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Spring 2021 Our Drought Plan Summary 2021 Summary Our draft Drought Plan 2021: supply in adrought your waterManaging

2 Our Drought Plan Summary 2021 Thames Valley. 10 millionhouseholdcustomersand215,000businessesinLondon andacrossthe businesses. It’sourjobtoprovideareliablesupply of safe drinkingwater toaround associated withwater-use, suchascar washes,brewers, andhairdressers,butall hospitals, andservicessuchastheFireService.Andfor businessestoo–notjustthose activities suchaswashing,cooking,andrecreation.It’salsovital for runningschools, Water isessentialfor allourlives. Every daywe usewater for drinkingandroutine other sources. of water aswell astaking morefrom theenvironmentand customers’ drinkingwater supplyby usingadditionalsources households andbusinesses;howwe’d maintain reduce theirwater use;therestrictionswe’d placeon customers aboutadrought;howwe’d workwithcustomersto when we wouldtake them.Itoutlineswhatwe’d dotoinform Our DroughtPlansetsouttheactionswe wouldtake, and environment. provide essentialsuppliesofwater, whileprotecting the depleted, andwe mayneedtotake actionstocontinue periods oflowrainfall ourwater suppliescan become However, we can’t planfor alleventualities. Duringextended of dryweather andtake intoaccountchangestoourclimate. sustainable supplyofwater toourcustomersduringperiods We planaheadtomake surewe can provideasecureand You can find ourfull draft Drought Planhere:thameswater.co.uk/droughtplan. Page 8 Page 7 Page 6 Page 5 Page 4 In itwe explain: This documentisasummaryofourdraft Drought Plan 2021. We are updating ourDrought Plan Actions we’ll take inadrought What happensinadrought? How dowe knowwhenadroughtisdeveloping? Your water supplyandhow itcouldbeaffected inadrought What isadrought? water supplyto2100. to provideasecureandsustainable resources toensurewe can continue investment thatisneeded innew change anditsetsoutthesignificant growth andtheimpactsofclimate challenges includingpopulation Plan 2019considersfuture Our Water Resources Management

