Craig Coch Field Surveys Group meeting, Malvern February 1976: UWIST Paper 1. Water quality - R. Wye

The R. Wye, which is 250 km long and drains an area of 4183 km2, rises at Plynlimon (677m O.D.) in Powys, mid-Wales. The Wye catchment is most simply divided into two characteristic geological areas. In the upper catchment (above Erwood, see Table 2) the R. Wye drains generally impermeable Ordivician and Silurian sediments (41% of total catchment), principally mudstones and shales. Below Erwood the river drains mainly the Devonian Old Red Sandstone series (55% of the total catchment) (Fig. 1). A more detailed description of the geology of the Wye catchment is contained in ‘Survey of Water Resources and Demands’ (Wye River Authority, 1972). With the proposal to enlarge the Craig Goch Reservoir and regulate the discharge of the R. Wye a general programme of surveillance, designed to provide baseline data for water quality, fisheries (UWIST 1976b) and general ecology (UWIST 1976 d, f) of the R. Wye has been established by UWIST under contract to the Welsh National Water Development Authority