The South West Water Authority is building a new river regulating reservoir to meet growing demands for water supplies in the Plymouth and Bideford areas of Devon, England. The new reservoir impounds the river Wolf within the Tamar catchment (see figure). The Tamar and its tributaries are prime fishing rivers rich in sea trout and Atlantic salmon. Construction of the Roadford dam began early in 1987, and by 1990 a reservoir capable of storing 37×106 m3 will be created. Releases from the reservoir will regulate the low flows of the river Tamar, from which water will be pumped near its tidal limit at Gunnislake, to water treatment plants supplying Plymouth. Additionally, reservoir water will be pumped over the divide to the river Torridge, thus permitting increased abstraction from the latter catchment.