3 Our Drought Plan Summary 2021 How we develop ourDrought Plan (Defra) on1April2021. We submitted ourdraft DroughtPlantotheSecretary ofState Our lastDroughtPlanwaspublishedin2020. Once approved, we’ll publishourfinal DroughtPlan. We’ll sendtheupdated draft Plan toDefra for approval. of Response, andupdate ourdraft Plan. We’ll review feedback totheconsultation, produceaStatement following approval from Defra. We’ll holdapublicconsultation onourdraft Plan.Thiswillstart companies intheSouthEast. We’ve consulted stakeholders andworked closelywithother guidelines, andupdated information onoursupplyschemes. We’ve refreshed ourPlan,taking accountofrevised government • Here isasummaryofthemainchangestoourDroughtPlan: What’s new? • • • • droughts thanwe’ve experiencedinthepast. We’ve tested ourPlantounderstand howwe can copeinmoresevere such asmobiledesalinationplants. reductions inwater useandtheofadditionalemergencywater sources referred toas‘MoreBefore Level 4measures’,theseincludesignificant We’ve developed additionalmeasuresfor themostseriousdroughts, scheme, asitisnolongeroperational. (the desalinationplant)to100Ml/dandremoved theHoddesdontransfer that can besuppliedby theThamesGateway Works Based onanupdated assessment,we’ve reducedtheamountofwater aligning anyexemptionsthatmaybeapplied. companies intheSouthEast if water userestrictionsareneeded,including We’ve agreedtotake acoordinated approachwiththeotherwater other water companiesintheSouthEast. (see page8)willnowbeimplemented atthesametimeasappliedby the need toapplywater userestrictions.Temporary UseBan(TUB)restrictions We’ve updated ourlevels ofservice–thefrequency thatwe expectto 4 Our Drought Plan Summary 2021 growing season,whereas adroughtthat affects public water supplycan take manymonths ofbelow average rainfall. Droughts can affect different water usersin different ways and happenatvarying times. For farmers, adroughtcan occurafter just afew weeks ofdryandsunnyweather duringthe rainfall isreallyimportant, asitrefills thenatural undergroundaquifers thatfill upthe rainfall throughouttheyear tomake surewe alwayshave enoughwater. Winter by afew dryweeks, andthey can’t besolved by afew wet ones.We needregular A droughtisaprolongedperiodofabnormallylowrainfall. Droughtsaren’tcaused Istanbul, Sydney, orBarcelona. people thinkwe have plentyofrain, butitactuallyrains lessinLondon thanin The water we usefor publicwater supplyreliesontheweather, specifically rain. Most What isadrought? groundwater ground andmaintains our Rainfall percolates intothe aquifers thatmaintains theflowofrivers During periodsoflowrainfall, it’sthe flow ofwater from The aquifers feed ourrivers and helpkeep themflowing. percolated intotheground – rainfall thathasn’t comes from surface run-off Water flowinrivers also rivers We abstract water from The diagram below explains why suchweather patterns cause problems. below average rainfall. Thelastmajordroughtinoursupplyareawas1975-76. affects. Inourarea,theworstdroughtshave followed twoconsecutive winters of Every droughtdiffers interms ofhowlongitlasts,intense itisandtheareas very littleavailable torechargegroundwater sources.. rivers. Summerrain islargelyusedupby plantsandlostthroughevaporation leaving boreholes groundwater using We abstract treatment plants groundwater to We pumptheabstracted Rivers rainfall inwinter thentheaquifers arenotrefilled bearing rockscalled aquifers. Ifthere’snotenough Groundwater isstorednaturally inlayers ofwater- plants. we pumpittotreatment raw-water before We storewater inlarge,open Your and how it could be affected in a drought Your water comes from rivers and groundwater and is either stored in large reservoirs zones. A drought can affect each zone differently, depending on where the water until needed or treated and put directly into supply. The water is always treated to a comes from and how those sources respond to different types of droughts. This is high standard before it reaches your tap. why during a drought one area may have different usage restrictions to another.

Thames Water’s supply area is divided into six water resource zones: London; The map shows our water supply area, the water resource zones and the main and ; Kennet Valley; Guildford; Slough, Wycombe and Aylesbury; sources of water in each zone. and Henley. Water can be moved around in each zone and, in some cases, between

anbury

Stevenage London – Water is mainly taken from the River uton Thames and the River Lee and stored in reservoirs in south-west London and the Lee ishop’s Stortford Valley. The remainder (roughly 20 percent) comes from groundwater. We also have a desalination plant in London for use in drought. Farmoor irencester NE London Swindon and Oxfordshire – Water is mainly Oxford Groundwater Waltham ross groundwater (60 percent) taken from the upper Kennet Valley and the Cotswolds, and High Wycombe North London we have a water main from Gatehampton. We Aquifer Recharge also take water from the and Lee Valley Swindon Reservoirs have a reservoir at Farmoor, near Oxford. Gatehampton Slough Kennet Valley – Some water is pumped Chalk Sources Desalination directly from the River Kennet to treatment works, and other supplies are from groundwater.

Ring Dartford Guildford – Some water is pumped directly ewbury Reading Main Lower from the River Wey to treatment works, and Thames Reservoirs SE London other supplies are from groundwater. Groundwater roydon Slough, Wycombe and Aylesbury – All water comes from groundwater. uildford Henley – All water comes from groundwater.

