The morphometry and hydrology of Oak Mere, a lowland kataglacial lake in the north-west Midlands, England

Abstract

SUMMARY 1. This paper presents geological, climatic, morphometric and hydrological data, collected from 1941 to 1991, on a lowland kataglacial lake and its catchment, as a basis for the development of a descriptive hydrological model. 2. The catchment occupies an area of 2.56 km2, at altitudes of 73–130 m above sea level, and receives an average annual net precipitation of 558 000 m3. The surface geology consists principally of sandy glacial drift and peat overlying Triassic strata which are exposed at the western extremity of the catchment. 3. The mere (lake) has an asymmetrical basin lying in sandy glacial drift and peat. The area (18.4–22.9 ha), depth (7–8 m) and volume (320000–453000m3) fluctuate in relation to net precipitation in at least two ways: an immediate response and a response with a rime lag of approximately 2 years. 4. The pH, normally <5.5 but varying from 4.0 to 7,8, and ionic composition of the mere fluctuate. The evidence suggests that the fluctuation is a response to at least two essentially separate types of water supply: a base-poor surface supply and a base-richer supply entering at a depth of 4m. 5. Essentially, the descriptive model postulates that the mere waters are controlled by a water-table of varying level, in relation to net precipitation, which is base poor at the surface but becomes increasingly base rich with depth.