Celebrating 25 Years of the Chilterns Chalk Streams Project

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CURRENT AND LEGACY THREATSThe Chilterns area hassome of the highest percapita demand fordomestic water in the UK173litres of waterper person per daycompared to anational average of142litres of waterper person per dayand environmentallyunsustainable abstractionhas persisted in someareas of the Chilterns forover 50 years.The Chilterns Chalk Streams are under threat from a range of issues – sometimes referred to as the ‘chalkstreams malaise’. A useful starting point to examine some of the issues facing chalk streams is the EuropeanUnion Water Framework Directive (WFD), which requires English rivers to meet ‘Good Ecological Status’by 2027 at the latest. All the streams failed to reach ‘Good Chemical Status’ under the 2019 WaterFramework Directive analysis, and only the Ewelme Brook and the Hughenden Stream were considered tohave a hydrological regime that could support ‘Good Ecological Status’. All of the streams failed to reach‘Good Chemical Status’ due to the variety of issues listed in the table on page 15.This combination of abstraction for public supply, coupled with high water demand, has led to a chronic declinein flows in all of the Chilterns’ streams, with winterbourne sections increasing in length and in frequency ofdrying. Increasing water demand and climate change are placing additional pressure on river flows. Under thecurrent water industry national environment programme (WINEP), Affinity Water has embarked on a 36 millionlitre reduction in abstraction, and Thames Water has committed to a 9 million litre reduction in the Chilternsby March 2025.The table on page 15 highlights some of the threats to our chalk streams arising from current and past useof chemicals in our homes and for industrial purposes. Elevated mercury levels are a legacy of past industrialactivity. Perfluorooctane sulfonate (PFAS) and polybrominated diphenyl ethers (PBDEs) areregularly detected in rivers across England. PFAS was used in the past on textiles to repelwater and reduce stains. Similarly, PBDE is a ‘legacy’ chemical which was used as a flameretardant in a variety of products, including textiles. Although these chemicals are nowbanned, they are persistent in the environment and can travel through wastewatertreatment works and out to our rivers, due to the washing of treated carpets, textilesand upholstery in our homes. Polyaromatic hydrocarbons (PAHs) are the products offossil fuel combustion, and much of the load in our rivers is also derived from pasthuman activity. Domestic wood burning, and petrol and diesel-powered vehicles,are both current sources of PAHs to rivers.14 | CELEBRATING 25 YEARS OF THE CHILTERNS CHALK STREAMS PROJECT
The reasons for these chemicalfailures are examined furtherin the pages that describe theBulbourne, Gade and Ewelme Brookrespectively.OVERVIEWWater Framework Directive assessment of Chilterns Chalk Streams (2019)RiverBulbourneChessEwelmeBrookGade (upper)Gade (lower)HambleBrookHughendenStreamMisbourneVerWye (upper)Wye (lowerEcologicalChemical(overall)XXXXXXXXXXXSpecific chemicalsPBDE, PFOS, Dissolved oxygen(moderate)PBDE, Phosphate (poor)Hg, PBDE,PFOS, cypermethrinPhosphate (moderate)PBDE, Dissolved oxygen (moderate)PBDE, PFOS, Phosphate (moderate)Hg, PBDE,PFOS,Hg, PBDEPBDEPAHs, PFOS, PBDE Dissolved oxygen(moderate)PAHs, Hg, PBDEPAHs, Hg, PBDE, PFOSHydrologicalregime!!!!!!!MorphologyContains Environment Agency data. All data is available under the Open Government Licence v3.0 © Crown Copyright 2022X!KEYPoorModerateFailDoes not support goodHighSupports goodModerate and poor dissolvedoxygen concentrationsin chalk streams of theChilterns, alongside elevatedphosphate and cypermethrinconcentrations are all causedby recent activities in thedifferent river catchments.CURRENT AND LEGACY THREATS TO CHILTERNS CHALK STREAMS | 15
Page 1 and 2: CELEBRATING 25 YEARS OF THECHILTERN
Page 3 and 4: FOREWORD2022 marks the 25th anniver
Page 5 and 6: CONTENTSIntroduction 4Milestones of
Page 7 and 8: THE REPORT HAS BEEN SPLIT INTOTHREE
Page 9 and 10: THE TIMELINE ALSOSHOWS HOW THECCSP
Page 11 and 12: 2001First watervole Survey2002Produ
Page 13 and 14: KEYChalk scarp andvale fringesPlate
Page 15: OVERVIEWChalk streams have not only
Page 19 and 20: 5040Abstraction in the Ver Valley (
Page 21 and 22: WWF-UK, The Wildlife Trusts, The Ri
Page 23 and 24: OVERVIEWMISBOURNE‘Chalk Streams i
Page 25 and 26: RAISING AWARENESSOF THE NEED FORCON
Page 27 and 28: BEFORE DURING AFTERRIVER RESTORATIO
Page 29 and 30: WATER VOLE SURVEYSACTIVITIESWater v
Page 31 and 32: FESTIVALS, FAMILY EVENTSAND CONFERE
Page 33 and 34: ACTIVITIESProject workand school vi
Page 35 and 36: The earliest river flow records fro
Page 37 and 38: River Chess Smarter WaterCatchmentT
Page 39 and 40: The Ewelme Brook is a small chalkst
Page 41 and 42: The River Gade is under pressurefro
Page 43 and 44: The Hamble Brook is an ephemeralstr
Page 45 and 46: The 3.5 km Hughenden Streamis sprin
Page 47 and 48: The Misbourne is an intriguingchalk
Page 49 and 50: 1. Source of the VerThe embryonic R
Page 51 and 52: The Wye flows 17 km fromWest Wycomb
Page 53 and 54: Scarp slope streamsHorsenden BrookH
Page 55 and 56: For the first time in its history,
Page 57 and 58: WAYS YOU CAN HELPRiverfly monitorin
Page 59 and 60: The River Chess at Sarratt BottomFo

Celebrating 25 Years of the Chilterns Chalk Streams Project

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