rawley Guildford Groundwater Our Drought Plan Summary 2021 Our Drought

5 6 Our Drought Plan Summary 2021 it mightevolve andtoaskfor theirhelpandsupport. the protocolsisclearandtimelycommunications withcustomerstoexplainthesituationandhow action andtohelpusavoid orminimisethe needfor emergencymeasures.Animportant partof have recovered. Theprotocolsaredesignedtomake surewe have enoughtimetoplanandtake need totake –before adroughthappens,asdevelops, duringadroughtandafter levels In adroughtwe follow aseriesof‘protocols’–decision-makingsteps thatguidetheactionswe patterns ofrainfall andwater usagetohelpusdecideonwhatwe needtodo. terms ofhowlongitlasts,intense itis,andtheareasaffects. We usescenariosofdifferent might develop and,onceit’sbegun,howsevere itcouldbecome.Every droughtisdifferent in constantly monitorwater levels inourregion–thisgives usearly warningofwhenadrought the amountofwater storedinreservoirs fall belowthenormallevels for thetimeofyear. We Droughts develop over aperiodofmonths,duringwhichtimeriver flows,groundwater levels and How dowe know whenadrought isdeveloping? • • • • To identify apotential drought,we: prolonged drought Monitor theamountofwater storedinreservoirs –thisiscritical tohowwe’ll copeina recent rainfall Analyse river flows–thesedependonbaseflowfrom aquifers andaresupplemented by Analyse groundwater levels – thelower thelevel, theworsedrought Look atrainfall records 2030/31 anddroughtsof1:500years by 2040. to becomeresilientdroughtsofaseverity of1:200years by provide asecureandsustainable water supplyto2100,willenableus Management Plan(WRMP)–ourlongterm plantoensurewe can Investment innewsources ofwater, assetoutinourWater Resources protect ourcustomers’water supplyandalsotheenvironment. the future, we needtodevelop additionalwater sources,tohelp In ordertomeetthechallengeofpotentially very severe droughtsin the environment,andDroughtOrderscouldimpactbusinesses. Permits for longperiodswouldhave asignificant adverse impacton (see page8)for extended periodsoftime.ThisrelianceonDrought to severe drought,butwe’d needtouseDroughtPermits andOrders The assessmentsshowthatallourwater resourcezonesareresilient parts ofitare, todrought. of years ofweather data, toassesshow vulnerable oursystem is,or We’ve usedhistoricweather records, equivalent ofmany thousands 7 Our Drought Plan Summary 2021 and helpreducetheirbills.Inadroughtwe wouldstep upsomeoftheseactivities. supplies. Andwe alsoinstall free water meters, whichencourage peopletousewater sparingly water wisely,providingarange offree water-saving devices andgivingadviceonhowtoconserve our water pipesandourcustomers’throughleakage. We encourage ourcustomerstouse water resourcesefficiently. For instance, we workhardtoreducetheamountofwater lostthrough referred toas‘demandmeasures’.Aspartofournormaldayto-dayoperations, we aimtouseour We’ll alsotrytoreducetheamountofwater thatwe and ourcustomersuse–taking actionsoften we’ll extend ouractivityanduseadverts andothermethodstoraise theprofile. regular updates onthedroughtsituationandadvicesaving water. Ifthedroughtcontinues, possible, we’ll usenewspapers,radio, andTVaswell asourwebsite andsocialmedia,providing uncertainty andtheneedtoplanresponsiblyfor theworstcase. To reachasmanypeople Because long-term weather forecasts aren’tfully reliable,we’ll needtoexplainthedegreeof needed. are likely. We’ll aimtostart ourdroughtcommunications campaign well before restrictionsare everyone informed andletcustomersknowwhatthey can dotohelpand ifwater-use restrictions Good communications withourcustomersaremorevital thanever inadrought.We needtokeep What happensinadrought? washing your carwithahosepipe can useamassive 225 litres of increase theamountofwater we have. Theseinclude: Alongside activitiestoreducewater use,we’ll alsotake actionsto • • • well assharing resourcesasfar aspossible. consistent messagingandcoordinationofwater userestrictionsas work withotherwater companiesintheSouthEast toensure A droughtisunlikely tobelimited totheThamesWater area,sowe’ll water injust 15minutes. Watering thegarden or lesser impactontheenvironmentwhenever possible. We aimtoprioritisethePermits we use,selectingthosewith a everything elsewe can before askingtouseDroughtPermits. the potential harmtotheenvironment,we needtohave done water from theenvironment,viaDroughtPermits. Because of Seeking permissionfrom theenvironmental regulatortotake more capital for useinadroughtperiod. surplus winter suppliesinthedeepchalkaquifer beneaththe and theNorthLondon Artificial Recharge Scheme, whichstores the River Thamesandremoves thesalttoproducedrinkingwater, located inEast London, whichtakes water from thetidalpart of Starting updroughtschemes,suchasusingthedesalinationplant water storedinreservoirs. resource zones,we mightusemoregroundwater toconserve the For example,inLondon andtheSwindon andOxfordshire water Using existingwater sourcesthataremoreresistant todrought. That’s like flushingthe toilet 25times

