cubicmetre millionmr kilometre kilogram tonne hectare number nominaldiameter(pipework) percent millimetreperday litre litresper second milligramsper litre partsper thousand cubicmetresper second megalitresperday megalitresperyear

1.7 Acknowledgements andindividualshavegivenwillingly andgenerouslyof their time Many organisations and other resources,to assistus with our investigationsand the preparationof this we shouldlike to recordour report. To all these,too numerousto mentionseparately, aooreciation. However, particular thanks are due individually to all the members of the ManagementGroup for their valuableadviceand guidancethroughoutthe various of theproject. stages

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Restorationof the Wilts & Berks Canal: Feasibility Study

2, RourE SELECTToN

2.1 Introduction Although a significant proportion ofthe original Canal and its branchescan be traced on currently published maps, and on the ground, urban development in Melksham, Swindon, Abingdon and Cricklade since abandonmentin 1914 has rendered restoration on or close to the original alignment in these areasvery doubtful. Thus fiom the outset of this Study a need to develop altemative routes was appreciated,to overcome theseand other more localisedobstructionsto restoration.In planning these alternative options, we consideredit important to bear in mind that the main function of canals today is rather diflerent from that lor which they were originally constructed. Canals are no longer primarily used as a means of transport for goods and materials, but as a recreationand leisure facility for a multitude of activities such as boating, walking, fishing, canoeing, heritage interest and the like, and they can provide significant benefits in education, nature conservation, habitat creation and environmentalenlancement. Therefore in the planning and assessmentof new route options, we have bome in mind the question of whether the route proposed will satisfy this latter day raison d'atre, so that maximum benefit will ultimately be realised ffom the restoration project. This we have seenas particularly important when significant departuresfiom the original alignment have had to be contemplated,but the principle has also been applied to relatively short diversions such as at major highway crossings: here the emphasishas beendirectedto mitigation,to minimiseany disincentiveto users,since it is rare for such crossingsto prove an attractionin themselves. Hence whilst the developmentof route options has required a professionalengineer's view ofwhat is practicableand achievable,the driving force has been the ultimate end user and the benefits to be gained. Engineeringsolutions can ultimately be found to almost any obstruction. We have taken the art of effective route planning to be the achievementof the best balancebetweenpracticality, benefits and costs. It shouldbe notedthat, evenwhereit was consideredby inspectionthat restorationon the original alignmentwas probablyimpracticable, this was still the first route option we considered. As a basecasethis original alignmentwas permittedto deviate in only a very minor way from the historic route (where to do so would avoid what would otherwise be a major and costly obstruction) but major deviations were not permitted: so where the route has been built over or otherwiselost, the cost and consequences ofrestorationhavebeenassessed, evenif this would requiredemolition of properties and/or major disruption to existing infrastructure. We consideredthis approachto be essentialevenif sucha routewas likely to be unacceptable politically or on other grounds,in order to providea control for comparisonwith other options which deviatedsignificantlyfrom the originalalignment. It should also be noted that in the selectionof prefened(or optimum) routes,which have then been developedin more detail and are presentedand costedon the Route Maps in Appendix D, it must be stressedthat theseroutesshouldnot be regardedas

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Restorationof the Wilts & Berks Canal: Feasibility Study.

definitive.None of the route optionsis absolutelyruled out at this stage,since changingcircumstances and opportunitiesor more detailedstudiesas the restoration project progresses could favour altemativeroutesor indeedrouteswhich have not beenconsidered by thisstudy(although this is unlikely).Neitheraretherouteoptions considered exhaustive ofall possiblevariations. Theaim hasbeento identifywhether present restorationis leasibleandto by the a schemewhich is likely to be supportable majorityof interested parties.The selectionof 'prefened'routesthus necessarily involvescompromise.Attendanceof an appropriate crosssectionof interestedparties at a seriesof routeselectionworkshopmeetingswasintendedto ensurethat,as far as possible,all significantfactors (engineering,environmental, economic,social, political etc) which could influenceroute selectionwere represented and taken into account. 2.2 Approach 2.2.1 Identification of Possible Routes Followingtheguidelines to routeselection notedin theprevioussectionour approach startedwith the developmentby desk study and by limited walk-over survey of possibleroute options which we consideredwould overcomethe identified obstructionsto restoration. The resultingroute optionswere essentiallygenericin principle - that is to say that whilst other optionsundoubtedlyexisted,they would only be 'variationson a theme' within a relativelynarrowcorridor,and would thus achievethe sameobjective. Where appropriatefor comparisonpurposes,budget was madeof the relativemerits of costingswere prepared,and an initial assessment the optionsdeveloped. The budgetcostsgiven in this Chapterof the reportare first orderestimates,and are indicativeof constructionworks tenderpricesfor comparisonpurposesonly. Thus they are exclusiveof all commoncosts (design,supervision,legal costs,land acquisition,contingenciesetc.). It is stressedthat thesebudgetcosts are therefore relativecostslor route comparisononly, and it shouldbe noted that they have not subsequently beenmodified to match the more detailedestimatespreparedfor the preferredroutespresented elsewhere in this report. 2.2.2 WorkshopMeetings This initialexercise wasfollowedby a seriesof'workshop'meetings, theintentionof which was to ensurethat full accountwastakenof the concemsofthe key interested parties,andwith theprimaryaimsof identifying: . Route options that were significantly less favoured becauseof fundamental problemsor objections; e The key issues,benefitsand problemsto be overcome, that neededto be further studied for theremaining optionsl

SconWilsonKirkoatrick& Co Ltd

Restoration of the Wilts & BerksCanal: FeasibilityStudy o Minor deviations from route options which might overcome or alleviate a key

problem,or generategreaterbenefit;or major deviationswhich might constitute newootions: . Initial rankingofoptions to targetandprioritiseeffort; The workshopmeetingswerealsointendedto providea generalbrainstormingsession to generate solutionsto problems or newideas.Foursuchmeetings wereheld,onefor eachof the District Councilareas(UnitaryAuthority in the caseof Swindon)through which the originalroutepassed.Themeetingswereattendedby olficer representatives from planningand technicalsectionsof the appropriateLocal Authorities(District, County and Town), from the CanalTrust and the CanalAmenity Group, fi'om the EnvironmentAgency,and from the engineering andenvironmental divisionsof Scott Wilson.Representatives wereaskedto considernot only their own particularinterests but also the likely views and reactionsof other interest groups within their organisations andelsewhere but not directlyrepresented at theworkshops. 2.2.3 Resultsof WorkshopMeetings The remainderof this Chapterof the reportpresentsthe resultsof this routeselection processon a districtby districtbasis,workingwestto east.For eachdistrict,following a description of the options(essentially as presented at the workshops), the issues raisedat (and in somecasessubsequent to) the meetingsand the outcomeof the exercisearedescribed. 2.3 WestWiltshire 2.3.1 Introduction The West WiltshireDC commonboundarywith North WiltshireDC follows the line of the RomanRoadrunningeast-westsome3km north of Melkshamand about lkm southof Lacock. Thusthe WestWiltshireDC areacoversthe originaljunction of the Wilts & BerksCanalwith the Kennetof Avon Canalat Semingtonaswell asthe route through Melksham. Altogether eight new route options were developed for restoration of the Canalthrough,or in the vicinity of Melksham(seeFigure 2.1 overleaf;,andthesetogether with theoriginalalignment werethetopicsfor discussion at a workshopheldon 8'nAugust1997. Thelengthsgivenin thefollowingdiscussions purposes arefor comparison only from junction just south the with theKennet& Avon Canal(K&A) to theDistrictboundary of LacockLock.In additionto budgetcapitalcosts(asdefinedbefore)an assessment ofannualoperating andmaintenance costswasmadefor eachoption. 2.3.2 Development of RouteOptionsfor Melksham Route optionsutilisingthe River Avon were investigated in a study by Oxford (1987)andreference Poly,technic wasmadeto thisstudyin theAmenityGroup'sown studyof 1988(GriffithsandWilliams,1988).In reviewingtheseanddeveloping other

Scon Wilson Kirkpatrick& Co Ltd

Restoration of theWilts& BerksCanal: FeasibiliryStudy. route options we realised that in terms of overall benefits to Melksham (and recognising as discussed later that restoration of the Canal on or near the original

alignmenttkough the Town shouldnow be consideredvery doubtful),an altemative routeoptionwhichwouldstill allownavigation throughtheTownbut alongtheAvon would probablybe preferredto any new routeoptionaroundthe outsideofthe Town. Such an intemal route would, however, be potentially more problematic and controversial thanan externalroute. Betweenthe K&A and the River Avon southof the Town, all routeswould needto passthroughTerraceGravelsrequiringlining, andAlluvium in the flood plain. The eastemroute options we developedwere in fact the main focus of 'The MelkshamProject' (Allen & Harris, 1994).The favouredoption fiom that Report quitecloselywith RouteE herein.Onceclearof theurbanconstraints corresponds of fieedomin routeplanningbetweenthe K&A andthe Melksham,thereis considerable oneof originalalignmentwhich canbe recoveredsouthofLacock. We havepresented many possiblevariationson a basictheme,as routeoptionG. Theseoptionspass areminimised. mainlythroughOxfordClay,henceliningrequirements The option of an altemativeroute aroundthe west sideof Melkshamwas considered sinceit would sufferthe sameprincipaldrawback but was foundto be unsatisfactory namely and sideliningthe town, and additionally option, bypassing as an eastem would be far more costly and complexas it would needfwo major crossingsof the Avon andtwo railwaycrossings.This optionwasnot thereforepursuedfurther. 2.3.3 RouteDescnption 2.3.3.I OripinalRouteThrouphMelksham Length: Locks: Cost:

7.2 krn 3 f8.3M + f33k pa

The problems of restoration from Junction Lock to the .4350 south of the Town are common to other routes and are describedelsewhere.From the .4.350 through to the northem limit of the Town, the original route is now heavily developed,mainly with gardens (perhaps 2km in total), but with some properties on the line, and in many casesthe construction impact and land take in gardenswould make further property acquisitionnecessary. 2.3.3.2 AlternativeRouteA This route would require a new, short, link canal between the K&A and the River Avon at Whaddon. The River Avon would then be used for navigation through Melksham, and another new, short, link canal would be provided to the north of the Town to rejoin the original line. There would be considerableengineeringworks requiredto make the River Avon navigable between Whaddon and Melksham Town Weir: the Poly'technicstudy concludedthat dredgingto maintainnavigabledepthwould be impracticable,and that

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RESTORATION OF THE WILTS& BERKSCANAL FEASIBILITY STUDY PossibleRoute Options M e l k s hm o

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Restoration ofthe*\gffi,H:il:i threeor four long (70m or more)controlweirs(or shorterweirswith flood gatesasat Notwithstanding theconsiderable Melksham)andlockswouldberequired. costof the engineeringworks, the environmentalimpact would probably give rise to serious This optionis therelorenot considered satisfactory but is includedin the objections. presentstudyonly for completeness. The northem part of this route does appearpracticablehowever and is further aspartofwhat is considered to be thefirstviableroute,RouteB. discussed RouteB 2.3.3.3Alternative Length: Locks: Cost:

8.8kmcomprising: 3.5km(K&A to R.Avon);2.lkm (R.Avon);0.5km (R.Avonto W&B); 2.7km(restored W&B to LacockLock) 8 f5.9M + f48k pa

This route is designedto avoid the ongoing developmenton and around the original route to the south of Melksham.It would leavethe K&A west of SemingtonBridge (closeto the originaljunction point) via a regulatinglock and passaroundthe west of Berryfield until it reachedthe A350. From this point the route would descendvia two locks into the River Avon just downstreamof the A350 bridge.Somedredgingwork would be required to make the river navigablebetweenhere and the Town Weir some 0.7km upstream.A low weir might be required to ensurenavigable depth, but a more detailed study would need to be carried out to confirm this. At Town Weir, a lock would be required, for which there is spaceon the eastbank adjacentto the weir. Upstream of Town Weir, almost certainly as far as the northemmostof the three new link canal options indicated on Figure 2.1, the River Avon should be navigable by canal boats without any dredging work, and is indeed presently being used for navigation. This northemmost link (which is the costed option) has the advantageof being the most straightforward in engineering terms, the least costly, and likely to require the minimum of constructionwithin the flood plain. It would utilise about 1.2km of the river upstreamof the weir. The southemmostlink would minimise the use of the river, eliminating use of the river upstream of the weir, but at a cost premium of perhapsf0.4M. In betweenthesepoints,the middle link canalwould also have to cross the local parallel channel.Any of the three link canals would probably require3 locks to overcomelevel differences. The Avon bridges over the reach proposed for navigation all have ample clearance. The river over this reachis wide and generallysluggish(at leastin summer),being very much in the nature of a canal in appearance.It would be necessaryto design works in the flood plain in such a marurerthat neither dischargenor storagecapacity were reduced, and in consequencesuch works would need to be designed to be submergedin a flood. This would render the route un-navigablein a flood, and river velocitiesin winter might alsorenderthe reachun-navigableduring this period. Pumping facilities would be requiredat each lock or flight for water conservation purposes(this is common to all options),and specialmeasuresmight be requiredto limit mixing of Canalwaterand Avon water,dependingon watersource.

ScottWilson Kirkpatrick& Co Ltd

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Restoration of theWilts& Berks Canal: Feasibility Study. The original Canal route is recoverablefrom the immediatenorthem outskirts of Melksham,and for the purposesof routecomparisonthis optionis costedthroughto theDistrictboundarysouthofLacockLock. RouteC 2.3.3.4Alternative Length:

Locks: Cost:

8.2kmcomprisingl.5km restoredW&B and 1.4kmnew canal(K&A to R.Avon);2.lkmR.Avon;0.5kmnewcanal,R.Avonto W&B; 2.7km restoredW&B to LacockLock. 8 f6.6M + f52k pa

This routediffersfrom RouteB only over its southemsection,and is designedto maximiserecoveryof the original alignmentsouth of Melksham.The original alignmentwould be followed to a point north of the sewageworks. Here a lock wouldneedto beprovidedto allowtheCanalto passundertheexistingA350,andto continuein cutting (up to about3m deepto towpathlevel) to rejoin RouteB at the intotheAvon southof theA350bridge. locksdescending on the original At the K&A junction at Semington,thereis currentlya slaughterhouse not be recovered at this point, a if the original line could even line. However, lock wouldbe requiredat A regulating relativelyminordiversionwouldbe possible. junction. the in this area.The landto the north Of moreconcemaretheproposedsitedevelopments of the old railway is earmarkedfor businessdevelopmentin the Local Plan, and the plot includingthe Canalis cunentlyup for sale.The Councilwould thereforeneedto ofa restored moverapidlyto protectthis routeifthis optionis preferred.Thepresence site. At Lane, which attractive development Shails canal could make this a more site,thereis a propertybuilt on the formsthe northemboundaryof the development to the east is feasible. originallinebut a minordiversion Arother factor affecting this route option is the possibleMelksham-Semington Bypass, for which a corridor is reserved through the earmarked Business DevelopmentArea, althoughno preciseroute has yet been frnalised.Although the describedcanalrouteoption shouldnot affectany proposalsfor the bypass,the close to boatersandother proximityofsucha newroadmaymakethisoptionlessattractive to optionB. userswhencompared 2.3.3.5RouteD Length: Locks: Cost:

8.3kmcomprising1.5kmrestoredW&B (K&A to Melksham);4.4km W&B Melkshamto LacockLock. newcanali2.4kmrestored 6 f7.2M+ f37k pa

The southemandnorthernreachesof this routeoptionarecommonwith RouteC, but insteadof divertingwestand usingthe River Avon, the routedivertsto the eastern outskirtsof the Town, keepingas close as practicablegiven the topographyand proposals. As the route tums eastfrom the original currentknown development

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Scott Wilson Kirkoatrick & Co Ltd

Restoration orthewu?*rlr",fi :il:i alignmentsouthof Melksham, a lockwouldneedto be providedto allow lor crossing proposed A350 underthe bypass. This dropto a lowerlevelshouldalsoenableroads to be crossedat the A365 Bowerhillroundabout: the Canalwould needto be in cuttingbetweenthesepointsup to about3.5mdeepto towpathlevel. Oncebeyondthe4.365,anothertwo lockswouldbeneeded to lift theCanalto a more suitablelevel to traversethe eastemoutskirts,crossingunder SnarltonLane, the .43102andForestRoad;thenthroughonefurtherlock to rejointhe originalalignment northofthe Town.Thispartof theroutewouldleaturecuttingsup to about4.5mdeep and an embankment up to 6m high (acrossClackersBrook). The presenceofa sump pound is an undesirablefeature,but overflows from the sump pound betweenthe .4350and,4.365couldbe takento the BerrvfieldBrook At both the SnarltonLaneandpo."rt noud ..ossings,landtakefiom gardenswould be required,but, otherthantheseandthepropertyalreadyreferredto for RouteC, no otherpropertywould be affected RouteE 2.3.3.6Alternative Length: Locks: Cost:

8.6kmcomprisingl.5km restoredW&B (K&A to Melksham);4.7km newcanal;2.4kmrestoredW&B Melkshamto LacockLock. 4 f6.4M + f3lk oa

This route is essentially the same as Route D, but crossesroads south of Bowerhill roundabout, which would avoid the need for a sump pound and thereby eliminates would be the possibleimpacton the ,4350bypass,which two locks.The disadvantage would need to be raisedto crossthe Canal (and thus might raise a strong or overriding objection),and the impacton Bowerhill Farm. 2.3.3.7 AlternativeRouteF Length: Locks: Cost:

6.7km comprising4.3km new canal(K&A to north of Melksham); 2.4kmrestoredW&B Melkshamto LacockLock. 3 f4.9M + f23kpa

This route is essentiallythe sameas Route E eastand north of Melksham,but would commencefrom the K&A immediatelyto the south eastof Bowerhill. It would run north through the planned developmentarea, with associatedenhancementpotential for the site and would descendvia a lock to crossunder the 4365, to join Route E. The route would avoid all existingpropertydisturbancesouthof Melksham,and any conflict with the proposedbypass,and shouldin consequence be significantlycheaper than RoutesD or E. It would howeverresultin the creationof a sumooound.

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Restorationof the Wilts & Berks Canal: FeasibilityStudy.

2.3.3.8Alternative RouteG Length: Locks: Cost:

6.5kmcomprising 6.5kmnewcanalto LacockLock 3 f4.9M+ L21kpa

This routeis one of severalfeasiblerouteswell to the eastof Melksham.It would drop fiom the K&A througha single lock to crossthe A365 and the valley of the ClackersBrook,thenrisethrough2 locks(onemight suffice)and follows closeto the 44m contour to Lacock Lock. This route has the advantageover Route F of not but would againrequirea encroaching on gardens,andwould thusbe lesscontentious, sumppound. RouteH 2.3.3.9Alternative Length: Locks: Cost:

8.5kmcomprising 8.5kmnewcanalto LacockLock I f5.6M + f20k pa

This would essentiallybe a contourcanal;the route being adjustedto suit field and land ownership boundariesas required.Only one lock should be required, at the K&A junction. The main advantageof this route over Route G (and all other routes) is its simplicity: a single lock should makes navigationeasier.However, its remoteness fiom Melksham meansthere would be little direct or significant benefit to the Town. 2.3.4 Discussionon MelkshamRoutes The original alignmentand all ofthe developedroute optionswere fully discussedat the workshop and as a result a number were consideredas unlikely to be feasible. The historic interest of the original route through Melskham was recognised and it was 'A walk noted that the Amenity Group had recently published a pamphlet entitled along the lost waterway of Melksham'. It was also recognised, however, that restorationto navigable standardswould probably not be practicable given the nature and extent of developmenton the original alignment in the years since the Canal had ceasedto operate. Route A, which would requireuseof a considerablelengthof the River Avon, could find little support due to its potential impact on the river environment: neither did it appearto offer any cost benefits,referencethe earlier Oxford Poly'technicstudy. In respectof the proposedroutesfrom Semingtonto the southemedgeof Melksham (RoutesC, D and E), north of the old railway line, thesewould passthroughland now allocatedfor businessdevelopment,for which planningconsenthasbeengranted. To protectthe route now would be very difficult. The old Canalbed here is also a habitat for the GreatCrestedNewt. a DrotectedsDecies.

The proposed A350 Semington-Melksham Bypassfollowsa line some250meastof the originalCanalroute.This is WiltshireCountyCouncil'shighestpriorityscheme, but construction is likelyto be in themediumterm.

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Restoration or thew' \*""r',lH:ffi i The just published(August 1997)local plan review document'HousingGrowth Optionsto 201f indicates additionalareasofland allocated for housingwhichwould impingedirectlyon RoutesC, D, E andF. Therewasno consensus at theworkshopas possible to the benefitof integratinga canalwith proposedbusinessor housing development. RouteD would passthrougha recentinfill housingdevelopment north-westof the Bowerhill roundabout.All variantsof this route would require some garden (or possiblyproperty)acquisition, andthiswasseenasa potentialmajordrawback. Thus optionsC, D, E and F wereconsidered to havesignificantproblemsin relation to existingplanningallocations, andthe consensus wasto settheseoptionsasidein favourof themoreviablealtematives. 2.3.5 Preferred Routesfor Melksham The remainingrouteoptionswereconsidered in moredetailby the workshopand this resultedin a choicebetweenusing the River Avon (RouteB) throughthe centreof Melkshamor bypassing Melkshamentirelywith a routewell to theeast(G or H). indicateda strongpreference The workshopattendees for the River Avon option,with the Environment the exceptionof Agency,becausethis routewould bring significant benefitto the Town. The Agencyexpressed concemson severalissues,which would not apply to an eastemroute. Theseincludedthe impact of existing navigation, conservationand fisheriesinterests,the needfor dredging,and the possibleneedfor anotherweir to maintainwater depth lor navigationdownstreamof Town Bridge. The environmentalissuesare discussedfurther in Chapter5 of this report. Town Bridgeis a listedstructure,but therewouldbe ampleclearance for navigation. Flooddefence wouldalsobe a concem.Thiswouldneedto be studiedin detail,but in practicethe proposedcanalworks shouldnot makethe presentsituationworse. With carefuldesignthe situationcouldevenbe improved. MelkshamGate(a float operatedflood gateadjacentto the weir) hassomeproblems andmooringsupstreamof this couldbe at risk from careless operation.Henceany day mooringswould best be situateddownstream. Therecould be mutualbenefit,if navigationwere to be permitted,by rebuildingthis structureentirelyas a combined long fixedweir andlock structure. Avon Rubberhasa licensedabstraction pointjust upstream of theweirwhichwouldneedto bemaintained. North of Town Weir, becauseof the impactof route optionswhich cross the subsidiary channel(whichis in facttheoriginalriverchannel), theprefenedoptionis themostnortherlyof thethreeroutesconsidered andshownon Figure2.1. Sincethis reachof the river shouldbe navigablewithout any dredgingwork, this would alsobe theleastcostoption. In view of thecomplexrelationship between river flowsandcanalised sections of the River Avon options,closeco-operation wouldbe requiredbetweenthe Environment AgencyandtheCanalauthorityto ensure thatall interests wereeffectively dealtwith.

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Restorationof the Wilts & Berks Canal: FeasibilityShrdy.

In respectof the eastemrouteoptionsthereappearsto be somefieedomfor precise routeselection but thekey issueon theseroutesis likelyto behighwaycrossings. For thepurposesofthe presentStudy,the RiverAvon (RouteB) hasbeenselectedas the EnvironmentAgency'ssignificant the prefenedroute,but, notingandaddressing concerns,an eastemrouteoptionhasbeenretainedasa fall-back. 2.4 North Wiltshire 2.4.1 Introduction North Wiltshire District Council areaincludestwo separatesectionsof the original Canals.The longestsectioncoversthe route of the Wilts & Berks Canal from the boundarywith WestWiltshireDC (RomanRoad,nearLacockLock) throughto Hay Lane(thecommonboundarywith SwindonBC). The secondsectionis the North Wilts Canal,from the District boundarynorth of Swindon(MouldonHill) throughto thejunction with the Thames& SevemCanalat Latton. Theworkshopmeetingwasheldon I 9thAugust1997. 2.4.2 Development of RouteOptionsfor Wilts& BerksCanal Thereare somedifficult (or potentiallydifficult) highwaycrossingson this section, but only minor deviationsfrom the original route would be required.A signifrcant diversion might have been requiredat the A3 102 at Vastem, Wootton Bassett. However,plansfor the new bypasswould allow (andindicate)closureof the existing road at this point thus allowing restorationof the Canalon the original alignment. Sinceit would appearlikely that the new road will proceed,alternativeoptions for dealingwith the currentblockagehavenot beendeveloped. Theseissuesaretherefore coveredin Chapter3 andon RouteMap Section17andschedules appended 2.4.3 Development of RouteOptionsfor North Wilts Canalat Cricklade The optionsdeveloped for consideration at the Workshopareshownon Figure 2.2 given overleaf.The lengths below are for comparisonpurposesand havebeentaken just southof the River Key from the commonongin of all the optionsconsidered, aqueduct. Housingdevelopment alongtheoriginalCanalalignment to thewestof Crickladewill undoubtedlynecessitate a local diversionof the channelor the provisionof a completelynew routeto the eastof the Town. Threealtemativerouteswere therefore preparedandconsidered in theworkshop.

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2.4.3.1 Original RourethroughCricklade

Length: Locks: Cost:

3.4km 0 f3.8M + f6k pa

The original route has been infilled and incorporatedinto gardensand domestic properties. The originalCrickladeTunnelis blockedat bothendsandis inaccessible, (fl.8M henceits conditionis unknown.If thepropertyon theroutecouldbe acquired of the budgetcosthasbeenallowedfor this),andassuming the tunnelis restorable, Accessproblemsto Stone's this routecould be of similarcost to the altematives. Farmdevelopment in particularwould remain,however. RouteA 2.4.3.2Alternative Length: Locks: Cost:

3.4km (l.7km restored,l.7km new) A

f.4.7M+ f22kpa

This route would involve a diversion to the west of Cricklade, departing from the original route close to The Forty and locking up to an intermediate high pound to cross Common Hill and Horsey Down (Oxford Clay). The use of four locks would enablethe depthof cuttingsto be limited to a maximum of about4.5m: this would be cheaperthan the alternative of 2 locks with depths of cuttings then up to 8m but in either case a new short summit pound would be created.A short cut and cover tunnel would be required under the 84040. The original alignment would be rejoined to the east of Hailstone Farm. The route would follow the same corridor that would be required for an extension of the proposed restoration for the Swindon-Cricklade railway through to Cirencester(the lormer Midland and South Westem Joint Railway, This would providecost sharingpotential M&SWJR) which is also being considered. betweentheserestorationprojects. The option of a bored tunnel through Horsey Down (predominantly Oxford Clays) is feasiblein engineeringterms and would avoid the need for locks. However the cost is likely to be far greater,perhapsan additional!4.0M. 2.4.3.3 AlternativeRouteB

Length: Locks: Cost:

l.0kmnew) 3.5km(2.5kmrestored, 0 f.4.2M+ Il 1kpa

This route would leavethe original alignmentat the samepoint as Route A but would avoid the need to lock up the hillside. It would rejoin the original route near the leisure centre.A cut and cover tunnel is indicatedunder the 84040 and perhaps3 residentialpropertieswould needto be acquiredplus othermiscellaneous outbuildings (f.0.6M is includedin the budgetcost for this). More of the original route would be recoveredunderthis option,and the capitalcostofnew locks and additionaloperating costsof a new summit sectionwould be avoided.However,recoveryof the original

Scon Wilson KirkDatrick & Co Ltd

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Restorationof the Wilts & BerksCanal: FeasibilityStudy.

route by the leisure centre and the recent Stone's Farm developmentwould be problematic. 2.4.3.4 AlternativeRouteC

Length: Locks: Cost:

2.6 km (all new) I f3.3M+ fl3k pa

routeto theeastof Crickladewouldjoin theThames& SevemCanal This altemative near Eysey.This route would leavethe original alignmentbeforethe 84553 to the southof the Town, and crossthe River Key beforefollowingthe 84553. After passingunderthe old railway at Godby'sFarmthe routewould tum to the north-east, the site ofan originalbut badlydamagedbrick archbridge.The routewould then run acrossopen farmlandto the 84040. This road would needto be divertedonto an embankmentsouthof its presentalignmentto crossthe new Canal.The embankment would be about4m high at the crossingpoint. Beyondthis, the Thameswould be on a low aqueduct. crossed Withinthe scopeof this Studyit hasnot beenpossibleto checkthenavigationrights on the Thamesat this point to confirm that adequateheadroomwould be available. Thiswouldneedto be doneto checktheviabilityof thisproposal.TheCanalwould then passunderthe A4i9, possiblyby adaptingan existinglargeaccommodation bridge,or alternativelya new culvert,beforecrossingfarmlandto join the Thames& SevemCanalto thewestof Eysey. This route would recoverlessof the original route of the Canalbut would offer an attractiverouteacrossfieldscloseto the Town, andon budgetcostingsalsoappearsto be the most economicroute.It would alsoprovidea direct link to a restoredrailway terminatingat Cricklade.The main issuesare likely to be the impact on the River Thames flood plain (including navigation rights), aqueduct headroom, and impacton anancientridgeandfurrowsite. archaeological on Cricklade Routes 2.4.4 Discussion at the workshopindicatedthat it was unlikely that restorationon the The discussions onginal Canal route throughCrickladewould be acceptable.Whilst Route B appearedcheaperthan RouteA, RouteA had the advantageof a potentialto share with the railway. Even the limited numberof costsin a combineddevelopment with RouteB would be problematic,and access associated propertyacquisitions wouldbe created.On the to the StonesFarmdevelopment) problems(particularly worthyof moredetailedattention. otherhand,both RouteA andRouteC appeared 2.4.5 PrefenedRoutesfor Cricklade RoutesA & C in moredetail. Theworkshopthenexamined ofRouteC, it wasnotedthattherewaspotentialfor a housingdevelopment In respect sportsfacilitiesandpublicopenspaceto the eastof the Town,north with associated intothis. However,access of CalcuttStreet,andCanalRouteC couldbe integrated to

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Restoration orthew\*,Ti[:il:i the housingwould probablybe adverselyaffectedby the needto raisethe road to allowtheCanalto passbeneath. The Canal corridor throughHorseyDown (RouteA) would also needto include a throughHorsey cyclewayandpossiblebridleway.Both the rail andCanalrestorations Down would requiresignificantcuttings. However,if the cost of the work were divided betweenthe two restorationprojects,this route option would be the most economicfor the Canal. Otherwise,RouteC would likely be thecheapest. The relativelydeepcutting would tend to isolatethis sectionof the Canalfrom the Town visually,but closerlinkageto the town centrewould occurat The Forty,belore theroutewent into cutting,andthis wasnot thereforeseenasa problem. with RouteC issuesassociated It was felt that therewould be major archaeological which would pass through a site of ancient ridges and furrows. Although the EnvironmentAgency had not raisedany concernsaboutthe potentialimpactof the Canalon the Thamesflood plain or the headroomavailableat the new aqueduct,these needto be resolved. Therecouldbeconcemovertheviabilityofa wouldundoubtedly replacementaqueductover the Chum on the original route near Latton (seeRoute Maps, Section 207), in terms of water freeboardrequirementssince the original clearancemay not now be consideredadequate.This would also be an issuewith RouteC crossingtheThames. Sincethe CotswoldCanal culvert underthe Latton bypasswill now proceed,thereis no preferencebetween Routes A and C in terms of their linkage to the Thames and SevemCanal. On balance the prefened route for the study has beentakenas Route A which will corridor. Route C accord with and support planning policy lor the leisure/transDort should be retainedas an altemative,however.

2.5 Swindon 2.5.1 Introduction Within the boundary of Swindon Borough Council, the Wilts & Berks Canal originally ran fiom Hay Lane in the west to Acorn Bridge in the east, and the North Wilts Canalfrom its junction with the wilts & BerksCanalin the southto just west of Mouldon Hill in the north. There is now very little left of the original route which would be potentially recoverablewithout significant effort. To restorethe Canal links to Abingdon, Melksham and Cricklade would thereforerequire the provision of reaches of new channel in the Borough, with some difficult engineeringand environmentalproblemsto be overcome.The route options workshop was held on 26'" June 1997. 2.5.2 Developmentof RouteOptionsfor Swindon In developingrouteoptionsfor Swindonfor consideration at the workshop,it became clear that relative cost was unlikelv to be a sienificant factor in the selectionof

SconWilsonKirkpatrrck & Co Ltd

10

Restorationof the Wilts & Berks Canall Feasibility Study.

prefenedroutes,sincethe viability of optionswas constrainedby other factors,in particular the engineeringand environmentalissues. Hence the budget costing exercisecarriedout for the otherrouteoptionworkshopswasconsidered inappropriate for Swindon. 2.5.3 OriginalRoutesThroughSwindon The LocalPlanrecognises thehistoricinterestof theoriginalroutethroughSwindon, and future developmentwill be restrictedwhere appropriateto safeguardthis. It is recognisedhowever that restorationto navigable standardsis unlikely to be practicable.The Town Centrehasrecentlyundergonesubstantialredevelopment, and thereis thuslittle scopein the foreseeable futurelor any majorbuilding works which might incorporatea canalrestoration. Theremay be a possibilityfor the creationof a Town Arm alongthe original line of the Wilts & BerksCanalto Milton RoadBridgeandtheprovisionof a windinghole. This could be consideredin the future subjectto the route remainingavailable,but doesnot form partof thepresentstudynor of theprefenedroute. Linear pondsalongthe original canalroute hereor elsewherewould strengthenthe historic link and awareness:such possibilities could be consideredwhen an opportunityarises. 2.5.4 NorthemRouteOptions A northemroute option,illustratedon Figure 2.3 overleaf,which could serveas an altemativeto either a southernroute or a westemroute (North Wilts Canal),was postulatedfrom a deskstudyat an earlystageof investigations but hasbeenrendered impracticableby virtue of the infill housingat Kingsdownand the pace of other developmentto the north of Swindon. It has not thereforebeen given further in this report. consideration 2.5.5 WesternRouteOptions Optionsconsidered for routesto the west of Swindonare shownon Figure 2.4 following.Thisparticularareawassubjectto a detailedstudyby Maunsell(1991).In our study we have reviewedand extendedtheir proposals,taking accountof site sincethatdate,andof othercomments developments andissues raised. the SwindonBC own thelandbetween HayLaneandRushyPlattwhichencompasses M4 crossing.Hencetheremay be opportunities to optimisethe route subjectto agreement on landowner,tenantfarmerandgeneralplanningissues. On thesouthsideof theM4, routeswhichcrossbothHay Laneandthe84005(Wharf Road)in thevicinityof thejunctionwouldrequirecarefulconsideration on highways junction. safetyissuesby sitingthe crossingsouthof the RouteswhichcrossWharf Roadfurthereastand thus clearof the junctionwould be lessproblematicin this resDect.

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Restoration of thewtt.;*rlr,',[tT:i Therewere no particularlystrongpreferences voicedat the workshopfor any of the route optionsindicatedsouthof the M4, (MaunsellRoutesA, B or C, or the shorter altemativeshownon Figure 2.4); option C which maximisesrestorationon the historic alignmenthasthereforebeenselectedas the preferredoption for the present study. Oncenorth of the M4, a route somedistancefrom the motorwayas indicatedin the in amenitytermsto a routefollowingalongthe toeof Figure2.4wouldbe preferable The optionof followingthe railwaycouldeliminateany conflict the M4 embankment. with the proposedWharf Link Road,but this would only really work if the west-east alignmentcontinuedalongthe edgeof the M4 (which is not the preferredoption)thus Platt/WestLeazeareaentirely. avoidingthe Mannington/Rushy Assumingthe route were to rejoin the original Canalline just north of the M4, (he prefenedroute),this would link into the existingin-watersectionof Canalat West Leaze.SwindonBC arecurrentlymakinga Lottery Fund applicationto enablethem to link this sectionthroughthe SkewBridge(underthe formerM&SWJR) to the inwatersectionto thenorth. RouteD from the earlierstudy(Maunsell& Partners,1991)throughRushyPlatt and following the River Ray throughto ManningtonRecreationGroundwas carefully evenlesspracticabledueto: reviewedby theworkshopbut appeared o Rushy Platt housing development,nearing completion, limiting space and introducinganotherbridgewhichwouldhaveto be rebuilt; . Designationof the southempart of the site as the first naturereservein Swindon for theWiltshireWildlileTrust; o Lack of interestin the project fiom the developerfor the businessdevelopment northof WoottonBassettRoad,which is continuingapace; o andimpactof canalisation of theRiverRay,a majorissueof concemto theEA. considered likely to be theonly practicable Maunsell'sRouteE wastherefore option but it was noted also to have significantproblems.The most fundamental was the availabilityof a passage consideration under Sainsbury'scar park. The existingculvertwhich carriesElcombeBrook underthe car park may just be of navigabledimensionsbut is far lessthan the designstandard.Enlargingthe culvert wouldbe difficultandthefeasibilityof its useis considered furtherin Chapter3. The problem was major the need for canalisation of the ElcombeBrook and the second River Ray. Of the two route optionsfrom ManningtonRecreationGroundthroughto Mouldon Hill, Maunsell'srouteG wouldinvolvecanalisation of significant lengthsof theRiver Ray. This was reportedto be of major and possiblyfundamental concemto the Environment Agency.RouteC mightalsoconflictwith the SpineRoadproposalon thenorthsideof theSwindon-Stroud Railwayline.ThetreatedeffluentfromSwindon worksis knownto be vital to supportflowsin the RiverRay,andcomments sewage lrom the EA indicatethatsuchdischarges wouldnot be available for consideration as Scott Wilson Kirknatrick & Co Ltd

21

Restorationof the Wilts & Berks Canal: Feasibility Study.

for the Canal(seeChapter4 clause4.7.8).Henceonly the potential a waterresource disbenefitsof treatedsewageeffluentwould be realisedby routeG, namelypotential and publichealthissuesto Canal derogationof waterquality,as well as aesthetic users. in the Maunsellstudywas The main concemoverthe altemativeRouteF aspresented a result of havingto traversethis M&SWJR cycleway as potential impact on the the routeup to 2m belowcurrentlevel.This would severelylimit spaceandcould impact on drainagefrom the tips. Wideningbetweenthe tips was consideredimpracticable. Leachatewould alsobe a concem,althoughthis problemis currentlybeingaddressed. be alleviated by provisionof a pair thattheseproblems In view of thisit wasproposed of locks to createa local summit pound along the M&SWJR. This would require backpumpingto maintainlevel in the pound,but sincebackpumpingat locks would be a standardfeatureof restorationfor water conservation,this was not seenas a particularburden.The routing of the Canalthroughthe proposedShaw Tip Forest boththesefacilities. Parkwould likely enhance The prefened route thus comprisesoptions E and F. In order to addressthe ofthe RayandtheElcombeBrook, overcanalisation Agency'sconcems Environment the preferredroute hasbeenfurthermodified fiom the Maunsellstudy proposalsto for navigation(seeFigure 2.5 and Figure 2.6 eliminateuseof thesewatercourses following). We now proposethat new culvertsshouldbe installedunder Wootton BassettRoad,Sainsbury'scar park andGreatWestemWay to takedry weatherflow Storm flows would overflowto the Canal. The route only fiom thesewatercourses. would then pass around the other two sides of ManningtonRecreationGround: altemativesites for existing sportspitchesthus affectedwould need to be found. throughout. andCanalwouldbe preserved betweenwatercourse Separation 2.5.6 SouthemRouteOptions The optionsconsideredfor routingof theCanalto the southof Swindonareshownon Figure 2.7 following.Of the two routeoptionsbetweenthe originalCanalroutenorth of the M4 though to NightingaleFarm(a-c andb-c), therewas strongsupportat the Workshopfor the northemmostroute (b-c) via Westleaze.This would be far more attractiveto usersthanthe southemaltemativewhichwouldrun alongsidetheM4. For the northemrouteoption(b-c),benveenSkewBridgeandCroft Road,thereis a potentialengineenngdifficulty with fine sandsand water issuesfrom the slope of SwindonHill, althoughthe route shouldbe just on the edgeor just clearof this problematicgeology.The crossingof the River Ray would needto ensurethat free surfaceflow couldbe maintainedat leastat normalflows, anda futureeast-westroad mightalsoneedto be considered. crossing A park and ride schemeis plannedfor the land immediatelyeastof Croft Road(both optionswould needto takethis into account).Beyondherethe routeswould pass betweenPipersWay and the cricketpitch (seeRoutePlansRouteSection25). We to routethe Canalacrossthe BroomeManor golf it inappropriate haveconsidered practicable alignmentherewouldneedto run for a short courseand hencethe only Farm(c-d). to theM4 up to Nightingale lengthadjacent

22

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From NightingaleFarm,the option of a route utilising the DorcanStream(d-e-j-m) was carefully considered.Although probably feasiblein engineeringterms, there appeared to be manyproblemswith acceptabilityincludingproximity to housingnear canalisation impact;potentialvandalism; theA'419;lossoftrees;generalconstruction issues;and,possiblyoverriding,the fact that a canalwould seemto providelittle additionalbenefit abovethe significantrecreationalfacility that the DorcanStream alreadyprovides.This routewas thereforenot prefened. The optionof a routearoundthe northsideof CoateWater(d-e-j-k),whilstit would bring the Canalvery much to the forefrontof an existingwell-usedleisurefacility, problemswith would involvethe provisionof an additionalsix locks,engineering and therewould be adversetemporaryand permanent foundationsin the Greensand, impacton the existingfacilities. It was consideredthat a routecloseto the southern boundaryof CoateWater(d-e-f-g)would be closeenoughto be well integratedwith the CountryPark,andhencethis is thepreferredrouteoverthis section. The option of following the northemedgeof the Ma (d-g) wasnot prefenedbecause andit would in any caseimpingeon andgeneralunattractiveness ofnoise, remoteness objectionfiom part of BurderopWood (whichwould be likely to raisea fundamental EnglishNature). The main engineeringproblemswith the preferredroute would be the potential and the presenceof an old brickwork's spoil foundationproblemsin the Greensand, cost). a slightdiversiontowardstheM4 mayavoidthisat additional heap(although Of the two optionseastof CoateWaterfor crossingthe 4419, the northernoption of 'gateway' feature,was crossingon an aqueduct(k-h), whilst this could be a key rejectedprimarily becauseof likely objection from the Highways Agency. The aqueductstructurewould haveto be foundedon HA land and would preventfuture gradeseparationof the adjacentroadjunction. In additionthe land at the southwest for a parkandride facility.Thereforethepreferred comerof thejunction is earmarked (g-h) with route a culvertto be thrustboredunderthe existing is the southem option road. 2.5.7 EastemRouteOptions Once acrossthe A419, thereis considerablefreedomfor route selection.The options we have prepared for consideration at the Workshop are shown on Figure 2.8 followins.

routepasses Betweenthe A419 crossingandGreatMoor LeazeFarm,the proposed throughan Area of OutstandingNaturalBeauty.Carewould be requiredto ensurea sympathetic designoverthisreach. From Great Moor Leaze Farm through to the Wanborough Road, the adopted alignmentis further eastthan indicatedon the Figure,both to minimise problemsof Greensandsand to avoid services,in pa(icular a DN500 water main. The greater separationfrom the .A419would also limit traffic noiseimpact.

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Restorationof the Wilts & Berks Canal: FeasibilityStudy.

Of the threeoptionsshorvnbetweenWanboroughRoadand Acom Bridge,the most direct route (C) followingthe valley of the Liden Stream(but not canalisingthe waterway)was preferred.To rejoin the original Canalroute soonerwould require passingthough a fairly extensive siteof a Romansettlement; 2 locksup would be requiredto rejoin the original line next to Sainsburys(RouteA); whilst restoration betweenhereand Acom Bridgeon the original alignmentwould alsobe problematic dueto proximityofhousesandgardens (Routes A andB). 2.6 Vale of White HorseDistrict 2.6.1 Introduction Althoughmuchof theoriginalWilts& BerksCanalrouteremainstraceable withinthe Vale of White Horse District, betweenAcom Bridge and the River Thames at Abingdon, thereare threeareaswheresignificantobstructionsare encountered and for which diversionsmay or will be requiredto allow restoration,namely at East Challow, at the site of the proposedThamesWater Reservoirto the southwest of Abingdonand in Abingdonitself. Theseobstructions areconsideredin detail below. Elsewherethereare somedifficult highwaycrossingsto be undertaken(in particular at Grove) but no major deviationsfrom the original alignmentare likely to be required,hencetheseissuesaredealtwith in Chapter3 of this reportandon the Route PlanSectionsandschedules appended. Theoptionsworkshopfor Oxfordshire washeldon 5thAugust1997. 2.6.2 EastChallowRouteOptions At East Challow residentialpropertieshaveencroached upon the historicalroute of the Canal.We havethereforeconsidered optionsfor restorationon (or very closeto) the original alignment,or a diversionto the north of the settlement(seeFigure 2.9 following). 2.6.2.I Alternative RouteA Length: Locks: Cost:

1 . 5 5k m 0 f I .9 million

This routeinvolvesrestoration as far aspossiblealongthehistoncalalignment. Land takewould be requiredfrom the gardensof up to 19 properties. A nanow channel throughthis section(4-5 m) would avoid the need to divert an accessroad to properties on thenorthemsideof theroute.On thewesternsideof the.A417thetotal width of the restored Canalwouldhaveto be reclaimedfrom residential gardensand theacquisition of onepropertywouldprobablybenecessary. Themajorimpediment to restoration on this routewouldbe thecrossingof theA417 over the Canal.The roadat this point wouldneedto be raisedto the originallevel (about1m) to allow sufficientheadroom or the Canalwould needto be deepened along perhapsa 2 km section,or somecombinationof theseoptionswould be

24

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Restoration of the*t\*rr"'rtt[:illi requiredlor verticalalignment.Any raisingof the bridgewould needto incorporate appropriate sightlines. It maybe possible to movea lockto thewestof EastChallow to minimisedeepening of a longpound. A lift bridge could be constructedto give accessto CanalFarm and CanalWay, or altematively a narrowstraightsectionofchannelcouldmaintainaccess. The major issuesarethusrelatedto propertyacquisition,land take from gardensand theroadcrossing. 2.6.2.2Alternative RouteB Length: Locks: Cost:

1.65km 0 f2.3 million

An altemative route at East Challow would have to be to the north to avoid the main village housing. Due to unfavourable ground levels and the likely cost and unacceptableenvironmental impact of a high embankment,it would be necessaryto lock down into a low pound from the level of the original Canal through two new locks at either end. The route proposedwould avoid land take from residentialproperties.Two new minor bridges would be required to maintain access. A new section of the .4417 incorporating a navigation culvert would needto be built on embankment. The use ofan intermediatesump pound would be an undesirablefeatureof this option and it would introduce additional operating costs owing to the necessity to pump water ftom the new pound to reduce water losses fiom the Canal and to prevent flooding. 2.6.2.3 Preferred Routefor East Challow The actual preferred route would dependvery much on negotiation lor the necessary land. This could equally apply to the historical Route A and the northem Route Option B, and therefore for the present study the consensusview at the workshop meeting was to work on the basisof restorationon the original alignment Route A but with the retention of the northem route as a fall back option. 2.6.3 ThamesWaterReservoirRouteOotions Thames Water have proposedto construct a large raw water storagereservoir south west of Abingdon.A revisedplanningapplicationis likely to be submittedwithin the next 2 years. The reservoir would be roughly circular in shapeand formed with an earth bund constructeddirectly over the original Canal route. The likely site and impactis shownon Figure 2.10 following.

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Restoration of theWilts& BerksCanal: FeasibilityStudy.

2.6.3.I Alternative RouteA Length: Locks: Cost:

i.75 km 2 f 1.3million

This route,along the historicalalignment,would be viable shouldthe reservoir proposalsbe abandoned. RouteB 2.6.3.2Alternative Length: Locks: Cost:

2.15km 2 11.9million

to the north andwest This routewould follow aroundthe toe of the new embankment side of the proposedreservoir.Although longer than the original route, the levels would be similarandtwo lockswouldbe requiredasfor RouteA. that evenif thereareno furtherdelaysto programme,the reservoiris We understand unlikely to be in operationbefore 2015 and would involve perhapsa 7-l0yr constructionprogramme.It shouldbe possibleto reachan agreementwith Thames Water to divert the Canalaroundthe north side of the reservoir,eitherat the same time as the reservoiris built or beforethen. This route could havea betteramenity valuethantheexistingalignment. 2.6.3.3 Thamesll'ater ResemoirPreferredRoute Due to the uncertaintyover the reservoir'sfuture,no decisionon canalrouting canbe givenat this time;if the reservoiris not to be built,the originalalignmentwouldbe preferredfor economyand historicalreasons.If the reservoiris built, the diversion would be required. 2.6.4 AbingdonRouteOptions In Abingdon,the originalrouteofthe CanalthroughCaldecott to the RiverThames near the confluencewith the River Ock is now significantlyaffectedby housing development.Three altemative route options were therefore developed for examination alongside the originalrouteat the workshopas shownon Figure 2,11. following. Lengthsgiven for comparisonin the following discussionaretakenfrom the commonoriginof optionson the originalCanalline westof the A34 throughto theRiverThames. 2.6.4.1OriginalRouteThroughAbingdon Length: Locks: Cost:

26

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Restoration of the Wilts & BerksCanal: FeasibilityStudy 1.4km of the original Canal is now within the urban limits of Abingdon, and is

incorporatedinto properties,gardensand underroads. We estimatethat at least25 propertyacquisitions would be requiredto makerestoration viableon the original route. Political,socialandconstruction impactswouldbe major,andbridgingworks would also be a significantengineeringproblem.Nevertheless, the estimated with altemative costis comparable southem routeoptions,partlybecause comparision theoriginalrouteis the shortest. RouteA 2.6.4.2Alternative Length: Locks: Cost:

3.4km (1.6kmrestored; 1.4kmnew;0.4kmcanalised watercourse) 3 f2.5million

The canalisationof any significant length of the River Ock (as for the Avon and the Ray) is likely to raise objections becauseof an unacceptableenvironmental impact. We have therefore developedthis altemative route along the floodplain which avoids canalisationof the main river and minimises impact on Sandford Brook which shares the Ock floodplain. Use would be made of the original Canal route to the west of the A34 but a new culvert would be required under the trunk road. The route would continue along the original alignment to the west of the A34 to New Cut Mill where it would tum to the north. Shortly after passing under a minor road the route would depart fiom the original line and continue north and then east parallel to the fuver Ock to pass under the southem arch of the 84017 Ock Bridge. Two locks would be required on this section. The route would then continue eastwardson the line ofthe Sandford Brook, passing through an existing informal open space and urban woodland area before passing tkough a regulating lock to enter the lower 100m length of the River Ock where the Canal and river would share an existing canalised section. The Sandford Brook would thus haveto be madenavigableover a lengthofabout 0.8km. Major issues associatedwith this route include the potential impact on the Ock Bridge; the navigation arrangementsat the Canal junction with the River Thames; clearanceat the St. Helen's Wharf Bridge; routing of the Canal through an existing attractive amenity and woodland area;and canalisationofpart ofSandford Brook. The Ock Bridge is a Listed Building and a ScheduledAncient Monument. Any alterationor interferenceis unlikely to be acceptable.Since a new bridge for a new canal cut south of the Ock Bridge would require road raising at the Ock Bridge itself, this is also unlikely to be acceptable. However,the southemarchof the Bridge,which Brook. is carriesthe Sandlord 3.65m wide and would be of navisabledimensionsif the brook were deepened. St. Helen's Wharf Bridge (erectedas accommodationworks by the Wilts & Berks CanalCompanyin 1824)at the confluencewith the Thames,hasclearanceinadequate for navigation.Hence either the bridge must be raised,the Canal moved to allow constructionof a new bridge with adequateheadroom,or a pair of locks must be provided allowing local water level to be lowered.This issueis discussedin more detail in Chapter 3 of this Report.

Scott Wilson Kirkpatrick & Co Ltd

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Restoration of theWilts& Berks Canal: Feasibility Study. High River Thamesflow velocitiesbelow AbingdonWeir occurat high water levels duringthe winter.This would compoundthe difficultiesof navigatingthejunction on a comerof a busysectionof theRiverThames. The route would impact on what is consideredto be an environmentallysensitive Mooringswould be a problemon this route corridorand thusmay not be acceptable. of the town centrelocation). (and mooringswould be essentialto take full advantage The works would resultin the lossof somematuretreesanda changein characterof would be a area.Canalisation of the stream(as elsewhere) the informalrecreation significant concem in principle to the EnvironmentAgency, primarily on nature would grounds- the flood defencefunctionof this particularwatercourse conservation by beingmadenavigable. probablybe enhanced RouteB 2.6.4.3Alternative Length: Locks: Cost:

3.95km 3 f 6.2million

Someinvestigationof the possiblealignmentof a new Canalroute to the south of Abingdonhadbeencarriedout in previousstudiesby OxfordPolyechnic(1987)and WBCAG members(Griffiths andWilliams,1988).The routewe havedevelopedfiom thesepreviousstudieswould run southof Abingdonftom the originalalignmentwest of the A34, but would then tum southeastto passunderthe trunk road to the north west of Drayon, beforetuming eastto join the River Thamesat CulhamCut. This routewould requirea regulatorylock at the River Thamesandtwo furtherlocksin the vicinity of StonehillFarm.The route would requirea major cutting up to 9 metres depthbut averagingabout5 metres,betweenthe 84017 nearStonehillFarm and the junclion with the onginal alignment,enablingit to passunderthe A34 some600m southofthe originalline.The levelofthe A34 andthe groundin this vicinitywould makean altemativetunnelsolutionprohibitivelyexpensive. The major issueswith this routeincludethe locationof a landfill site closeto the proposedroute. The Canal channelwould have to be constructedwith a fully of the Canal, and imperviouslining along this reach to avoid contamination groundwater. polluted potentiallytheRiverThames, aswell from The routewould needto be developedhavingregardto any futureproposalsfor a bypassing pass(possiblyfrom MarchamInterchange, closeto New Cut Mill andaround river crossing.An IntegratedTransport the southemedgeof the Town) and a new Studyfor Abingdonis due to be publishedin July 1998and may leaturesucha proposal. The inlet/outletfor the proposedThamesWaterreservoirmay be locatedmid-way up to 1000 Ml/d of along CulhamReach. Shouldthe reservoirbe constructed fromtheRiverThamesduringtimesof high flows and waterare likelyto be abstracted up to 500 Ml/d couldbe retumedto the Riverat othertimes. This couldhavesome on theThames. effectuponlocalnavigation

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Restoration orthewtt.i*.r"'r'i,[:Tli There may be scopeto use a floodedgravel pit to the south of this route, by the sewage works,asa canalbasinfor additional moorings.Thismaynot be a primesite for moorings,however,andthe EA hasraisedthe issueof connectinga waterbody to theThames. The deepcuttingrequiredto thewestof the B4017wouldhelpmuffle traffic noisebut would haveno otherbenefit,andwould resultin significantquantitiesof materialto be disposed of. Delay costs associatedwith traffic disruptionat the A34 crossingcould be considerablebut there is sufficientheadroomfor a thrust bore which would avoid lor the purpose thesecostsand this is the methodof constructionassumedacceptable of thisReport. RouteC 2.6.4.4Alternative Length: Locks: Cost:

4.35km 7 f4.6 million

This routeis a combinationof the historicrouteandpartof altemativeRouteB with a reachin new cut. The originalCanalroutewould be usedto the shortinterconnecting westof the A34, andto the eastasfar asNew Cut Mill. Justbeforethe Mill the route wouldturn southeastthensouthto join up with RouteB at the 84017 crossing.It would thenfollow the RouteB courseto theRiver Thames. This route would make slightly greateruse of the original alignmentthan Route B. From the topographicinlormationavailableat the momenttheremay be a needfor an intermediatesummitpoundon the new cut southof New Cut Mill, or a deep(l0m) sumrnitpoundwould require cuttingshorterthanon RouteB. Clearlyan intermediate give locks and backpumping facilities, and rise to severalnavigationand additional watersupplyissuesandshouldbe avoidedif at all possible.For this presentReport howeverthe summitpoundoption hasbeenusedlor route evaluationpurposes.On this basis,the route appearsto be cheaperthan RouteB and to haveno other issues acceptthosecommonto RoutesA & B. 2.6.4.5Discussion onAbingdonRoutes Therewas majority supportat the workshopmeetingfor RouteA (the Ock Valley route),mainly on amenitygrounds,providedthatthe potentialproblemswith the Ock and other issuesbeing Bridge could be dealtwith and subjectto natureconservation that restorationon the original satisfactorilyresolved.However,it was appreciated viablein spiteofthe housingdevelopment. linecouldbe economically Subsequent to the workshopwe were advisedof a stronglocal preferencefor a southemroute to avoidthe problemswith the otherroutesandto takeadvantage ofthe existingmarina facilitiesor providean oppo(unityto developa new canalbasinin oneof the lakes left by the formergravelrvorkings.

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Restorationof the Wilts & Berks Canal: Feasibility Study.

2.6.4.6 PreferredRoutesfor Abingdon Thereforeat the Workshopthere was no consensusas to a preferredroute. For presentpurposes,in view of the more extensivedifficultiesand concernsanticipated with RouteA and restorationon the originalalignment,andpotentialcost advantage overRouteB, we haveelectedfor this studyto presentthe southemoptionRouteC as beingthemostlikelyto gainacceptance. 2.7 Conclusions This Chapterof the Reporthasexaminedrouteoptionsfor restorationof the Wilts & Berks Canaland the North Wils Canalwherethe original routeshave beenlost or obstructedby development.It concludesthat there appearsto be a feasible engineeringsolution in every casewhich achievesthe major restorationobjectives parties. by theprincipalinterested whilst beingsupportable For the main urbancentres(Melksham,Swindon,CrickladeandAbingdon)in no case has restorationon the onginal alignment,which would requiresignificantproperty However,otherthan in Swindon,this option acquisition,beenfelt to be supportable. could be cost effective and would maximise the historic/heritagevalue of the restoratlon. At Melksham,the preferredalternativeroute is to makeuse of a short reachof the Avon through the centreof the town. This route option does createa significant morework will be neededin the next phaseof impacton the river, and considerably studiesto develop this option belore the EnvironmentAgency could olfer their support. However, there is a viable altemative route should the Environment namelya routeto the eastof Melksham. Agency'sconcemsproveto be fundamental, Both optionsneedto be retainedfor thepresent. however, is theA3102crossing; to restoration themainobstacle At WoottonBassett, currentplansfor a new bypassprovidefor the A3102to be closedoff at this point which will allow restorationon the original line and level; hencealthoughthere are routesshouldthe.A3102remainin its presentform,thesehave practicable altemative study. in anydetailin thepresent notbeendeveloped is the Conigretunnel.Should to restoration On the Calnebranch,the majorobstacle the tunnelprove to be impracticableto restore,thenthereis sufficientspaceto cut a new tunnelto the north.This will be costly;structuralsurveyand investigationwork whichoptionwill be adopted. on theexistingtunnelto establish will be necessary At the outsetit wasanticipatedthatthe majorobstacleto restorationwould arisefiom in Swindon,and this hasprovedto be the case,most particularlyin development respectof the restorationof the North Wilts Canalthroughwest Swindon.The (i.e.makingnavigable) of canalisation principalissuesfor thisbrancharethepossible proximity Agencywill stronglyoppose;andthe whichtheEnvironment watercourses, whichstraddles the only storeat Bridgemead especially Sainsbury's of development, possible viableandsupportable meanthatonly one practicable route.Theconstraints

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SconWilsonKirkparick & Co Ltd

Restoration of thet t \*""r.'r,n :ffi i route for the North Wilts branchhas been identified (see later lor descriptionof Furtherwork will be necessary detailedissues). to confirmtheviabilityof thisroute. A routeoption to the north of Swindon(whichcould haveservedas an altemativeto the problematicsouthemreachesof the North Wilts CanalthroughSwindon)hasbeen found to be not viable, largelydue to the rapidpaceof developmentin this area.To the southof the Town, a prefenedroutehasbeenidentifiedwhich keepsthe Canalas lar from the M4 as possible:a route which lollows the M4 would be quite straightforwardin engineeringtermsbut would be highly unattractiveto users. A crossingof the M4 at the west end of Swindonwould requirea thrustboredculvert, but thereis ampleheadroomandthus in routingtermsthe M4 hasnot provedto be a At the eastendof Swindon,the optionof a routeutilisingthe significantconstraint. but rejected,mainlybecauseof the negativeimpactof DorcanStreamwasconsidered to the currentamenityvalue the works which would bring little (if any) enhancement of this corridor,in favourof crossingthe A419 closerto the M4 againusinga thrust boredculvert. The southernroute option resultsin creationof a new short summit poundat a levelsome17mabovethe originalsummit.More detailedstudieswill be requiredto confirmtheprecisealignmentandviability of this route. theproblemsinvolvedin Onceeastof theA419,therouteis relativelyunconstrained; gettingbackto the originalalignmentat the earliestoppo(unity resultin thepreferred altemativewhich essentiallyfollows (but does not canalise)the Liden Stream, rejoiningthe originalCanalrouteat AcornBridge. At East Challow, an option to divert the Canal north of the village to avoid the developmenton the originalline was rejectedin favourof restorationon the original route,but needsto be retainedasa fall backsolution. The proposedThamesWaterReservoirto the southwestof Abingdonwould be sited directlyoverthe originalCanalline,requiringa diversion.Sucha diversionis likely to be includedin ThamesWater'splans,and hencethe basecasefor this study has shouldthe reservoir beenrestorationon the originalline, which is readilyrecoverable not proceed. At Abingdon,a route down the Ock corridoris feasible,and would appearto ofler costsavingsoveran altemativerouteto the southof the Town.However,therewasno in favourof eitheroption,and sincethe latteris likely to be less clearconsensus controversial,this is thepreferredroutefor thepresentstudy. routesboth eastand westof the At Cricklade,thereappearto be viablealtemative Town. Theformercouldbe significantly cheaper sinceit avoidsdeepexcavations and locks necessary to crossHorseyDown; however,given the desireto allow for restoration of the Swindon-Cricklade railwaythroughto Cirencester, which would needto sharethe samecorridorasthe CanalthroughHorseyDown, the westemroute optionis adopted asthepreferred altemative.

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Restorationof the Wilts & Berks Canal: Feasibility Study.

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Restqrationof the Wilts & Berks Canal: Feasibiliry Study

3 . E N G T N E E R I NC Go N S t D E R A T t o N S

3.1 Introduction the generalengineeringconsiderations This sectionof the Reportdiscusses andissues with the preferrednew route(s)identifiedfrom the routeoptionsstudyand associated the restorationof the original Canal. The detailedresultsof the engineering assessments on a featureby featurebasis,including costs, are presentedon the comprehensive1:10,000scale Route Plans and Schedulesin Appendix D. Engineeringissuesspecificallyrelatingto waterresources aredescribedin Chapter4; theseinclude (in particular)canal linings, surfaceand groundwaterabstractionand storage. 3,2 RestorationStandards 3.2.1 Specified Criteria The Terms of Referencefor the study defineda set of basicdesignstandardsto be belowin Table 3. I andon adopted.Thesehavebeendevelopedandaresummarized Figure3.1 following. Table3. 1 CanalDesignCriteria Craftmaximumsize: 22.0m Length 2.13m Beam 1.0m Draught Channelsize: Bedwidth Depthof water Freeboard Waterwayarea Widthat locks Lock length width Bridgeholes Air draught Watervelocity

(or asoriginal) 4.27mminimum;5.33mdesirable (or asoriginal) I .37mminimum;1.5mdesirable 0.3m '10m2 minimum;13m2desirable 2.2mminimum(or asoriginal) 22.6mminimum(or asoriginal) (or asoriginal) 2.4mminimum;2.7mdesirable 2.3mminimum,2.7mdesirable, over2m width 0.37mls(0.83mph) maximum

OtherCriteria Towpathwidth 2.0mmrnrmum (for pedestrians) Towpathheadroom 2.0mminimum,2.3m desirable WaterSupply:

I in l0 yeardrought

Boat Usage:

As determinedbv the useandbenefitsand environmental

Scon Wilson Kirkpafiick & Co Ltd

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Restorationof the Wilts & Berks Canal: Feasibilify Study.

3.2.2 DesignDimensions of lockson the Wilts & Berks,are reportedin the Royal The originaldimensions and Waterways1907.All lockswerereportedas havinga Commissionon Canals themajoritywereof width 7'2" (2.184m)with the widest lengthof 74'0" (22.555m); (2.286m). as4'0" (1.219m)between Depthof wateroverthecill wasreported at7'6" with a maximumof SwindonandAbingdonandgenerally4'2" (1.270m)elsewhere, (Summit) Top Lock. 4'8" (1.422m)at Chaddington to It is usefulto setboth absoluteanddesirableminimato ensurethat rigid adherence preclude overcoming cost effective solutions to major does not standards desirable obstructionswhich might be achievedthrougha relaxationof standards.This is a particularissuewith the potentialuseof the existingElcombeBrook culvertunder aswell in detaillaterin this section), at Bridgemead, Swindon(discussed Sainsbury's potential rather than build new. where is to use existing structures there as generally In this respectan absoluteminimumwaterdepthof 1.2mand air draughtof 2.0m mightbe considered. A typicalchanneltrapezoidalcrosssectionwith I in 2 sideslopesandminimumwater depth1.37m,wouldrequirea bed width of 4.56mto providea minimumwaterway areaof 10m'.This crosssectionyieldsa surfacewidth of 10.04m.A cross-section with verticalbankswould requirea bed width of 7.30mfor the samewaterwayarea and depth. Hence the minimum bed width criterion is not a primary parameter. Applying the samecalculationto the l3m' desirablewaterwayarea and l.5m depthyieldssurfacewidth of I1.67mandbed width 5.67mat 1 in 2 side desirable the desirable bed slopes,andwidth of 8.67mwith verticalbanks.Againthis exceeds that thesedesirabledimensionsareadoptedwhere width criterion.It is recommended spaceallows. on existingwatercourses is required. Watervelocitywill be an issuewherenavigation regularlyduringtimesof flood. maximumvelocitymaybe exceeded Thedesirable The fieeboardrequirementwill need to be expandedin due course to indicate Thesecouldvary with location(amenity maximumandabsoluteminimumacceptable. valuein urbanareasmay dictatelesstoleranceof variationof levelsthan in the rural will becomeimportantin assessing water Theseconstraints sections) andwith season. paticularly backpumping andlockage. issuesandhydraulics, resource Towpath width and headroomrequirementswill be influencedby the need to cyclistsand horseridersin somelocations.Criteriawill needto be accommodate otherthan definedin duecourse,andsectionsof the routewhich shouldaccommodate will needto be identified.It will be preferable, wherepracticable, pedestrians to provideseparate pathsfor cyclewaysor bndlewaysto avoidconflictsbetweenusers. (Harrison,1996)suggests that for new and The IWA paper"WaterwayRestoration" rebuilt lengthsof channelthe bed width shouldbe at least2.5 timesthe beamof minimumbed width of 5.33m. typicalcraft.This hasbeenusedto setthe desirable Desirable andminimumcnteriafor windingholes dimensions andfrequency- will but arenotof majorconcernto thispresentstudy. needto be setin duecourse,

34

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RESTORATIONOF' THE }Y]LTS & BERKS CANAL FEASIBIUTY STUDY Typical Canal Sections and Dimensions D B4 V

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Restorationof the Wilts & Berks Canal: Feasibility Study

Criteria for capacity and clearancesfor aqueductsover or culverts under significant watercourseswrll need to be set in due coursein consultationwith the Environment Agency. In general there will be a need to ensure fiee surface flow in the watercourses under normal conditions although a degree of surcharge may be acceolablelor extremefloods.

requiredfor an aqueduct over a highwayis 5.3m.For the The minimumclearance of the line,wouldmean mainrailwayline,allowingfor possiblefutureelectrification abovetracklevelof 4.78m,and2.78mclearance berween a minimumclearance track and abutmentson eachside. However,none of the preferredroute optionsrequire over highwaysor railways. aqueducts In the caseof a crossingundermain railway lines (of which thereare several),the would be for 300mmof ballastbeneaththe track.A rectangular minimumrequirement culvert section is likely to be prefenedto circular. Runoff slabs are commonly required.A temporaryspeedrestrictionwould be requiredto install the structureand for whicha paymentwouldbe required. for a shortperiodof time thereafter, 3.3 Earthworksand Geology The earthworksrequired the Canal restorationinvolve in the main only small up to 3.5m aboveexistingground level, and cuttingsgenerallyof a embankments similar depth,but up to a maximumof 6m at Cricklade.Someof the non-preferred Therewill be a net surplusof materialarisingfiom routeshavehigherembankments. will be significantlymore material arising from cuttings the restoration,ie there (perhaps (perhaps 1.4Mmr) thanrequired to formembankments 0.lMmi ;. Potential problemswith disposalof surplusmaterial from the canal restoration, including contaminated land through illicit dumping, are discussed under environmental issues.It would be intendedhoweverthat as far aspossibleall suitable materialarisingfrom the works is put to beneficialre-use,and in particularit would be appropriatewhereverpossibleto utilise surplusmaterialin the forming of the to meetthe water demandsof the restoredcanal. surlacewater reservoirsnecessary couldpotentially utiliseup to 0.5Mmrof surplus. Theformingof thesereservoirs The useof materialsarisingfrom the worksandtheirusein embankments, together with the stabilityofcut slopes,is discussed below. However,it shouldbe notedthat geotechnical will dependupontheprecisenatureof design,particularly of cut slopes, by siteinvestigation. thesoilsasdetermined In all casesthe initial operationwill be the stripping of topsoil from all areaswhere new earthworksare required; this should be stockpiled for re-useas far as possible on the completed earthworks. The outcrop geology along the route of the Canal is indicatedin Table 4.1 of later Chapter4.

ScottWrlsonKirkparrck& Co Ltd

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Restoration of theWilts& BerksCanal: FeasibilityStudy. 3.3.1 Embankment and Materials

It is likely thattheonly materials thatwill proveunsuitable for usein earthworks will be soft claysof the alluviumdeposits.Otherwise, all materialsshouldbe useable althoughdifferenttechniques mayhaveto be employed in theirplacement. relativelylightplantcanbe used Sandsandgravelscanbe easyto placeandcompact; depending uponthe layerthickness adoptedduringplacement.Someproblemshave encountered during earthworks in the Lower Greensand, asthe upperweathered been layersof this materialcan be clayey and difficult to handle. However,the use of lighterplanteasestheseproblems,so it is not anticipated thatmajordifficultieswill on this typeofproject. In view of theirpermeability, a liningwill be be encountered gravelsrequiredfor new embankments formedofsandsand The Coralliandepositscan,dependingon their degreeof weathering,be excavatedas producea difficultyprovidingsuch largeindividualblocks.Thisdoesnotnecessarily somebreakingdown of such materialis usedon higherembankments.Nevertheless, material,if encountered, wouldprobablybeworthwhile. The main dilficulty envisagedlies with the stiff claysof the Gault,Kimmeridgeand Oxford Clays. These tend to be excavated,and thereforedeposited,as large individual "lumps" unlessheavy compactionplant is used (including use of sheepsfoottype rollers). The use of lighter plant leadsto a more open textured andhencerequiresa liner,but compactedmaterial,which not only is morepermeable, by an can softenwith time resultingin settlement.The lattercan be accommodated increase in fieeboard. 3.3.2 Cuttings It is unlikely that cuttingswill be requiredin the flat topographywhere alluvial deposits areto beencountered. Cuttingsinto Lower Greensanddepositsand sandsand gravelsmay require some stabilityanalysis, but slopesof 1(v) : 2(h) canbe usedfor preliminarydesign. The mainconcemwith thesematerials is theearlyplacement of topsoilto preventerosion. Cuttings into the Gault, Kimmeridgeand Oxford Clays will require more This particularlyappliesto the deepestsectionof cut (up to 6m) consideration. proposedto cross Horsey Down at Cricklade.Therehas been considerablerecent followinga seriesof slopelailuressome studyof cuttingsformedin thesematerials, to equalisation ofthe time(upto 20 years)afterconstruction. Thishasbeenattributed porewater pressures negative developed withintheclaysasa resultof theremovalof material. The solution that has been adoptedfor motorway cuttings is to form for this relativelyflat slopes,between1(v)to 4 or 5(h);this wouldbe impracticable project.Possible solutions maybeprovisionofretainingwallsat thetoeofcuttingsto ofpore water reducesoil slopes,or theuseof bio-engineering to minimiserestoration pressures. Thisaspectrequires furtherstudy.

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Restoration of the Wilts & BerksCanal: FeasibilityStudy

3.4 Structures 3.4.1 BridgeTypeSelection Therearethreeprincipalfactorswhich influencebndgetype selection; function,form andcost. In consideration of the functionof a bridge,the end use of the bridgeshouldbe examinedin detail.For the purposeof this study,therearethreeprincipalcrossing types; primary and secondarypublic roads,private accessroads and tracks, and railwaylines. The public roadsvary from motorwayswith high volumesof traffic, particularlyat peak hours, to quiet country lanes with little or no traffic during a single day. Similarly the privateaccessroadsor tracksmay havelittle or no traffic. Both public and privateroadscarry vehiclesof varying sizeand weightsand, from 1999,public roadbridgeswill be requiredto carryvehicleswith 40T grossvehicles,or 11Taxles for shortspans. Privateroadsmay generallycarry lighter vehicles;this doesnot meanhoweverthat accessfor largervehiclesis not required.A privateaccessroadto a farm,for example, may on occasionscarryheavyvehicles(farm machineryor deliveriesof bulk animal feed).A furtherexamplemay be a privateaccess trackusedvery little (onceor twice a week) by a farmerdriving an off-roadvehicleto visit a fallow field. It is therefore necessary to carry out a detailedstudyof the typesof vehicleswhich could possibly usea bridgebeforethe tlpe of bridgecanbe selected. The Londonto Bristol railwayline crossesthe routeofthe Canalat lour locationsand the Swindonto Stroudrailway line crossesthe Canalat one location,both of which are in continualuse.The loadingfrom rail vehiclesis greaterthan that arisingfiom roadvehiclesandthis hasanimpacton bridgetypeselection.OvermanyyearsBritish Rail developed'standard'bridgedesigns,with both steelworkandreinforcedconcrete decks.Thesestandarddesignsarerelativelycosteffectiveandeasyto constructanda major beneht of adoptingsuch a designis that the gaining of approvalfiom theinfrastructure owner (Railtrack)shouldbe straightforward. It should be noted howeverthat structurejacking (thrust boring) of reinforcedconcreteboxes under railwaylineshasbeensuccessfully completed at a numberof locationson the rail network. The secondmajorconsideration is the form of the bridge.Form is relatedto function, indeedmanydesigners believethat'form followsfunction'andthatsimplefunctional arethe mostaesthetically pleasing structures to the eye.Visualimpactandaesthetics are major considerations, togetherwith the appropriateness for a particularlocation. For example,a footbridgeconstructed in timberwouldbe morein keepingwithin a rural settingthan a similarstructureformedin concrete. Aesthetics is an emotive subjectand individualtastesvary considerably. Thereforein determiningbridge thereshouldbe a high degreeof involvement aesthetics from all the interested parties (where and localresidents appropriate). The structurallorm of the bridgescouldbe chosenin sucha way so as to projectan imagefor the Canaland whereappropriate

SconWilsonKirkprrrick& Co Lld

Restorationof the Wilts & Berks Canal: Feasibility Study.

couldbe replicated traditionalcanalarchitecture to producea "family" ofbridges.It is will be utilisedto dressbasicconcrete expected thatbrickfacades structures. The bridgetype shouldalsobe selectedto suit the expectedgroundconditionsand its impacton the environmentand any existinginfrastructure. Consideration shouldalso be given to the methodof demolitionwhen the structurehas reachedthe end of its economiclife. Structuralform hasan impacton buildability.Placinghorizontalandverticalconcrete surfacesis easierto form thaninclinedsurfacesor arches.Formingconcretewithin a thework on site. is easierthanundertaking lactory(pre-casting) to be the mostimportantfactorin bridgetype selection.It is Costmay be considered essentialto considerthewholelile costfor a particularbridgetlpe andnot merelythe constructioncost. The cost of constructiondoeshoweverplay a major part in the selectionprocess.Materialselection(steel,concrete,timber,etc.) and the cost of protectionandmaintenance of thematerialsshouldbe considered. free,whereassteelworkrequiresregularprotective Concreteis relativelymaintenance provided Timber hardwoods, they are fully treatedbefore erectingon maintenance. freelor 50 yearsor more. site,generallyremainmaintenance The locationof the crossingpoint hasan effecton the total cost of the construction work. A crossingat or adjacentto the originalcrossingpoint of a road for example, will createlittle dilficulty for thecontractorto gainaccess.In contrasta footbridgeor a culvert which is a considerabledistancefrom a public road will result in the contractorneedingto negotiaterightsof accessandconstructa temporaryroad for the plant,materials,etc.to the siteof thework. movementof construction betweenthe The numberofbridgeswithin a contractandthe degreeof standardisation bridge types will affect the costs such that to increaseeither will give rise to a reductionin unit cost. The mannerin which the constructionwork is procuredhas an impacton the whole life cost. Modem methodsof procurement(Design& Construct,Managementand Partnering)can lead to significantsavingsin constructioncosts.With long term projections will be ableto reduceprofit margins. of tumover,thePrincipalContractor with sufficient It shouldbe noted that the majorityof contractingorganisations resourcesto undertakea projectsuchas the Wilts & BerksCanalare moving away from traditionalcompetitivetenderingandtowardnegotiatedcontracts.Oneaspectof this approachis that the contractorwill wish to standardise the bridge types, for 'productionline' constructionand this will have an impacton structuralform. The level of acceptability for standardisation will needto be determined in consultation partiesandlocalresidents. with the interested Methodsof BridseConstruction 3.4.2 Standard The mostappropnate and cheapest methodof construction for mostroad crossings will usuallybe to temporarily divertthe roadaroundthe site. At someof the wider roadcrossings, it maybe possibleto halvethewidth of theroadanddivertall tralfic

38

Scott Wilson Kirkpatrick & Co Ltd

Restoration orthew\*.:,r",',Ii,tffi i onto one half whilst the bridgeis constructed over the otherhalf. Oncethe road has beenremoved,the form of bridge constructedis likely to be one of the following t)?es: . Precastconcretebridgebeamson conventionalconcreteabutments; o In situ concretebox structure: . Precastconcretearch. A conventionalbridge (a deck supportedon abutments)will commencewith the provisionof the abutmentfoundation,and dependingon the groundconditionswill of piles which are driven or rangefrom a simple spreadfooting to an arrangement placedinto position. The abutmentsare generallyof castin situ concrete,which is either plain or reinforced dependingon the design. The bridge deck, either prefabricatedsteelwork of precastconcretebeams, is then placed on bearings supportedby the abutments.The final tasksare to placewaterproofingto the deck andthe roadsurfacing/ railwaytrack. The foundationfor an in situ reinforcedconcretebox structurealso dependson the a spreadfootingis all groundconditions, althoughin the vastmajorityof situations that is required. A horizontalbaseslab is placedat the foundationlevel and is followed by the ve(ical walls of the box. Temporaryformwork is then fixed into positionto providesupportfor the top slabwhile it is beingcast. On completionof the box structurefilling materialis placedonto the top slab and the road surface/ railwaytrackis completed. usingsegmental unitssupportedon strip A precastconcretearchbridgeis constructed of piles. Two rows of piles foundationswhich may be supportedon an arrangement (oneverticalandoneraked)wouldbe requiredat eachfoundationto carrythe vertical andhorizontalloadsarisingfrom the archunits. A key is castinto eachfoundationto locate the arch units and transmitthe horizontalforcesto the piles. The precast concretearch units are usually one completesemi-circularsection,althoughtwo halvescanbe usedfor largerspans.On completiona precastconcretespandrelwall is fixed into position and granularbackfill materialis placedon top of the arch units lollowedby completion of theroadsurlacing. formsof areillustrated in Figure3.2,Figure3.3andFigure3.4. Theabovestructural The most appropriateandeconomicform of structurewill needto be established at a there would for be considerable scope standardisation laterstage.It is anticipatedthat for bridgesalongthe lengthof theCanal,whichshouldlenditselfmorereadilyto the elements useof pre-cast concrete or prefabricated steelwork The use of altemativematerialsfor the majority of the crossingsmay lead to cost savings.The use of reinforcedsoils for examplehas recently considerable emergedin the UK and the techniquehas primarilybeenusedfor stabilisingand repairingsoil slopesandactingfor retainingwalls.Useof the technique for forming particularlyfor bndgeson privateroadsor access bndgeabutments, trackswith little traffic loading,may be advantageous. Its use for bridgeson publichighwayswith high traffic loading is questionableat presentdue to uncertaintyover long term Scon Wilson Kirkpatrick& Co Ltd

39

Restorationof the Wilts & BerksCanal: FeasibilityStudy.

durability. More evidencein respectof its suitabilitymay becomeavailablein the future. A numberof masonry/brickarcheshave beenbuilt in recentyears and, assuming of arch profiles, this could be a low maintenanceand very some standardisation but costis likelvto be a constraint. traditionalformof construction. Wherelocks occurimmediatelyadjacentto crossings(andin planningthe locationof thereis an opportunityto proposednew locks this has often beena consideration), the bridgebecominga 'tailbridge' below the combinethe bridgeand lock structures, bottomgate. 3.4.3 AdditionalFactorsfor RailwayCrossings 'The For eachrailway line, Railtrackproducesan annualprivatepublicationknownas Rulesof the Route' which detailsthe notrain periodsin which normalweekdayand of the line may be available.Also includedin the publication weekendpossessions which havebeenallocatedto major itemsof work, suchas are abnormalpossessions of Railtrack,it or permanentway renewal.With the agreement bridgereconstruction for installinga structure may be possibleto utilisesuitableabnormalpossessions acrosstherailway. requiredfor crossingthe railway,the ownershipof Underthe termsofthe agreement the structurewill be vestedin Railtrack.Railtrackwould wish to recovermaintenance costson an "as andwhen"basisandundertaketo give a minimumof two yearsnotice or repair. Railtrackwould alsorequirean of the requirementfor major maintenance per expenditure off5000 annum for day+o-daymaintenance. authoritylor the Methods 3.4.4 AltemativeCrossing Therearea numberofcrossingsof majorroadsandrailwaylinesalongthe line of the Canal for which the standardmethodsmentionedabovewould not be appropriate. The following three techniqueswould be availableto createopeningsat these crossingswithout diverting the road/railwayand with little disruptionto existing users. 3.4.4.I StntctureJacking concretetunnelStructurejacking is a techniqueof installinga circularor rectangular by thrustinghorizontallya singleor severalpre-fabricated like structureunderground (usuallyboxes),from a prepared pit. A shieldis providedat the frontto cut elements the groundand supportthe exposedface whilst spoil is removedfrom the face by mining andpassedbackthroughthebox. The structureis thrustforwardby meansof hydraulicjacksbearingagainsta temporary thrustwall orjackingbase.To reducethe effectofthe movingstructureon the overlyingroad/ railwayan anti-dragsystemcan at thetopandbottomofthe box to reduceffiction. be introduced jackingis essentially a soft groundtunnellingtechnique and its success Structure is on an adequate foreknowledge dependant of the groundconditionsto be expected jackingis stiff drive. The idealgroundconditionsfor structure alongthe proposed

40

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Restoration of the Wilts & BerksCanal: FeasibilityStudy clay or dense fine sands with apparent cohesion as these require the minimum support and can readily be mined.

of

A small amountof settlementof the road/railwayabovewill inevitablyarisefrom this method,but can be controlledby carefuldesignof tunnellingshield and interaction andprogress of shield.If a structure hasvery little cover,thena betweenexcavation grillage of steel beamsmay be requiredto maintainthe vertical alignmentof the road/railway. particularlyunderrailway lines It shouldbe notedthat thejacking of box structures, where the limitationson the variationof verticalalignmentare more stringentthan on a numberof occasionsandthat therearea roads,hasbeencompletedsuccessfully with the expertiseto carryout suchwork. numberof contractors The pre-fabricatedunits are most economicallymadeof reinforcedconcreteas this materialprovidesa rigid unit capableof withstandingthejacking forcesin additionto earthpressureandlive loadswithoutunduedistortion. primarilyby adjustingtheinclinationof the shieldor ofthe unit is achieved Steerage leadunit. Thejacking work is normallycarriedout on a continuousround-the-clock basisboth to minimisethe installationperiodandto avoida high restartjacking force delayin jacking dueto settlementof the ground which may resultfiom an appreciable againstthe units. build up ofgroundpressure anda consequent whena bridgeis requiredunderan existingroad, Structurejacking may be considered railway or otherservice,wheredisruptionof the serviceduringconstructionwould be either inconvenientor costly. The direct civil engineeringcost of structurejacking altemativemethod. will generallybe higherthanthatof a moreconventional An alternativeto structurejackingundera live railwayasdescribedabovewould be to jack a similarstructure into an opencut shouldit be possibleto utilisean abnormal The structurev.'ouldbe constructedadjacentto the railway line, railway possession. of the railwayline, thetracksand togetherwith ajackingpit and,on takingpossession embankmentwould be removed. The structurewould then be jacked into its final position and the embankmentand railway line reinstated.The major advantages of a reduction in costs. technique are speed ofinstallation and considerable this 3.4.4.2 Work llithin a Cofferdam The canal bridge structurewill be approximately6m overall span and temporary to copewith this span.To constructa bridgingunitscan be obtainedor fabricated bridge, two lines of steel sheetpiles are driven acrossthe road/railwayduring a weekendclosure.Duringa furtherclosure, thegapbetween the linesof sheetpilesis spannedby temporarybndge units. The areaunderthe temporarybridge units can then be excavatedwithout furtherdisruptionto the road/railtraffic and a reinforced castin-situ. concrete box structure structure the temporarybridgeunits are removed On completionof the permanent duringa finalclosureof theroad/railway andthecarriageway/track reinstated directly structure. on thenewbox

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Restoration of theWilts& BerksCanal: FeasibilityStudy.

3.4.4.3 Tunnelling Standardtunnelling methodsusing a circular tunnelling shield and off-the-shelf precastconcretelinings could providea suitableopening. Standardlinings are availablefor tunnelsof intemaldiameter 4.5m, 5.0m, 5.5m, 6.0m or larger. As with structurejacking the tunnel would requireboth a start and receptionpit at eitherend and settlementsimilar to the structurejacking techniquecan be expected. A possibledifficultycouldbe findinga tunnellingshieldavailableto suit the chosen diameter. Tunnellingcouldbe cheaperthanstructurejacking sincethereis lesstemporaryworks andthe lining is availableas a standard precastitem. Its suitabilitywould,however, be dependent on thetlpe ofgroundto beencountered. 3.4.5 Bridgesfor Footpaths andBridleways Both footbridgesand bridlewayscan be constructedof steel,concreteor timber. In the rural settingof the Canal,timber bridgeswould mergein with the countryside better. However,in more urban areaswherevandalismis likely, steelor concrete would be more appropriate. Durable hardwoodtimber bridges would be more expensivethan steelor concrete,but would needlessmaintenance than a steelbridge andhavelighterloundationsthana concretebridge. 3.4.6 Particularcrossinss 3.4.6.1 A4, near Chippenham(RoutePlans,Section7, 5T946717) A rise in the ground profile at the original crossing point is evident. The original bridge is off-line from the current road alignment. Each of the approaches is reasonablystraight with the crossingpoint on a slight curve. It is anticipatedthat the road could be raised in the order of 2.0m at the crossingpoint for the installation of a new bridge. The need to reduce the canal pound level (as currently proposed) is reduced and there is a possibility that the Chippenham Branch could be re-opened. There is a car show room in close proximity to the crossingpoint and the accessto it will requirere-gradingand re-modelling.There is also a nearbyhouseand its access may also need re-gradingand re-modelling. There is scopefor improvementsto the alignment of the A4 which may allow the road to be raised further at the crossing point, togetherwith the addedbenefitthat the bridge could be built off-line, thereby reducingtraffic disruptionand constructioncosts. 3.4.6.2 A3102Public Road, Vastern(RoutePlans,Section17,5U053815) Currentproposalsfor a by-passto Wootton Bassettindicateclosureof the A3102 to allow restorationofthe canalat original line and level. Therefore,assumingplans for the by-passareimplemented,therewill be no needfor a canalcrossingofthe road. Should the plans not be implementedit rvould be possibleto align the canal to the west of the original courseto crossthe ,{3102 in a cutting. In this situationa bridge would be requiredwith re-modellingwork to thejunction of the public road leadingto

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Restoration ofthew'\*,H[:ilx] Vasternitself. This canalalignmentwould removethe needto providea bridgeat the in thevillage. originalroadcrossing 3.4.6.3 M4 Motorway(RoutePlans,Section22, SUl l7825) junctions15and16of theM4. As all motorways Thiscrossingoccursbetween canbe extremelybusy, particularlyat peak hours,and given the likely high cost of lane closures(for which the HighwaysAgency imposelane rental charges)it has been determinedthat the most practicablemethodof providing a canal crossingof the motorwayis to jack a structurethroughthe motorwayembankment.From inspection betweenthe carriagewaysurfaceandthe adjacent thereis sulficientverticalclearance (at ground level the foot of the motorway embankment)to undertakesuch an operationwithoutdisruptionto the motorwaytraffic. Swindon(RoutePlans,Section27,5U192813) 3.4.6.4A4l9(T)Dual Carriageway, it is possibleto providea crossingof the A4l9 giventhe heightof From inspection at theproposedcrossingpoint. As the roadis very busy,particularly the embankment at peakhours,a cut & covermethodfor theprovisionof a bridgeis not practicable. Adopting a similar techniqueas proposedlor the M4 Motorway,a precastconcrete culvert could be jacked throughthe road embankment.A slip road from the ,4'419 andis gradeddownto a junction with a minor runsparallelwith the dualcarriageway pointhasbeenchosenasit is close passing publicroad undertheA419. Thecrossing to raisethe sliproadto pass to theexit ofthe off-slipandthereis scope(if necessary) junction. grade downto the existing overthe canalculvertandthen 3.4.6.5 A420AcornBridge(RoutePlans,Section30,5U218874) The A420 currentlyusesboth archesof the Acom Bridge (GreatWestemRailway), wasoriginallyprovidedby the railwaycompanyfor the oneof which it is understood canal. It is also understoodthat a new link road,to the North of the railway line, avoidingthe Acom Bridgeis proposed.It is thereforepossiblethat the original arch openingwill becomeavailableonceagainfor the canal. If this is the caseremedial workswill be requiredto providea channelfor the canalthroughtheopening. in which casea new It is alsopossiblethat the link roadwill not be implemented, crossingof the railway line will be required. From inspectionthereis sufficient clearancefrom the track level to the adjacentgroundlevel (at the foot of the railway to jack a concretestructurethroughthe railwayembankment.A jacked embankment) will causelittle or no disruptionto rail traffic. While this optionwould structure appearcostly, the provisionof a 'standard'structurerequiringlong weekendtrack (whichrequiresa roadconnection possessions for rail customers) is likely to be of sreatercost.

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Restoration of the Wilts & BerksCanal: FeasibilityStudy. 3.4.6.6 Belmont Roundabout, Wantage (Route Plans, Section 42, 5U394891)

Original canal crossing point (known as Hunters Bridge) is too close to the roundaboutto raise the road without raising the roundabout,which is impractical giventherearea furtherthreeapproachroads. Thereis alsoan electricitysub-station in closeproximrty. Align the canalto the North of the roundaboutandprovidebridgesfor accessto the TechnologyParkandthepublicroadheadingNorth from the roundabout.The roadat re-gradedto give eachbridge locationwill have to be raisedand both approaches for the canal. sulficientverticalclearance 3.4.6.7A338PublicRoad,Grove(RoutePlans,Section43,5U401894) During the site visit it was determinedthat the level differencebetweenthe invert of the existingculvert to LetcombeBrook and the carriagewayis approximately3.0m. theroadwouldneedto be raisedin the orderof 1.0m Giventhe designrequirements, to provide sufficientclearance.This would be possiblewith the re-gradingof the to the crossingpoint, accessto private residencesalong the ,{338 and approaches GroveBridge Farm. The nearbyjunction with a minor road,which is controlledby traffic lights,would alsoneedre-modellingandtheapproachre-graded. 3.4.6.8 St HelensIlharf Bridge,Abingdon(RoutePlans,Section49,5U496966) The headroomat this bridge is critical to the viability of the River Ock corridor thatthereis no viablealtemative to theraisingofthe original option. It is considered bridge. The differencebetweenthe bridge soffit and water levels is approximately will therefore 1.30mandthestructure needto beraisedin theorderof 1.0mto provide sufficientclearancefor the canal. Jackingof the main girdersand deck is possible howeverspecialcare will have to be taken during such an operation. During the jacking operationthe bearingsto the abutmentscould be raisedusing sympathetic materials.Bothofthe approaches, together with a privateaccess roadandpublicroad will require re-gradingand retainingwalls will be requiredadjacentto the River Thamesandthecanalisedsectionofthe River Ock. An alternativecanal alignmentimmediatelyto the South of the St Helens Wharf Bridgewouldstill resultin theneedto jack the existingbridge. The roadlevelat an altemativecrossingpointwill requireraisingin the orderof 1.0mandthe re-graded will affecttheexistingbridge. approach 3.4.6.9ElcombeBrookCulvert,Swindon(RoutePlans.Section201,5U132844) Following an earlier study by Maunsell& Partners(1991), it was proposedthat the canalutilisesthe existingElcombeBrook culvertwhich passesunderSainsbury'scar park, Bridgemead.A survey of the culvert revealedthat the fall over its length is approximately400mm and that the crosssectionchangeswithin its length. A drawing for the developmentof the site for Sainsbury'sindicatesthat the change in cross sectionrs at the siteboundary.

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:illi

The upstreamportalinvertto soffit levelis approx.2.00manda width of 2.46mat the springinglevel to a brickwork archedroof. The existingcrosssectionis insufficient for the canal clearancerequirements.Given that the original railway embankment, underis no longerin use(or likelyto be used whichthis sectionof theculvertpasses in thefuture),thissectionofthe culvertcouldbe removed. portalinvertto soffitlevelis approx.3.20manda width of3.70m at Thedownstream the springinglevel to a castin-situ concretearchedroof. This crosssectionis also insufficientfor the canaland remedialwork to lower the invert level (the preferred practicable, will be costly.ThamesWater option),while removingthe fall appears yards fiom up streamportal. An into the existing culvert approx. 100 havean outlall andthis is likelyto be in outfallinto a naturalwatercoursewill haveto be maintained culvertfor ElcombeBrook. the form of a replacement The dry weatherflow of ElcombeBrook is low andit is anticipatedthat a culvertof the orderof 0.75mdiameterwould be sufficient. Stormweatherflow would spill into the canaland the existingculvertto passunderthe car park. Existingplansindicate an easementof 5.0m to the Southof the existingculvert and the foundationsfor Sainsbury'sbuilding. Assumingthat the building is not supportedon piled foundationsit would be possibleto install the new culvert using a micro-tunnelling techniquewithin the width of the easement.Somesettlementdue to tunnellingis grouting. by compensation but thiscouldbeprevented anticipated Alternativelyit might be possibleto constructa new walkway in the reconstructed culvertin sucha mannerasto providea conduitfor the ElcombeBrookwithin it. (with theco-operation wouldbe to providea new of Sainsbury's) A viablealtemative coveredchannelfor the canalusing a cut & covertechniquelor approximatelyhalf of the cost of the above. This option would requirethe closureand reinstatement sectionsof the car park (say 50.0mat a time), installingtemporaryworks,placinga reinforcedconcretebaseslab and sidewalls with a precastconcreteroof slab. The principaladvantages of this option is the reducedcost. A furtherbenefitis that the canalwould not be requiredto act asa stormwaterchannelandthe slight bendwhich occursasit exitstheculvertwouldbe eliminated. 3.5 PoundLevels,Locksand Backpumping 3.5.1 PoundLevelandLockLifts requirements at The poundlevel betweenlocks fixes the verticalalignmenVclearance all the crossingson that reach, and is thereforeof fundamentalimportance.In pound levels for restoredsections,the Study has identifiedsignificant assessing in particularthe lock lift datain the 1907 betweenpublishedsources, discrepancies (Royal retums 1907),in the appendices to Dalby Commission, Royal Commission (1986)andthepoundlevelsindicated in thestudyby Allen & Harris(1994).We have knownlevelsat thesummit(99.1mAOD), the reviewedthesedata,takinginto account (43.2mAODaboveSemington Top),anda meanfor theThames K&A at Semington at Abingdon(49.5mAODrangingfrom 49.3at low flow to 50.1at a low flood).The on Table3.2 resultsarepresented

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Restorationofthe Wilts & Berks Canall Feasibility Study.

Table3.2 HistoricLock Lifts and PoundLevels Lock

Royal Comm 1907 Lifr Level (m) ( m )

LJ

Dalby Difference

A&H Comments Levels

Lifi Level Lift Level (m) 1m) (m) {ml

39.6SemingtonTop : 43.2,less 2.39,less2.51= 38.3mAOD 0 . l 9 -0.2 40.4 Junction 0.69 3 9.0 0.5 0 3 8 . 8 Seminston Melksham Forest t.08 4 2 . 1 2 . 8 6 4t.'7 -0.22 -0.4 42.9 2.75 44.8 2 . 1 9 44.0 -0.36 -0.8 45.4 Cueenheld 46-47m 1 . 0 4 7. 0 OSmapsussests 3 . 0 6 4 7. 9 2 . 8 4 46.9 -0.22 Lacock 3 . 0 8 5 1 . 0 1 . 0 1 49.9 -0.07 t . l 49.7 PewshamBottom 2.90 53 . 9 3 . 0 1 52.9 0 . 1 1 1 . 0 52.3 PewshamMiddle 2 . 6 8 56.5 2 . 6 1 55.5 -0.06 1 . 0 55.0 GL at ,A.4crossine = 55m PewshamTop 2 . 9 0 59.4 2.74 58 . 3 - 0 . 1 7 -t.2 57.'7 StanleyBottom 60.4HugsOS 60m contour 2 . 6 8 6 2 . l 2 . 3 6 60.6 - 0 . 3 1 Top Stanlev -0.06 1 . 6 63.0 2 . 8 0 64.9 2.7 4 63.4 Bottom Foxham 0 . 1 1 2.' 7 | 6 6 . I t . 7 65.7HussOS 65mcontour 2.83 6 7. 7 FoxhamToo 0 . 1 9 2 . 88 70.6 2 . b 9 6 8 . 8 L 9 68.4 WoodCommon ' 7 1 . 4-0.09 - t . 9 7l.0 2 . 6 8 73.3 2 . 5 9 Dauntsey between 1 5 . 9 58 9 . 3 t 7. 9 7 8 9 . 3 2.02 0 . 1 8 9 . 7Big discrepancy Lyneham Flight fisuresfor total lift. lSevenLocks) 0 . I 92.4 2 . 4 5 91.7 2 . 4 6 9 l . 8 0.02 Wootton BasseftBot. 2 . 5 2 94.2 2 . 6 1 94.4 0.09 0.2 9 5 . 1 Wootton BassettToD 0 . 1 9't.7 Bonom 96.7 2 . 3 4 96.'7 - 0 . 1 I Chaddineton 2 . 4 5 9 9 . I 2 . 3 9 9 9 . I -0.06 0.0 1 0 0 . 1 ChaddinstonToo 99.1 0.0 99.lm AOD actual 99.1 SummitPound 1.003 0.980 Enor Faclor: 0.2 VarstonLocks (4No) 9 . 7 8 8 9 . 3 9 . 6 1 8 9 . 5 -0.t'l 2 . 7 9 8 6 . 5 2 . 7 9 86.7 0.00 0 . 2 Lonscot Top Townath 84.1 East Challow 0.2 2 . 9 7 8 3 . 6 2 . 9 2 8 3 . 8 -0.05 Lonscot Bottom 0 . (6 0 . 4 1875OS mapgivestowpath 16.84 66.7 t 6 . 6 6 6 7 . 1 l 8 Grovelocks No) level67.4m 2 . 9 0 6 3 . 8 2 . 9 2 64.2 0.02 0.4 Ditto. towDath level 64.3m Ardinston Top Ditto. towDath level 61.9m Ardington Bottom 2.74 6 l . l 2 . 9 2 6 l . l 0 . 1 8 0 . 2 2 . 8 4 58 . 2 2 . 8 9 5 8 . 4 Ditto. townath level 58.8m Steventon Ditto. towDathlevel 55.8m 3 . 0 2 55.2 3.0'7 55.3 Drayton Ditto. towDathlevel 53.0m 2.' 79 52.4 2 . 8 4 52.5 Tithe Bam Thamesmean= 49.5; 1907 2 . 9 0 49.5 2 . 9 4 49.5 Abingdon K&A 0t Semington Junction

38.3

38.3

1.000

1.017

fisures match exactlv Error Factor

NOTES: l.Dalbyquotes21'(6.40m)risefromStanleyJunction(StanleyTop)to CalneWharf. OSmapshowsGL 68mat CalneWharf;1907figswouldgiveWL : 68.4,too high fromtheimpenalmeasurements asreportedin the 2. Lock lifts aremetricconversions surveyandLJ Dalby.Levelsin bothcaseshavebeenadjusted RoyalCommission (usingthe errorfactor)to matchthereferencelevelsat the summit,Semingtonand theThamesat Abingdon. USE I9O7FIGURESFOR SUMMIT TO ABINGDON;ADJUSTEDDALBY FIGURESFOR SUMMIT TO MELKSHAM

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The enor factorrepresents the correctionappliedto the total lift ascalulatedfrom the sumofthe statedindividuallock lifts, in orderto matchtheactuallift. It will be seen that the overall error is around2Volor the Dalby figures;and under 0.3% for the RoyalCommission figuressuggesting thatthelatterwouldbemostreliable.However, (up to 2m), in particularthe reportedlift through there are significantdiscrepancies (Seven the Lyncham flight Locks) and the evidencefrom the OS mappingwould suggestthat the adjustedDalby figuresaremore representative for Semingtonto the Summitpound.Thereareno majordiscrepancies in the Summitto Abingdonsection (still up to 0.4m however),and sincethe adjustedDalby figuresindicateinadequate freeboardin somereachesagainstlevelslor historic(1875OS) mapping,the 1907 figures(which providean exactmatchin total lift) aretakenasrepresentative for this section. Thesepound levels,and the lock lifts arisingas a consequence, are reportedon the detailedroute plans and schedulesappended.It shouldbe notedthat the levels for eachpoundwill needto be refinedin due courseas designsare developedin detail, and the levels finally selectedneedto optimisethe cost and practicalitiesof bridge raisingagainstcanallowering/deepening. 3.5.2 LocksandBackpumping Waterresourcesarelikely to be criticalto theprospectslor full restoration,andlosses will need to be minimised.It is becomingmore and more commonto provide backpumpinglacilities to recoverwater usedin lock operations,the K&A being a prime localexample.It is thereforeproposedthat,from the outset,backpumpingof all lockagewaterwill be an integralfeatureof the Wilts & Berksrestoration.In view of the disparatenatureof the likely watersources,suchpumpingfacilitiesmay alsobe requiredfor watertransferup the systemandwill needto be designedaccordingly.In somelocationstheremay be a net transferrequirement down the system,aftertaking lockageinto account;in thesecircumstances backpumpingwould not be necessary. However, for presentpurposesit is assumedthat a backpumpingstationwill be requiredlor everylock or flight of locks. Therewill be an economicoptimumsolutionin respectof the diametersand lengths of pipeline('risingmain')andnumbersof pumpingstationsfor eachflight.We have indicatedlikely requirements on therouteplansandschedules. Thepumpingstations (wet well) pumps(probablymostcommon)or pumps can utilizeeithersubmersible locatedin a dry well, andbecause of the importance of this system,shouldinclude standbyprovision(typicallyI duty and 1 standbypump,on rotatingduty to equalise hoursrun).Powersupplyto thesestations couldbe a significant costitem,andwhere possibleloctionsshouldbe selected closeto road access andpoweravailability. This will not alwaysbepossible however. Pump sizing/capacity will dependon maximumnumberof lock operationsto be cateredfor, and the storagecapacitybetweenminimum and maximum acceptable operatingwaterlevelsin the poundsconnected by the station.The largerthe storage capacity, the lowertherateat whichwaterneedsto beretumed,andhencethecheaper the installation andrunningcosts.Detaileddesignwill needto considerwhetheroff peak(Economy7) tariffsareviable.

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Restorationof the Wilts & Berks Canal: Feasibility Study.

In respectof pump control,the operationreally needsto be fully automatic.Use of a simplefloat switchor electrodein a stilling well adjacentto the lock chambercan be usedto give a countof lock usage;this countcanthenbe usedfor pumpcontrolto run the pumpfor'x'hours per lock operation to ensurethat all lockageis backpumped. This will needto be delayedor overriddenaccordingto levelsin the upstreamand downstreampounds:i.e. don't pump if the upstreampound is overflowing or the lowerpoundis belowminimumlevel;andpumpif lowerpoundis overflowingand upperpoundis not. thatthe aim shouldbe to providea telemetrysystemfor the whole It is recommended of the Canal,with a centralisedcontrol/monitoringfacility. This will enablepound pumpingoperations levels,lock usage, andfaultconditions to be monitoredremotely in real time. Remote control may also be considered,enabling pump control parameters to be adjustedin response Whilst this may all to changingcircumstances. 'high tech', the basic technologyis very well established,and, since seemrather elfective water managementwill be absolutelycrucial to the successof full restoration,it is consideredvital that effectivetools areprovidedfor monitoringand controlof thesystem. 3.6 Conclusions It is proposedthat the Canal be restoredto accommodatestandardnarrowboat up to 22.0mlength,2.13m dimensions beamand 1.0mdraft.Broaderbeamcraftwill not be accommodated. A range of minimum and desirablestandardshave been proposedfor the dimensionsof channel,bridgeholesand locks, and thesewill be generallyachievable. However,marginalrelaxationof standards may be, or may need to be, consideredat certaincritical obstructions.This appliesin particularto the option for use of the existing ElcombeBrook culvert under Sainsbury'sat Bridgemead, Swindon. The total volume of excavatedmaterialarisins from the restorationis estimatedat around 1.4Mmr, of which only perhaps 0.t l,t.' will be required to form embankments. The materialsarising,mainly stiff clays,whilst generallysuitablefor embankmentconstruction,will needcarefuland appropnatedesignand construction techniques. The maximumheight of embankment is about 3.5m. If anticipated. contracts canbe soarranged, thereis potential to useup to 0.5Mm'of surplusmaterial in the formingof the surfacewaterreservoirsrequiredfor watersupplyto the restored canal. The most significantnew canalcut would be throughthe OxfordClay of Horsey Down at Cricklade,wherea depthof up to 6m is anticipated.This cuttingwould be sharedwith a restoredrailway. Problemsare anticipatedwith this, and other lesser cutsthroughclays,sincelongtermslopestabilityideallyrequires slopesasflat as I in 5, but the land take will generallymakethis impracticable. Furtherstudywill be requiredin theseareasto identifyappropriate solutionswhichmay involveretaining wallsor bio-engineering techniques.

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Restoration of theWilts& BerksCanal: FeasibilityStudy Potential problems with disposal of surplus material from the canal restoration, including contaminated land through illicit dumping, are discussed under

environmentalissues. Therewill be numerousstructuresto be constructed or reconstructed for a restoration to full navigablestandardsof 108kmof canal.In respectof bridges,thereare three principal vehiculartypes: public highways(from the M4 to secondaryand tertiary roads);privateaccessroadsandtracks;andrailwaycrossings.For the vastmajorityof thesecrossings,the engineeringsolutionis straightforward, and thereis considerable andresultingeconomyof construction. scopefor standardisation Somegenerictlpical presented for theseconventionalstructures arrangements are on Figures3.1 to 3.3. points,theoriginalstructure In themajorityofcasesat originalCanalcrossing is lost, the Canalinfilled and culverted,and thereis often insuffrcientheadroomfor a new In thesecases,we bridge over a restoredCanalwith the road alignmentunchanged. to determinewhetherraisingof the road level to haveexaminedthe road approaches standardsof verticaland achievesufficientheadroom(whilst maintainingacceptable horizontalalignmentandsight lines)is practicable.Wherethis appearsso, andwhere the crossingis relativelystraightforward, thereis alreadysufficientclearance, andnot beensubjectto more detailedstudy.In somecases,wherevery light traffic usageis anticipated,traditionallift bridgeswill be appropriate;and similarly,traditionalarch bridgescouldbe usedwherethetraffictypepermits(neitherofthesetypesis likely to on publicroads).Costsfor these'standard' tlpes ofcrossing(excluding be acceptable areestimated typicallyin therange160,000-f.100,000. services diversions) For crossingsunderthe M4 andthe A419 at Swindon,andthe A34 at Abingdon,it is proposedto usethe techniqueof structurejacking (commonlyknownasthrustboring) which enablesthe crossingto be undertakenwithout disturbanceto the traffic. The sametechniquewould be employedfor the railway crossings- the GWR main line crossingof the North Wilts Branchin Swindon;at Acom Bridgeeastof Swindon (whichmay not be necessary if a proposed new link roadgoesahead,allowingthe canalto usethe original crossingcurrentlyusedlor the highway);and a little further eastat Ulfington (which alsomay not be neededif useof a nearbyfarm crossingcan be negotiated).In every casethere is adequateroom to allow this techniqueto be (estimated employed,and,whilstthe methodis somewhat specialised andexpensive costrangingfrom f 1.75Mfor railwaycrossings up to f2.25M for the M4), it is well tried andtested,andthereforethesecrossingsarenot considered likely to be critical in engineering termsto thefeasibilty ofrestoration. In additionto thesevehicularcrossings arefootbridges andbridgesaccommodating A varietyof formscanbe used(concrete, bridlewaysand cycleways. steel,timber), andunit costshavebeenestimated typicallyin therangef.25,000 to 150,000. on thewholelengthof therestoration Themostcriticalobstruction is identifiedasthe crossingunderthe car park of Sainsbury's storeat Bridgemead, Swindon,for the NorthWilts Canal.We haveinvestigated theuseof the existingculvertwhichcarries practicable the ElcombeBrook underthis site,and find that it appears to lower the invert to achievenavigabledepth (budget f350,000). However, becausethe Environment Agencyindicatethat it will be necessary to provide,as a minimum,a new dry weatherflow culvertfor the Brook,(whichshouldbe small enoughto be

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Restorationof the Wilts & BerksCanal: FeasibilityStudy.

feasibleusing microtunnelling techniques, budgetf600,000),the overallcost and difficulty exceedsthat of what appearsto be a betteraltemative,namelya new canal method.Thiscouldbe installedtkough thecar culvertinstalledusinga cut-and-cover park in shortsections(say 50m possessions), and would requirethe agreement of Sainsbury's,but would be less costly overall (budget f.450,000)and, more importantly,would ensurethatfull restorationstandardcouldbe achieved. for therestored Canal,against54 for the original.The A totalof 82 locksis projected additionallocks are requiredprimarily to crossthe highersummit level on the new at Melksham, CrickladeandAbingdon. routesouthof Swindon,andfor thediversions to the samelengthand breadthas for Lockswould be constructed(or reconstructed) the originalCanal.Eachlock or lock flight is likely to requirebackpumpingfor water that conservation.A total of 39 pumping stationsis projected.It is recommended system be remotely monitored thesestationsbe automaticallycontrolledandthat the via a telemetrysystemat a centrallocation. In all casesas designsdevelop,eachproposedcanal pound (betweenexisting or proposedlocks)mustbe examinedin the light of moredetailedtopographicsurveysto determinethe optimum water level which achievesthe best balance between earthworksandbridgingcosts(i.e betweenroadraisingandcanallowering).

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Restorationof the Wilts & Berks Canal: Feasibility Study

4. WATERREsouRcEs

4.1 Introduction Along much of its length,the main line of the Wilts & BerksCanalruns across Kimmeridge,Gaultand Oxfordclay depositswithin 8 km of the baseof the chalk escarpmentof the Lamboum,and MarlboroughDowns.A large numberof springs occuralongthe footslopeofthe Downs,wherewaterfiom the extensivechalk aquifer is forcedto the surfaceby the underlyingclay deposits.Thesespringsfeed a large numberof brooksand streams,someof which are seasonalin the headwaterareas, runningroughlysouth-northandwhich eventuallydischargeinto eitherthe Thamesor Avon river systems.Owing to the relatively short distancebetweenthe chalk andthe Canal,mostof the surfacewatercatchmentareasof watercourses escarpment which traversethe routeof theCanalarerelativelysmall. 4.2 Backgroundand PreviousStudies 4.2.1 OriginalWaterSupply A rich sourceof historicalinformationon the Canalis providedin the accountof ofthe mainlinein 1810,thespring-fed surface Dalby( 1986).Initiallyaftercompletion water With supplied the Canal's requirements. a few water courses directly exceptions,the CanalAct empoweredthe Companyto take water from all rivers, within 2000 yards of the Canal(Dalby, springs,brooks,streamsand watercourses p 107). Abstractionswere not permittedfrom the Avon or its tributariesbetween Trowbridgeand StanleyAbbey, or from TockenhamWater,Trow Lane Water or Dalbyreportsthatat this WoottonBassettBrookbetweenl0 Juneand 10September. with Wanborough feeder supplied the Canal 3.7 Ml d-'; this watercourseis time the infened to be a tributaryof the River Cole (seeDrawing No. DBKEP/004102). The were also required to construct and maintain drains to convey water from Company adjoininglands;this is inferredto meantakingwaterunderthe Canalbut it is unclear (Dalby,p107). To provideadditionalin-linewaterstorage,the summitsectionof the Canalnear wideranddeeperthanthe restof the Canal(Dalby,pl0).2 Swindonwasconstructed wereapparentlya major constrainton the operationof the water shortages However, shortages would havebeenmost seriousduring the summer Canal.Presumably, streamflowsandthelackof storage.In 1816,shortages monthsowingto reduced led to the diggingof a well to tap the Corallianaquiferto the northof Swindon,where waterwas struckat 80m depth.However,the supplieswerelimited and the well was quicklyabandoned. To provide off-line storage of surface runoff during the winter, the Coate Water reservoirwith a capacityof 555 Ml was completedin 1822 (Dalby, p65). However, -

but recentrestorationworks havecastdoubton Dalbv's assenions.

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Restoration of the Wilts & Berks Canal: Feasibility Study.

watersupplieswere still apparently inadequate.Historically,this was a penod of peakusageof the Canal.For example,in 1838the Wilts & BerksCanalCo. paid compensation to divert water from Dray Mill into the Canalto augmentsupplies (Dalby,p73).To furtherincrease storage, theTockenham reservoirwascompleted in 1840(Dalby,p74)with a capacity of 273Ml (Allen& Harris/Royal Insurance, 1994). During the latter part of the lgth Century,traffrc along the Canal declinedand evidencesuggeststhat the water supply problemsalso lessened.In 1843, the Wilts & BerksCanalCo. enteredinto an agreement to sell waterto the GreatWestern Railway (Dalby,p86). In 1871,in a disputeover the abstraction of water from 'except WroughtonBrook, a courtremarkedthat duringthe exceptionallydry yearof 1870,therehad not been,nor was therenow any deficiencyof water' for the Canal (Dalby,p87). to efforts to minimiselossesof water fiom the Dalby also makesuseful references Canal.Firstly, the channelwas requiredto be puddledduring constructionto reduce wouldbe a major thatseepage seepage losses(p107).Therewasclearlyrecognition puddling water loss and that this could be minimised by the excavated causeof channel,presumablywith in-situclay. Second,a referenceis madeto pumpingto the summitwhich ceasedin 1898(p92).During the periodof historicaloperationit thereforeappearsthatpumpingwasrequiredto minimisethe effectof lockagelosses, althoughthe rateof anypumpingis not known. In summary,waterresourcesfor the histoncaloperationof the Canalwere supplied fiom: o a largenumberofsurfacewatercourseswhichwerelargelyspring-fed; . storagein CoateWater,TockenhamReservoirand to a lesserextent,the summit reachofthe Canal;and . presumed,but unconfirmeddrainageof adjoiningagriculturalland. to minimiselossesin thehistoricaloperation of theCanalincluded: Measures . construction acrossclay soilsalongmuchof the Canallength,and puddlingthe to minimise sidesandbedof thechannel seepage' o pumpingwaterthataccumulated in lowerpoundsbackto thesummit. studies 4.2.2 Previous Previous studies which have addressed aspects of the water supply needs for restoratlonwere: . A report by Griffiths (1986) which consideredsome aspectsof the amount and Basedon local experience,and convertedto an likely cost of water requirements. '

lf lining was restrictedto puddling in situ clay, the full extent of lining will not have covered the whole lensth of the canal.

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equivalent depth,of water using an assumedaveragebed width of 10m, a seepage rateof 4.7mm d-' was suggestedfor water balancestudies. r An outline feasibility study by Allen & Hanis/Royal Insurance( 1994) which includedan approximatewater balancefor the westemsectionof the mainlineand the North Wilts Canal. Assuminga seepagerate of 20mm d-' and an evaporation rate of 4.5mm d-', a summerwater requirementof 1.9M1d-l was estimatedb"fo." allowing for any lossdue to lockage.

4.3 Methodology A monthly water balance model of the original Canal system was developed for the four main reaches (Eastemmainline,Summit, Westemmainline,North Wilts), and including branches at Chippenham, Calne, Longcot and Wantage. This model was usedto: r Analysethe historicalwatersupplymanagement of the Canal; o Make an assessmentof the water requirementsfor a restoredCanal; r Analyse various water supply, construction and operation scenarioslor a restored Canal. The model was calculatedon a monthly basis for improved representationof storage within the Canal water supply system, and the likely importance of seasonal fluctuationsin resourceavailabilityand operationofthe Canal. 4.3.1 Data collectionand analysis All data were derived fiom published or official sources.Meteorological data were provided by the Environment Agency for the Upper Thamesregion. Evaporation data for a grass surface were corrected to open water evaporation using coefficients determinedby Penman (in Shaw, 1994). Rainfall and open water evaporationduring an average l:10 year retum period drought were determined for subsequent computationof the waterbalance.Droughtwas definedfor this purposeas the deficit between rainfall and open water evaporation.On averagethe annual defrcit was 82 mm, and for a l:10 year retum period droughtthe deficit was 262mm. The monthly input data for a 1:10 drought year for the water balancemodel were computedby reducing the monthly mean rainfall, and increasing the monthly mean open water evaporationin proportion to the monthly mean totals to obtain an overall deficit reflectinga I :10yeardrought. No quantitativesite investigations(such as flow measurement)were carried out during this Study. In a phasedprogrammeof restoration,such monitoringwould be desirableto test the resultsof the water balancemodel and options for new water resources.

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Restoration of theWilts& BerksCanal: FeasibilityStudy.

4.3.2 Waterrequirements 4.3.2.1Seepage andLeakage Seepagecan be definedas the diffuse outflow from the Canalbed which may be reducedby lining,whereasleakage is usuallya localisedlossof waterwhichmay be reducedor eliminatedby repair. In this study, seepageand leakagelosseswere tosether. considered Initial considerationof the water balancefor a restoredCanalshowedseepageand leakageto be the mostimportantparameter, not least,owing to the long lengthof the proposedrestoration.The outcrop geology along the route of the Canal was determinedfrom the publishedgeologicalmap, at 1:100000scalea(Instituteof WaterAuthority,1978)(Table4.1). Geological Sciences/Thames Table4, Reach

Westem mainline (inc. branches)

Summit EastemMainline (inc.branches) NorthWilts branch W & B total % total length by cutcrop geology

Alo

o

CanalRoute Total Lengthby outcropgeology(km) length Allu- Fluvial Gault Lower Kimme Coral- Oxford (km) vium sands& Clay Green- -ridge lian Clay gravels sand Clay A.' '1 0.6 1.4 0.0 0.0 2.6 36.9 I J_)

0.0

0.0

0.0

I J_)

ll.3

0.0 8.4

37.2

J.O

14.5

t.2

0.7

0.7

0.0

107.9 4 . 9 100.0 4.6

t -).+

8.4 7.8

12.4

I 1.3

0.0 1.4

0.0 0.0

0.0

2.9

2.2

8.0

1.2

30.3 28.1

4.8 4.5

44.9 41.6

1.1

Over most of its length the original Canal was constructedon clays of the Gault, Kimmeridge and Oxford formations.The total length on theseclay depositsamounted to 83.8km(77.4%).Thesematerialshavethe lowestpermeabilityratesand,depending on local constructionmethods,a relativelylow seepagerate would be expectedfrom the Canal in theseareas.Other geologicalunits along the original route are alluvium, fluvial sands and gravels, Lower Greensandand Corallian deposits.The alluvial deposits, fluvial sands and gravels tend to have higher permeabilities, and greater seepagerates from the Canal would be expectedunless it was lined with clay. According to the publishedmaps, a total length of 18.3km was constructedacross these materials, primarily at the eastem end towards Abingdon. However, investigationsby ThamesWaterin relationto the siting ofa proposedreservoirin this area have shown that clays rather than fluvial sandsand gravels dominate the surface geology. Short lengthsofCanal were constructedin areaswherethe mappedoutcrop geology is Lower Greensandsands(1.1km) and Corallianlimestonesand sands(4.5 '

This map is basedon geologrcalmapspublishedat 1:50,000by Instituteof GeologicalSciences(now British GeologrcalSurvey). Soilshavedevelopedon theseformations,comprisingthe solid and drift geology,often reflectingcloselythe geology.

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Restoration of theWilts & BerksCanal: FeasibilityStudy Sand and Gravel Aqufer - The main areas where river sands and gravels occur are as

follows: L The main outcropis found betweenGrove and Abingdon. However,previous

studiesby ThamesWaterrevealedthe formationto be clay-rich,thereforeits low permeability, andpooraquiferproperties, wouldlimit theresources available. 2. The sandand gravelaquiferis presentin the extremeeastof the River Ock subcatchmentat the greatestdistancefiom the Canal'shigh point aroundSwindon. A significantpumping schemewould be requiredto pump the groundwaterto the mostefficientlengthof the Canal. However,infenedgroundwaterlevelsareoften abovethe probableCanalwaterlevelindicatinga groundwater influx. 3 . In the extremewestemreachof the Canal,sandsand gravelsassociated with the River Avon out crop within half a kilometreof the Canal. Thereare a numberof small licensedabstractions for agricultural use(0.02M1d-') aroundLacock(e.g. LacockAbbey;licenceno. 175301G139 at ST914675).It is not anticipated that individual boreholescould sustaina large abstractionbut a carefully designed yield. However,the EA havecommentedthat schemecouldproducea reasonable theywouldnot supportdevelopment of thegroundwater (AMgwle)dueto resource with the River Avon althoughthe main concemsare low flow concemsassociated to be signihcantly upstream believed ofthe suggested abstraction schemes. Chalk-UpperGreensandAquifer - The CretaceousChalk is the most important aquiferin England. The flow is fracturecontrolledwith a low matrix porosity. The upper60m of the Chalk is the most productiveas this is the principalfissuredzone with occasionalfissuredhorizonsat depth. The featheredgeof the westemextremityof the Chalk outcropformsthe Berkshire Downs escarpment,running east-westfiom the east before tuming at Compton Bassettto a morenorth-southlineation. The Canalroutemirrorsthis arc to the north andwest. Althoughthe main flow directionswithin the Chalkaquiferareto the south east, the groundwaterhighs found in the highest Downs do generatea small proportionof flow to the north andnorth-westdischargingin a prominentspringline at thefootof theDowns. Borehole yields are greaterfor the Middle and Upper Chalk horizons although abstractions of up to 4Ml/d arerecordedfrom the Lower Chalk. The Chalk is a very sensitiveaquiferandfurtherdevelopment of theresourcewould needa strict licensing procedure pumping involvingdetailedtest of an exploratory boreholeand,if granted, the licencewould almostcertainlycarry a winter only abstractioncondition. The SouthWestRegionof the EA haveresponded that,dueto theChalk'scontribution to a number of springsand the baseflowof a few brooks, they would not support of Chalkgroundwater. development Althoughno officialresponse hasbeenreceived from the ThamesRegion,the samehydrogeological conditionsexistandthereforeit is would be possiblefiom the Chalk unlessa detailed expectedthat no abstraction impactassessment wasconducted includingtestpumping.

'Coding

systemrefersin tum to. the main catchment(A:Avon; T=Thames);the sub-catchment (e.g. M=Marden: seeDwg. No. DBKEPr004i0l);"gw" refersto groundwatersource,and the proposed schemenumber.SeeAooendixF.

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Restorationof the Wilts & BerksCanal: Feasibility Study.

aquiferis separated from the Chalk aquiferin the eastby the The Upper Greensand relativelyimpermeableChalk Marl, howeverfor the majority of the study areathe Upper Greensandis believed to be in hydraulic continuity with the Chalk and potentialandlimitations. thereforeholdsa similardevelopment Lower GreensandAquifer - This is an impersistantminor aquifer of high permeability.It waserodedto a varyingextentprior to the depositionof the overlying Gault Clay, causinguncertaintyin estimatingaquiferthickness. Where significant thicknessesof sand exist boreholesmay yield small quantitiesof iron-rich groundwaterwhich wouldprobablyrequiretreatmentprior to usage. outcropsare locatednorth of Uffington,to the west of The largestLower Greensand Compton Basset and between Rowde and Bowden Hill (Drawing No. DBKEP/004/01). North of Uffington, the significant outcrop appearsto offer developmentpotential,but given the numberof boreholescurrentlybelievedto be abstractingand its limited thicknessit is unlikely that there would be significant potentialfor anymajorsupply Within the South West Region of the EA two outcropsof Lower Greensandare observed(Drawing No. DBKEP/004/01). The EA havestatedthat they would not owing to in the Mardensub-catchment of the Lower Greensand supportdevelopment low flow concemsin the River Avon. In additionthereare small existinglicensed (e.g.ComptonBasset;licenceno. at SU035729for 0.011MId-'1in the abstractions vicinity of the proposedabstractionarea (AMgw2). In the Lower Avon subcatchment,the EA comment that there may be potential for winter/high flow thereforemore detailedstudy is neededto abstractionfrom the Lower Greensand, potential. development assess the resource Corallian Aquifer - The Corallianaquifervariesboth laterally and vertically, with clays acting as aquitardsand occasionallyconfining the underlyinglimestoneand aquifers. The yieldsproducedby boreholestappingthe aquiferare limited sandstone within the usuallybelow 1MVd. The lateralvariationsobserved to smallquantities, previous by the greater in borehole location exemplified Corallian a risk aquifercreate boreholedrilled as a top-upsupplyfor the Canalwhich failed to supplythe required quantities. Proposalsmadehere includea boredwell in the River Cole catchment yield assessment by BGS (TCgw3)yieldingabout0.25M1d-r,but the groundwater (less than 0.5 I s-'). Information made yield of the order of 0.04M1 d-' a suggests yieldsrangingfrom theorderof 0.05to 0.5 indicates availablefrom the EA database uncertainty in makingyieldassessments. which demonstrates the significant Ml d-r The Canal crossesportionsof the aquifer which are confinedand are potentially artesian. Artesian groundwateris believedto show increasedsalinity and total Today,this aquiferis considered solidswhichcouldprohibitdevelopment. dissolved to yield only smallsuppliesin mostareas,althoughbetteryieldsarepossibleon the eastemmarginsofthe aquifernearAbingdon(IGS,1978).

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Restorationof the Wilts & Berks Canal: Feasibility Study

Within the EA South West regionthere are two main outcrops (Drawing Nos. DBKEP/004/01andDBKEP/004/02): Tockenlam- no otherboreholesarecurrentlyabstracting fiom this outcropandthe EA haveno datato be ableto expressa detailedview on the resourcepotential. It would be prudentto conductfurther desk and walk-over studiesto assessthe potential. development . Calne- this part of the aquiferis tappedby a significantnumberof licensed boreholesandthe EA would not supportfurtherdevelopment of the aquiferin this area. Within the Thamesregionthe Coralliancropsout extensively.Many boreholesare currentlylicensedto abstractfrom the aquiferalthough,without detailedassessment, it is unclearhow manyareabstracting at present. - the Corallianis potentiallyin hydrauliccontinuitywith o River Ock sub-catchment the Lower Greensand as the Kimmeridge Clay is of limited thickness. The potential for developing small supplies here is good although yields are not anticipated to be high and the deteriorating water quality down gradient could preventa significantsupply.

. River Cole sub-catchment- here there are many disusedCorallian boreholes locatedon the exposedaquifer. The reasonsfor the currentlack of abstractionis unclear,and theremay be merit in approaching the licensees'ofdisusedboreholes possible regarding transferor renewalof licences. o River Ray sub-catchment- this hasa smallnumberof boreholesabstractingftom the Corallian and potentiallor further developmentof small suppliesis good, althoughwater quality may prohibit significantdevelopmentas a supply for the Canal. Great Oolite Aquifer - Beneath the Canal route the limestone aquiler of the Great Oolite is confined by the Oxford Clay. Rechargeoccurs in the Cotswolds where limestonehills allow precipitationto permeateinto the aquifer. The confinedaquifer has dominantly fracture characteristicswith bedding planes and solution fissures creatinga high permeability. Some boreholesyield high quantitiesof good quality groundwatersuchas the public supplyboreholesat Latton and Ashton Keynes,which yield 25 and 10Ml/d respectively. Several boreholes constructed into the deeply confined areas of the aquifer have producedpoor quality water that would prove expensiveto treat prior to supplying the Canal. Generally with increasing distance fiom the outcrop area the water quality deteriorates,however drastic deteriorationgenerallyoccurs approximately6-1Okm from the outcrop. The two large public water supplies,mentioned above, both abstractgood quality water at greaterdistancesfrom the outcrop. Howeverthis could be relatedto lhe very high abstractionratesthat encouragerapid groundwaterflow from the recharqearea.

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Restoration of the Wilts & BerksCanal: FeasibilityStudy.

The areaofgreatestpotentialfor developingthe GreatOoliteaquiferis within the EA SouthWest Regionas boreholescould be positionedcloserto outcropand could producefresherwater(i.e. boreholelocationsAUgw3, AUgw5, ALgw3, AMgw4; shownon Drawings DBKEP/004/01and DBKEP/004102).The EA haveresponded by statingthat thereis developmentpotentialwithin the GreatOolite althoughthere areconcernsover: . low flows in the Avon in the MardenandLower Avon sub-catchments, causingthe EA to commentthatonly winterabstractions (Table may be feasible 4.9),despite theGreatOolitebeingconfinedby theOxfordClay; . impacton the two majorpublicwatersupplyboreholesnotedabove. It is unclearwhetheror not the proposedlocationfor a boreholeinto the GreatOolite in the far west of the EA ThamesRegion(i.e. TRgw4 nearPurton)would yield good quality or whetherthe distancefrom outcropwould causea rapiddeteriorationin the water quality. A responseis awaitedat presentftom the ThamesRegion water resources whichmay give a betterunderstanding ofthe potential. department, 4.7.6 Reactivation & Purchase of Abstraction Licences Thereis a growing awareness that former groundwaterabstractionlicencesmay be suitable for reactivation. Many licenceshave been revoked,typically when the resourcesbecameredundantafter the industriesthey suppliedclosed down. In addition,theremay be caseswherelicenceholdersretaintheir abstractionlicence,but do not activelyabstractwater,asit is potentiallya very beneficialitem whentrying to sell land or industry. There has beenmuch attentionover recentmonthsto such inactiveandrevokedlicenceswhichcouldbe reactivated. It could prove beneficialto searchout both revokedand lapsedlicenceswithin close proximityofthe Canalrouteto assess thepotentialfor additionalresources. 4.7.7 UrbanRunoff Giventhe largeurbanareacloseto the summitsectionofthe Canal,thereis potential to makeuseof urbanrunoff particularlyin the Swindonareaasa watersupply. There is similarpotentialfor utilisingtreatedrunoff from RAf Lynhamandroadswithin the is considered here, Canalcorridor. The principleof usingthesepotentialresources but the detailedestimates of volumesavailablefiom suchsourcescannotbe made untilthelaterstages oftheproject. A possibleprocesssequencefor treatmentof urban runoff, including runoff lrom with theEA, is asfollows: roadsandotherimpermeable areas, asdiscussed l. urbanrunoffpassed throughsilt trapandoil interceptor pond,with overspillto watercourse 2. stormbalancing wetlands to specially constructed 3. discharge 4. feedto Canalfrom storage lagoon,probablyby pumping 5. retumofexcesswater(i.e.overspill)to watercourse.

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Restoration orthe*\:.TiT;tlllt; ThamesWater have responsibilityfor surfacewater drainagein the Swindonarea. Currently,all stormrunoff is routedinto surfacewater courses.ThamesWater look lor the most flexibility whenplanningdischargeof stormwaterandit is reportedthat discharge via non{raditional routes,suchasa Canal,cancauselegalcomplications in futureoperation,for exampleover liabilitiesregardingpoor water quality. Although possible,the contractualarrangements would thereforeneedto be carefullydrawnup. The EA would also be requiredto consentto storm water dischargeto the Canal. Benefitsanddisbenefits ofre-usingurbanrunoffaresummarised in Table4.10;these wereidentifiedwith theassistance of theEA. Table4.10 Benefitsand Disbenefits of Re-usingUrban Runoff Benefits 1. Treatment ofpreviouslyuntreated runolf 2. Habitat& amenitvimorovements

Disbenefits 1. Net lossof waterto watercourse, particularconcemsoverdrversron duringlow river flow periods. 2. Construction, operation& maintenance costs.

3. Improvedflow attenuation & storm balancing

There may be suitable opportunities for storm drainage from new building developmentsto supply the Canal. The EA have suggestedMelksham, north and north-west of Calne and south of Wootton Bassett as locations of potential development. With a phasedprograrnmeof restoration,it would be important that the Canal could provide a reliabledischargeroute for such storm water. It is anticipated that such schemes would also make a small contribution to the water balance. Importantly, the supply is unreliable but runoff during summer storms would be p articul arly benefrcial. 4.7.8 SewageEffluent Sewagetreatmentworks (STW) could potentially provide a limited water resourcefor the restored Canal. The advantageof using sewage effluent is the potential for a continuoussupplyduring the year,with summersuppliesbeing of considerable value. Sewageeffluentwould requiretreatmentand storagewhich could be providedby the following sequence: l. 2. 3. 4.

dischargeto speciallyconstructed wetlands storageand flow, through a seriesof maturation/storagelagoons feedto Canal retum overspillto watercourse.

There are about 14 sewageworks servingtowns and villagesalong,and adjacentto, the Wilts & Berks Canal(Table 4.1I later). As might be expectedthey rangein size, and thus dischargerates,from the largestrn west Swindon to small works serving small towns suchas LetcombeRegis. Basedon a productionrateof200 l/person/day, a sewagetreatmentworks serving a town of 55.000 people would need a base ', treatmentcapacityof I lMl d which is the calculatedwater deficit for the Wilts &

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Restoration of theWilts& BerksCanal: FeasibilityStudy. Berks Canal assuming a seepagerate of lOmm d-'. The total population served by the

treatment worksincludedin Table4.1I is at leastof theorderof500,000andpossibly more, which potentiallyequatesto l00Ml d-r. Those sewagetreatmentworks consideredheretogetherwith the issuesassociated with re-useof treatedeffluentare ''. summarised in Table4.11 The benefitsanddisbenefitsof re-usingelfluentfiom STWsaresummarised in Table 4.12;thesewereidentifiedwith theassistance of theEA. Themainconcemis the loss of contributionto streamsandriverswhichsufferfiom low flow problems.This latter issueleadthe EA to indicatethat they would not look favourablyon the use of discharges from the westSwindontreatmentworksto supplythe North Wilts Canalas judged the EA that flows in the River Ray would suffer. Despitethis potential difficulty, there is a generalpotentialfor divertingtreatedeffluent dischargesfrom watercoursesduringwinter/highflow periods,followedby treatmentand storagefor use in periodsof lower flow. In addition,increasedvolumesof treatedsewage effluent are likely to derive from new building developments, along similar lines notedfor increased opportunitiesfor usingstormwaterdrainage(Clause4.7.7) From this preliminaryassessment, the potentialfor year-rounduse of treatedsewage effluent appearslimited, but the following treatmentworks ranked in order of potentialneedto be considered decreasing further: 1. Wroughton; 2. Swindon(south); 3. SouthMarston; 4. Steventon; 5. Abingdon; 6. Childrey. With regardto using treatedsewageeffluentduring winter/highflow periods,all of the treatmentworks listed havepotentialto providewater resourcesfor storageand subsequent use. If suchproposalswereimplemented they would replace,at least partially,winter/highflow abstractions takendirectly from the receivingwatercourse. In this case,it is likely that costswould be higherfor re-useof sewageeffluentdueto treatmentcosts. Thusthis sourceof wateris of reducedintereston purelv economic srounds.

'"

The locationsofthe sewagetreatmentworks consideredwere takenfrom l:25,000 OS maps. The current operation, nature and volumes oftreated effluent dischargeofthese works was not confirmed.

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Table 4.11 SewageWorks Consideredfor Supplying Treated Effluent

Melksham

Watercourse Receiving Discharge RiverAvon

Chippenham

River Avon

Calne

River Marden

Location

Wootton BrinkworthBrook Bassett Swindon(east) RiverRay Swindon (south)

UpperRiver Ray

Wroughton

RiverRay(?)

SouthMarston Tributaryof River (x2) Cole Sparsholt Unnamedchalk stream

Issues

Contributionpotentiallyincludedin resources of LowerAvon sub-catchment, & locatedat lower(westem) endof Canal Contributionpotentiallyincludedin resources of LowerAvon sub-catchment Dischargesupportingriver duringlow flow stages Contributioneffectivelyincludedin resources of sub-catchment AUI Dischargesupportingriver duringlow flow stases Dischargepossiblysupportingriver during low flow stages;somepotentiallor Canaluse Dischargepossiblysupportingriver flows; somepotentiallor Canaluse Small treatmentworks: someootential for Canaluse

Contributioneffectivelyincludedin resources of sub-catchment T06 Dischargepossiblysupportingriver flows; someDotentialfor Canaluse

Childrey

ChildreyBrook

Letcombe Regis Steventon

LetcombeBrook

Dischargesupportingriver during low flow stases

Cow Common Brook River Thames

Smalltreatmentworks;somepotentialfor Canaluse

Abingdon

Locatedat lower (eastem)end of Canal; some potential for Canal use

Table4.12 Benefitsand Disbenefits ofRe-usins Effluent Benefits 1. Higherdilutionfor remaining effluent;supportedby overflowof effluenttreatedin wetlands. 2. Habitat& amenitvimorovements

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Disbenefits l. Net lossof waterto watercourse; particularconcemsover diversionduring low river flow periods

2. Construction, operation & maintenance costs

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4.7 .9 Land Drainage

Land drainson agriculturalland could potentiallybe modifiedto supply the Canal. Such works would not be subjectto EnvironmentAgency consent.Furthermore, restorationof the Canal would probablyrequireameliorativemeasuresto improve drainageof landsdetrimentallyaffectedby seepage fiom the Canal.The contribution to thewatersupplywouldbe mainlyduringthewinter,whenwaterwouldbe of lesser valueto the Canal. However,sumpsfor watercollection,and pumpsfor feeding waterto the Canalwould probablybe requiredunlessthe Canalwasin a cutting. 4.8 Water Quality Issues Informationsummarisedin Table 4,9 beforeindicatesthat waterquality is likely to constraindevelopmentof groundwaterresourceslor supplyingthe Wilts & Berks Canal. Theseconstraintsinclude naturalvariationsin groundwaterchemistryas lollows: o Lower Greensand- potentiallyiron-rich groundwaterleadingto precipitationof on abstraction anddischarge; iron oxides./hydroxides o Corallian- increase in salinity(totaldissolved solids;TDS)in theconfinedaquifer areast distantfromrecharge . GreatOolite - increasein TDS in the confinedaquiferdistantfrom rechargeareas; (AshtonKeynesand Latton, thereis evidencefrom largepublic waterabstractions north west of Swindon)that the act of abstractingcan improvewater quality by from therechargeareas. drawingin groundwater In addition to these natural variations, unconfinedaquifers are susceptibleto contamination by variouspoint anddiffusesources;shallowpartsofconfined aquifers are also potentiallysusceptible. The typesof contamination include,but are not restrictedto, (a) nitrateandpesticides, mainly from agriculturaluse,and(b) a rangeof organic compounds,particularly petroleum hydrocarbonsand solvents, due to unplannedreleases from manufacturing andcommercialuses. Due to unknowndistributions of artificiallyintroducedcontaminants, the potential impactwasnot includedin guidingtheconsideration ofsuitablegroundwater sources. However, natural water quality variations were used to dismiss the following groundwater sources: r LowerGreensand sourcenorthof Wroughton(TRgw2),potentiallywith high iron andTDS r GreatOolitesources (AUgw4) nearChristianMelford(AMgw4)andBradenstoke with total dissolvedsolidsconcentrations of the orderof 10,000mg/l (Bromley, 1975).

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Restontion ofthew\gffinHli No dataarecurrentlyavailableon the historicalwaterqualityof the Wilts & Berks Canal,and any changes in qualitygradients alongits length. It is probablethat the historicalwater quality was dominatedby contributionsfrom chalk-fedstreamsand reservoirs.Nevertheless, restoration of the Canalis not constrained to matchingthe historicalwaterquality,but the introduction of waterqualitygradientscouldbe of significantbenefitin ecological terms(seeChapter5). Usingthewaterbalancefor a restoredCanal(Table 4.5 ), and proposedgroundwatersourcesaccountingfor about 50%of thewaterdeficit. Table4. 13 showsanestimated average waterqualitycomposition for theCanal.The sourceof wateris asfollows: 1. Rainwater 2. RiverSand& GravelAquifer 3. ChalkAquifer& Streams 4. Lower Greensand Aquifer 5. CorallianAquiler 6. GreatOoliteAquifer

14.t% 23% 51.2% 10.3% 3.9% 18.2%

Theseresultsgiveanindicationofthe waterquality,but owingto limiteddatait is not possibleto confirmwhetherthe suppliedwaterwouldresultin the Canalmeetingthe design standardsproposedin Table 3. I before.As the groundwatersourcesare distributedalongthe lengthof the Canalit is probablethatwaterqualitygradientswill result, particularlyif backpumpinglimits overall circulationwithin the Canal. An approximateestimateof waterqualityin theCanalin theEastandWestlengthsis also givenin Table4. 13to illustrate potentialwaterqualitygradients.

Table4. 13AverageWater Quality for RestoredCanal* Quality Darameter PH

TDS Na+K Ca Mg

EstimatedConcentration(mg/l) Whole Canal E )

530 88 65 6.8 265

)

394 34 66 6.7 229

HCO. /J CI ,/.o 1n SO, 25 NO. 7.5 7.4 * - seeAppendixH for waterqualitydatausedin calculations ++- E andW referto theCanaleastandwestof Swindon

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w )

617 tzJ

65 6.9 289 103 z.)

7.6

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Restoration of theWilts& Berks Canal: Feasibiliry Snrdy. 4.9 Strategyto MeetCanalWater Demand With a targetseepage/leakage of the orderof l0mm d-r, the annualwaterresource requirementof the Wilts & BerksCanalis estimatedas 4200M1,assumingno net bypassor lockagelosses. This is not a fixed daily amountthroughoutthe year,but it averages about12Ml (Table 4.5 before). Fromwaterresourceestimatesin this Study, this requirementcanbe met by a combinationof: o surfacewaterabstraction at high river flows,lollowedby storagein reservoirs; o groundwaterabstraction,either year round or only during winter months in catchmentssubjectto low flow problems;winter abstractedgroundwatermay requirestoragein surfacewaterreservoirs; . interceptingandtreatingurbanrunoff, which would be of particularbenefitduring periodsof low flow; o furthertreatmentof treatedsewageeffluentbeforestorageanduse,potentiallyonly duringperiodsofhigh riverflow. As thereis muchcurrentuncertaintyaboutthe volumes,reliability and availabilityof treatedurbanrunoff and sewageeffluent,the basicstrategyto meetthe Canal'swater resources.Table 4.14 demandrelies solely on surfacewater and groundwater suggeststhat surlacewater and groundwaterresourceswould be able to supply the estimated4200M1y'' requiredby the restoredCanal,evenif thoseGreatOolite and Lower Greensandsourceswith presumedpoor water quality are excluded fiom consideration. Available Table4.14 SurfaceWater and GroundwaterResources Source Surfacewater abstraction

abstraction Groundwater - winteronly (all sources) - winter only (excl.poorqualirywarcr) - yearround(all sources) - vearround(excl.poorqualitywater) TOTAL All sources Excludingsottrcesof poor quality

EstimatedResourceAvailable(Ml y-')

2030 860* 770* 1910 t 400 4800 4200

* - assumeswinter only usegroundwaterabstracted for 6 months Excluding those locations where groundwater quality may be poor, groundwater would need to be developedat a total of 14 locations,with a total of about 20 bored wells to producethe resourcesincluded in Table 4.14. This estimateis basedon currentinformation,and it is possiblethat the numberof locationsand wells might need to be increasedor decreasedto meet the water requirements.With regardto spatialdistributionof theseresources, the following pointsareof note:

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o 4.2M|d-r is availableto the eastof Swindon o 7.5M1d-r to the west of swindon

o about3.5M1d-r of this totalis availablein thevicinityof Swindonandthe North Wilts Canal,i.e.at thesummitof theCanal. Estimatedcosts for developingboth surfacewater and groundwaterresourcesare in Table 4.15;thesearepresented summarised for comparative purposes only. Most of the proposedgroundwatersourcesare locatedsome distancelrom the Canal, varying betweenabout 300m to 4.5km. As a result,the costs of developing groundwaterinclude for construction,operationand maintenanceof a pipeline to deliverabstractedgroundwaterto the Canal,but it is assumedthat the waterwill be deliveredunder gravity, and the majority of the water fiom winter groundwater would be storedin surfacewaterreservoirs.Table 4.15 indicatesan abstractions approximately50:50 percentagespilt betweensurfacewater and groundwater,and showsthat comparativecosts(basedon constructionalone)for supplyinglMl d'r are about: r surfacewater- !2.100.000 r groundwater=

f.404,000.

Assumingthat additionalsurfacestorageis requiredfor the whole of the 860M1 abstractedfrom winter-only groundwatersources,the total constructioncost for developinggroundwatersourceswould increasesignificantlyto aboutf7 million, thus increasing thecostof supplying1Ml d-' fromgroundwater to about!1.1 million. Table4.15 Costsof DevelopingResources SurfaceWater Resources No. of Average Annual (Ml d-') Yield reservoirs

10 5.6 GroundwaterResources No. of wells

14-20

Construction Annual Operation& Costs(9) Maintenance Costs(t)* R? l?5 I 1,730.000

Construction Annual Operation& Costs(f) Maintenance Costs(f,)* 6.1 2,463,000 32,000 Totals 14.193.000 I14,125

AverageAnnual Yield (Ml d-')

t : O&M costsincludeannualabstraction charses Although groundwaterresourcesappearto be the most favourabletarget on economic grounds, there remains uncertainty over the resources available from both groundwater and surface water sources, thus further investigations are required. Furtherinvestigationof surfacewater resourcesrequiresadditionaldesk study, field data collection and perhapsmathematicalmodelling,whereasto reduceuncertainty associatedwith groundwaterresourcesdesk study followed by drilling and testingof exploratory wells is required. Consequently,the cost of further groundwater investigationsis much more expensive(seeChapter9), and the choice of pursuing

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surface water or groundwater resourcesmight be dependenton the capital available for the nexl stageof the study. Where the Canal crossesmore permeableground, leakage is likely to be increased. Two pa(icular casesare consideredbelow. Case I - North of Uffington, where the Canal crossesthe Lower Greensand,a loss of 0.16M1d-r over a l.2km length has been estimated. The economicsof lining this stretchare as follows: .

liningcouldreducethis lossto about0.032M1d'l

o cost of lining is aboutf468,000 o as the water deficit is reduced,the proposedreservoir(T06) south of Uffington couldbe reducedslightlyin size r cost savingfor smallerreservoiris negligible. As the cost saving for a smaller reservoirdoesnot cover the costsof lining, the lining ofthis stretchof the Canaldoesnot appeareconomic.However,in practicethe lining of this stretch may be driven by environmental requirements, therefore lining is recommended. Case2 - Between Chippenhamand Melksham lossesfrom the Canal to the underlying river sandsand gravelswere calculatedas 1.9M1d-r over a 2km stretch. Groundwater and surfacewater abstractionsare proposedin this area,but the EA has concemsover Lower Avon as it may well play a role in long term solutionsfor addressinglow flow problems in the Upper Avon. By lining this stretchof the Canal, losseswould be reduced significantly and the proposed surface water abstraction from the Lower Avon sub-catchmentcould be reduced effectively to zero. The economics of lining this stretchare as follows: o liningcouldreducethis lossto about0.4Mld-r o cost of lining is about!780,000 . as the water deficit is reduced.the Lower Avon surfacewater abstractionscould perhapsbe omitted .

the cost of surfacewater abstractionfrom the Lower Avon and reservoirstorageis f2,230,000

. cost savingby lining is approximatelyf1,450,000.

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4.10 Conclusions Water balance modelling of the Wilts & Berks Canal has revealedthat seepage/leakage dominate water losses from the Canal at all but the lowest seepage/leakage ratesconsidered.However,asthe geologyunderlyingthemajorityof the Wilts & Berks Canal route is dominatedby clay, it is estimatedthat seepage/leakage losseswill be closeto the lower endofthe rangeinfened lor British Canals(10-60mmd-'),andlowerthantheBritishWaterway targetof 25mmd-r. A targetseepage/leakage of theorderof lOmmd-r wasset. This targetis supported by: o estimation of the historical water balance for the Canal, which showed that water demands.and infened supplies approacha balance with a seepageileakage rate of lumm o : .

calculations using permeability values for in situ clays also indicating seepage/leakage rates< | Ommd-'.

Assuminga seepage/leakage of lOmm d'r, water balancemodellinghas estimatedthe annual water resourcerequirement to be about 4200M1,in addition to direct rainfall on the Canal. This supply has been calculatedto maintaina minimum Canal water depth of about 1.4m, assumingthat, (a) backpumpingminimiseslockagelosses,and (b) ultimate lossesof by-pass flows to wasteweirs and downstreamends of the Canal are minimised. To ensurethat the use of the additional water resourcessupplied to the Canal is optimised, the following channel lining requirements have been recommended: o puddling of in situ clay where localised liactures and fissures occur and,/or preparingthe channelfloor by rolling or producinga cleanlycut surface; o lining of reaches which cross permeable formations where losses are inferred, using puddledclay, bentonitemattingor concrete;currentestimatessuggesta total lengthofjust over 3 km at a costofabout f I -1.5 million. An evaluationof water resourcesalong the full lengthof the Canal has identifiedthe following resourcesas havingthe potentialto supplyabout4800M1of water annually, and thus satisfythe calculateddeficit in supply: o surface water abstraction at high river flows, generally during winter months, followed by storagein about l0 reservoirs; r groundwater abstraction from the Great Oolite, Corallian, Lower Greensand, Chalk, River Sands& Gravelsaquifers,usingabout20 boredwells at 14 locations; groundrvater winter abstracted may requirestoragein surfacewaterreservoirs. The surfacewater reservoirswould supply about 2030M1y'r, while the wells would supply about 860M1y-r from "winter only" abstractionsand 19lOMl y-' from "year round" abstractions. Horvever, there is significant uncertainty conceming the

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Restoralionof the Wilts & BerksCanal: FeasibilityStudy. availability ofthese water resources. One of the issuesconcems groundwater quality, e.g. the potential for high salinity in the Great Oolite and high iron and manganese

concentrations in the Lower Greensand aquifers,which could potentiallyreducethe totalresource identifiedto dateto about4200M1y'r. The basicwatersupplystrategynotedaboverelieson surfacewaterand groundwater may potentiallybe availablefrom, (a) intercepting resources, but additionalresources would be of andtreatingurbanrunoff, and(b) treatedsewageeffluent. Both resources particularbenefitduringpenodsof low flow, but the lattermay only be available duringperiodsofhigh nver flow becauseduring low flow stages,the treatedeffluent supportsnatural flows. Use of treatedsewageeffluent rather than surfacewater resourcesappearsenvironmentallyfriendly, but it is likely that the costswould be higher for re-useof sewageeffluentdue to the additionaltreatmentcosts,thus on groundsthisresource is ofreducedinterest. economic The cunent, approximatecost estimateof developingadditionalwater resourcesto meetthesupplydeficitareasfollows: o surface water: constructioncosts - t11.7 million; annual operation and maintenance costs- !82k; o groundwaterresources:constructioncosts - f2.5 million; annualoperationand costs- f32k. maintenance costestimate of just over f14 million and an annual This givesa total construction cost of fl14k. However,it is clearthat the costsfor operationand maintenance arecheaper;the comparativecosts(basedonly on developinggroundwaterresources lor supplyinglMl d-r are, (a) surfacewater f2.1 million, and (b) construction) groundwaterf0.4 million (this increases to f 1.1 million if more reservoirsare Despitethis, investigationsto requiredfor the winter-onlygroundwaterabstraction). reducethe remaininguncertaintyin both resourcesare much more expensivefor groundwater.Thus, if funding for the next stageof the study is limited, surface althoughastheprognosisis goodfor watersmight becomethetargetfor development, groundwater should not neglectthe potentialof this development, efforts at leastsome resource. of both, (a) the deltcit in water remainsin the assessment Significantuncertainty (b) the surfacewater and groundwater supply to restore the whole Canal, and a numberofkey tasksare thisdeficit. Consequently, resources available to overcome (see Chapter9); in order of recommended for action in the next stageof the study priority theseare: of the Wilts & usingexisting"in-water"sections L Measurement of seepage/leakage BerksCanal. river flows & 2. Programme of hydrologicaldatacollectionto improveestimates; sites. waterlevels,especially in winter,at carefullyselected potential,followedby a programme of groundwater resource 3. Furtherdeskstudres pumping. of exploratory drillingandtest

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A

Desk study and site investigation of key sectionsof the Eastem Mainline and North Wilts Branch overlying permeable ground to determine whether lining is

necessary. 5 . Discussions regarding the potential use of urban and road run-off with local authorities,the MOD (re. RA-FLyneham), and further discussionswith the EA.

6 . Programmeof water quality data collectionto establishtrends over a period of about 2 years,in water courseswith potential to supply the restoredCanal.

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5. txvlnoxrrreNTALAssEssMENT

5.1 Introduction 5 . 1 . 1A i m s This EnvironmentalAppraisalhasbeenpreparedaspartofthe feasibilitystudyfor the restorationof the Wilts andBerksCanal. This Chapterof the Reportaimsto identify the: o key environmentalissues,includingopportunitiesand constraintsalong the route optionsfor restoration; . any key issueswhich extendbeyondthe Canalcorridor; . impactsassociated with bothconstruction andoperation of theCanal; o environmentallegislativeobligationsassociatedwith construction,operation& maintenance;

realisticmitigationmeasures; opportunitiesfor enhancement; furtherenvironmentalstudiesthat would be requiredto be carriedout prior to the actualrestorationof theCanal 5.1.2 Methodology The environmentalanalysishasbeenbasedupon: . a desk study evaluatingpublishedand unpublishedinformation. A comprehensive list of this informationis given in Appendix C; . a two day site visit, which concentrated upon strategicsectionsalong the lengthof the Canaland areasto which accesscould be gainedvia public rights ofway. The site visit allowed a greater appreciationof the environmental characterof areas through which the Canal passesas well as the identificationof featureswhich could not readilybe determinedfrom the published/unpublished information; o a seriesof meetingswith key consulteesincluding four workshopsto consider preferred options around Abingdon, the proposed Abingdon Reservoir Site, Grove/Wantage,East Challow, Swindon, Wootton Bassett, Cricklade and Melkshamas well as optionsaroundotherisolatedobstructionssuchas major road, rail and river crossines:

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Restoration of theWilts& BerksCanali Feasibility Snrdy. o additional meetings and consultation with the Environment Agency regarding use of the River Avon at Melkshamand River Ray (Swinboume)at Swindon; . consultationwith otherkey consultees by meansof a telephonecall or in writing; r closeliaisonwith ScottWilson's engineeringand waterresourcesteams. The main topic areaswhich the environmentalstudy focusedupon were land use, ecology and nature conservation,archaeology& cultural heritage,landscape,amenity includinggeology& soils,noise,waterquality and air and leisure,wastemanagement policies quality. Planning relating to these topic areas are discussedunder the individualtopic headings. Environmental issueswere taken into accountat the workshop meetingsin relations to all the options put forward (refer to Chapter 2). However, the environmental assessmentconcentrates upon the prefened route options agreed during these meetlngs.

5.2 Existing Land Uses The main land use types along and dominating the areas which the Canal passes through are: 5.2.1 AgriculturalLand 5.2.1.I ExistingSituation The majority of agriculturalland is Grade3 with smallerareasof Grade4 interspersed between. Thesegradesare defined as follows: .

Grade3 - good to moderatequality agriculturalland

Land with moderatelimitationswhich affect the choiceof crops,timing and type of cultivation, harvestingor the level of yield. Where more demandingcrops are grown yields are generally lower or more variable than on land in grades1 or 2. .

Grade4 - poor quality agriculturalland

Land with severelimitations which significantlyrestrict the range of crops and/or level of yields. It is mainly suitedto grasswith occasionalarablecrops (e.g. cereal and foragecrops)the yields of which are variable. In moist climates,yields of grass may be moderateto high but theremay be difhcultieswith utilisation.The gradealso includesdroughtpronearableland.

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Restoration of thew'\:,Ti[.rT:i 5.2.1.2 AgriculturalImpacts& Mitigation Thekey impactsuponagricultural landusesare o Lossof agriculturallandwherethe Canalhasbeenin-filled and the routerestored to agriculturaluseor the lossofagriculturallandwherea newrouteis required. o Severance . Interception of fielddrains The landis not high qualityagncultural landandin a regionalcontextits losswould probablynot be significant.Howeverin additionto landpurchase costs,additional payment may be required as compensationto individual farmers,including the disruptioncausedby any severance effects. It may be necessary to build lift bridges or a similar structuresacrossthe Canal at strategicpoints to mitigate severance effects. The main areaswherethis may be a consideration is between Wantageand Abingdon,along the Calnebranchwheremuch of the original alignmenthas been filled in andbetweenSwindonandBourtonwherea newalignmentis required. In the remainingreachesthe Canalchannelhas not beenfilled in and often forms a heldboundary. Interceptionof field drainsis a consideration that would needto be takenaccountof in the detaileddesign. It shouldnot presenta significantproblemin terms of agriculturalinterests,but theremay be someimplicationsfor waterqualitywherehigh levelsof lertilisers or pesticides arebeingused. 5.2.2 Settlements whichtheCanalroutepasses Themainsettlements throughor closeto include: a a a a a a a a a a a a

a

Melksham(R. Avon routeoption); Lacock; Chippenham(approximatelylkm to the eastemsideof the town); Calne(Calnebranch); Foxham; Dauntsey; Wootton Bassett; Swindon; Cricklade(North Wilts Branch); West Challow; EastChallow; Wantage; Grove; Abingdon.

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Restoration of the Wilts & BerksCanal: FeasibilityStudy. The lollowing key impacts are likely to arise in the vicinity of these settlements:

o Somedisruption& disturbancedunng the constructionphase(referto Sections,5.7 & 5.9) later; o Amenity, recreational,socio economicand aestheticbenefits. Thereare potentiallymore positiveimpactsassociated with the route running closeto settlementsrather than negativeimpacts. Particularlyin the larger settlements,i.e. Melksham, Wootton Bassett, Swindon, Cricklade, Wantage and Grove, the Canal would potentially add a significant local recreational resource and provide deeper links into the countryside. In Melksham it is felt by the local authoritiesthat the creationof a navigation through central Melksham would offer both aesthetic,recreationaland economic opportunities along a river frontagethat has becomequite degradedover the years. The reach of the River Avon above the Melksham weir up to Beanacreis cunently used for canoeing, pleasureboating and sailing. A slipwayis locatedin King GeorgePlayingField. Some Canal restorationhas alreadytakenplace at Calne and Wootton Bassettwhich has been integrated into the amenity facilities of the Towns, particularly use of the tow paths for walking & cycling. Other areas where restoration has taken place include Dauntseyand Foxham Locks althoughthe extent of public accessalong these areasdoesnot yet appearto be as extensiveas at other restoredsections. Around Swindon, the southem route flanks the southem edge of a golf course. For the most part the Canal runs through existing landscapingand rights of way and does not impinge directly on the golf course. This route also provides good access into/from Coate Water County Park and links into the countrysideboth to the east and west of Swindon. The North Wilts Canal link through Swindon integrateswell into the recreation and amenity area running up from Mannington Recreation ground to Mordon via the valley of the River Ray and extendstheseopportunitiesto the north. Cycle ways and extensive landscapingworks have been taking place through this area and the Canal would need to be designed to fit and complement these works with minimal disruptionto the new landscaping. In Abingdon thereis someconflict over the recreationalbenefitof the Canal through the Ock Valley. The Ock Valley alreadyprovidesgood passiverecreationalfacilities with a network of pathsand cycleways,someof which are next to the River Ock. It also likely that a children'splaygroundwould needto be relocated.The introduction of a Canal along this route would supplementthe existing recreationleaturesand would probablybe more interestingto the Canal usersand allow direct accessto the sites and facilitiesof Abingdon. Howeverthere are potentialconstraintsassociated with the Ock Bridge (Section5.6) and local concemsthat building a Canal along this route would changethe characterof the existing landscapeand ecologicalfeatures. The only place where property would be directly affectedby preferredrestoration route options is at East Challow, where one property is built over the prefened alignment. Accessinto CanalFarm and CanalWay would needto be modified unless

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Restoration ofthew'\:,Tlh.rffit; the Canalcould be engineered to be narrowenoughto maintainthe existingaccess. The Canalwould alsoaffectthe carparkof thepublic houseat Lacockandaltemative parkingfacilitieswouldneedto beprovided. 5.2.3 Recreation & Leisure Recreationand leisure benefits basedupon existing attractionsare discussedin Chapter6 of this Reportandsomediscussionon local amenitybenefitsto settlements along the route has beenhighlightedabove. However,opportunitiesare presented routefor suchactivitiesaswalking,cycling,fishing, alongthe lengthof the restored informalboating& canoeing.Equestrian useof towpathsis prohibitedunderBritish WaterwaysByelawsandalthoughsuchbyelawsmay not applyto the restoredWilts & BerksCanalhorseswill probablybe prohibitedfrom towpathsexceptthosewhich are statutorybridleways. It is recognisedin Local, District and CatchmentManagementPlansthat there is a general need within the area covered by the Canal to promote and improve recreationalandamenityfeatures.The GreatWestemCommunityForestplan which covers a wide area from the west to east of Swindon highlights that water for recreationis in shortsupplyin the forestarea. 5.2.4Angling popularpastimeon Canals.Stockingofthe Canalwith fish Fishingis a particularly will requirea Section30 licencefromtheEnvironment Agency,undertheSalmonand FreshwaterFisheriesAct 1975. In additionthe releaseof any exotic species,for a licencefrom MAFF,underSection14of theWildlife exampleGrassCarp,requires Act 1981.Thisis to ensurethatsuchintroductions & Countryside arecontrolledand precautionto preventthe fish releasesaremadein suitablelocationswith appropriate in to thewild. escaping species are Themostcommonlystocked . CarpCyprinuscarpio - a bottomfeederwhich uprootsplantsandcancreateturbid conditionsthroughits feedingbehaviourandis generallynot favoured. o BreamAbramisbrama- behavesin a similarfashionto carpbut is not quiteso destructive o RoachRali/asrutilus- littleknowneffecton vesetation .

GudgeonGobiogobio - little known effecton vegetation

r Tench Tincatinca - little known effecton vegetation The general stocking density which is recommendedby English Nature and the EnvironmentAgency is 200 to 300 kg/ha. But as discussedlaterin this Chapterthere arevariousenvironmentalinfluencesrvhichcan affectthe qualityofthe fishery.

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Restoration of the Wilts & BerksCanal: Feasibility Study. In order to provide ease of access and to protect bankside vegetation and minimise

erosion,fishingplatformscan be built (suchas thoseinstalledat WoottonBassett). couldalsobe givento platformswhichcanbe accessed Consideration by wheelchair users. 5.2.5Walking popularpast-timeassociated Walkingis a particularly with Canalusers. As well as the scopepresented by the creationof new lengthsof towpaththereis alsoscopeto link thetowpathroutesinto theexistinglocalnetworkof publicrightsof way in order to createcircularroutes,andinto longdistancefootpaths. Key lengthsof the Canalwhich are not currentlyrights of way and which would particularly openup greateraccess intothecountryside for walkersinclude: . Along the riversidethroughMelksham . Sectionsof theCanalbetweenChippenham, DauntseyandEastChallow o Eastof WoottonBassett(PadbrookFarmto Swindon) r Up to Crickladefrom Moredon In orderto maximisethe benefitsfrom towpathsthe followingshouldbe takeninto consideration in thedetailed desien: r Routingthe towpathalongonly onesideofthe Canalanddivertingit to the least issuesprevail. sensitive sidewherenatureconservation . Decidingon the classof towpaththat is suitablefor particularsectionsof Canal. For example,British Waterwaysdivide their towpathsup into three grades. A suggestionas to wheresuchgradesof towpathwould fit into the Wilts & Berks Canalis givenin Table5.1. Table5.1 PotentialGradesof Towpath Tow path class ClassA

ClassB

ClassC

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SurfaceConditions

Potentialusealongthe Wilts & BerksCanal

Even hardsurfacethat drains immediatelyafterrainfallwith no ponding.Suitablefor people wearingtown shoes Generallyevensurfacewith only nominalpondingafterrainfall and with minimalformaldrainage. Suitablefor peoplewearingcountry shoes Somelengthsof unevensurface with no lormal drainageto remove rainfall. Suitablefor people weanngwalking bootsor *'ellinqtons

Area of high usage e.g.Melksham,Swindon,Abingdon

Areasof moderateusage e.g. Grove/Wantage, Wootton Bassettandothervillagesalongthe route Area of low usage e.g.rural sections

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Restorationof the Wilts & Berks Canal: Feasibility Study

5.2.6 Cycling Cyclingis alsoa popularpastimealongtowpathsbut thereareoftenconflictswith other towpathusersand safetyissuesto consider. Thereare a numberof measures thatcanbe adoptedin orderto reducepotentialconflicts: . Use of a permit system- this has not alwaysbeensuccessful on other Canals becausecyclists were unaware of the need for a permit and an efficient administration systemis requiredwith effectivepolicing. . Constructionofa wider towpathwhich couldbe segregated in strategicplaces,for example in the larger settlementswhere the Canal could be integratedwith cycleways. In additionthere are sectionsof the Canalnetwork which link into major cycleways,for examplethe WiltshireCyclewayto the eastof Wootton Bassett. o Restrictingcycling to certainpartsof the Canalroute,althoughthis could be difficult to enforce. 5.3 ExistingEcology Inlormationrelatingto the presentecologicalstatusof the Canalhasbeendrawnfrom the OxfordBiologicalRecordsCentre,WiltshireBiologicalRecordsCentre,English Nature,Alert Maps producedfor Oxfordshire,the EnvironmentAgency(Catchment ManagementPlans,River Corridor Surveydata and consultation),Local Plansand District Plans. In additionthreeecologicalsurveyshavebeencommissioned by the Wilts & Berks CanalTrust lor the areasat Calne,WoottonBassettand Moredon. Partsof the formertwo sectionsof theCanalhavesubsequently beenrestored. At this phaseof the projectno additionalsurveywork has been commissioned althoughit is recognised that this will needto be done as the projectproceeds. Howeverit is importantthat the timescaleof the projectis bome in mind as restorationcould take more than 20 years,by which time the natureand statusof habitatsalong the route,as well as natureconservation legislation,could have changed significantly. 5.3.1 HabitatsAlongtheExistingRoute TheexistingCanalcanbroadlybedividedup intothefollowinghabitattypes: Open standing water typified by the restoredsectionsof the Canal at Calne, WoottonBassett(Platel) (Dauntsey andFoxhamLocks. Thesesectionssupporta and emergentspecieswith a well developedand bankside rangeof submerged community. Duckweed(Lemnaspp.)was notedas beingparticularlyabundantin certain areas,particularlyat Calne where there is potentialfor it to become troublesome.It would appearthat the Canalis supporting a rangeof invertebrates with includingdamselfliesand dragonflies severalspeciesof dragonflynoted at FoxhamLocks.

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Swampwhichgenerallycomprises manysections of the Canalwhichhavenot been filled in over the yearsand arestill shownas standingwateron the OrdnanceSurvey maps. Overthe yearsthe Canalbedhassiltedup andduringthetime of the field visit (l lth & 12thJune,1997)eitherthe bed was dampand marshyor containeda few (Plate2). A varietyof damploving centimetres waterin isolatedsections of standing species currently colonise such areas including Reed canary-grassPhalaris arundinacea, Reed sweet grass Glyceria maxima, Common rced Phragmites australis, MeadowsweetFilipendula ulmaria, Yellow iris lris pseudacorus, HorsetailsEquisetumspp.andrushes./axczrs spp. Woodlandand Scrub which hascolonisedthe Canalbed particularlywhereit has beenfilled in or becomedry over the years(Plate 3). Typical speciesincludeAsh, Hawthomand Elder and in many areasthe formerbanksidetreesare still noticeable (e.g. salix and alder spp). In theseareasthe ground flora tends to be fairly rank dominatedby suchspeciesasNettle Urtica dioica,GroundIvy Glechomahederacea andCommonCleavers Galiumaparine. havedeveloped in openareaswheretheCanal Tall herb and fern type communities bedhassiltedup to anextentthatthechannel bedis dry. Arable habitatsdominateparticularlyacrossthe Oxfordshiresectionsof the Canal betweenAbingdonand Wantagewherethe former route has been filled in and the landuserevertedto agriculture(Plate4). of the Canal moreacrosstheWiltshiresections Neutralgrasslandwhichdominates (Plate 5). A rangeof wherethe Canalhasbeenfilled in andthe landusedfor grazing pasturetypescan be foundincludingimproved,semi-improved and somelocalised (identihedfromexistinghabitatsurveys). fieldsofunimprovedpasture 5.3.2 HabitatsalongAlternative Routes whereit is not possiblefor As identifiedin Chapter2 of this Reporttherearestretches the Canalto lollow the originalalignment.In additionto thosementionedabovethe lollowinghabitattypespredominate: Runningwater wheretheCanalrouteproposes to useor runparallelto theRiverRay (ElmcombeBrook) throughSwindon,the River Avon throughMelkshamand the in moredetailin Clauses River Ock throughAbingdon. Theseareasarediscussed 2 . 3 . 4 . 2 . 5&. 2 5.6.4. Amenity grasslandfor examplewherethe Canalruns acrossthe golf courseat areasin theOckValley Swindonandrecreational 5.3.3 Statutory andNon Statutory NatureConservation Sites sitesof havebeencheckedfor designated The Canalroutes(originalandaltemative) nature conservation interest. notably: o SitesofSpecialScientific (SSSI); Interest . SpecialAreasof Conservation (SAC);

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PlateL: Restoredcanalat WoottonBassett.

Plate2z Original canal,marsh/wetlandhabitat.

!I I L*

\ { L ! I

I I

t

i

t_

Plate3: Typical woodlandand scrubhabitat.

Plate4: Arable habitat.

Plate 5: Neutral grasslandhabitat.

Restoration of theWilts & BerksCanal: FeasibilityStudy a a a !

RAMSAR/Special Protected Areas(SPA); NationalNatureReserves; CountyWildlifeSites; LocalWildlifeSites.

A checkhasalsobeen carriedout of siteswhich areknownto be sensitivebut which (AlertSites). arenot currentlydesignated Althoughvery few sitesactuallylie on theCanalrouteitself,severallie within lkm of theCanal,asshownin theRouteMaps(AppendixD) andTable5.2. Act 1981(& amendments). Faunais protected Countryside underSchedule 5 while flora is protectedunderSchedule8. Badgersareaffordedspecialprotectionunderthe BadgerAct 1992. It is an olfenceto purposelykill, injure or destroyany protected speciesor its habitat. Whereprotectedspeciesoccuralongthe Canalrouteit will be necessary to avoid them eitherthroughdetailedalignmentor by devisingappropriate in closeconsultation mitigationmeasures with EnglishNature. (EnglishNatureis currently conferringwith their speciesofficer regardingthe possiblepresenceof protectedsites along the Canalroute but this has not been notified at the time of writing. The following protectedspeciesareknownto bepresentalongtheroute. e Badgers Certainlyone badgerset is known of closeto the route in the vicinity of Cow Commonanda numberof badsersetsarelocatedwithintheWiltshiresections of the route. o GreatCrestedNewts GreatCrestedNewts are reportedto be colonisingthe former Canalroute north of Semington.Althoughtherearea numberof constraintsto restorationon their part of the original alignment,as discussedin Chapter2, and it is not the prefenedoption, thereis still keeninterestto recoverthehistoricrouteifpossible.Clearlythepresence of GreatCrestedNewtswill haveto be takeninto full account. but it shouldalsobe Newtsmaybepresent notedthat CreatCrested in othersmallareasof standing water andthusarelikelyto affectotherreaches of thehistoricroute.

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Table5.2Sitesof NatureConservation Interest Site

OS Grid Ref

Comments/Selection Criteria

sT905643

Freshwaterhabitat

WILTSHIRE BristolAvon River

(sr96.43)

Tacklemore Wood,Wheelers sT936695 Wood,HazelCopse(ST96.3) StanleyAbbeyFarm sT965719 Meadows(ST97.2) BencroftHill Meadows sT959727

(sr97.5)

Woodland

Grassland Grassland

BremhillGrove(ST97.38) MelsomeWood(ST985787) LackhamWood(ST97.55) Hazeland Wood(ST97.44) MiddleLodgeWood (s197.68)

sT973746 sT985787 sT927720 sT977720 sT93170s

Woodland Woodland Woodland

GreatBodnageCopse

sT968722

Woodland

(sT97.45)

BencroftHill MeadowsSSSI sr962732

(sr962732\

Bremhill Field Farm Meadows(ST97.16) Elm Farm Meadows

Woodland Woodland

SSSI

sT979743

Grassland

sT983780

Grassland

(sT97.16) Charwood Copse(ST97.57) sT982782

Woodland

sT991 794

Grassland

Round Wood, Christian Malford HorseLeys Wood (ST97.25) SwalletFarm Meadow

sT993796

Woodland

sT996797 r sT98780

Woodland

CanalSide,Tockenham Manor(SU08.52) MomingsideFarm Meadow

s u 0 3 3 83l

Grassland

su092817

Grassland

TockenhamReservoir

su026806

Freshwater

Bittlesea Farm Meadow

(sr97.14)

( s T 9 8s. )l

(su08.s2)

(su08.s4)

102

Grassland

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Table5.2SitesofNature Conservation Interest (continued) Site

OS Grid Ref

WestCloseCopse(SU08.56) s u 0 3 2 8 1 1 VastemWood(SU08.50) su043815

Comments/Selection Criteria Woodland

su042812

Grassland Grassland

(SU08.65) Oaklands su041863 WoottonBassettMud Spring s u 0 7 8 8 1 5

Woodland SSSI

Tockenham Manor Slope

(su08.16)

sssr(su08.66)

ChaddingtonLane Verge

su092820

unknown

KingshillCanalandOld Railway(SU18.50) BurderopWoodNorth

su133837

Freshwater, artificial habitat

sul7l814

Woodland

(su08.s3)

(su18.24)

CoateWaterSSSI(SU18.16) s u 1 7 8 8 2 0 RushyPlatt Swamp su136836

SSSI Mires.Swamp,Fen

RiverCole(SU28.19) OXFORDSHIRE

su217880

Freshwater

UfhngtonGorse(38 803/1)

su 314899

LongSpinneyCopse(38 J02) TheCutting(49F01)

su 330895

A WoodlandTrustNature Reserve A semi-natural ancient woodland

(su18.60)

A badgersett(49SS5)

SconWrlsonKrrkpatrick & Co Ltd

s u 4 3 7 96r Not given for secuntyreasons

Wetland, woodland & scrub. ProposedCanal route intersectsthis site Exact location and foraging routeswould need to be checkedin the field

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5.4 Ecological Impacts

with the reachesofthe The only established aquaticcommunitiesarethoseassociated Canal that which have recently been restored. Many of these communities are still evolving. As the great majority of the Canal is not currently in water, there is not an establishedaquatic community. The scope for a diverse aquatic community to developin the restoredreacheswill mainly dependupon: o The level ofboating activity . The crosssectionalprofile and bank design o Water quality and chemistry PositiveImpacts o Potential to createextensivelinear open water habitat with range of habitat niches. Scopewill ultimatelydependupon the level ofboating activity. . Opportunity to improve habitat diversity in areaswhere habitats are currently poor and under developed e.g. arable areas, areas of improved pasture, through settlements r Scope to develop adjacent wetlands associatedwith both the Canal and adjacent storagereservolrs o Scopeto incorporatesuch leaturesasbat boxes in new or restoredbrick structures Negativeimpacts(pnor to mitigation) .

Some loss, disturbanceand changesto existing habitat types e.g. loss of trees, scrub,hedges,and marshy areasestablishedalong former Canal bed

r Changesin the habitattypesassociated with olf line storagereservoirs o Changein characterof limited sectionsof river coursesshouldthesebe selectedas the prefened route options e.g. River Ock, River Ray and River Avon due to "Canalisation"leadingto changesin the flow regimeand effectsofboating activity knock on effectson macro on water quality and turbidity with potentialassociated plant communitiesand fisheries. invertebratecommunities, r Disturbanceat river crossings,primarily during the constructionphase. e Effectsof boatinsactivitv.

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Restoration ofthew\:ffifl:Tll 5.4.1 VegetationClearance Clearanceof vegetationwill required from the existing Canal corridor which has become choked and overgrown, either with marsh loving specieswhere the Canal bed is damp or trees and scrub where the channelbed is drier. The vegetation will also require to be stnpped along the new Canal channel.This may particularly affect short sections of hedgerows which intercept the Canal corridor. Clearanceof hedgeswill need to take accountof the requirementsofSI 1160 The HedgerowsRegulations1997,which cameinto forceon I June,97. Theseregulations apply to any hedgerow growing in, or adjacentto, any common land, protected land, or land used for agriculture, forestry or the keeping of horses,ponies or donkeys if it has a continuouslengthof, or exceeding,20m or has a continuouslengthof lessthan 20m where it intersectsanotherhedgerowat either end. Under Section 6 of the Regulations - Permitted Work, hedgerowsare allowed to be removed if planning permission has been obtainedor work is being carried out under the Land Drainage Act l99l , Water ResourcesAct 1991 or the EnvironmentAct 1995. Otherwise,written permissionneedsto be given from the local authoritythat removalofthe hedgerowis authorised. Under the Wildlife & CountrysideAct 1981,it is an olfenceto knowingly disturb or destroythe nest,eggsor fledglingsof any wild bird. Thereforein order to comply with the Act and to minimise general ecological disturbance,it is recommendedthat any vegetationclearancetakesplace outsidethe nesting season(ie betweenSeptember to March). 5.4.2 Effect on River Sections 5.4.2.I River Avon 2,100 m of the River Avon through Melkshamfrom the Melksham Weir to the off take lock for the Canal would need to be altered to allow navigation should this be selectedas the preferredrouteoption. The main works that would be requiredwould be dredginga channeldeepenoughto allow navigation. The river is currently slow flowing and shallow in places with a silty substrate. Yellow water-lily (Nupharlutea) ^nd standsof bur reed,which are speciestypical of slow flow conditionsdominate(Plates6&7). The EnvironmentAgency advisethat the Avon is important lor the rare white legged damsel fly, loddon pond weed and flowering rush. However, it is not possible to determine due to the lack of data whetherthesespeciesarepresentin the reachwhich would require"Canalisation". The channelhas becomedegradedover the years,principally due to changesin its character from former widening and straightening as part of land drainage/flood defenceschemes. The EnvironmentAgency is planning a river restorationscheme involving natural regenerationof meandersand channeldeepeningthough channel narrowingby meansof coir frontedgabionsand plantedtops to createa flood berm and two stagechannel.This is expectedto takeplacewithin the next 18 months.

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Restoration of the Wilts & BerksCanal: FeasibilityStudy. The aim for this section of the River Avon is to attain River Ecosystem class 3, which

is waterofquality suitablefor high classcoarsefish populations,by 1998. As well as the potential conflict with the river restoration scheme,the Environment Agency have a number of concemsregardingthe eflect ofboating on the condition of channel, particularly on the likelihood of increasedturbidity and siltation, eflects on water quality and erosion which can all have knock-on effects on the aquatic communities(seeSection5.5). 5.4.2.2 River Ray An important strategic area in terms of restoration is the link to Cricklade which follows the valley of the River Ray. As describedin Chapter 2, the Canal cannot be restored along its original alignment for much of its length, therefore an altemative alignment has been developed. For most of the route every effort has been made to ensure that the Canal avoids the River Ray and its associatedtributaries. However, there is one significant pinch point befween the Swindon - Paddington railway line and the culvert below the former railway works/Sainsbury'scar park where the route is heavily constrainedby new retail and commercial developmentto the west and the embankmentof a disusedrailway track to the east. This sectionis critical in the overall strategy to restorethe remainderof the alignment up to Cricklade and it will be impossibleto avoid disturbanceto the 450m of the river in someway. From analysisofriver corridor surveysof this reachit would appearthat the river is 1 to 2m wide, less than 20cm deep with shallow slopes. The stream winds gently through a low marshy areawith the water margin being a transition fiom a perennially water coveredcourseto damp marshy land (Comet Marsh). The habitat quality in this areais consideredto range from reasonableto good to critical. It is recommendedin the River Corridor Survey that "every-elfort should be made to conserl'e the wet habitatsfor what must be a jirst class location for wildlife". Relevant extracts fiom the nver corridorsurveyareincludedin Appendix I. Two restorationoptionshavebeenconsidered: r Canalisationof450 m of the River Ray Moving the River Ray into a new channeland building a new Canalsectionalongside which would use the Sainsbury'sculvert. The River would then be diverted into a new thrust bored culvert beneaththe A420 and Sainsbury'scar park. Both options would have significant impact on the existing characterof this reach. With the Canalisationoption the characterof the river channelitself would be entirelychanged and some bankside habitat required to accommodatethe extra width ofthe Canal and the towpath. However it should be possibleto maintain a good part of the marshy habitat.Soft banks and an appropriateprofile could be developedto maximise the nature conservationbenefit of the Canal through this reach, although the ultimate nature conservationpotential would depend on the level of boating activity (as discussedfurtherin Sub-clause5.3.2.4). The option ofrelocating the River Ray into a new channelcould offer somepotential to enhancethe new river channelitself and at leastrecreatethe eeneralcharacterof

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Plate 6: River Avon below Melksham.

Plnte 7z River Avon downstreamfrom Town Bridge' Melksham.

Restoration ofthe*",.*ff

lh:Txl

the former channel.The existingsubstratecould also be translocatedinto the new channel to preservemuch of the substratecharacterand existing invertebrate community. Howeverthis optionwould do little to conservethe existingmarshy habitatdue to the amountof land take in an alreadyrestrictedareathat would be requiredto accommodate the Canalandriver channel. It is anticipatedthat neitheroption will be readilyacceptable to all partieswithin the EnvironmentAgency. From an environmentalpoint of view it is importantthat the significantimpactsthat would occurin this reachareweighedagainstthe overallbenefitsthatwould accruein opening up the remaining Canal route to Cricklade. In particular appropriate mitigationcouldbe incorporated into key areasin the remainingsectionsto ensure that marshyhabitatdevelopselsewhere.Certainlyit would be expectedthat similar vegetationspecieswould developalongsectionsof the restoredCanalas seenalong existingrestoredsections(i.e. Glyceriamaxima,Filipendulaulmaria andEpilobium hirsutum,PhragmitesAustralisandGlyceriamaxima). 5.4.2.3RiverOck Effortshavebeenmadeover the last few yearsto improvethe habitatand quality of the Ock throughAbingdonand this haslargelybeenachieved.The River Ecosystem (RE) useclassis RE2 which meansthat the wateris of goodquality suitablefor all fish species.It is recognisedthat in placesthe Ock supportsa good fish population but this is variabledependinguponthehabitatqualityofvarious sections.Effortsare still continuingto improveandenlancethe River Ock further.Therearecurrentlyno statutorydesignated natureconservation siteson theriver. The Canalwould avoid the River Ock for the majority of its lengthif this were the selected routeoption,with theexception ofthe last100m.Thissectionof theriver is alreadyCanalisedfor much of the lengththat would be incorporatedinto the Canal and supportssome limited navigationfor small boats. Some dredging and tree would probablybe necessary to allow largerboatsto pass. clearance The Thames(Eynshamto Benson)and Ock Local EnvironmentAgency Plan Draft Report,underIssueNo l4: Wilts and BerksCanalRestoration, Consultation raised thefollowine: " One proposal put Jbrwartl involves Canalising the lower reachesof the Ock to link it ruith the River Thantes. Thisproposal however,would be detrimental to the existing habitat and is therefore unacceptablefrom a conservation and fsheries point of view" . From feedback on consultationsheld with the Environment Agency it would appear that there is no fundamentalobjection to Canalisationof the extreme lower reach as this is already affected by Canalisationand influenced by navigation from the Thames. However,the Ock Valley is identifiedin the Vale of White HorseLocal Plan (Policy L6) as an environmentallysensitivecorridorwhich deservesspecialrecognitionand

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Restorationof the Wilts & Berks Canal: Feasibility Study.

protection. Localopinionis thattheestablishment of a Canalthroughthe Ock Valley will not preservethevalley'sspecialcharacter nor protectits opennature. at RiverCrossinss 5.4.3Disturbance Where the Canal crossesexisting river and drains (highlightedin Chapter2 and Section5.5)it is importantthatconstruction worksminimisetherisk of pollutionand increased turbiditythroughadoptinggoodconstruction practice.The designof the river crossingsis importantto ensurethatthrough-flowcontinueswith minimal effect uponthe aquaticenvironmentandpassage of fish. This is alsotrue of the drainsand ditchesfeedingCoateWater SSSI. Invertedsiphonsare not recommended because theycanimpedethepassage offish andotheraquaticanimals.Clearspanbridgesor culvertsare preferred. Wherethereis any chancethat otter may be using the river coursesthenthe culvertsshouldbe an adequate sizewith a ledgeinsideto encourage ottersto passthrough.Furthercomments on rivercrossings aremadein Section5.5. 5.4.4 Effectsof Boating Initial estimatessuggestthat the annualnumberof throughboat movementsis likely to be in theorderof3000to 5000,although it couldbe someyearsbeforethis levelof boattraffic is achieved.However,in orderto maximiseany ecologicalbenefitwhich thislevelofboatingcouldsustaintheCanalwill needto be designed with this levelof in mind. boatine A unique property of the Wilts and Berks Canal is that about 55km of the original routehas not beeninfilled over the years. Of this only 8km is cunently in water (due to the efforts of recent small restorationprojects). The remainder tends to be either marshy or dry as outlined in Sub-clause5.3.1.1. From the biological recordsand surveys carried out to date it would appearthat relatively few, if any Canal sections, have developed a unique or particularly diverse ecological character(although there are valuable undesignatednature conservationsites close to the Canal corridor). This situationshould help to avoid some of the controversyassociatedwith other Canal restoration projects in the uK. The river sections (2km) are potentially likely to be more sensitiveto boat traffic. In orderto determinethe issueswhich needto be takeninto accountin the design,it is necessaryto understandsome of the impactswhich boating can cause.Canals are multi functional, supporting recreationalboating, angling, active and passive recreationsuch as walking and cycling as well as providing nature conservation, landscapeand heritagevalue. Although the primary aim of the restorationproject is for navigation,maintainingthe environmentalquality of the Canal is still essentialto derive the maximum benefit to other multi functional users. For example, it is important to maintain a reasonablewater quality to support the plant and macro invertebratelife which is in tum essentialto supportthe fish populationsnecessaryto satisfythe anglinginterests. will be importantbecauseuncontrolledboating(i.e. high numberof Boat management boats, travelling at high speed, carelessmoonng and steering, or unrestricted discharges)could lead to the following undesirableeffects, particularly in the narrower,more sensitiverural Canalssuchas the Wilts & Berks:

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o physicaldamage to vegetation by propellers & hulls o increasedturbidity causingreductionin light penetration,degradationof plants from increasedsiltationandsmotheringof invertebrates o decrease in thequalityanddiversityofthe fishpopulations . reductionin varietyanddensityof submerged andfloatingmacrophyes o bankerosionanddegradation ofemergentbanksidevegetation o pollutionlrom engines andwastewater o generaldisturbance to waterfowlandnestingbirds At the levelof boatingenvisaged, thereis still a goodrangeof plantspecies which could potentiallycolonisethe Canal.Appendix J lists a rangeof typical species which, lrom researchon otherCanals,might be expectedto be tolerantof the density of boat trafhc predictedfor the Wilts & BerksCanal. Many of thesespeciesalready occurin the wetter,marshysections of the old Canalbed. Duringclearance of the channel,thereis scopefor non invasiveplantsto be laid to one sideand replantedat theCanaledgeor bermwhentheexcavation workis complete. In order to maintaina healthyhshery,an ecologicalbalanceneedsto be struck. A reasonable amountof marginalvegetationis requiredto provideshelterandrefugefor small fish and fry. In termsof food supplyfor fish, submergedand floating plants providea more taxonrich faunathan non-macrophltesubstrata, while emergentand tall emergentmacrophytecommunitiesare even richer. Submergedplants also providea substrate for fish to lay their eggson. Thusa balanceneedsto be struck betweendensityof plantcoverand fishinginterests. Thecreationof areasof deeper, coolerwatermaybenefitfish,particularly duringperiodsofhot summertemperatures andpromotethegrowthof submergent plantspecies whichwouldbe deepenoughin thewatercolumnto avoidtanglinglines. Thereare a numberof ecologicaldesignoptionswhich can be considered through consideration ofthe crosssectional profileandbankdesignasoutlinedbelow. Thedesignofcrosssectionoffersopportunity to maximisetheecological diversityof the Canaland to integratenaturalerosionprotectionmeasures.Depth and cross profileareimportantconsiderations. If designed properly,the crosssectiontogether with bank designcan minimisethe potentialimpactsof boatingand improvethe conditions for supporting a diverseecosystem andgoodqualityfishery. Theidealsiluationis to havea rangeof channeldepthsoverthecrossprofile,ranging fromshallow,gentlyslopingbermsto a deeper centralchannel.A crossprofilewhich is too shallowcanencourage excessive weedgrowth,theeffectiveness of theCanalto conveydrainage & floodwateris reduced, facilitiesfor fishingdeteriorate andleisure activitiessuchas boatingarecurtailcd. In orderto be effective,the main channel

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Restoration of theWilts& BerksCanal: Feasibility Study. needsto be at least lm deep and this will be achievedthrough the design depth of 1.37mset for the Study. In order to restrictthe disturbanceof the silt, the navigation channelshould be at least300mm deeperthan the draft of the typical boat using the Canal.Again a depthof 1.37mwill satisfythis requirement. The wider the berm that can be accomodated,the greater the potential to achieve natural erosion protection measuresthrough use of reeds and natural vegetation. A variety of techniquescan also give some berm protection in areas where levels of boating activity will potentiallyresult in an erosionrisk, particularlywhere the berm is narrow. Such techniquesinclude use of geotextiles,spiling and toe boards.There may also be scope in winding holes to create shallower berms towards the edges. . However it may not always be possibleto achievethe width of berm required to combat erosionwithin the minimum design specificationand a wider cross profile would be requiredresultingin a greaterland take. However the cost of adopting softer, more environmentally friendly techniqueswould needto be consideredagainst the generally higher costsofharder bank protectionmeasures. In certain areas,for example close to moorings and where land take is constrainedby surroundingland usesit is likely that harderprotectionmeasureswill be requiredsuch as sheetsteelor woodenpiling. There is also the potential to site marinas strategicallyin order to provide more control over boat movementsthrough different parts ofthe Canal therefore indirectly controllingthe pressureon certainpartsofthe Canalcorridor. Imposition of strict speedlimits can do much to limit boat wash and the resulting damagewhich this causes. Considerationcould be given to restrictingboatingactivity in certainsectionsof the Canal. For exampleit is likely that the highestnumberof boat movementswill occur at the Kennet & Avon end and at the Abingdon end. Thereforethere may be scopeto limit boat movement in the central section.for examDlebetweenWootton Bassettand the Calnebranch. Table 5.3 highlightsthe bank protectionoptionswhich could be appliedalong the Canal where boat movementsare likely to result in potentialerosion. The need for bank protectionand suitabilityof the optionswould need more considerationat the detaileddesignphase. This is becauseeachreachof the Canalis differentin character and this would needto be consideredalongwith the level ofboating activity,tow path recreationalusesand ecological/landscape character.

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Table5. 3 Bank ProtectionOptions Bank Profile

Sloping

Water depth lm

np-rap gabionmattresses cable tied/geotextilebondedconcreteblocks grout-filledcontainer densestoneasphalt prefabricatedasphaltmattress 0.5m Pilingisheeting comprising: steel,concrete& timber Source:RW Hemphill & ME Bramley,Protectionof River and CanalBanks Effectson river sectionswere discussedin Sub-clause5.3.2.2. In additionit is highly likely that somedredgingwill be requiredin theseriver section.From discussionheld with the EA to date it is likely that any river dredgingwill be a sensitivematter and carefulconsiderationof suitabledredgingprofileswill be required. 5.4.5 Off- line StorageReservorrs At this stageit is difficult to predictthe impactscreatedby off line storagereservoirs becausetheir preciselocationsare not yet defined. Howeverit can be assumedthat therewill be somehabitatloss.The significanceofany impactwould dependupon the quality and statusof this habitatbut there may well be scopeto improve upon the existing habitat through the creationof well designedlakes and wetlands. Issues relating to water quality are highlighted in Section 5.5. One important factor to consider in any design is that water level is likely to fluctuate considerably, particularlyduring the summermonths when there will be increaseddemandupon water resourcesfor the Canal. Potential enhancementmeasureswhich could be consideredinclude:

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Use of a diversecrossprofile to maximisehabitatniches

o Creation of adjacentmarshy areas o Plantingof trees,hedges& scrubfor example: Osier & Sallow speciesas part of landscapingand screeningmeasures although coppicing would be necessaryevery 2 to 3 years to promote dense scrubby growth. Blackthom,Hawthom and Dog Rose o Constructionofcentral islandsand scrapesas nestingsiteslor birds. At least lm depth of water needsto be maintained around the islands to prevent predation by foxes. Islandsare best placed l00m from overhangingtrees.Severalislandsare better than one. o Fluctuating water levels can be useful for creating gravel, mud shorelines and shallow pools which provide valuable feed in areasfor waders. In order to retain their value suchareasshouldbe kept freeofvegetation o Planting of marginal reed beds (dependingupon the likely fluctuationof water levels)

5.5 Landscape 5.5.1 ExistingLandscapeCharacter& Features For most of its length the Canal corridor runs through the Clay Vale LandscapeZone, formed by the broad lowland of Kimmeridge and Gault clays. The key landscape characterofthe Canalis describedbelow: 5.5.L l

Ilest lliltshire Districr

From Semington northwards the Canal runs though the flat gently undulating topographyof the valley of the River Avon. Near views aredominatedby pastureland and hedgerows.The existingnver landscapethroughMelkshamup to the Melksham Weir is somewhat degraded with the river flowing between high walled embankments.BetweenMelkshamand Chippenhamthe eastemCanal route options run close to the edge of a SpecialLandscapeArea, which is recogniseda having county-wide landscapeimportance. Specific planning policies apply to Special LandscapeAreas, in terms of developmentswhich could be detrimental to the landscapecharacter.However,due to its location,none of theseare directly relevant to the Wilts & BerksCanal. 5.5.1.2 North WiltshireDisrrict From Spye Park to Wootton Bassettthe views from the Canal are dominatedby a ridge of Corallianlimestoneto the southand the Canalgenerallyhas a more enclosed

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From the point wherethe Canalcrossesthe SwindonBoroughboundaryandalongthe majority of its route to the A419 (T) the route runs through an Area of Local LandscapeImportance.This areamakesan importantcontributionto the quality and characterof the Borough's landscapeand has particular value or potential for recreation. countryside To the eastof Swindonfrom the A4l9 (T) to PackHill the Canalpassesthroughthe North WessexDowns Areas of OutstandingNatural Beauty. The purposeof the AONB designationis to conserveandenhance the naturalbeautyofthis areawhich is formally recognised as having a landscape of nationalimportance.Policiesfor protecting thisareaaregivenin PolicyTEV55whichis setoutin clause5.5.3. 5.5.1.4 Valeof WhiteHorseDistrict Within the Vale of White Horse the route runs throughthe Western,Central and EastemClay Vale. The WestemClay vale has beencelebratedin literaturefor its atmosphericlandscape andis characterised by the pasturesandhedgerowsestablished on the clay soil and gently undulatingtopography.Althoughthe loss of Elm Trees hasleft the landscape moreopenthanit usedto be therearestill plentyofhedgerows, copses,greendamp channelsand brick & tiled hamletsand villagesusuallyon outcropsof gravelabovethedampland. The remainingtreesstill retainthe feelingof the traditionallandscape. The land to the north of the CanalbetweenStockhamBridgeandthe westemsideof Grove of Wantageis designatedas an Areas for LandscapeEnhancement (Policy wasclearedof woodlandandtreesduringthe Second C12). Much of this landscape World War to makeway lor airstripsandotherinstallations.The areahasneverfully recoveredandthe Councilconsiderthat opportunitiesshouldbe takento enhancethis area. BeyondGrove & Wantageto the A34 the topographyis flatter and thereare more hedgeless larger,arablefields,particularly on the thin gravelterraces which overlie the clay sub soil. The areais generallycharacterised by a feelingof wide spaces, expansiveness andrurality. The flat openlandscape providesviewsof theBerkshire Downsto thesouthandConallianRidseto theNorth. At the edgesof some of the settlementsalong the route e.g. Grove, Wantageand Abingdon,a more rural fringetype landscape prevails. East of the A34 the Canal route becomesmore urban fringe in nature. The route following the Ock valley runs through a mixture of meadows,open more formal recreationalareasand urban woodland/parkland.Housesdominatethe more distant vie*,s towardsthe edgeof the flood plain.

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5.5.2 Impactsof the Canal wtrere the canal route will follow its original alignment there is likely to be little visual intrusion. This is becausemany ofthe original tree lines still persistand these will largely be preserved. Some tree and vegetation clearance, pollarding and coppicing will be necessary,either where trees and scrub have encroachedinto the or to improve the nature conservation beneht of the area. The originut ittu*"I sunounding vegetation,particularly hedgesand trees,screensthe canal from medium and distantrangeviews. The canal will potentially have the greatestvisual impact where it passesalong entirely new routes introducing a new, large linear feature into the landscape. But even in these areasthe near, medium and distant view tend to be restricted by trees and hedgerows. Areas where the canal could have the greatestimpact, by changing the landscape characteris through settlementssuch as Melksham, Lacock, parts of swindon, Grove and Abingdon. Mitigation 5.5.3 LandscaPe The aestheticappearanceof the canal is important becauseit promotes greater enjoyment by useis. Featureswhich generallyenhancethe landscapeoften have other posiiive attributese.g. nature conservation,or heritagebenefits' Generally, the softer the techniques that can be used and the more natural the materiali e.g.wood versussheetpiling, the betterthe aestheticappearance.A number of suggestiJnsin relation to bank treatmentshave been made in Enor! Reference source not found.. However, the choice of material is often constrainedby the anticipatedlevel ofuse and thus the strengthand enduranceof materials' The Local Authorities along the length of the route have set out various landscape policieswhich the designofthe canal will needto take accountofas setout below: ".... The Districtcouncil will seekto enhancedamagedor compromisedlandscapes. It will particularly look for landscapeimprot'ementschemesin the areas identified on " rheproposals map. Policy C 12, Vale of White Horse Local Plan "The District Council will normally expectthe landscapefeatures \uhich contribute to the ecologl,-, character and appearance of the landscape (such as trees and hedgerowi) shoukl he protected and integrated into the landscaping schemefor any proposed rlevelopment" Policy C9, Vale of White Horse Local PIan ,,proposals loss of trees of amenity for new developmentwhich would result in the valui will not nornnlh be acceptable"Policy C10, Vale of White HorseLocal Plan

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"In

connection with the restoration of the ll/ilts and Berks ... Canal, developmentwill not be permitled whereproposals are likely to result in: l. A signifcant adverseeffect on the amenitiesand open landscapeof the Canal corridor..." Policy RTM5, North Ililtshire Local Plan "Development

will not normally be permitted except where it is essentialto the local rural economy, or desirable for the enjoyment of its amenities, or is otherwise acceptable having regard to other policies in the plan. Ilhere in these areas development in these categories, is permitted, particular care should be taken to integrdte it into the rural landscape. Special landscapeor other conditions may also be imposed"Policy TEV55, SwindonLocal Plan Aims of the Local Authoritiesalong the routewhich would be compatiblewith Canal restorationinclude: r replantingof hedgerows; o treeplantingwithin hedgerows,beltsor copses; . clearance& restorationofponds; . replacementof hedges; . retention and maintenanceof willows along streams. In some areasgrants are available for small planting schemesand willow pollarding. Restorationof industrial heritagefeaturessuch as locks and wharves can also do much to enhancethe appearanceand interestofthe Canal environmentand can act as a focal point to view the Canalfrom. Attention should also be given to the visual appearanceofbridges and lock structures. From analysis of historic pictures, it would appearthat many of the original bridge structures were brick built arches with either brick or iron gridwork parapets. Although it may not be possibleto restoretraditionalhump back bridgesdue to the constraintsimposedby modem sight lines and road safety,the use of brick where possibleis recommended.Thereis alsoscopewith brick to installsuchfeaturesas bat bricks.

5.6 Water Quality potentialwater quality impacts arising from the restorationand This sectionaddresses construction, as well as the future maintenance and operation of the Canal. Specifically, this includes: impacts on the Canal and adjoining watercoursesduring restoration & .^ncfn

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.

impactson the water quality of watercourses and groundwaterusedto supply theCanal;

.

impactson Canalwaterquality duringoperation.

5.6.I Legislation and Regulation Thereare a numberofpieces oflegislationdealingwith waterpollution.The potential for deteriorationin the water quality ofboth the Canal and adjoining watercourseshas to be consideredwithin the framework of the statutory requirementswhich aim to prevent pollution or deal with the consequences once pollution has occurred. In addition to liability under Common Law, there are two main statutory environmental laws to be consideredin this case: Act l99l 5.6.1.1 WaterResources The WaterResourcesAct l99l setsout a numberof offenceswhich are committedby "controlledwaters". Controlledwatersare describedin Section allowing pollution of 104 of the Act and include inland freshwaters,lakes and ponds (natural or artificial and above or below ground) which discharge into rivers and watercoursestogether which are not public sewersnor drainsor sewersinto a with rivers and watercourses public sewer, and groundwaters;those in undergroundstrata. Under Section 85 of the Water ResourcesAct 1991, it is an offence to causeor knowingly permit any poisonous,noxious or polluting matter or any solid waste matter (which includes silt, cement, concrete,oil, petroleum spirit, sewage or other polluting matter)to enterany "controlledwaters". As for the control of waterquality,Sections82 - 84 ofthe Act provide for a systemof statutory Water Quality Objectives (WQOs) in order to maintain and improve the quality of controlledwaters. The WQO schemeis designedto provide a range of standardsfor water quality which reflect the uses of the particular watercourse,e.g. fishery, ecosystem,abstraction,amenity etc., however so far only one standard has Regulations beenintroduced.The SurfaceWaters(River Ecosystem)(Classifrcation) 1994,define five use classesof water quality for fish communitieswhich rangefrom REI - water of very good qualrtysuitablefor all fish species,to RE5 - water of poor quality which is likely to limit coarse fish populations. Maintenance and improvementof the WQOs is a duty of the Secretaryof Stateand the Environment Agency,and is facilitatedthroughthe useoftheir pollutioncontrolpowers. Act 1995 5.6.1.2 Environment The Environment Act 1995 further strengthensthe provisions available to the EnvironmentAgency by providing it with the ability to forestallpotentiallypolluting "works notice" on any person in events,undertakeanti-pollutionworks or serve a situationswhere polluting matter has entered,or is likely to enter any controlled water. The "works notice"canrequirethe personto undertake:

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Restoration of theWilts& BerksCanal: Feasibility Srudy o the removalor disposalof the pollutingmatter; . the remedyingor mitigationof any of the effectsof pollution; . the restoration of the affected water(s) and any flora and fauna dependenton the aquatic environment.

Under the 1995 Act, for the first time there is also a statutorydefinitionof contaminated land,namelv: "any landwhich appearsto the localauthorityin whose areait is situatedto be in sucha condition,by reasons of substances in, or undertheland,that(al

significantharmis beingcausedor thereis a significantpossibilityof suchharmbeingcaused; or

(b)

pollutionofcontrolledwateris beins.or is likelyto be.caused".

'Harm'is definedby the Act to meanharmto the health of living organismsor other interferencewith the ecologicalsystemsof which they form part, and, in the caseof man,includesharmto his property. 5.6.L3 Common Law The ownersof a site may be held liable undercommonlaw if contaminants escape andinterferewith an adjacentlandownersuseof the land (riparianrights)or interfere with a right suchasabstraction of groundwater. 5.6.2 Baseline Conditions As partof the baseline survey,it is essential to assess the qualityof thoseriversand streamswhich the Canalaffects,eitherthroughdirectabstractionduringpeakwinter flows to fill supplyreservoirs,or throughjoining the rivers or canalsat somestage alongtherouteof theCanal,e.g.riversAvon andOck. In doingso it will be possible to determinethe main issueswhich are currentlyaffectingeach watercourse,and determine how restoration of theWilts & BerksCanal,will affectthewaterqualityof boththerestored Canalandtheriversystems whichit will interactwith (TableS.4)

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Table5.4 Watercourses Affectedbv CanalInfrastructure Watercourse ClackersBrook

Location E. of Melksham

Approx.NGR

Reasonfor Studv

s T9 1 4 6 3 7

Avon Tributary

S. of ForestFarm

sT 917646

Avon FloodPlain

S.ofChippenham sT 920705

Fishers/Cowage Brook

N.W.of Calne

sT 980720

CadeBuma

S.W. of Stockholm Marsh Farm

sr 990768

Surfacewater reservoirsupply Surfacewater reservoirsupply Surfacewater reservoirsupply Surfacewater reservoirsupply Surfacewater reservoirsupply

RAF Lyneham Brinkworth Brook

S. of Wootton Bassett

su 00s785 su062815

Storm watersupply Surfacewater reservoir supDly

R. Cole

S. of Acom Bridge

su216873

Surfacewater reservoirsupply

Ock Tributary

ds CowleazeFarm

su28s894

Surfacewater reservoir suDply

Ock Tributary

ds Uffington

su 302898

Surfacewater reservoirsuDDly

StutfieldBrook Thames

S.E.of Broadleaze su 344888 Farm at Abingdon su 500957

Ock

at Abingdon

su 475960

Ray/ Elcombe Brook Oxford Canal

at Swindon

su 137834

Avon

at Melksham

Kennet and Avon Canal

S. of Melksham

N. of Cricklade

Surfacewater reservoir supply

Confluencewith W&B Canal Confluencewith W&B Canal

Confluencewith W&B Canal su 0879471t09944 Confluencewith W&B Canal sT 900638 Confluencewith W&B Canal

with sr 900610/932614 Confluence W&B Canal

Until the conceptsand plans developedwithin the feasibility study are more fully defined, it would be both time consumingand potentiallywasteful to undertakea detailedstudy of the water quality of eachof the watercourses outlined above,as it would require a large volume of detailed monitoring data fiom the Environment Agency (EA), as well as some additionalsurveywork, in order to comprehensively assessthe effectsof the restorationas it is currentlyenvisaged.In addition,it has not beenpossibleto obtainpublcly availablewater quality dataon groundwater supplies which have been outlined for potential use in this report. All the information containedwithin NRA CatchmentManagementPlans or EA Local Environment Agency Planshas been assessed for both surfacewater abstractionand ground water abstraction,and the main issuesarepresented below.

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Restoration of thew'\*.Ti[rrTli 5.6.3 GeneralQualityAssessment & WaterQualityObjectives TheEnvironment Agencyundertake routinesamplingof controlled watersin England andWalesusingboth biologicalandchemicalparameters in orderto monitorwater quality. Since 1994,the EnvironmentAgency have used the GeneralQuality (GQA) schemelor riversand Canalswhich hasthe benefitof providing Assessment waterqualityassessment resultswhicharenationally consistent. In additionto assessing waterqualitythroughthe GQA scheme, the EA alsouse a (WQOs)whichestablish systemof WaterQualityObjectives clearqualitytargetsfor individualreachesofwatercourses.At presentonly the River Ecosystem usecategory hasbeendeveloped,and is in widespreaduse following its introductionthroughthe (Classification) SurlaceWaters(RiverEcosystem) Regulations 1994. The biologicalandchemicalparameters for the GQA scheme,aswell asa description andstandards requiredto meettheuseclasses of theuseclasses is givenin Appendix L. K andAppendix For each of the reachesof rivers and streamswhich are affectedby the Canal infrastructure,the biological and chemicalGQA grades,and the WQO gradesare presented in Table 5.5 following. (N.B. someof the streamshighlightedin are so smallthat samplinghaseithernot occurredor beenreportedby the EA). Also, where it has beenpublished,compliance with the River Ecosystem use classtargetsare presented. WaterQualityIssues 5.6.4 SpecificCatchment In additionto theassessment ofbiologicalandchemicalwaterquality,andthe setting of water quality targets,a number of issuesspecific to certain catchmentsand watercourses are discussedwithin the publishedCatchmentManagementPlansand Local EnvironmentAgencyPlans.Someof the main issuessurroundingwaterquality in reaches ofriversandstreams identifiedin Table5.5areasfollows: 5.6.4.1 UpperBristolAvonCatchment This catchmentis covered under two NRA reports: The Upper Bristol Avon Management PlanConsultation Catchment Report,datedJune1994;andThe Upper BristolAvon Catchment Management PlanActionPlan,datedMarch1995. General:there is ongoing surveywork to establishthe nutrient statusof the catchment,especiallydownstreamof the SewageTreatmentWorks (STW) at Chippenham,in order to assesswhetherthis part of the catchmentshouldbe designatedas sensitive under the Urban Waste Water Treatment Directive (91l27lIEEC).This wouldallow nutrientremovalat qualifyingSTWs(NRA, 1994, p p 1 0& s 0 ) .

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Table5.5 Water Quality for Watercourses Location

NGR

GQA Biol

Year of Data

GQA Year wQo Chem of Ecology Data UseClass

Pass/ Fail

Year of Data

Unnamedtributary of su34488 8 StutfieldBrook to SE of Broardleaze Farm (Westof Wantase) Unnamedtributary of su30289 8 River Ock downstream of of UffingtonQ.,lorth Uffinston) Unnamed tributary of River Ock downstream of Cowleaze Farm (West of Uffinston)

su28s89

River Coleto Southof Acom Bridge (Southwest of Shrivenham) Brinkworth Brook Eastof Greenhill CommonFarm(South of WoottonBassett) RAIFLyreham

su2t 687 3

4

B

RE3(1994)

19911993

,|

su0628l 5

su00578 5

Point whereCanaljoins River Ock in Abingdon

su47596

1995

0

PointwhereCanaljoins su I 3783 Fair 4 River Rav in Swindon End point North of Cricklade(E)

su08794 7

EndpointNorthof Cricklade(W)

su10994

Point whereCanaljoins River Thames at Abingdon Cade Burna SW of StockhamMarsh Farm (Southwestof RAF Lyneham)

su50095

t20

B (1 9 9 3 l99s)

RE2

Pass

C ( 19931995)

RE2(1998)

Fail

19931995

4 7

B

r 993

sr990768

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Restoration of theWilts & BerksCanal: FeasibilityStudy

Table 5.5 Water Oualitv for Watercourses(continued Location

Fisher'sandCowage Brook at SwervesFarm fNorthwestof Calne) Unnam€dtributary of River Avon Southof ForestFarm(Northeast of Melksham) ClackersBrook North of BowerhillLodge Farm(Eastof Melsham) near Avon Floodplain Chippenham PointwhereCanaljoins River Avon in Melksham Endpoint Southof Melksham(E) (K & A Canal) Endpoint Southof Melksham(W) (K & A Canal)

NGR

GQA Biol

sr980720

Year of Data

GQA Year Chem of Data

wQo Ecology UseClass RE3

Pass/ Fail

Year of Data

Pass March 1995

sT9l 7646

sT914635

sT920705

RE3

Pass March 1995

sT900618 sTg00610

RE3(r998) Fail RE5

March (signif 1 9 9 5 rcant) Pass March 1995

sT932614

Canal compliant with proposed

Pass March 1995

wQo Note: Awaiting further information from the Environment Agency. Comments will be made at a later stage. In addition to the above, studies are also being undertaken to establish if the catchment,or part of it, should be designatedas a Nitrate Vulnerable Zone (NVZ), as potable water supplies downstream of the catchment boundary have high concentrationsof nitrate. Designationas a NVZ is governedby the EC Directive 'conceming the protection of waters against pollution caused by nitrates from agricultural sources' (9ll676lEEC), and would require action plans to be drawn up to reducenitratepollution from agnculturalsources(NRA, 1994,p51). The combinationof thesetwo sourcesof nutrientshas led to eutrophicationproblems occurringin long sectionsofthe Avon, and the reachbetweenChippenhamSTW and Avoncliffe Weir at Bradford-on-Avonis specificallytargetedfor furtherstudy (NRA,

1 9 9 sp,8 ) . r Avon at Melksham: Owing to the above,the Avon at Melksham appearsto have significantproblems associatedwith a high nutrient load lrom both point (STWs) and diffuse sources of nitrate have exceeded50 mg (agriculturalrunoff). In Melksham,concentrations NOr/l (NRA, 1994. 62). Melksham STW is degradingdownstreamwater quality (NRA, 1994,p63) possiblyas a resultof increasedorganicinput from an expanding population,and the current consentedeffluent dischargeis due for review (NRA,

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1994,p64). If the UpperBristol Avon catchmentis designated as 'sensitive' under the Urban Waste Water TreatmentDirective (UWWTD), then the population equivalentfigure(which is indicativeof the volumeof treatedeffluentbeingreturned to theAvon)underwhichtheSTWoperates will bereviewed(NRA, 199a,p65). In addition to the above,there is mention of the possibility of an urban river restorationprojectin Melkshamwhich would reducethe amountof siltation in the riverwithinthetown(NRA, 199a,pl5). r CowaseBrook / RAF Lvneham: Examination ofthe waterqualityofthesetwo potentialsources goeshand-in-hand as both sewageeffluent and storrnwater dischargeswhich are liable to contain oils, rubber compoundsand, in winter, de-icing fluids (NRA, 1994, p65) from RAI Lynehamare fed in to the Stringswatercoursesituatedat the headwatersof the Brook(NRA, 1995,p12).In addition,to theeffluents Cowerage whicharedischarged to the Stringswatercourse, thereare intermittentpollution eventswhich are usually large scale fuel spillages which have a highly damagingeffect on the small watercourse(NRA, 1994,p65). The EA are currently in negotiationwith RA_F Lynehamto improvethe performance of the STW, employ improvedpollution prevent emergencyresponsemeasures, and fuel oil and de-icingfluid fiom entering (NRA, 1994,p66). thewatercourse o BrinkworthBrook: Brinkworth Brook, upstreamof the likely locationfor the proposedsurfacewater supplyreservoir,hasa numberof significantelfluentsdischargedinto it. Thereis a fish farm; Ivy HouseLakes,to the northwestof WoottonBassettwhich both extracts waterfrom the Brook,anddischarges farm derivedeffluentinto it (NRA, 1994,p39). Wootton Upstreamof Bassettthe St. Ivel factoryhasa consentto dischargefactory waste(1500m'/d)to thewatercourse, although thereis no detailof consent conditions (NRA, 1994,p37), and finally there is a STW below WoottonBassett,which dischargesinto HancocksWater(a tributaryof BrinkworthBrook), upstreamof the proposedsurfacewatersupplyreservoir(NRA, 1994,p37). Problemswith water qualitydownstream ofthe STW is beingdealtwith by the EA throughrenegotiation of WessexWater'sconsented discharge conditionsto bring aboutimprovements in finaleffluentsleavingtheworks(NRA, 1994,p64;NRA, 1995,p10). 5.6.4.2 UpperThames Thiscatchment coversa relativelysmallpartof theWilts& BerksCanalgeographical area,howeverit includesthe areaaroundSwindon,andthe riversRay and Cole,as well asthe Coletributaries to the eastof Swindon.The onlyproposed surfacewater supplyreservoirin thiscatchment is locatedon theRiverColesouthof AcornBridge, howevertherewill be a smallstretchof theCanalwhichadjoinstheRiverRay to the southof Swindonfor a shortlengthbeforeseparating oncemore. The NRA Reportwhich coversthis catchmentis the Upper ThamesCatchment Management PlanConsultation Reportwhichwaspublished in January1995.

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Restorarion ofthew"l*lJlflrrtll The River Ray, throughSwindon,and especiallydownstreamof SwindonSTW, has poor water quality and has beendesignateda 'SensitiveArea' underthe UWWTD (NRA, 1995,p58). Improvements havebeenmadeto SwindonSTW to improvefrnal effluents,howeverphosphatestrippinghas not beenincludedin the improvements, and may be incorporated at a laterstage(NRA, i995, p58). Owing to the poor water qualityin theRiverRay,EC Fisheries Directivewaterqualitystandards havenot been (NRA, p64), met 1995, nor havefisheriesbiomasstargetsfor the river (NRA, 1995, p7l). It is hopedthat as a resultof upgradingat the SwindonSTW, both of these failureswill beconectedin thefuture. 5.6.4.3 Thames(Eynshamto Benson)and Ock Catchment This catchmentis coveredby the Thames(Eynshamto Benson)and Ock Local EnvironmentAgency Plan Draft ConsultationReport (Secondand Final Draft) publishedin June1997,andcoversthegeographical areato theeastof Swindonup to Abingdon. There is no data containedwithin the Reportwhich specificallyidentifiesthe Ock tributarieswhich are listed as potential feeds for surfacewater supply reservoirs, howeverthe Ock catchmentis definedas having poor water quality as a result of agriculturalrunoff (EA, 1997, p42)andthe EA is currentlyvisiting larmsto assess the risks associatedwith each holding and advisefarmerson surfacewater pollution preventlon. The Wilts & BerksCanalrestorationis specificallyhighlightedasan issuewith regard to Canalisationof the lower reachesof the Ock, andwatersuppliesto feedthe Canal (EA, i 997,p48),howeversomeof thesemisgivings mayhavebeenassuaged in recent discussions betweenthe EA andmembersof the Wilts & BerksAmenitvGrouo. 5.6.4.4 Groundwater Quali0) The issue of groundwaterquality is very poorly coveredin any of the NRA/EA reports,save that there are no GroundwaterProtectionZones aroundthe aquilers which may be usedto feedtheCanal. Informationwhichhasbeenmadeavailableby the EA in thecalculation of potential groundwatersuppliesfor the Canalhas indicatedthat in many casesthere may be problemswith usinggroundwater resources; in the majorityof cases,this includes increased salinityandexcessive ironconcentrations. 5.6.5 ImpactPrediction Determining the exactnatureof the impactswhichmay takeplacecannot be precise at this time becausethe final locationsandrequirements for Canalinfiastructurehave not been decided,and a much greaterlevel of detail on existingsurfaceand groundwater qualitywouldbe required.As a result,genericimpactsassociated with this type of development are highlightedhere,and wherepossible,predictionsare augmented by theinformation presented in thebaseline datasection.

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As outlinedin the introduction,the waterquality impactsthat arelikely to ariselrom can be brokendown into threedistinctsectionsas the Canalrestoratior/construction follows: 5.6.5.I ConstructionRelatedImpacts There will be a variety of structuralworks which will affect the quality of both existingriver quality wherethe Canaljoins other rivers and Canals,and the water quality of thoselengthsof the Canalin water.The main impactsfrom construction relatedactivitiesare: o Increasedturbiditv/siltation with restoration,as This is likely to be one of the most common impactsassociated jacking, bypassing whenever dredging, excavation work, thrust boring or box channels(especiallyassociatedwith coffer dams) and piling take place, to a greateror lesser extent muds and silts will be mobilised either from channel banks and substratesor from extemal sources.Mobilising thesesedimentsand arisings will have a number of effects on channel morphology, habitat and water quality. Dealing specificallywith the waterquality issues,releasingsedimentsor otherorganicarisings into a waterbody has three main effects: it increases the organic load on the watercourse leading to an increased biochemical oxygen demand (BOD) on the surrounding waters as the organic particles are colonised by bacteria; it releases nutrients into the watercoursewhich may have hitherto been locked up in the chamel substrate; and it reduces ability of submerged and benthic plant species to photosynthesiseeffi ciently. Increasing the organic load on a watercourse may be acceptable where there is sufhciently high concentrationsof dissolved oxygen, however as with many watercoursesin the catchmentsstudied, there are already problems with the BOD of and wherethis type ofproblem is severe,increasedsedimentload existingdischarges, pulse deoxygenatedwater travelling downstream,killing fauna which to a of may lead are not able to evade it. This problem may be further exacerbatedas phosphorousin sedimentsis releasedin anaerobicconditions,providing further nutrient enrichmentof the waterbody. Where nutrientsare releasedinto the watercourse,especiallyphosphorouswhich is often the limiting nutrient in many waterbodies,it can causeexcessivealgal and macrophye growth, followed by a high BOD in the waterbody once the flora have died-back. Once phosphorousis freely availablein a waterbody,it is notoriously difficult to remove. Increasingthe organic/nutrientload on an impounded waterbody often leads to eutrophication,and this is a particularproblem for many standing waters in the LrK. When a waterbody suffers from eutrophication,water quality and ecosystem are degraded such that the only organisms able to thrive are algae/phytoplankton. Algal blooms effectively shade-outhigher plants (macrophytes) which support and offer refuge to macroinvertebrates,fry and zooplankton, the latter of which is the phytoplankton'sonly predator. When zooplanktonno longer have a refuge they are predatedmore easilyby fish, and thereafterthere is little to stop the algalpopulationfrom expandingunchallenged.

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Restoration orthew \:,Tlh.rTli Eutrophic waters,characterisedby algal blooms, have low amenity value as they olfer little in the way of speciesand habitat diversity, they have limited angling potential (fisheriesare initially dominatedby cyprinidswhich eventuallydie out if the situation worsens),and watersportsare often curtailed as a result of the potentially toxic effects from ingesting cyanobacteria(blue-greenalgae). Increasedturbidity/siltation can affect a plant's ability to photosynthesiseefficiently, however in most cases,where there is movement in the water body, the sediment load will travel in the directionof the current,and the water will clearoncemore. Thereis a problem where silt gets depositedon the leavesof plants and effectively smothers them, or where there is no movementin the waterbody,and fine sedimentstake longer to settleout. In thesesituations,some of the flora affectedmav die. and once more the BOD of the surroundingwaterwill be increased. o Pollutionfrom construction related materials Whether the restorationworks involve the use of an engineeringcontractor,or a volunteer workforce, there will be certain materials in use which have the ability to createa significantpollution problem. Fuels,oils and ancillary fluids required for items of plant offer the greatest potential for pollution either through accidental spillage, unauthoriseduse or vandalism. In addition there are likely to be materials stored on site such as constructionrelatedchemicalsor concrete. Where construction compounds are formed adjacent to the area of working, there is the additional potential lor pollution to occur liom domestic waste, litter and accumulateddebris from the runoff lrom the compound. Where oils or oil derivatives enter a waterbody a number of changesoccur: plants which become coated in oil are unable to respirateor photosyrthesiseand hence die; in addition the water soluble componentsof oil are highly toxic to most organisms living within the waterbody, regardlessof their lifestage (although the younger they are the more vulnerablethey are likely to be). The secondaryeffects ofan oil spill are similar to those mentioned in the preceding paragraph,that of increasedBOD and nutrient releaseas a result of bacterial colonisation of the dead flora and fauna. In addition to the above, oil pollution has a derogatory effect on the amenity and aestheticvalue of a waterbody,limiting its potentialfor the durationof the pollution eventfor suchactivitiesas fishingand canoeing. Cementis particularlytoxic to fish in its uncuredform, having lethal effectswithin the localityof a spillage. As for pollution associatedwith compoundestablishment, much of the potentialfor detriment to a watercourseis as a result of nutrient enrichment,and the effects of this havebeenadequatelydescribedhitherto. 5.6.5.2 WaterSupplv Possibleimpactson waterquality issuesfor eachof the potentialresourcesare:

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o Surfacewater In almost all cases,wherebaselinewater quality datahasbeenavailableon the rivers and streamsidentified in this report, there are water quality problems associatedwith elevated nutrient levels derived from either STWs or agricultural runoff. To some extent, these problems are ameliorated through the movement of water in the river channel, where any turbulence in the water helps aerate it, and hence increase the supplyofdissolved oxygen. In addition,the movementof water ensuresthat organic pollution is continuallymoved downstream,henceno one areais permanentlyunder severeorganic pollution unlessit is downstreamof a STW, although this will be amelioratedin times of peakwinter flows. Canal systems and the reservoirs that feed them are, on the whole, quite different. The reservoirsand the Canal system will act to impound the water, and a high organic/nutrient load can have long lasting detrimentaleffects on individual locations wheremovementis restricted. As with river systems,this effect will be amelioratedto a certain extent especially where there are weirs or lock systemswhich allow the water to fall through the air and act turbulently with the receiving water, thereby aerating it. In addition, there is the added bonus that water from the streamsand rivers identified will be taken only in times of peak flow which will mean that any organic/nutrientload on the river from point sources such as STWs will be diluted to its greatestextent, and the river or streamwill also be at its most turbulent,hencepotentiallywith an elevatedlevel of dissolvedoxygen. Unfortunately, there are also disadvantagesto taking water fiom a stream or river at times of peak flow, as it is likely that there will be a greater sediment load on the river, much of which will either be attributable to road runoff (in urban areas) or agricultural runoff (in rural areas). Once the water reachesthe storagereservoir, its velocity will be abruptly diminished,and its sedimentload will be depositedat the bottom of the reservoir, or for finer organic sedimentsin suspension,degradedby bacteria,therebyreducingavailabledissolvedoxygen.In additionto the above,whilst the benefits to the Canal system around locks and weirs have been identified, there will remain large sectionsof the Canal located some distancefrom the nearestsource ofturbulence,and the increasedoxygensupplythat goeswith it. In a worst case,whereno mitigationis usedto preventexcessivenutrientinput to the Canal, one would expect to observe water quality typical of a hyper-eutrophic conditions,dominatedby algal bloomsand potentiallyanaerobicconditionswhich do not support higher forms of floral or faunal species. This situation would be amelioratedslightly aroundlocks and weirs however,wherethe Canal adjoinedother rivers and Canalstherewould potentiallybe reducedwater quality aroundthe locality of the confluence. The issue of reducedwater quality in times of low flows has not been addressed becausenoneofthe suppliesto the storagereservoirswill be takenat thesetimes.

