Chalkstreams are a very special type of river, almost unique to England: 85% of the 200 chalkstreams in the world are in England. They are fed primarily by spring water from the chalk aquifer, not rain, which means they have clear, cold water and very stable flows. They are rich in minerals, especially calcium, and this base rich’ environment supports a very distinctive and rich ecology. 
Most anglers will know of the Wessex chalk streams, the famous fisheries of the Rivers Test and Itchen in Hampshire and the Wiltshire/​Hampshire Avon. However, chalk streams with very similar characteristics are found in a broad sweep from Driffield in East Yorkshire, through Norfolk and the Chilterns to Dorset. (see map below).

Cretacious chalk
Map of Upper Cretaceous Chalk. Credit Mark Williams, ResearchGate.

Chalkstreams are precious, unique and iconic rivers, but they suffer from many problems, of which the worst is abstraction. 

There is high demand for waters in the heavily populated areas of south-east England, and the chalk aquifer is a prime source of cheap, clean water. Abstraction from chalk aquifers results in reduced flows in the rivers — they can dry up completely — and damages the ecology. There have been many campaigns to reduce abstraction and protect our chalkstreams, for example this 2014 report by WWF. 

WTT founder and Vice President Charles Rangeley Wilson has been restoring, writing about and campaigning for chalkstreams for many years. The video presentation below, from March 2021, gives a very good overview of chalkstreams and the issues they face, including the idea of Chalkstreams First’.