Frequency: onceevery 10years onaverage Early stages ofadrough Frequency: onceevery 20years onaverage Severe drought t

8 Our Drought Plan Summary 2021 restrictions ontheirwater usage.We have four escalating levels –theselevels andtheactionsthatwe’ll take ateachoneareexplainedbelow. Our DroughtPlanisbasedonourlevels ofservicetocustomers.Thesesetouthowoften, andtowhatextent, customersshouldexpect Actions we’ll take inadrought before More More 4 4 3 2 1 1920). worse thanany onrecord (since which would involve adrought We plannever toreach thislevel, Extreme drought years onaverage Frequency: onceevery 50to100 droughts for themost serious Additional measures on average Frequency: onceevery 20years Severe drought average Frequency: onceevery 5years on Impending drought on average Frequency: onceevery 10years drought Early stages ofa throughout thedrought. an impendingdrought,letthemknowhowseriousitisandasktousewater sparingly.Thecampaign willbecontinued Begin anawarenesscampaign –typically viaradio, newspapers,socialmediaandotheronlinechannels–totell customersabout • • Actions wouldinclude: Step upactionstoreducedemand and provideadditionalsuppliestotryavoid reachingemergency restrictions(Level 4). • • would needto grant anEmergency DroughtOrder. in thestreetfor customerstocollectwater. Thiswould have amassive impact onsocietyandtheeconomy, andthegovernment Extreme measures toreducewater use,suchasrota cuts(when water usageisrestricted atcertain periodsoftime) andstandpipes • • sources for non-potable use. Bring onlineadditionalsupply,suchasemergencyraw water pipelinetransfers, temporary desalinationunitsandalternative litres/person/day. (Onaverage ourcustomersusearound140litres/person/day) Widespread communications askingcustomerstomake significant reductionsintheirwater use,aimingfor around80-100 filling paddlingandswimmingpools,cleaningcars –thisisreferred toasaTemporary UseBan. Restrict theuseofsprinklersandhosepipesinaround homefor usesincludingwatering gardens,toppingupponds, efficiency gadgetsincustomers’homes. Step uptheawarenesscampaign andencourage customerstoreducetheirwater usethroughadvice andinstalling water Apply totheEnvironmentAgencyfor DroughtPermits toallowustake morewater from certain sources. restrictions. We’d notify customersatleast ten weeks before introducingthesemeasures. and suppressingdustonconstructionsites. Thegovernment wouldhave togrant aDroughtOrdertoallowusintroducethese Restrict non-essentialwater use.Thiswouldaffect businesses,andrestrictactivitiessuchascleaningwindowsatindustrialplants 9 Our Drought Plan Summary 2021 Our draft Drought Planhas3parts: Drought Plan,pleasevisitthameswater.co.uk/droughtplan Thank you for taking thetimetoread through thisdocument. Ifyou’d like toread ourfull 3 2 1 Strategic Environmental Assessment andHabitats Regulation Assessment Technical appendicesAtoM–Theseincludeenvironmental assessments ofourPlan: Main Report –Executive summaryandSections 1-10 Summary (thisdocument)