Thursday 14 July 2022
A coalition of conservation and river organisations is working to tackle a major threat to our chalk streams in the Chilterns: groundwater abstraction for our water supply. Chalk streams are amongst the planet’s most rare and threatened habitats and the Chilterns has one of the highest per capita domestic water uses in the UK. These streams are fed by groundwater – or aquifers – within the chalk. Pumping water from the groundwater to supply water for homes and businesses can cause low flows and can, in combination with drought, even cause the streams to dry out completely, threatening the rich diversity of plants and animals these unique habitats support. In 2019, 67% of the total length of chalk stream habitat in the Chilterns AONB was dry as a result of the combined effect of drought and abstraction.
Chalk Streams First proposes a reduction in groundwater abstraction that would enable a flow recovery of approximately 80% in the Chiltern chalk streams. A planned pipeline scheme, “Supply 2040”, which already forms part of Affinity Water’s long term plans, could move the water from the lower Thames to homes and businesses in the Chilterns formerly supplied by the chalk aquifer. The proposal would effectively restore chalk streams flows and improve their resilience to climate change, protecting the delicate ecology of the streams, whilst ensuring the resilience of public water supply.
Launched in October 2020, Chalk Streams First (CSF) was supported by The Rivers Trust, The Angling Trust, The Wild Trout Trust, WWF UK, Salmon & Trout Conservation and is now joined by the Chilterns Conservation Board, Chilterns Chalk Streams Project, the River Chess Association, the Ver Valley Society and the Chiltern Society.
Historically, groundwater abstraction from the chalk streams around London ballooned in the post-war decades, to the point that in some river catchments in the late 1980s over half the average water available to the river was taken for our water use. In dry years all the water was taken and iconic chalk streams like the Misbourne and Ver dried up completely.
Since then, Environment Agency schemes such as “Alleviation of Low Flows” and “Restoring Sustainable Abstraction” have made some progress in returning some water to the streams’ environment, but the streams still suffer from a very heavy abstraction burden and dry up – for example in 2019. The CSF coalition argues that only a regional and large-scale reduction will re-naturalise flows to these streams to the point where we see good ecological recovery.
The proposals have been recognised by the National Chalk Stream Restoration Strategy as a flagship project tackling low flows in chalk streams. It’s also won the recognition and conditional support of water regulators such as Ofwat. The CSF coalition is pushing for the proposals to be included in the Water Resources South East Regional Plan.
Chilterns Conservation Board CEO Dr Elaine King says: “We are pleased to be a part of Chalk Streams First - a galvanised approach to tackling one of the most urgent threats to these rare habitats. Tackling abstraction must happen now, to ensure the survival of these streams for future generations.”
Chilterns Society Chief Officer Tom Beeston says: “we are delighted to be able to work with everyone involved in Chalk Streams First, it a great opportunity for us to be part of reversing the damage we have been doing to chalk streams.”
CaBA chalk stream restoration group chair Charles Rangeley-Wilson says: “Chalk Streams First is the best chance we've had to undo the damage caused to our precious chalk streams by decades of over abstraction. Future generations will judge us harshly if we don't take it.”