Chalk streams are a characteristic and attractive feature of the Chilterns landscape. They are also a globally rare habitat. In fact there are only 283 chalk streams in the UK, and the UK accounts for around 85% of the global total.

Chalk streams are important habitats for wildlife and support a massive range of species. They are home to some of our most threatened plants and animals, such as the water vole and brown trout. They also have a fascinating history and supported many thriving industries in the past.

Our three films provide an excellent overview, explaining ‘What are chalk streams, and why are they special‘, How chalk streams work, and exploring the threats they face.

The nine Chilterns’ chalk streams are so important that a special partnership project has been created to conserve them. Uniting all the organisations with an interest in the streams, the Chilterns Chalk Streams Project works with local people across the Chilterns to improve river habitats, improve access and enjoyment and promote the sustainable use of water.


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Chilterns Chalk Streams Project Annual Report 2022/23

Find out more about the work of the Chilterns Chalk Streams Project – Read our latest Annual Report.

Find out what we achieved through the Chalk Streams and Wetland Meadows Project, along with an update from the ground breaking River Chess Smarter Water Catchment Initiative.

Recent News

Free Wildlife posters for Chiltern Schools

With funding from Smarter Water Catchment Project we are now able to offer free "wildlife of the Chilterns" posters for schools in our area.

Position statement on sewage discharges in the Chilterns National Landscape

The Chilterns National Landscape has released a position statement expressing dismay that local communities, including Chalfont St Giles and Chalfont St Peter, are yet again suffering from raw sewage discharges flowing from overloaded sewage pipes owned and managed by Thames Water.

First annual Riverfly Newsletter

We're delighted to share that we've completed our first annual Riverfly Newsletter.


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Riverfly training day

  • 3 August 2024
  • 9:30

The Chilterns Chalk Stream Project are hosting this Riverfly monitoring training day...

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A walk in the fascinating world of Ancient and Veteran Trees

  • 11 July 2024
  • 19:00

An evening guided walk in the world of ancient and...

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Chess Priority Ponds Training evening

  • 2 July 2024
  • 18:30

Get involved in our landscape survey and help guide conservation...

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Riverfly Open Day 2024

  • Saturday 5th October
  • 12pm

The Chilterns Chalk Stream Project and Herts & Middlesex Wildlife Trust...

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River Chess Smarter Water Catchment

We're key partners in this ground breaking initiative - working on a catchment scale to restore one of the Chilterns’ finest chalk streams to health.
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