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