River pollution survey, England and Wales 1975 : chemical classification of rivers and discharge of sewage effluent /
Great Britain.Department of the Environment.Cartographic Services.
London : [Department of the Environment],
1979.
01: North West Water Authority -- 02: Northumbrian Water Authority -- 03: Severn-Trent Water Authority -- 04: Yorkshire Water Authority -- 05: Anglian Water Authority -- 06: Thames Water Authority -- 07: Southern Water Authority -- 08: Wessex Water Authority -- 09: South-West Water Authority -- 10: Welsh Water Authority.