Freshwaters are among our most threatened habitats globally. In large parts of England unpolluted waters have almost vanished, 75% of all rivers fail to meet even minimum legal standards set for a healthy river by the Water Framework Directive, and 80% of ponds are chemically and biologically degraded (Countryside Survey 2007).
Sensitive vertebrate and invertebrate populations, and pollution intolerant aquatic plants (macrophytes) have reached all-time lows. River health in the UK shows little recent improvement and there is evidence that the quality of rural ponds has decreased within the last decade. Additional problems include increases in drinking water pollution incidents, widespread flooding and the urgency to manage such events, and the repercussions of unsustainable water abstraction.
Diffuse pollution plays a key role in contributing to the degradation of aquatic systems. Pollutants from a range of activities including run-off from roads, houses and commercial areas, run-off from farmland, and seepage into groundwater from developed landscapes of all kinds, individually may have no effect on the water environment, but at the catchment scale can have a significant impact on water quality and habitat biodiversity. Each year the British government invests money to try to reduce diffuse pollution but as yet to little effect. A key problem is moving from mitigation that researchers have shown worked at small scale, to the more realistic and larger catchment idea. We now urgently need better evidence to show the extent to which the best management practices work in agricultural catchments.
Top soil loss caused by water run-off due to disturbed soils in the Barkby brook Catchment
Turbid water caused by disturbance on roads in the Barkby brook catchment
To tackle the paucity of scientific evidence in regulating catchment management the Freshwater Habitats Trust and Game and Wildlife Conservation Trust have teamed up with agrochemical company Syngenta, regulators and water companies to find and demonstrate the measures that will make a difference in protecting the water environment from diffuse pollution. The project is the first catchment scale study of its kind in the UK to include a diversity of freshwater habitats such as streams, ponds and ditches. It builds on a series of research projects undertaken by FHT and their partners which have evaluated the comparative importance and roles of different aquatic habitats in agricultural landscapes. As a result of such studies there is now an increasing recognition of the importance of smaller waters, both still and running, influencing both policy and practice in the protection of freshwater ecosystems.
The following sites are helpful for finding further information on diffuse pollution and its effects: