RiversTrustCaBAWorkshop22.6.2017
ManagingAbstrac-onintheRiversWyeandUsk
BenefitsofEvidence,BadgeringandCollabora-on
JohnLawson,FREng,FICE,FCIWEMWaterResourcesAdvisertoWUF
WhatIwillcover• Howacatchmentpartnershipreconciledtheneedsoffishandwatersupplies
• HowWUFcampaignedpriortothepartnership
• Theimportanceofevidence
• TheresulFngimprovements
Cardiff
Brecon Hereford
Usk
Usk
Crai Talybont
Llandegfedd
R Wye
TheWye/UskWaterSupplySystemElan valley reservoirs Elan valley aqueduct
supplying 360Ml/d to Birmingham
Releases from Elan valley to regulate flows in Wye
Upper Usk dams supplying about 55 Ml/d to Swansea area
Releases from Usk dam to support drought flows
Lower Usk 175 Ml/d to Cardiff and Newport
Wye/Usk transfer 125 Ml/d Monmouth
Total all abstraction c 900 Ml/d
Builth Wells
Supplying 3 million people
Canal
ImpactsonsalmonWUF’s concerns: • Impact of the original dams • Major flow regime changes since 1970s
• Much less reservoir spillage
• Big fall in salmon numbers since 1970s
• Salmon stuck in lower river
• Uncontrolled canal abstraction
Original2007-10proposalsforHabitatsDirec-veCompliance
• FocusedonachievingHD“EcologicalRiverFlows”
• Used“benchmarkflows”,iedamsarenatural!
• Didn’treduceimpactsofdamsonspates
• Didn’tachievenaturalflowvariaFons
• Hadbigimpactoncanalwatersupplies,probablyrequiringcanalclosure
BUT,compliedwith“rules”,sodeemedOK!
WUFWhingeing&Badgering
• From2007to2010,wewroteleRers,hadmeeFngs,madeFoIrequests
• Andgotnowhere!
NRWresponsetoWUFWhingeing
• We’vecompliedwith“therules”• Ourmodellingshowsit’sOK• It’sbeenagreedbyeveryone• It’stoolatetochange
WUFEvidenceGathering
Our own investigation to break the impasse
WUFtoolsforgenera-ngevidence
• Wholeriversalmoncatchanalysis
• Individualbeatcatchanalysis• Modellingofwatersupplies,riverflows,watertemperatureandsalmonmigraFon
GeneraFngevidence-basedcounter-proposals
Wye water resource model • Daily flows 1973-2011 • Elan reservoir storage • Transfers to B’ham & S. Wales • Farm supplies
Water temperature model • Daily flows 1973-2011 • Daily temps • Impact of reservoirs
WUF Wye modelling tools
WyeSalmonCatchAnalysisFor 4 beats: Analysis of daily catch v flow records for c.9000 salmon
For whole river: Analysis of 100 years of records by season and reach
Sampleevidencefrombeatcatchanalysis
SummerFlownearErwood–600Ml/d
Combinedcatchandflowanalysis
ConclusionsontheWyeabstrac-onimpacts
• MigraFonfromtheestuarycurtailedindryyears
• MigraFonwithinriverdelayedbyspateclipping
• SituaFongeZngworseasabstracFonincreases
WUF’sproposedsolu-on
• Makemoreuseofthereservoirstosupportriverflowsandecology
• Especiallyinnon-droughtyears• Majorimprovementwithnoimpactonwatersupplies
MoreWUFBadgering
Using evidence to press for a better way
Mid-2012:Forma-onofUsk&WyeAbstrac-onGroup(UWAG)
WelshWater,SevernTrent,NRW,EA,CRTandWUF
Workingtogetherto:• maximiseecologicalbenefits• minimiseimpactsonwatersupplies• improveoperaFonratherthancutsupplies• makebeReruseofreservoirstohelpfish
KeyplayersinUWAG
Gail Davies, Welsh Water Owain Sheppard, NRW
Supported by Cascade Consulting (now Ricardo)
UWAGEvidenceGathering• Ecologicalwalkoversurveys• Fishandmacrophytesurveys• Salmontracking• Waterqualitymonitoring• Temperaturemonitoring
Wye water resource model • Daily flows 1973-2011 • Elan reservoir storage • Transfers to B’ham & S. Wales • Farm supplies
Estuary salmon migration models • Daily flows 1973-2011 • Daily salmon entry • Impact of flow changes
Water temperature model • Daily flows 1973-2011 • Daily temps • Impact of reservoirs
Usk water resource model • Daily flows 1973-2011 • 5 reservoirs storage • Canal supplies • Supplies to S.Wales
UWAG modelling tools
UWAGcollabora-on• 4workinggroups–strategic,technical,modelling,fisheries
• 36workinggroupmeeFngsin2years
• Freesharingofdataanddraapapers• SharingandharmonisaFonofmodels
• Numerousdiscussionpapers,proposalsandcounter-proposals,leadingto:
UWAGAgreementofDecember2014
TheUWAGAgreement
Signed by affected parties, supported by NRW & EA
SummaryofWyeimprovementsNewUWAGproposals
Exceptinseveredroughts,useElanreservoirsto:
• Releaseupto700Ml/dfromElandamstoboostexisFngspates
• Delayswitch-offofregulaFonfor7daysaaerstartofspates
• IncreasecompensaFonreleasesbyupto330Ml/dtorestorenaturalflowsinElanandWye
020040060080010001200140016001800200022002400
-2000-1500-1000-500
05001000150020002500300035004000
Environm
entalreleasesM
l/d
RiverflowM
l/d
Redbrookflows
Naturalflowreduced Naturalflowincreased NormalcompensationHEPrelease Normalregulation ExtracompreleaseDroughtcompboost Spateboost NaturalflowScenarioflow
Withfulluseofexistinglicences 1994Spates clipped
Regulation switch-offs
020040060080010001200140016001800200022002400
-2000-1500-1000-500
05001000150020002500300035004000
Environm
entalreleasesM
l/d
RiverflowM
l/d
Redbrookflows
Naturalflowreduced Naturalflowincreased NormalcompensationHEPrelease Normalregulation ExtracompreleaseDroughtcompboost Spateboost NaturalflowScenarioflow
Withproposedlicences 1994Higher spate peaks and recession flows
More reservoir releases
Improved migration from estuary
SummerFlownearErwood–600Ml/d
0
1000
2000
3000
4000RiverflowM
l/d
Erwood
Naturalflowincreased Naturalflowreduced ReservoiroutflowWithhistoricabstraction Naturalflow
2004 Withhistoricabstraction
Spates much reduced by Elan dams
0
1000
2000
3000
4000RiverflowM
l/d
Erwood
Naturalflowincreased Naturalflowreduced ReservoiroutflowWithproposedlicences Naturalflow
2004 Withproposedlicences
Spates and natural recession restored by reservoir releases Releases from
dams up to 700 Ml/d
Improved migration for adults and smolts Improvements achieved without impact on supplies
SummaryofUskimprovementsNewUWAGproposals
• MinimalLowerUskpumpingfromApriltoOctober
• TherebyalsoavoidingdiurnalfluctuaFons• Reservoirrefillmainlyinwinter
• Extrareleasesfromupperreservoirstoboostspates
• ReleasesfromUskreservoirtokeepcanalopenwhilekeepingBreconflowswithin5-10%ofnatural
Withnoaddi-onaleffectonpublicwatersupplies
To Canal
• Canal & Rivers Trust have unlimited Licence of Right • Limited to 25 Ml/d under informal agreement in 1999 • Until 2007, no reliable means of regular measuring • Gaugings at 50 Ml/d + in 2007
Canal abstraction at Brecon weir
ImpactonlowsummerflowonUskatBrecon
40 Ml/d diverted into canal?
Residual flow in river 40 Ml/d?
Flow above weir 80 Ml/d
Drought flows reduced by 50%
Historic flows at Brecon
Canal kept open by Usk reservoir releases and new canal feeders
UWAG improved flows at Brecon
LowsummerflowinthelowerUsk
Stranded ranunculus from diurnal pumping variation
Withnatural
riverflows
WithUWAG
proposals DiffToendJune
ToendSep
ToendDec
5445 4093 1352 24.7% 24.8% 10.5%
SalmonmigrationtoendSep %losses
Flow reduced by c.40%
Salmon migration to end September reduced by 1350
Much reduced pumping in migration season
1100 more salmon in river by end Sep With
naturalriverflows
WithUWAG
proposals DiffToendJune
ToendSep
ToendDec
5445 5175 270 4.1% 5.0% 2.4%
SalmonmigrationtoendSep %losses
Benefitsofimprovements• Reducedspateclippinginbothrivers• MinimalsummerabstracFonfromlowerUsk• DailypumpingfluctuaFonsavoided• MuchbeRerflowsforspawningandjuveniles• MuchreducedmigraFonimpacts• CanaloperaFonsecuredindroughtsNoaddiFonalimpactonpublicwatersupplies
Recentprogress• DraaingandagreeingnewlicencesandoperaFngmanuals(inprogress)
• NewpumpingstaFon,reservoiroutletvalvesandtelemetry(designsreadyforAMP6installaFon)
• CRTandWelshWaternegoFaFngtermsforUskreservoirsupportforcanalsupply
• ConFnuingphasedintroducFon(started2016)Benefitsalreadybeingseen
Whatwe’velearned• Whingeingwithoutnewevidencedoesn’twork
• Badgeringwithnewevidencecanchangeminds
• GeneraFonofnewevidenceandproposalsthroughcollaboraFonworksbest
• Nothinggetsachievedwithoutmutualunderstandingofconcernsandgoals