The United States Geological Survey are a government science agency for the United States of America. This agency specialises in the provision of reliable scientific information on the US natural environment. The USGS water science school is a useful information centre for all ages to learn about the water cycle and water quality.
The Wildlife Trusts are a partnership of independent UK charities with an interest in saving wildlife and wild places. They work to restore and protect freshwater habitats for wildlife and people. They have a useful page on their website describing chalk rivers. Sussex Wildlife Trust have produced an informative leaflet about chalk streams in Sussex with useful advice on how to help manage this valuable environment.
World Wide Fund for Nature are an independent conservation organisation with an interest in the conservation of chalk streams. In their website they explain why UK Chalk streams are unique and important. In 2004 they published a report on the State of England's Chalk Streams.
Natural England are the UK government's adviser for the natural environment in England, helping to protect England's nature and landscapes for people to enjoy and for the services they provide. You can download their Chalk Rivers handbook from their website, and search for lots more valuable scientific reports on Chalks Streams.
The Environment Agency is an executive non-departmental public body sponsored by the Department for Environment, Food and Rural Affairs. They have responsibility for water quality and resources within England, and are responsible for managing the risk of flooding from main rivers, reservoirs, estuaries and the sea. You can download their State of England's Chalk Rivers report from the Defra website.