River Coln - United Kingdom

Both of the limestone aquifers are sources for water abstration; a total of 55 ml per day are consented from the catchment. There are no large conurbations on the upper catchment, although Cheltenham, from where surface water drains into the limestone above the river´s source, has a population of over 100,000. The Coln catchment supports a population of around 9,000. The main sewage inputs to the river are from works at Andoversford, Bibury and Fairford. Bibury Tout farm is the largest discharge into the river, although most of this is on-line through fish-ponds. The river has been subject to various enhancement schemes to improve ecology and fisheries. The biological quality of the river is very good. The river supports a brown trout (Salmo trutta) fishery with good spawning beds. Natural populations of grayling (Thymallus thymallus) also exist. Native crayfish (Austropotamobius pallipes) have been recorded but not since 1991; populations of the introduced American signal crayfish (Pacifastacus leniusculus) are also present. Several pollution-sensitive caddisfly and mayfly families have been found, along with true-bugs, beetles and snails.