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Restoration orthew'\*.Tl[tTl'; o Stormwaterrunofffrom MF Lyneham The option of using storm water runoff from RAF Lynehamhas beenraisedas a potential additional water supply. Earlier, the problems which are cunently experienced with the qualityofthe effluentand its effectson the Stringswatercourse wereexolored. If the Canalwas suppliedwith stormwaterrunoff fiom RAI Lyneham,a numberof impactswouldoccuraroundthedischarge point. Thepollutantsandtheireffectsare asfollows: - Oil and fuel - The elfectsof thesepollutantswere describedearlierand include suffocation ofplant life, andpoisoning of fishandlowerfaunallifeforms. - Increasedsuspendedsediment load, especially mud, grit, metal particles and tyre organics. This increasedsediment load would lead to siltation, increasedturbidity, toxic substancecontaminationand nutrient enrichment. - De-icing fluids/compounds- Thesewill be seasonallydependentbut will consist mainly ofsodium and chloride. Increasingthe salinityofa waterbodywill causethe reductionofspeciesdiversityeitherthroughevasion(suchas fish), or deathas a result of the toxic effectson specieswhich arelessmobile. - Metals,suchas lead,zinc and cadmium- Although it is unlikely that therewould be large volumes of these materials entering the Canal, most elevated levels of metals have a toxic effect on fauna, dependingon the individual species' resistancelevels. The sublethaleffectsof thesetoxic pollutantsmay reducean organism'sability to perform necessaryfunctions, lowering its efficiency and hence survival chances. In addition, there can be cumulativeeffectson fauna when there is a combinationof toxic pollutants entenng the waterbodywhich may have a synergisticor additive effectso that sublethalconcentrations of individualmetalsbecomelethal. Apart from the primary effects of the pollutants on the waterbody, it is worth considering how the silts and muds around these offtakes will be disposedoff when managementdredgingtakesplace. If samplesindicatethat the silts containelevated levelsofpollutants suchas heavymetals,it will not be possibleto disposeof them to agricultural land, and tliey will be treatedas contaminatedwaste (see Sub-clause

s.9.4.3). o Groundwuter Little water quality dataon the potentialgroundwatersuppliesis currentlyavailable, howeverit is acceptedthat most of the possiblesuppliesare contaminatedwith iron, and haveelevatedsalinitv. Iron contaminationof groundwateris a commonphenomenon.Iron is solublein its fenous state (Fe'*) where water is totally deoxygenated, however when the water becomesoxygenatedit r.villoxidiseinto its fenic form (Fer*1 and becomeinsoluble. If the groundwaterwas pumped directly into the Canal systemthis would lead to

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Restoration of thewilts& BerksCanal: Feasibility Study. ochreousdeposits around the area of the dischargeunless the water could be aerated belorehand. of ions in solution,without determiningwhich As salinity describesthe concentration elements are to be found in the water it is not possible to make any meaningful commentregardingthe likely effectsofusing thesesupplies. . Runofffrom new develoPment The water resourceselement of the report identifies the potential for additional water supplies by taking stormwaterrunoff from new development(housing). Runoff from residential areaswill typically consist of dust, litter and grit, organics such as leaves, grasscuttings and pet faeces,and fuel and lubricantsfrom drives and roads. The problems associatedwith these tlpes of pollutants have been adequately described above and include increased turbidity, siltation, nutrient load and oil pollution. The problem can be exacerbated,particularly in summer months after a long dry period when DO levels in the Canal are particularly low, by storm events which place a shock load of the above pollutants on the Canal. Such an event can create localised anaerobicconditions and, where speciesare unable to evadethe area, can have lethaleffects. 5.6.5.3 Operationsand Maintenance The water quality aspectsassociatedwith the operation of the Canal are difficult to predict as it is not yet known what mitigation measureswill be incorporated into the restoration, however there are certain impacts which will occur if mitigation is not carried out. These are split into impacts resulting fiom amenity use, and impacts with maintenance. associated o Amenityuse It is predictedthat therewill be up to 5,000boat movementsper year on the restored Canal, in addition there are likely to be permanentmoorings, boat maintenanceand pubs,shopsetc.). refuellingfacilitiesand servicefacilities(restaurants, The variousimpactsthat can occurthroughfuel spills,litter etc.havebeenadequately describedabove,howeverthe types of impactsassociatedwith boat traffic have not been explored. The leakageof lubricantsto the canal as a result of the cycle of engine cooling rvater is a relatively minor impact, and even with boat traffic approaching5,000movementsit is not expectedto be a particularproblem. Boatsdo discharge'greywater' effluents(suchas washing-upwater which containphosphates) which are allowed to be pumped straight into the waterbody. However it is likely that run off of fertilizers from sunounding agricultural areas would potentially have a thandischargefrom boats. greaterpotentialeffect(risk of eutrophication) The movementofthe boatsthroughthe waterbodyalsohas a numberof effects,if the channel is shallow enough, base sedimentswill be constantly moved, thereby increasingturbidity locally and makingnutrientsavailableoncemore. In addition,the boat's movementsmay have the effect of eroding banks and releasesoils into the

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Restoration orthew\*,Tiflrrffit; waterbody(Clause5.4.4.) The propswill, however,have a beneficialimpact as they will createturbulencein the water aroundthe blades,aiding the aerationof the water. Angling can also have some impacts on the waterbody, for example water fowl can become entangledin discardedfishing line and hooks and unless adequateaccessis provided to the waterside bankside vegetation can be degraded. However, good managementof the fishery can do much to avoid problems developing, as outlined in Clause5.2.4. o Maintenance There are two areasofroutine maintenanceon the Canal which can have an effect on water quality, they are dredging and banksidevegetationcontrol. Dredging has a major beneficial impact on Canalswhich have poor water quality as a result of elevated nutrient levels. Dredging is an effective method of removing nutrients and organic matter fiom the system completely. This is especially true of phosphorouswhich can be locked up in sediments,but releasedwhen conditions become anaerobic.Purely organic dredgings have a value to agricultural land, and dredgings should always be removed from the bankside otherwise nutrients may be leachedback into the waterbody. The only negativeimpact of dredging on water quality is a localisedincreasein turbidity and,ifthere is any flow in the channel,downstreamsiltation. It will be essentialas part of the day{o-day managementof the Canal to maintain accessto boat traffic in the channel and pedestriantraffrc on the towpath. Banks and verges will be cut on a regular basis,however there will be an effect on water quality if cuttingsare allowedenterthe waterbody,this will providean elevatedorganicload leadingto many of the problemsdiscussedearlier. Cuttingsshouldbe removedfrom the bankside, however there may be a conservationinterest in keeping cuttings and dieback within the Canal comdor. Although some shade from overhangingtrees helps to maintaina balancedecosystem, too many overhangingtreescan be a hazard to boating and leaf fall can be detrimentalto water quality due to the build up of organic detritus. Thereforeregulartree maintenancemay be required. 5.6.6 Mitigation The single most importantlorm ofpollution identifiedin this study is the additionof organicmaterials/nutrients. The controlof the nutrientlevelswithin the Canalwill be ofparticular importancenotjust to waterquality,but alsoto amenityand conservation interest. During eachphaseof construction,supply and operation,the potential for nutrientinputshas beenidentified. In eachcasethis sectionwill presentthe typesof mitigationwhich could be usedto stemboth the shortterm impacts(deoxygenation of the water) and the long term impacts(eutrophication) of elevatednutrient levels,as well as the othertypesofpollution that may occur.

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5.6.6.I Construction The elfectsof siltationand turbidity dunng constructionwill be particularlydifficult to mitigate against, however contractorsshould be able take steps to ensureminimal uptake of sediments,especially when constructing cofferdams,/bypass channels or at confluences with major rivers such as the Avon. During excavation and dredging work, plant operativesshould ensurethat arisings are removed fiom the bankside so that they can not fall or be leachedback into the waterbody. Wherever compounds are constructed,fuel and oil storage should be such that it is secureand bundedin the eventof an accidentor vandalism.Plant shouldbe refuelled from the compound wherever this is possible, rather than bringing the fuel to the plant. Construction materials should be used such that only the immediate needs of the operative are satisfied in the areaof working, and matenals are stored away from the waterbody. All compoundsshould be fenced and secured,and positively drained away from the waterbody to a soakaway or to the mains sewer (consents will be required from the licensing authority in either case). In addition foul and grey effluents should either be dischargedto mains seweror, where this is not practicable, storedand takenoffsite for disposalat a licensedpremises. Undertakingthesemeasuresshould ensurethat risk of pollution to the waterbodyis reduced significantly, even though some of the effects sediment releasewill go unmitigated. 5.6.6.2 Supplv The main considerationwith supply is to ensurethat the wherever the water is derived from, it is as clean as is economicallypossiblebeforeit is dischargedinto the Canal. As mentioned in the baselinesurvey, a number of the catchmentsin the areaof supply haveparticularproblemswith nutrientloadingon nver systemsdue to a combination ofpoint and diffusepollution,and low flows. Somecatchments(e.g.River Ray) have already been designated with a status which recognises the problems of nutrient enrichment,and othersmay follow shortly(e.g.UpperBristol Avon). Allowing for the fact that the restoration of the Canal is likely to be a long term process,it may be possible that a number of the problems highlighted will be amelioratedto a certainextentthroughthe actionsof the EnvironmentAgency. They havebeenproactivein recognisingand attemptingto resolvethe problemsassociated with both STW final effluent limits/volumesand the standardsof housekeepingon farms. It is hoped that the actions that have been taken to date (such as tightened dischargelimits on certainSTWs),and thosewhich may happenin the future(suchas phosphatestrippingat certain STWs) will provide a betterriver water quality from which to take suppliesat times of peakflows. Even if the EnvironmentAgency is successfulin its mission to reduce nutrient loadingson local watercourses,it will still be necessaryto provide some form of treatmentto water abstractedfrom them. As discussedearlier,peak flow rates are usually attributableto winter storm events,and as it is likely that storm sewersalso identifiedlor supply,therewill be increasedloads of dischargeinto the watercourses organics,litter, dusts and sedimentsin the supply to the reservoirs. There are two

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main recommendationsfor treatmentof water that is taken fiom local rivers (this also applies to storm runoff from RAf Lyneham): settlement ponds and constructed wetlandslor supplypolishing. o SettlementPonds As discussedin the impactssection,peak flows will have heightenedvelocities,and hencewill be ableto carry an increasedsuspended sedimentload. Without utilising a settlementpond much of the suspended load will be depositedin the reservoirleading to lower capacity and a requirementfor regular maintenancedredging. If a seriesof settlement ponds were introduced, then these could be allowed to fill up with sedimentand be planted, or dredgedroutinely without allecting the reservoir capacity. In addition, much of the insolublepolluting matter such as litter, debris and some metalscan be settledout at this stage. Once the water is free of its sedimentload it could passto a constructedwetland. o Constructedwetlands Constructed wetlands or reed bed systems are a low technology and maintenance, economicand efficient method of cleaningwater. They can be used in a variety of situations and have a seemingly universal application. They are efficient at reducing nitrate, removing phosphorousand organics, oxidising ammonia and have variable successin removing metals. Their applicationwould not only benefit water quality, but also improve habitatas they are readily colonisedby bird and insectspecies. A view would needto be takenon the sitingofeach system(dependingon the quality of the water after it is dischargedfrom the settlementpond), however perhapsthe most applicable supply to benefit from constructedwetland treatment would be storm run off, whether it be from RAF Lyneham or lrom new development. o Eutrophication and Deorvgenation Where nutrient loads rn the Canal are not stripped out at source,and eutrophic conditionsdo arise,this can be particularlydifficult to manage,however there are somemeasureswhich canbe takento reducethe effects. Where there are long lengthsof Canal where there is relatively little cover, and no addedturbulencefrom lock functioning,it would be prudent to considerplacing a supplydischargein the centreof the length,and supplywater so that it is well aerated as it entersthe Canal,this rvill combatdeoxygenation in the localisedareawhich may occur after algal blooms have subsided,and can be undertakenusing an elevated water supplypoint so that the supplyreactsturbulentlywith the receivingwaters. In addition, landscapingcan be planned into the restoration so that lengths which may becomeeutrophicare shadedto a greaterextent. This will affectthe ability for algae to photosynthesise efficientlyand thereforethe successofalgal species. Once the Canal in restored,the treatmentoptions for eutrophicationbecomemore expensive,but include regular dredging to remove nutrient rich sedimentsin the localisedareaand placingbarleystrawin the channelwhich has an unexplainedtoxic effect on algae. As a last resort, where deoxygenationhas taken place, aeration

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This is often

undertakenas a last resort and in coniunction with a fish rescue. . Iron contamination In considerationof the treatmentwhich would be requiredfor groundwater,it is only possible to comment on the iron content of the water. As mentioned previously, as the iron is in its ferrousstateit will oxidisereadilyonceoxygenis addedto the water. Before making any decisionsaboutthe treatmentpossibilities,it is necessaryfirst to assesshow much iron is in the water. If iron levels are only slightly abovenormal levels,then it would be practicalto supply it directly into the Canal,all other things being equal, however there may be a need to remove other contaminants' and this processcould include exposureto oxygenatedwater. Where simple aeration is not a which involve the practicalproposal,or will not work effectively,thereare processes additionof othercompoundsto precipitateout the iron. Whichevermethodis used,it will be necessaryto removethe ochreousdepositsfrom the baseof any tank or clean obligations. filters,both of which havemanagement c Siltation and ntrbidity Canal channelsnaturallybecomesilted-upand chokedthrough the accumulationof organicdetritusand fine sediments.A dredgingregimewill ensureclearanceof the channel and Canal structures, as well as the removal of nutrient rich sediments. Dredging will be particularly important around the confluenceswith other systems such as the River Avon and the Kennet and Avon canal. It will not be acceptablefor 'partner' systems,especiallywhere they are already under silt to be washedinto these pressurebecauseof high nutrientload and siltation,e.g. the Avon at Melksham A dredging regime should therefore incorporate regular work at junctions and confluences.In addition,siltationis likely to occur aroundsupply points where fine sedimentswhich have not been settledout previouslyare deposited. The dredging regimeshouldalsotake accountofthis. 5.6.6.3 Operation It would be prudent r.vhenlicensing the retailing of fuel, to obtain a contractual commitmentfrom the prospectivelicenceholder to retainonsitepollution abatement equipmentsuchas oil booms,and for the licenceholderand their staff to be trainedin the useof the equipmentand possessa valid emergencyresponseplan. If therewas a significantoil/fuel spill into the Canal,without this equipmentto hand,much of the flora and faunawithin the vicinity of the spill would be harmedor killed. In addition there would be a costly and lengthy clean-upoperationwhich would have been avoidedif the equipmentwas onsiteto stopthe spreadof the spillage. Where other banksidefacilities are envisaged,it is essentialthat their effluent is directedto the seweragesystemwhereverpossible.However where this can not be achievedas a result of locationaldifficulties,the effluent should be dischargedinto properlysitedseptictank. Finally, when fishing rights for the Canal are licensed,it would be useful if notices were put up on notice boards alerting anglers to the consequencesposed by

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Restoration orthew\:ffltr-Tii irresponsibleactions auch as hazardsto wild fowl posedby discardedfishing line and hooks. Theremay alsobe potentialto developa leaflethighlightinga codeofpractice for anglerswhich could be issuedwith fishingpermits.

5.7 Archaeology Obtainingdetail on the whereaboutsof archaeological finds in closeproximity to the route of the Wilts & Berks Canal will be of particular signihcanceduring its restoration. New route options, accesspoints from road and alongside the Canal, construction compounds and the route itself may all be subject to constraintsif they are located within the confines of sites of archaeologicalimportanceor interest. It is therefore imperative that this early stage of the restoration planning process, archaeological considerations are assessedand intemrption with known sites of importanceis plannedout of the restorationwhereverpossible. archaeological Legislationcoveringarchaeological and culturalheritageis embodiedin a numberof different Acts and govemment guidance.The Ancient Monuments and Archaeological Areas Act 1979 and The Town and Country Planning Act 1990 are the main elements of primary legislation which afford protection to archaeologicaland cultural assets. Under the former, certain sites identified as being of national importance are given protection, and are referred to as ScheduledAncient Monuments (SAMs). Any works to or within a SAM, or even works which affect the setting of an SAM are govemed by a consentingsystem operatedby English Heritage. Under the latter Act, local authorities have the ability to protect areas which are of archaeological interest through the invocation of planning conditionson development. This will usually entail a commitmenton the behalf of the developerto undertakefield investigations and report on the findings prior to any developmenttaking place. The powers under both these Acts have the potential to affect the planning and development of the restoration of the old Canal alignment, but perhaps more significantly, the new with it suchas new routeoptionsand feederlakes. developmentassociated The objectiveof this part of the study has been to collect and presentexistingdata relatingto the historicalroute alignmentof the Canal as well as the most promising new routeoptrons. 5.7.1 Methods A desk based study of the entire Canal route, including the most favoured route options, has been undertaken.The main referencefor this has been the Sites and MonumentsRecord(SMR) held by Wiltshireand OxfordshireCountyCouncils. For each reach of the Canal, a corridor width of around I 00m was viewed, and a numberof separateitemswerenoted,theseareincludedin Appendix M. There are a number of limitationswith the Sitesand MonumentsRecord.Whilst the OxfordshireSMR includeslistedbuildingsand industrialarchaeology(evidencedby the references to Canal structures), it doesnot includecrop markingsinterpretedfrom aerial photography although rve understandthat this information is separately available. Similarly, with the Wiltshire SMR, crop markingswere included,but no

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bearing in mind that the vast majority of the Canal route passesthrough rural areas.It should also be notedthat whilst a'Find'may be noted at a specificlocation,it does not necessarilyfollow that all archaeologicalinterestin the area ceaseswhere the Find's boundariesare marked. This will require consultationwith the County Archaeologistover eachreachof the Canal. Until the restorationproposalsfor eachreachof the Canalaremore fully developed,it will not be possible to obtain comprehensivecoverage showing areas of archaeologicalinterestas, in order to do this, detail relatingto the locationof haul roads, compounds, feeder lakes etc. will be required. There should, therefore, be a separateand more detailed study undertakenfor each reach, in consultation with the relevantCounty Archaeologist. 5.7.2 Results Results from the SMR survey are presentedin Appendix M, and individual Finds/ ScheduledAncient Monumentshave been addedto the mappedsectionswithin the main body of the report. ln each case,where possible,information has been obtained on the exact location of each find, although care must be taken in interpreting this as many of the finds are linear features or enclosures,therefore where information relating to the geometry of the find is available it has been added to the mapped section. The Find number relerred to in the table is the same number as would appearin the particular SMR, and can thereforebe usedto refer back to the SMR if necessary. 'proximity' inlormationto the table. This should It was consideredbeneficialto add act as a guide only as all measurementsare rough, but will provide a good approximationofthe likelihoodofthe Canalworks affectingthe particularfrnd. 5.7.3 Impacts It is of primary impo(ance that none of the proposedoptions affect existing ScheduledAncient Monuments,and this has been successfullyachievedalong the historicalalignment,and the new route options.However,thereare four SAMs listed in the table which are passedcloselyby variousroute options,and thesesectionsof Canalmay requireconsentingby EnglishHeritageifthey aretaken forward.They are as follows: o CrickladeTown Wall (Saxon)to the eastof the town o West Leaze,a shrunkenmedievalvillageto the southof Swindon o A complexofenclosuresand field markingsto the southwest of Caldecott o The Ock bridge and siteofa l4th.centuryhospital.

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Restoration of thew'i:"T[.rT:t; In additionto the SAMs,therearea numberof Finds,andgroupsof Findswhich may be affected by certain route options, as well as the restorationof the existing alignment. Wherethe route passesthroughor in closeproximity to the Find area, closeconsultation must be established with the relevantCountyArchaeologist in order to both assessthe importanceof the area,and to deviseappropriatemitigation measures whereit is deemednecessary.It may be the casethat certainFindsarenot necessarilyindicatorsof greaterarchaeological interestin the specificarea,andhence mitigationmay not be required.Therearetwo main groupsof Findswhich are likely to be affectedbv certainootions.thev areasfollows: Routeoption A to the westof Cricklade:thereareat least7 findswhich areeitheron, or in closeproximityto this new routeoption,all of which relateto latemedieval potteryfragments. Route Option B to the south west of Melksham: there are a cluster of undated and unexploredringditches and earthworks,which as a group may have significant value. 5.7.4 Mitigation and Enhancement In order to avoid undue disturbanceof archaeologicalremains,it will be necessaryto ensurethat those route optionswhich lie on or in close proximity to archaeological frnds are given careful consideration against other factors used to establish route option acceptability. In essence,whereverpossible,theseroutesshould be avoided. Where the existing alignment lies in close proximity to areas of archaeological interest, restorationproposalsmust take this into account,hence ensuring that access points, haul routes etc. are positioned well away from the area. Where destructionof the areais unavoidable,consultationwith the CountyArchaeologistmust takeplacein order to assessthe requirement for survey work prior to the Canal restoration taking place. As the restorationof eachreachof the Canal is planned and programmed,negotiation with County Archaeologist,English Hentage(where a SAM is involved) must take place well in advanceof works starting. Under the Planninglegislationmentioned above, it is likely that the County Archaeologistwill require a certain amount of survey work to take place, especially with the new route options. Proceduresmust also be set up which accountfor the discoveryof'unexpectedfrnds'. This is where archaeologicalremainsare uncoveredduring the constructionprocess,and a set of predeterminedprocedureswill ensurethat finds are not unwittingly destroyed. Finally, it should be appreciatedthat the restorationof the Canal to its original line will entail the refurbishmentof many of the existing structuresalreadylisted as of archaeologicalrmpo(anceto the region. Restorationwill seek to enhanceboth the heritage and amenity value of these structures, as well as bring them back into productiveuseoncemore.

5.8 Noise Noise associatedwith demolition and constructionactivitiescan cause significant disturbanceto nearby residences,domesticlivestock,and to local animal habitat,

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of the Wilts & BerksCanal: Restoration FeasibilityStudy. especially bird habitats which are used as secure, feeding or overwintering sites. In

the longerterm, althoughit is difficult to makefirm predictions,the operationof the noisenuisance at anyof the sitesalongthe to causesignificant Canalis not expected Canalroute. are demolition, which will give rise to noisegeneration The typesof operations have the general however all operations construction, and structuraloperations potentialto causenuisanceifthey arelocatedin closeproximityto sensitivereceptors to identifywhere of importance suchashomes,schoolsandoffices. It is, therefore, the main areasof sensitivityalongthe Canalalignmentarelocated,and establishthe tlpes of operationwhich arelikely to impacton thosereceptorsat this early stageso that significantimpactscanbe mitigatedagainstbeforethe operationscommence. 5.8.1Regulation Constructionwork on the Wilts & Berks Canal may be locatedin a variety of situationsfrom predominantlyrural andurbanlocalitiesto city centres.The natureof the work canvary significantly,aswith all constructionactivities,henceregulationto activitiesrequiressomeflexibility.The standard controlthe noisefrom construction "Noise and open sites"attemptsto do this. It controlon construction BS 5228 part 2 dealswith compnsesfour parts;part I givesbasicinformationandprocedures; by open cast part to coal extraction demolitionand road maintenance; 3 applies methods; andpart4 dealswith pilingoperations. by variousitemsofequipment Part1 containsa largedatabankofnoiselevelscreated given power levelsand the equivalent as sound and operations.The noiselevelsare continuoussoundpressurelevel,Lo.o,at 10m from the noisesource.The test results on which the databankis basedwereobtainedin the 1970's,sincethenmanufacturers haveproducedsignificantreductionsin equipmentnoise.It is preferable,therefore,to datawhencarryingoutnoisepredictions. usemanufacturers the noiselevelsis outsidethe scopeof BS 5228because The definitionof acceptable local authorityhasthe powerto fix limits underthe Controlof PollutionAct, 1974 (seebelow) and the Environmental ProtectionAct, 1990.In the absenceof local given values in advisoryleafletnumber72, issuedby the guidance, the authonty defunctMinistryof PublicBuildingsandWorks,maybe used.The recommendation is that for daytimeworking the noise level outsidethe nearestwindow of the dwellingshouldnotexceed: receiver's . 70dB(A) in rural, suburbanand urbanareasaway from main roadsand industrial nolse r 75dB(A) in urbanareasnearmain roadsandheavyindustrialareas. Prosecutionsfor creating noise are normally brought under the Environmental ProtectionAct 1990.No objectivedefinition of a statutorynuisanceis given in the Act and acceptablelimits are not specified. In practice it is the duty of the EnvironmentalHealthOfficer to decidewhetheror not a pa(icular noiseis a statutory nuisance.

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Under the Control of Pollution Act 1974 Sections60 & 61, certaintypes of constructionactivity areregulatedthrougha consentingarrangement.Contractorsare 'Section61 Consent'.In doing so the obligedto applyto the localauthorityfor a plantutilised, a rangeofdetailson thetypesof operations, makesavailable contractor technicalinformationon noiseandvibrationemissionsandmitigation manufacturer's proposals.If the Consentis forthcoming,the contractorandthe local authorityhavea on thenoiseandvibrationemissionlevelsfiom the site. legallybindingagreement 5.8.2 lmpact Identification This sectionbnefly outlinesconstructionactivitieswhich are likely to cause from noiseemissions.It is not possiblepredictwith any degree significantnuisance asthesearedependent on many noise levelswhichwill be generated the of certainty factors,suchas the type and conditionof the plant used,the levelsof maintenance, at this time.In proposed, whichcannot be ascertained andthe methodsof operation thedurationofeachstageofconstruction, to determine addition,it is alsonotpossible factors suchas whetherthe contractis being upon a number of as this will depend contractors. or engineering by volunteers undenaken In general,constructionnoise will be confinedto specific sites along the proposed route alignment. Anticipated construction noise impacts are discussed under the following operations: 5.8.2.I Demolition It is difficult to determinethe absolutenoise levels lor demolition, and so make generalisations, becausemethodsusedtend to vary from site to site. Nevertheless, from demolition are generallyonly marginally louder than those from noise levels constructionactivities,but shorterin duration.However,as demolitionis only likely to take place in centresof population, there is a high potentialfor the activitiesto causenuisance,eventhoughthe durationof demolitionis expectedto be short in any one area. So far, only a few locations where the demolition of structuresis required (e.g.at EastChallow)howevertheremay be furthersitesas the havebeenestablished projectprogresses. 5.8.2.2 Structures Piling operationsare potentiallythe main sourceof noise during construction. The most prominent impacts are anticipatedto arise from the constructionof retaining walls, wharf frontsand mooring facilities. Suchfacilitiesaremost likely to be placed in or nearto centresofpopulation. As yet the locationsfor thesetlpes of facility have not beendetermined,howeverlocationswith the most potentialare likely to be some or all of the following: Abingdon, Grove/Wantage,Swindon, Cricklade, Wootton Bassett,Calne,Melkshamand eitherSemingtonor SeendCleeve. In the "worst case", that of sheet piling, day'timenoise levels may fall outside guidance levels outlined earlier, but the noise impact can be lowered by using altemativepiling methods,i.e. boredpiling for the constructionof retainingwalls. In general,however,noiseimpactsat the receptorswithin a closeproximity to the source of the emissionsare likely to be significant.

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whereit is necessaryto Thrustboring and box jacking operationswill only be used built over the piouiJ" n"*-Cunal accessthr:oughstructureswhich have eitherbeen Both techniquesare ", *tt.r. the original .'o'-'ing structureno longerexists' [}.i an embankment'The noise g"..*riv utliir.a *n"rJthe structur;to be crossedlies on generallyshort,term.in fiom theseactlvlllescan oe significant,although,onceagain, on the"proximiiyof sensitive-receptorsPredictionsfor noise au.utionanddependent oncethe exactlocationof "nriU""Uf. to tireseoperationscanbe ireparedin advance which areto be employed. ii" ^"ii"lry is known,andthetlpe of mitigationmeasures canbe usedareoutlinedin Table 5'6' Areaswherethts typeon construction Table5.6Box JackingLocations Name Structure NGR Location A34 (T) Trunk Road 475958 S.W.of Abingdon IntercitY Railway Line 298903 N.E.of Uffrngton Intercity Railway Line 292900 N.E.of Uffrngton Intercrty Railway Line 282893 W. of Uffington Intercity Railwav Line S.W.of Shrivenham 220875 A4l9(T) TrunkRoad 192814 S.E.of Swindon M4 Motorway 121823 S.W.of Swindon could be used' such as culverttng There may be other crosslngswhere this technique will become apparent as the. project *"unl, ^ra rivers under the canal, and these the crossingsabove is that they progresses. One lmportant aspectregarding each of of.population' hence significance are all relatively remote (> r Obm) frJm any centre slight' of the noire from theseparticularcrossingsmay be 5.8.2.3 GeneralConstructionand Excavation of compounds'constructlon Generalconstructionactivitieswill includeestablishment of materials and constructtorv of haul roads, bulk excavation, dredging, haulage restorationof Canal structuressuch as locks' impactson residentialor In general,constructionsiteswill only havesignificantl-oise o6"-1tthe receptor' areaswherenoiselevelsieachor exceed75dB(A)L'r.lq'l .oi*"..i"f Howev€r' there nature' temporary Where this is the case, lmpacts are generally of a ^ . a " * . " p t i o n r w h e r e t h e d u r a t i o n o f t h e c o n s t r u c t i o n a c t i v i t i e s a n d / o r tAreas heclose and residential premises are unavoidable buildings sensitive to ;;;-t;t;i '*ni"r, activities, basedupon their *itt be particularly sensiilveto generalconstruction O' proximity to the constructionactivity,arelistedin Appendix 5.8.3 Mitigation of ConstructionNoise techniques that can "-fttliYttY There are a number of establishedprocedures and will be neighbourho^ods reducethe level of noise to ivhich residentsof sunounding a following. by,pnor planning' exposed.Noise in.rpactsmay be largely avoided establishmentof baselinelevels. O"iuii"A ,tuOV of noise inrpactsthat ln.lud.r the

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Additional considerationshouldbe given to the different statutoryrequirementsof localauthorities, conceming noiselevelsandworkingmethods. For eachstageof the restorationprogrammethe contractorshouldseeka consentfiom the relevantlocal authorityunderthe Controlof PollutionAct 1974Section6l on noiselimits lor theproposed construction works. Detailsof construction activities,predictionmethodsand noise levelsshouldbe discussedwith the local authorityboth prior to constructionwork andthroughoutthe period. Sincedetailedconstruction construction programmes are only likely to be availablea shorttime in advanceof work startingon site,prediction,evaluationand assessment ofnoiseaswell asdiscussion between thecontractor andtherelevantlocal authorityshould,by necessity,be a continuousactivity throughoutthe construction period. Whereconstruction noiseis assessed ashavinga potentialimpacton residents or the environment,the Contractor shouldaim to achievecomplianceset out within the relevantlegislationand standards.Measuresto be consideredshouldbe consistent with therecommendations of BS5228andincludethefollowing: o Hoursof work shouldbe agreedwith the localauthority(e.g.0800to 1730)with working. limitationson weekend . Carefulselection of plantandconstruction methods.Only plantconformingwith relevantnationalor intemationalstandards,directivesand recommendations on noiseandvibrationemissions shouldbe used. r Designand useof site hoardingand screens,wherepracticableand necessary, to provideacousticscreening at the earliestopportunity. For example,noisefrom a pilingoperation hammer-dnven canbe limitedby enclosing thehammerheadin an acousticscreen, whichwill reducenoiselevelsby l0dB(A), i.e.sheetpiling noise impactsareexpected to drop from 75dB(A)at I lOm to 75dB(A)at 26m.Where practicable,doors and gatesshouldnot be locatedoppositeoccupiednoisesensitive buildings. . Useof altemative kindsof screening, suchas storagepiles(spoilor construction materials) Strategiclocation of temporarysite compounds,buildings (such as offices and stores) and haul roads to avoid sensitive locations. Choice of routes and programming for the transport of construction materials, spoil and personnel. Constructionvehicleroutingshouldtakeaccountof the needto reducenoise All plant items should be properly maintained,provided with effectivesilencers and operatedin sucha manneras to avoid causingany excessivenoiseor exhaust emission. All itemsof plant operatingon the site in intermittentuseshouldbe shut down in the interveningperiodsbetweenuse. All stationaryplant shouldbe sited within the defined constructionsite so as not to be a nuisanceto residentsand. wherenecessary, screeningshouldbe provided.

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Monitoring of noise and vibration levels at selected sensitive sites should be

undertakenon a regular basrs. o Where excavation takes place adjacent to residential or other types of units, considerationshouldbe paid to the possibilityof financialclaims for compensation lrom cracking, settlementor other structuraldefectsarising as a direct result of the works. Wheretheselocationsare identifiedit is recommended that a photographic survey be carried out on a "before and after" basis. o Where noise could significantlyaffect residentialpropertiesthe possibleneed to ofler financial compensationor short term alternativeaccommodationshould be bome in mind.

5.9 Waste Disposal 5.9.1 Introduction This sectionof the environmentalappraisalexploresthe type, quantity and disposal options lor wastes generatedduring the restoration/constructionand operation of the Canal. The following issueswill be identified and developedin light of cunent knowledgeof the Canalrestorationscheme: r the type ofwaste generatedand at what stage . the regulatory lramework o material excavatedlrom the Canal route o material dredgedfrom the channel . vegetationclearance . constructionwaste . disposalcosts,and r the requirementfor furtherstudies. Table 5. 7 below identifiesthe broadtypesof wastesthat are likely to ariseduring the constructionand operationof the Canal. Each of these types of waste di ffer in compositionand thereforehave differentoptions for disposal. The compositionand disposaloptionsfor eachwastetype areconsideredfurtherbelow:

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Table5. 7 l\laterialsGeneration Source

Wastetype

Phaseof WasteGeneration Construction Operation Material excavated from Canal excavation spoil X route Material dredgedto form / maintain dredgings channel greenwaste Vegetationclearance generalwastes Construction activities

X

5.9.2 Definitionsand Regulations The regulations goveming waste management are specific to the type of waste concemed.Definitionsfor somekey typesof wastesaregiven below. 5.9.2.I Inactive LVaste This covers materials which do not undergo significant physical, chemical or biological reactionsor causeenvironmentalpollution when depositedat a landfill under normal conditionse.g.,masonryand brick rubble,or uncontaminated soils in their natural state. Inactive waste cunently attracts Landfill Tax at f2 per tonne. Inactive waste includes soils and rocks, ceramics,concrete,minerals, lumace slags, and ash.

5.9.2.2 Active Waste Active waste includes acids, pesticides,fly ash, wood preservatives,oily sludges, batteries,wasteoils, asbestos, timber,and plastics. Active waste attractsLandfill Tax at f7 per tonne. 5.9.2.3 Dfficult Waste Generallythis term is appliedto describewasteswhich could in certaincircumstances be harmful to humanhealthor the environmentin the shortof long term due to their chemicalor biological properties,for example,dry cell battenesand mineral oils. This term is also applied to wastes whose physical propertiespresent handling problems at the point of disposal, for example, dredgingsthat have not been dewatered. 5.9.2.1 SpecialWaste The definition of specialwaste is waste that is deemedto be dangerousto lfe. They may be classified as special waste as they are for example: corrosive,reactive, explosive,oxidising,carcinogenrc or flammable. Someof the more common special wastesinclude:acids,alkalinesolutions,industrialsolvents,oily sludges,and waste oils. The criteria to be usedto determinewhethera rvasteis specialwaste is laid

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of the Wilts & BerksCanal: Restoration FeasibilityStudy. down in the Special waste Regulations 1996 and the technical guidance given in DoE

Circular6/96. of KeYLegislation 5.9.2.5Summary of The followinglegislationis particularlyrelevantwith regardto the management wasteson srte: '1990

.

Act Protection Environmental

.

1991 (DutyofCare)Regulations Protection Environmental 1996 SpecialWasteRegulations Landfill Ta.r(QualifyingMaterial)Order1996

o

WasteManagementLicensingRegulations1994.

5.9.3 MaterialExcavatedfrom the CanalRoute 5.9.3.I Introduction- quantit' and composition The material excavatedto form the route of the canal will be excavatedeither from natural undisturbed ground (where the Canal runs along a new route) or from made ground infill (where the canal runs along the existing route). A preliminary issessmentof the likely quantitiesofthese two typesof materialis presentedbelow in Table 5.8; the assumptionson which these figures are based are presentedin Appendix N.

Table5. 8 Quantitiesof ExcavatedMaterials Type of material Material excavatedfrom natural ground

Quantityarising(m")

330,000

Materialexcavatedfrom madeground infill

At this feasibilitystage,baselinesurveyshavenot beencarriedout to providedetailed informationon the likely compositionof the matenalthat will be excavatedto form havebeenmade: the channel. For this reason,the following assumptions 95% of the excavatedmaterial from natural ground is uncontaminatedand therefore inactive 7 50/"of the excavated material from nrade ground / inhll is uncontaminated and thereforeinactive.

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Uncontaminated naturalgroundwill consistpredominantly of clays(seeDrawingNo. DBKEP/004/01). Although there are currentlyno data available on any material that falls under the categoryof contaminated naturalground at this feasibility stage,it is possiblethat sucha materialtype may arisern excavatingthe channel. Investigative surveysalong the route shouldbe carriedout in order to identify areas of contaminated natural ground. o Excavationfrom madeground / infll This material will be found where the old Canal charutelhas been infilled, either purposelyor naturally.The compositionof this materialis likely to be highly variable along the route, varying from inactive wastes(such as soils) through to contaminated material that has been tipped in the channelover the years. The EnvironmentAgency have been consultedto find out whether they have any recordsofclosed landfills alongthe old route.Responses will be incorporatedinto the final draft of this report. There is someanecdotalevidenceregardingthe compositionof materialusedto infill the Canal. This informationis given below: o

The tunnel at Calne may have been infilled with waste from the nearby meat processingfactory.

.

The channel may have been 'used as a rubbish tip' near Broadleaze Farm (098923)according to Dalby(1986).

o

The channel from Cricklade to Moreton may now be infilled with ash produced from the now demolishedMoredonPowerStation,accordingto Dalby (1986).

r

Option E aroundSwindon,throughBridgemead,consistsof old railway sidings.

.

Option F to the north of Swindontakesthe CanalroutethroughShaw Tip, which is currentlyundergoingrestorationto a forestpark. This landfill was licensedto receivehouseholdwastes. However, as the channelwill be raisedthrough this areausing excessspoil generatedelsewherealongthe route,it is unlikely that the landfill will haveto be disturbed.

o

It is understoodthat thereis a brickwork spoil heaplocatedat GreenHill, situated to the eastof CoateWater.

In addition, as suggestedin the availableliterature(Dalby, 1986), it is likely that adjoining land usershave used the old Canal channelas a void in which to dump waste. As the length of the route passesthrough both agriculturalland and urban

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Restorationof the Wilts & BerksCanal: Feasibility Snrdy.

land, it is difficult to make furthercommentsregardingthe likely compositionof the inltll. 5.9.3.2 Disposaloptions Assumptions have been made as to the percentagesof material that may be suitable are presentedin Appendix N. In for reuse,recyclingor disposal.Theseassumptions order to assessthe disposaloptionsfor excavationspoil in more detail, investigative surveyswill be requiredto provideinformationon its composition. . Inactive material Where suitablein engineeringterms, this class of material may be reused in the scheme for landscaping, fill or to form banks. It is anticipated that 10% of the arisings which are inactive can be reused within the restoration, for example as fill material to form bridge abutments for roads that currently cross the Canal route at ground level. Opportunitiesto reuse this material outside of the scheme for constructionoflsite also exist, althoughit is not possibleto explorethese further at this stage. The excessmaterial(forming an esrimared733,500mr)will be acceptedat landfill for disposalas inactivewasteanclthereforewill be subjectto the lower rate of landfill tax (cunently !2 per tonne) and a disposalchargeof around f5 per tonne. However, this figure should be taken as indicative and highly subject to variation, as it will depend significantlyon the availabilityandproximity of appropriatelandfill sites. c Contaminatedmaterial The options for reuse of this material will dependon the level of contamination present. 'Interim guidance on the disposal of contaminatedsoils' prepared by the Environment Agency (1997) and identifies that a hazard assessmentand risk shoul I o r - : 9 ? a c! -o ; t s o o (!'o;

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9.5 Environmental Studies Tkoughout the courseof the environmenlalstudy,the needfor furtherresearchhas beenemphasised in a numberof sections.Theneedfor furtherstudystemsfrom the requirementto obtain qualitativedata in order to make detailedpredictionson the natureand significanceof the impactsof the restoration.Someof this work can be undertaken almostimmediately andwill be requiredin orderto obtainprotectionof the routein LocalPlans. However,otherareaswill requirea greaterlevelof detail relatingto the restorationandhow it is to be progressed. The requirements for further study are presented in Table 9. 2 alongsidean approximation of the prerequisite knowledge needed beforethestudiescanbemeaningfully achieved. In additionto the factorscoveredin the table,in eachof the areascoveredtherewill be a requirementto consultwith statutoryconsultees, interestgroupsand local communities duringthedevelopment of therestoration proposals. Most of additionalsurveywork requiredcan eitherbe carriedout for the canalas a wholeor, if the restoration is likely to be split into individuallengthsor reaches, as eachoneofthem is develooed.

