The many streams and of course the River Nidd both shape and define Nidderdale AONB, but equally important are the reservoirs which dominate the upper part of Nidderdale and the Washburn Valley. Clean flowing water is the lifeblood of the AONB, and watercourses of all sizes support many different plants, insects and animals both in and alongside.

The Environment Agency and Nidderdale AONB work to conserve and improve the water catchment areas of the AONB’s rivers through schemes such as Catchment Sensitive Farming. Improved water quality and flood prevention are the result.

Standing water is at a premium in limestone country where most water eventually finds its way underground and where natural lakes are rare as a result. Gouthwaite Reservoir’s purpose is to act as a top-up water source for the River Nidd to help maintain a constant flow. Today it is a nature reserve and is particularly important for both water and woodland birds.

Lindley Wood, Swinsty, Fewston and Thruscross Reservoirs in the Washburn Valley, Roundhill and Leighton near Masham, and Angram and Scar House in Upper Nidderdale were built in the late 19th and early 20th centuries to supply water to the growing industrial populations of Bradford and Leeds. These reservoirs are a haven for wildlife and vital for the flocks of migrating ducks and geese that use them as stop off points and for breeding.