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.
Find out more
Recent News
Big Chalk: the Hamble Brook project
We’re delighted that our Hamble Brook river restoration project is now featured as a case study by the Big Chalk Partership....
Latest Annual Report published
I’m delighted to introduce the Chilterns Chalk Streams Project Annual Report for 2024/25, which sets out not just the highlights...
Chilterns Chalk Streams Project set to ‘Mend the Misbourne’
The Chilterns Chalk Streams Project, which is hosted by the Chilterns National Landscape, has secured £1 million of investment from...
Events

Not Bourne Yesterday: stream-dipping at Desborough Recreation Grounds
- 28 September
- 10:00
This coming September 28th is World Rivers Day, and our chalk stream community engagement...

Extended Riverfly Training - Autumn 2025
- 14 October 2025
- 10:00
This Extended Riverfly Training has been designed for existing Riverfly...

Chalk Stream Storytime- Rickmansworth
- Monday 27th October
- 10.30
Come and find out about Chiltern chalk streams and why...