Table9.2 Further EnvironmentalStudiesRequired Area Ecology*

Water Quality*

Study PhaseI Habitatsurveyof entire canalroute,includingstorage reservoirs,compounds,river sectionsand accessareas.

Prerequisite information Land ownership: information for access. Detailon: final optionchoice, locationofreservoirs and compoundsand accessroutes.

Phase2 HabitatsurveywherePhase PhaseI Habitat I suneysrevealtheneed survey Specialistsurveysmay alsobe PhaseI Habitat protected requiredfor species survey Collectionand interpretation of Detailon choiceof long-temrchemicalandbiological final waterresource monitoringdata(existing)against options,specific hydrologicald31n+ pinpointgapsin locations of storage knowledge.For eachsupplyprepare reservolrs etc.

Approx. cost(f,) 10,000

Unknown Unknown

2,5005,000per supply

treatmentrecommendations.

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Table9, 2 Further EnvironmentalStudiesRequired (continued) Area Archaeology*

Noise

Waste Disposal

Study

Prerequisite information SMRsurveyof reservoir locations, Detailedof compounds andaccess routes. boundaries for each Locationof otherareasof historical location andarchaeological areas(e.g.listed structures) with County Negotiation Ditto plusarchaeological Archaeologist, surveyrvorkpnorto workstarting Baselinestudiesof background Reservoir,compound positions and accesslocations noiseat sensitive receptor Impactprediction Detailof operations,

Baselinegroundtestingof canal routeand ancillarystructures Landfill survey

Arisingsdisposal strategy General Landscape

AccessStudy

EnvironmentalCodeof ConstructionPractice Detailedlandscape assessment of the canalrouteand evaluationof detaileddesigncriteriafor canal structuresand fumiture

Approx. cost(f,)

2000

Unknown

7500

2500

plantusedat each location. Locationofreservoirs 30000 none

Thetwo surveys above Detailfrom baseline studies Engineeringdesigns needprogressing sufficiently for exact locationsand dimensionsof structuresto be determined. Landscapearchitect and design engineers shouldliaiseclosely to ensurethat the correctmaterial specifications are adopted. Final prefenedroute choice

2500 10000 5000 3500

Revier.vof existingrightsof way to 2500 detemrineexactrequirements for existingfootpathdiversions (permanentor temporary),needfor additionalaccessand scopeto improveboth footpath,/bridleway netu'orkand integrationrvith other countrvsideir.ritiatives. t this informationis likely to bc requiredto assistwith safeguardingof the route in Local Plans

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10. REFERENCES

Allen & Hanis/RoyalInsurance,1994.TheWiltsandBerksCanal,FeasibilityStudy. Austin,G. andMunell,R., 1993.Draftnoteon feasiblelinesfor canalto thesouthof Abingdon.WBCAG,EastValeBranch,Wantage, 4th amendment 11/8/93. BritishWaterways,1994.Research Matters-December 1994,Watford. Bromley,J., 1975.Unpublished PhDthesis.Universityof Bristol. Brook,J. et al, 1996.Guidanceon the disposalof dredgedmaterialto land.CIRIA Report157 BSI, 1997.BS 5228NoiseControlon construction andopensites(2 parrs),BSI 1997 Burgess, J., 1994.ThePoliticsof Trust:Reducing fearof crimein urbanparks. Comedia.Stroud. Circularon SpecialWasteRegulations, 6/96,HMSOJune13 1996 CIRIA, 1997.Wasteminimisationin construction-site guide.Construction Industry Researchand InformationAssociationSpecial Publication133. Guthrie, P., Woolveridge, C. & Patel,V. Controlof PollutionAct 1974,HMSO 1995.Themarketfor recreational Countryside Commission, cyclingin the countryside. Dalby,L.J. 1986.TheWiltsandBerksCanal.OakwoodPress. EA, 1997. Thames(Eynsham to Benson)andOck LocalEnvironment AgencyPlan (Second DraftConsultation Report andFinalDraft).Environment Agency,June1997. EA, 1997.Interim guidanceon the disposalof contaminated soils. (1" edition). Environment Agency,March1997. Ecotec Research& ConsultingLtd, 1996. The Economic Impact of Canal Development Schemes. Reportfor BritishWaterways, Watford. English Nature, 1996.EnglishNatureFreshwaterSeriesNo 2: Canal SSSIs management andplanningissues. EnglishNature,April 1996 EnglishTouristBoard,1991.Planningfor success: A strategy for England1991-1995. Environment Act 1995.HMSO Environmental Protection Act 1990.HMSO

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(Dutyof Care)Regulations Protection 1991,HMSO Environmental L. andWorpole,K., 1995. ParkLife: UrbanParksandSocialRenewal. Greenhalgh, Stroud. Comedia, reporton watersupplies.Wilts and BerksCanal Griffiths,FN, 1986.Unpublished AmenityGroup. Griffiths,FN andWilliams,JD, 1988.TheMelkshamProject:A reporton restoringa WaterwayLink betweenthe KennetandAvon Canal,MelkshamandLacock.Wilts & BerksCanalAmenityGroup,January1988. Gustard,A., Bullock, A., Dixon, J.M. 1992.Low flow estimationin the United Kingdom. Institute of Hydrology Report No. 108. Institute of Hydrology, Wallingford. of RiverandCanalBanks,CIRIA HemphillR.W. I 989.Protection IWA paper. Harrison,A., 1996.WaterwayRestoration. of natural of the chemicalcharacteristics Hem,J.D., 1992. Studyand interpretation Paper2254. SurveyWater-Supply water.(3'dedition).US Geological Britain'sEnvironmental Strategy.London. HMSO,1990.ThisCommonInheritance: PIANC24thInt.Nav.Congress. Hyde,T.M. 1977.Watersupplyfor waterways. map of the southwestChiltemsandthe Berkshireand IGS, 1978.Hydrogeological London. Dorvns.Instituteof Geological Sciences, Marlborough RegisterandStatistics1986-90.Institute Instituteof Hydrology,1993.Hydrological of Hydrology,Wallngford. LandfillTax (QualifyingMaterial)Order1996,HMSO 1989.Boatingandwatersportsin Britain. LeisureConsultants, 1996- 2000. 1996.LeisureForecasts, LeisureConsultants, 1991.WestSwindonRouteStudy.April 1991. Maunsell& Partners, NRA, 1994. The Upper Bristol Avon CatchmentManagementPlan Consultation Report.NationalRiversAuthority,June1994 NRA. 1995. The Upper Bristol Avon CatchmentManagementPlan Action Plan. NationalRiversAuthority, March 1995. NRA, I 995. Upper Thanres CatchmentManagementPlan ConsultationReport. NationalRiversAuthority,January1995.

194

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Restorationof the Wilts & Berks Canal: Feasibilitv Studv

-

Nolan,A. and Hopkinson,P., 1997. Valuationof canalattributesby non-paying towpathusers.Universityof Bradford.

.

North WiltshireDistrictCouncil.1995.North WiltshireLocalPlanReviewDeoosit Document. April 1995 Oxlord Polytechnic, Civil Engineering Degree,Final Year Students, July 1987.A PreliminaryDesignStudyfor theRestoration of the WiltshireandBerkshireCanalin thevicinityof Melksharn, Wiltshire. Oxfordshire CountyCouncil,SitesandMonuments Record,unpublished RoyalCommissionon CanalsandWaterways,1907. CanalandWaterwayRetums for 1907. RoyalCommission on Environmental Pollution,1994.Transport & theEnvironment. HMSO,London. ScottishTouristBoard,1993.ScottishTourismMultiplierStudy1992. Shaw,E.M. 1994.Hydrologyin Practice. Chapman & Hall,London. 1996,HMSO SpecialWasteRegulations Thamesdown BoroughCouncili994. Thamesdown Local PlanDepositDraft. May 1994 andArchaeological TheAncientMonuments AreasAct 1979,HMSO Regulations 1997,HMSO TheHedgerows TheTownandCountryPlanning Act 1990,HMSO Vale of White Horse 1995.Local Plan WrittenStatement DepositDraft. Vale of WhiteHorseDistrictCouncil.October1995 WasteManagement Licensing Regulations 1994,HMSO WaterResources Act 1991,HMSO WestWiltshireDistrictCouncil,1996.WestWiltshireDistrictPlan- AdoptedPlan, March1996 Act 1981(& amendments), Wildlife& Countryside HMSO Willis,K. andGarrod,G., 1990.ValuingOpenAccessRecreation on Inland Waterways.Reportby thc Dcptof Agricultural Economics & FoodMarketing, Universityof Nervcastle-upon-Tyne.

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Restoration of theWrlts& BerksCanal: FeasibilityStudy.

Reportby the Properties. Willis,K., andGarrod,G., 1993,TheValueof Waterside Unit, University of Newcastle-upon-Tyne. Countryside Change Record,unpublished WiltshireCountyCouncil,Sitesand Monuments

196

SconWilsonKrrkpanick& Co Ltd

Restoration of the wilts & BerksCanal: FeasibilityStudy

11. APPENDTCES

AppendixA StudyBrief Contacted AppendixB Organisations AppendixC ProjectDocumentRegister AppendixD RouteMaps and Schedules of Features AppendixE SurfaceWater CatchmentFlows AppendixF CodingSystemfor PotentialNewWater Supplies Report AppendixG GroundwaterYield Assessment AppendixH Water Quality Data AppendixI River Corridor Surveys AppendixJ Sensitivityof AquaticPlantsto BoatMovements AppendixK The GQA and WQO Standards UseClasses AppendixL Standardsfor River Ecosystem Finds AppendixM Detailsof Archaeological AppendixN MaterialsRequiringDisposal AppendixO ReceptorsSensitiveto Noiseand DustEmissions AppendixP EconomicBenefitAssessment To UtilitiesEnquiries AppendixQ Responses

ScottWilsonKirkpatrick& Co Ltd

197

Rcstorationolthe Wilts & BcrksCanal: F e a s i b i l i rSv t u d v

Appendix A Study Brief

S c o t tW i l s o nK i r k p a t r i c k& C o L t d

(now the EnvironmentAg-ency)and from a numberof charitiesand otherfundingagencies.With lhe Imminent formation of the Trust it hasnow beenagreedthat the time hascomi t6 commission a studyof the feasibilityof restorarion of the wholeCanal. 2.6 A list of relevantstudiesand publications,which will be availableto the consultant,is given in Appendix A. ObJectlves of the study 3. I The objectives of rhe study are to: (a) review the principal difficulties tobe facedin restoringthe Canal and to considerhow thesedilTicultiesmisht bestbe overcome. (b) considerthe u"r-t r*n, una sequenceoi carrying out the restorationwork and,where thereis a choice,determinetheoptimum route, (c) review the water requirementsof the restoredCanal and the bestmeansof providing the necessarywater resources, (d) assessthe benefitsof restorationto the local community, as well as regionally and nationally, (e) investigatethe env.ironmentalimpactsof restoration,assessingthe environmental enhancementsachievableand suggestingmitigation measureswhErean adverseimpact is likely, (f) providean estimateo[ of thecostof restorationfor separatesectionsof the Canal. Scope of stud_v {. t T.hestudy is to cover the main line of the Wilts & BerksCanaland the Calneand North Wilts branches. 4.2 Where the Canalis obstructedbl derelopmentthe Consultantshall reviervvariousoptions for deal.ingwith the situation;theseshallincluderestoration alongthe originalroute,restdrauon alongalternativeroute(s)suggesred by theTrust and restorationilong otfrerrouteswhich appear to the Consultantto be practicable. 4 3 The Con-sultant is not requiredto investigateland orvnership.Whereit is necessary to enkr pnVateland lor the purposeso[ the stud\',the ConsulLant shall makehis orvnarranqements rvith the lando\tner. Detailsof land orvnership, rvherekrorln to the Client,rvill be mad! availableto the Consultant. 4.4 Water resourcesshall be reviewedin consultationrvith the EnvironmentAgencv.Southlest reg.ions. This aspecto[ rhe_ study she]lconsidersurfaceand g,ouni't*rt.r -effluents rupp .., Tl l!1..r runoll lncludlng lrom major.paved surfaces(eg the M4), reuseof treated and posslDltrtres lor storagelvrthmor outsidethe Calal and of backpumping. The impactof restoratlonon lvaterquality,land drainageand flmd management ari to ue includid. 4.5 The Studv.shallincludesufficientengineering detarl,includingall criticaldimensionsand levels,to permit realisticestimates oi theiosts of'the rvork propoied. All costestimateishall be basedon the assumptionthat the \rorks $'ill be camedout b!: commercialcontractarvarded through.competrrive tendering.The Consulurntmav indicati thoservorksrvhichcould be undertaKen by voluntxrygroupsand thecost sa\.ingsthat rvouldbe achieved. 4.6 The assessment of theenvironmentalimpaclsof restorationshallbe baseduponan initia1 outlinebaselinesurvel'of the Canalrouteand ils environs.The magnitu'I ltuc

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RESTORATION OFTHE WILTS& BERKSCANAL - FeasibilityStudy SECTION 9: StanleyFarm Bridge to Bremhilt Wick Bridge Length: 1.75km OS Ref: ST 960732to969746 Level:60.6nAOD Description:Ruralreachwith limited access(no publicrightsof way) Geolory: OxfordClay Water Resources:Potentialwinter abstraction from River Sands& Gravelsin thevicinitv of WestTytherton Navigation,Recreationand Leisure: EnvironmentalFeatures: Services: Land Use:Agriculture,Grade3.

Scheduleof Featuresand RestorationCosts: Feature / Name Description Canal Reach

Services StanleyFarmBridge Bridge(?) King Fix Bridge Cat Brook Culvert

Othercrossings BremhillWick (Arch) Bridge

Canal bed well-defined but sidesover srown. Removed.Assumenew farm accommodationbridge required. Not vis ble. Assumenew farm accommodationbridge required. Not vis ble. Assumenew farm accommodationbridge required. Not vis ble. New culvert required.

Allow two furtherfarmaccommodation brideeson this reach

Cost(f,) 157,000 5,000

50,000 50,000 50,000 30,000

100,000

Seenext section

ESTIMATED TENDER PRICE FOR RESTORATION Notes: Lift bridges or traditional arch bridgesmay be appropriateon this reach.

442,000

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RESTORATIONOF TI{E WILTS & BERKSCANAL - FeasibilityStudy SECTION 10: Bremhill Wick Bridge to Charlcutt Hill Bridge Length: l.35km Level:60.6mAOD OS Ref: ST 969746to 978755 Description:Ruralreachthroughfarmland Geolory: OxfordClay in this section Water Resources:Cunentlyno proposalsfor waterresourcedevelopment Navigation,Recreationand Leisure: EnvironmentalFeatures: Services: Land Use:Agriculture,Grade3; woodland(BremhillGrove)

Scheduleof Featuresand RestorationCosts: Feature / Name Canal Reach

Services BremhillWick (Arch) Bridge FarmCrossing BremhillGrove(Lift) Bridee Culvert Culvert Charlcuff Hill Road Bridse .

Description

Cost(f,)

For the first 150mof this reach.the canalbedhasbeennarrowedand whichentersat Wick Bridgefrom the SE, carriesa watercourse, runningparallelto theroadandleavestumingNW. Thenext270mis infilled.Thebalanceis in-waterthoughnot restored,andotherwise generallyclear,but thetowpathis overgrown.

180,000

5,000 TheoriginalWick Arch Bridgeis infilled andthe canalbedpiped.New fixed bridgerequired.It will needa slightrisein theroadto achieve this,but this shouldnot be a problem. Accomodationbridgeto replaceexistingfarm crossing

75,000

Bridge abutmentsand wooden decking remain, serving as a public footpath.Restore,or replacewith fixed footbridge for right of way. Culvert requiredfor drainageoff the escarpment.

25,000

Culvertrequiredfor drainageoff the escarpment.

25,000 25,000

Seenext section

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

50,000

385,000

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RESTORATIONOF TIIE WILTS & BERKSCANAL - FeasibilityStudy SECTION 11: Charlcutt Hill Bridgeto FoxhamBridge Length: l.90km OS Ref: ST 978755to981775 Level: 60.6nAOD Description:Rtral reachthroughfarmlandendingat Foxham.No publicright of way or vehicleaccesssouthof Foxham. Geology:OxfordClay Water Resources:Potentialwinterabstraction from CadaBuma.with reservoirstorase.Possibleuseof treated runofffrom RAF Lyneham. Navigation,Recreationand Leisure: EnvironmentalFeafures: Senices: Land Use:Agriculture,Grade3; ruralresidentialat Foxham

Scheduleof Featuresand RestorationCosts: X'eature/ Name Description CanalReach Canalbedgenerallyclear,with water presentfor perhapshalf the length. Services CharlcuttHill Road Bridge removedand canal culvertedvia 3x30" pipes. Fixed bridge Bridge required,road to be raisedslightly. potential. Basinvisible.No buildings.Re-development CharlcuttWharf Lift Bridge Originalbridgeremoved.Assumeno longerrequired Lift Bridge Originalbridgeremoved,new(lift) bridgerequired. Poor condition. Provide new culvert. CadeBumaCulvert CadenhamManor Bridges

Assumeone vehicle and one foot bridge required.

FoxhamArch Bridse

Seenext section

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

Cost(f)

170,000 5,000

70,000 0

0 60,000 30,000 75,000

410,000

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RESTORATIONOF THE WILTS & BERKSCANAL - FeasibilityStudy SECTION 12: FoxhamBridgeto City Bridge Length:2.60km OS Ref: 5T981775to 985796 Level:60.6to 68.8nAOD;3locks Description:Partiallyrestoredsection.LynehamAirheld lkm to the east. Geology:OxfordClay Water Resources:Cunentlyno proposalsfor waterresourcedevelopment in this section Navigation,Recreationand Leisure: FoxhamInn 0.8kmwestof FoxhamLocks. EnvironmentalFeatures: Seruices: Land Use:AgricultureGrade3; residentialat Foxham(gardenon line) Scheduleof Featuresand RestorationCosts: Feature/ Name Description Canal Reach The first 1.65kmfrom Foxhamis generallyin goodorderwith water presentin places,but overgrown.Theremaining0.95kmup to City Bridgehasbeeninfilled. Gardenon line at Foxham.

Cost(f,)

330,000

15,000

Services

Foxham(Arch) Bridge Originalbridgeremovedandculverted.New bridgerequiredwith regradingof approaches. Also regradingof accessto Cadenham Manor, privateresidences andFoxhamLock. FoxhamWharf Wharfbuildingslost;WharfCotiagein originalcondition. AccessBridee Allow for new access,and land swap or compensation BackpumpingStation Requiredfor lockageconservation. Risingmainlength300mto dischargeaboveFoxhamTop Lock.

150,000

0 80,000

73,000

FoxhamBottom Lock

Fair condition; clearedand brickwork made safe 1992.Restore. Original lift 2.74m to 63.4mAOD

75,000

FoxhamTop Lock

Lockchamber restored. Gatesrequired. Lift2.7lm to 66.lmAOD New fixed bridgerequired4.6mwide. Restoration completed1993 Rebuiltin concretewith DN300exit pipe,completed1994

30,000 50,000 0 0 0

Farmcrossing Elm FarmLift Bridee FoxhamS.Spillway Park Farm Arch Bridse

ParkFarm(Lift) Bridge ElephantLift Bridge Foxham North Spillway

BackpumpingStation

Being restoredby landowner,but arch likely to be replacedby concrete slab.Navigation clearanceto be confirmed. Partially rebuilt with fixed deck. Deck to be raisedor new bridge requiredto permit navigation. Restorationwork completeexceptfor balancebeams,counterweights and supportingcolumns.Will carry right of way acrosscanal. Spillway now rebuilt; the adjacentwatercoursedischargesto the R.Avon approx 2.2km distant. Requiredfor lockageconservation.Rising main length 60m to dischargeabovelock.

Wood Common Lock and Arch Bridge

Buried,possiblydestroyed, appears asa risein thefield. Allow for new structureincludingfarmbridgeoverlock.Rightof way crossesat this location.Originallift 2.69mto 68.8mAOD

CiWFarmCulvert City Bridge

Existing culvertedwatercourse,culvert in good condition seenext section

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

30,000

0 5,000 60,000

230,000

0 1,128,000

SECTION13

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RESTORATIONOF TI{E WILTS & BERKSCANAL - FeasibilityStudy SECTION 13: City Bridgeto DauntseyLock Length: 1.35km OS Ref: ST 985796to 996802 Level:68.8to 71.4mAOD;1 lock Description:Ruralreach,restorationwork in hand.Development plansfor Daunstsey Lock andimmediate environsareincludedin the LocalPlan Geolory: OxfordClay Water Resources:Cunentlyno proposalsfor waterresourcedevelopment in this section Navigation,Recreationand Leisure: Peterborough Arms (listedbuilding)at Dauntsey,with possible extension,canalbasin,windinghole,slipwayandCanalVisitor Centreallowedfor in theLocalPlan. EnvironmentalFeatures: Services:Pylon0.6kmfrom City Bridgewith bracingwire anchorsin bedof canal Land Use:Agriculture,Grade3; residentialat Dauntsey.Canalreachfrom electricitypylon to DauntseyLock (andbeyond)is in ownershipof localW&BCAG chairmainandis beingrestored.

Scheduleof Features and Restoration Costs:

Feature/ Name

Description

Canal Reach

Generally clear but silted up. From the electricity pylon, the towpath is heavily wooded with overgrowntowpath hedge,but is being cleared. Canal has beendredgedlocally in the vicinity of DauntseyWharf and in water (but 0.6m below navigabledepth)

Services City FarmRoad Bridge Footbridge DauntseyWharf

15,000 Original bridge removed,canal infilled and culverted.Road risesat original crossingpoint. Farm bridge required. New bridge proposedto divert towpath to oppositeside of canal at DauntseyWharf to avoid canalsidecottages.

Canalfrontagerecentlysheetpiledandpavedasanamenityto the restoredcanalcottages(now in individualprivateoccupation).

DauntseyBridge Original bridge demolishedand culverted.Provide new bridge with (B406e) regradingof approaches.Also regradingof accessto private residences. BackpumpingStation Requiredfor lockageconservation.Rising main length 60m to

DauntseyLock

dischargeabovelock. A back pump systemis proposedas part of the current local restoration,but this would needupgradingfor the full canal restoration Restorationof brickwork almost complete,paddlesand gatesto be madeand fitted. Original lift 2.59mto 71.4mAOD

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

Cost(f) 148,000

55,000 25,000 0 80,000 45,000

0

368,000

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RESTORATIONOF TI{E WILTS & BERKSCANAL - FeasibilityStudy SECTION 14: DauntsevLock to Waite Hill Wharf Length:l.90km OS Ref: ST 995802to SU 014806 Level: 71.4mAOI) Description: Rural reach,restorationwork in hand. Geologr: OxfordClay Water Resources:Cunentlyno proposalsfor waterresourcedevelopment in this section Navigation,Recreationand Leisure: EnvironmentalFeatures: Services: Land Use:Agriculture,Grade3; Canalreachfrom DauntseyLock to approx100mshortof WaiteHill Bridgeis in ownershipof local W&BCAG memberandis beingrestored.

Schedule of Features and Restoration Costs:

Feature/ Name CanalReach

Description Sectioncurrentlybeingrestored,exceptthe lastapprox100mto Sodom Lanewhich is clearbut infilled andusedasfarrnland.

Services DauntseyLock Spillway @ridge) WaiteHill Farm Bridge

Completelyrestored No hace.Crossingassumedno longerrequired Bridgeremovedandcanalbedculverted.New farm accommodation bridgerequiredwith regradingof approaches.

waite Hill wharf

Seenext section

Seeprevious section

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

Cost(f)

30,000 5,000 0 0 0 70,000

r05.000

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RESTORATION OFTIIE WILTS& BERKSCANAL - FeasibilityStudy SECTION 15: Waite Hilt Wharf to Trow Lane Bridge Length: 1.60km OS Ref:SU014806 TO 027811 Level: 71.4to 89.3nAOD; 7 locks Description:Restorationarea.TheSevenLocksarevery overgrownandalthoughmanybrickshavebeen poundsetc,canbe found.Thetowpathfrom SodomLane removed,the sitesof all chambers, intermediate (WaiteHill Wharf)to Lock 5 is publicallyaccessible but not a right of way.At thetop of theflight the route passes througha ponytrainingpaddockandgardensbelongingto theold lock house.A minor diversioncould avoidthis land. Geolory: OxfordClay Water Resources:Currentlyno proposalsfor waterresourcedevelopment in this section Navigation,Recreationand Leisure: Fishingclubat TockenhamResrvoir EnvironmentalFeatures: Services: Land Use:Agriculture,Grade4 Scheduleof Features and Restoration Costs:

Feature/ Name Canal Reach

Description Generallyheavilysilted(0.6mtypical)andovergrown,but not deliberatelyinfilled.Theproximityof the locksmeansthatintermediate poundsarewide.HeavilywoodedbetweenLocks5 and7.

Services (WaiteHill WhaO Remainsnot visible. Risingmainlength900mto BackpumpingStation Requiredfor lockageconservation. dischargeaboveLock 7 (Top). SevenLocks Remainsbarelyvisible.Structuredemolished/robbed downto water levelincludingtop cill, but remainsprobablysoundandthuslock Lock I (Bottom) restorable. Believed to be in fair condition, restore. Culvert Bowd's Bridge and Originallya lift bridgespanningthe lock chamber,Bowd's Lanenow Lock 2 crossesLock2 on infill. Providenewfixed bridgeintegralwith Lock 2 restoration. Bowd's Bridge Wharf Remainsnot visible.

Cost(f,)

250,000

5,000 0

140,000 75,000

2,000 110,000

0 60,000

Lock 3

Chamberwalls lowered to water level and many bricks at head removed.Clearedand under restoration.

Lock4

Full heightwallsbut poorcondition,severelydamagedby wartime demolitionpractice.Clearedandunderrestoration.

30,000

Lock 5

Full height walls but poor condition, also severelydamagedby wartime demolition practice.Restore. Damaged,has a wall with drainagepipe built acrossthe head.Restore. Good condition, gatesstill present.Head of lock infilled and crossedby a farm track. Restore. Remainsnot visible. Seenext section

90,000

Lock 6

Lock 7 (Top) Trow Lane Wharf Trow Lane Bridge

ESTIMATED TENDER PRICE FOR RESTORATION Notes: Overall lift throughthe SevenLocks takenas 17.9m,average2.56mper lock

90,000

40,000 0

892,000

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RESTORATIONOF THE WILTS & BERKSCANAL - FeasibilityStudy SECTION 17: Hart Farm Bridge to Hunts Mill Bridge Length: 1.67km OS Ref: SU 0428f7to 057815 Level:89.3mAOD Description:Readilyrecoverable rural sectionasfar asVasternWoodyard.Betweenthe,{3102andBreach Lane,restorationmuchdependson the implementation andalignmentof theproposedWootonBassettBypass. No existingrightsof way. Geologr: OxfordClay; Corallianlimestonebetween,A.3102 andHuntsMill Bridge Water Resources:Cunentlyno proposalsfor waterresourcedevelopment in this section Navigation,Recreationand Leisure: EnvironmentalFeafures: Services: Land Use:Agriculture,Grade4; Commercial(VasternWoodyard);residentialat VastemWharf(garden)

Scheduleof Features and Restoration Costs: Feature / Name Description

CanalReach

Services HartFarmBridge GrovehillBridge Vastem Wharf

Canalis generallyclearandholdingwaterbetweenHart Farmbridge andVasternWoodyard,but heavilyovergrown.Relocationof wood storagewill berequired.Infilled betweenVasternBridgeandHunts Mill Bridge.Thecanalbedimmediatelyeastof VastemBridgenow formsan areaof lawnfor a recentlybuilt property'VastemHouse'. Westparapetcollapsed. Poorcondition.Restoreto safecondition. Accesstrack, no traceofbridge. Within Woodyard. Allow for a new fixed crossing. No trace of Wharf. Redevelopmentpotential. Bridge removed.Road at high level. Provide,newcanal culvert.

VasternBridee VasternHouseGarden Allow for cut andcoverculvertextensionfrom VasternBridge(30m) 43102Crossing Current plans for the Wootton BassetBypassindicatethat the A3102

HuntsMill Bridge

Cost(f,)

350,000

30,000 25,000 50,000 0 65,000

45,000

can be closedoff and infilled at this point allowing the canal to be restoredat its original line and level. Canal restorationcost therefore included in Canal Reach.Redevelopmentpotential eg canalsidepublic houseand roadsidefacilities. Seenext section.

ESTIMATED TENDER PRICE FOR RESTORATION

565,000

Notes: Altemative routeshave beenconsideredfor restorationshouldthe current situationwith the A3102 remain unchanged.Seeeg W&BAG "The Canalfrom SevenLocks to Hay Lane - A DiscussionDocument"

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RESTORATIONOF TIIE WILTS & BERKSCANAL - FeasibilityStudy SECTION 18: Hunts Hill Bridge to StationRoadBridge Length: 1.40km OS Ref: SU 057815to 070815 Level:89.3to 94.4nAOD; 2locks Description:Straightreachthroughfarmlandapproaching WoottonBassett Geolory: KimmeridgeClay Water Resources:Potentialwinterabstraction from BrinkworthBrookto theeastof GreenhillCommonFarm Navigation,Recreationand Leisure: EnvironmentalFeatures: Seruices: Land Use:Agricultural,Grade3 to 4; residentialat StationRoad.Possiblehousingdevelopment at Dunnington Farm.

Scheduleof Features and Restoration Costs:

Feafure/ Name Canal Reach

Description Generallyintactandholdingsomewaterasfar asthesiteof Lower DunningtonLock; infilled thereafter. Theoriginalcanalline is incorporated into gardensof propertiesalongDunningtonRoadfor a lengthofabout 200m

Services

HuntsMill Bridge No tracevisible.Roadbridgerequired,clearance adequate. DunningtonAqueduct Exisitingaqueductoverthe BrinkworthBrook,in excellentcondition. Restoreaqueduct. Backpumping Station Requiredfor lockageconservation. Risingmainlength400mto dischargeaboveUpperDunningtonLock Lower Dunnington No trace,buried.Rebuildlock.Originallock Lift2.46to 91.8mAOD

Cost(f)

290,000

10,000 60,000

15,000 85,000 150,000

Lock

Bridge UpperDunnington Lock TrucklesLaneBridge StationRoad Bridee

Buried.Assumenewfarmbridgerequired. No trace,buried.Rebuildlock.Originallock lift2.6l to 94.4mAOD Allow for new footbridge for right of way Seenext section.

ESTIMATED TENDER PRICE FOR RESTORATION Notes:

50,000 150,000 25,000

835,000

SECTION 19

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Restorationof the Wilts & BerksCanal: FeasibiliwStudv

Appendix G GroundwaterYield Assessment Report Commissionedfrom British GeologicalSurvey

ScottWilsonKirkpatrick& Co Ltd

British Geological Survey

7 October1997

ScottWilsonKirkpatrick& Co Ltd. ScottHouse 'BasingView Basingstoke Hampshire RG214JG

c-'".

0 9 0 C ;t

+44(0)i491838800 + 4 4 ( 0 ) i 4 9 i6 9 + 4 4 ( 0 ) 1 4 96 19 2 3 4 5 [email protected]

Attention Dr MA Jones

Dear Sir Groundwater Yield Assessments Thankyou for your letter of 22 Septemberregardingthe boreholeyield prognosesfor 5 sites in the SwindonDevizesareaand your chequefor the pro-former invoice. Detailedbelow are the geologicaland hydrogeologicalassessments. f. Grid Reference:ST 940 710 - West of Denry Eill, near Great Lodge Farm Our Ref: RE/ST97/7181 The ground elevationat the site is estimatedto be approximafely53 metresaboveOrdnance Datum. The geologicalsequencebeneaththe site is expectedto be as follows: @ord CIay and Kellm+,aysBeds (slwleyclay) Cornbrash (ntbbly limestonewith clay) ForestMuble (clay with limestone) Great Oolite Limestone (shellylimestonewith someclay) Fuller's Earth (claywith limestone)

40 to 50 m thick I to 1m thick 15-20mthick about 30 m thick 230m

The stratahavea shallowdip of ' tl

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Restorationof the Wilts & BerksCanal: FeasibilityStudy

Scott Wilson Kirkpatrick & Co Ltd

Restoration of the Wilts & BerksCanal: FeasibilityStudy

Appendix N Materials requiring disposal Quantitiesof material requiring disposal Total lengthof proposedrestoration(km) Approxlengthof originalcanalroutewhichhasbeeninfilled(km) Approxlengthof originalcanalroutewhichhasbeen(or is being)restored(km) Balanceof originalcanalroutewhichhasnot beeninfilled(km) Lengthof new canal(km) Lengthof river navigation(km) Dredging Lengthof canalthatwill be dredged(km) channelis 50%choked) Quantityof materialdredgedfrom channel(m') (assuming Assumeno dredgingsarereusedandthatall requiredisposal Excavation Material excavatedfrom original route Material excavatedfor new route Total quantity of material excavatedfrom old and new routeexcludingdredgings(m') Composition of excavation spoil Assume that95o/oof excavatednatural ground is not contaminated Quantity of excavatednatural ground that is not contaminated(m3) Assume that 5%oof excavatednatural ground is contaminated Quantity of excavatednatural ground that is contaminated(t') Assume that95Yoof infill is inert Quantity of infill that is inert (m3) Assume that5Yoof infill is non inert. Quantity of infill that is non inert (m') (m3) Total quantity of contaminated"spoil (m') Total quantity of inert spoil Total quantity of excavationspoil (m')

108.4 22.0 8.0 47.3 29.1 2.0

10 50,000

529,000 810,000 1,339,000

769,500 40,500 502,550 26,450 66,950 1,272-050 1,339,000

Reuse of excavation spoil (m3) Quantity of excavatedmaterial used for fillto new canalembankments (assume (m3) material used in landscaping l5%) of excavated Quantity Quantity of excavatedmaterial usedin formins new surfacewater reservoirs Total reuse

95,000 190,808 300.000 585,808

Disposal of excavation spoil (m') Quantity non contaminatedexcavatedmaterialrequiring disposa^l (m') material requiring contaminated excavated disposal Quantity

686,243 66,950

Disposal of both dredgings and excavated material Total disposalrequirement(assumingno dredgingsare reused)(ml) Assumedmeanbulk densityof spoil (tonne/m') Total disposalrequirement(assumingno dredgingsare reused)(tonne) Assumeaveragecostof disposalto landfill is f8 per tonne (plus landfill tax at f2 per tonne for inactivewasteand f7 per tonne for active waste)

ScottWilsonKirkpatrick& Co Ltd

803,I 93 1.5 1,204,789 12,550,012

Restorationof the Wils & BerksCanal: FeasibiliWStudv

Appendix O Receptorssensitiveto noiseand dust emissions Location

NGR (of residence)

Distance(m)

OutmarshFarm HolbrookFarm Berryfield

899614 889622 895624 896628 938621 936626 935631 913642 917643 926644 927645 917657 927660 925678 925681 927682 926685 925689 947718

250 200 200 200

Boundary Farm

RustvLaneFarm CraysmarshFarm

TanhouseFarm Melksham School,Melksham Blackmore Farm School,Blackmore Farm Forest Farm Near RhotteridseFarm

StrodeFarm Lacock Wharf

BewlevCrescent Bewlew Court

ReyMill Green Lane Farm

StanleyBridgeFarm HazelandMill Wick BridgeHoldings CharlcuttHillFarm CadenhamManor

Lock Farm Foxham Locks Elm Farm Dauntsy Lock Trow Lane Farm Hart Farm

Vastern HuntsMillFarm Wootton Bassett ChaddinstonLock House MorninssideFarm

Berrywood Near Wharf Farm Wharf Farm West Leaze Farm Westleaze Swindon(Near Westleaze) Rushy Platt Farm Bridsemead WestlecottFarm Near North Wroushton NightingaleFarm

ScottWilsonKirkpatrick& Co Ltd

9s9730 973724 969747 980756 982771 982774 981776 977777 995802 026812 0428I 8 052816 0 5 6 8I 6 0708l 6 092816 0 9 3 8I 8 18822

25822 28823 36828 38 8 3 2 43833 33838 31843 4 58 2 8 32824 67817

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Restorationof the Wilts & BerksCanal: FeasibilityStudy

BroomeFarm Nightingale Cottages

GreatMoor LeazeFarm AcornBridge AcornEnd StationRoad StainswickLane Cleaveland Farm Old Wharf Road Wharf Farm StallardsBridge KingstonCommonFarm Broardleaze Farm West Challow Bridge EastChallow Stockham'sBridee Near Stockham'sBridge Grove The Rookerv Steventon Road Caldecott Stonehll House Stoneh l F a r m SewageWorks (Abingdon) SewageWorks (SearchersWood) Conigre Farm

BerhillsFarm Calne

Swindon(EvenSwindon),Delta Swindon (Even Swindon),Westmead Swindon (Even Swindon), SewageWorks Swindon (Even Swindon),Near Sewage Works Swindon,School Elborough Bridge Swindon,Moredon

PryHolding Pry Farm WoodwardsbrideeFarm

Crosslanes Farm Dairy Farm Hayes Knoll Farm DudsemoreFarm BallickacreFarm Upper Broard LeazeFarm Horsey Down Stone'sFarm

r70819 r73817 t94827 216873

220877 238880

25 25

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203 203 204 204 204 204 204 205 205 205,206 206

ScottWilsonKirkpatrick& Co Ltd

Restorationof the Wilts & BerksCanal: FeasibilityStudy

Appendix P EconomicBenefitAssessment

ScottWilsonKirkpatrick& Co Ltd

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