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Diffuse water pollution

Report that sets out the evidence for the impacts of diffuse pollution and what needs to be done about it.

Diffuse water pollution is mainly related to the way we use and manage land and soil. It can affect rivers, lakes, coastal waters and groundwaters.

Groundwaters are vulnerable from, and affected by, leaching of pollutants from the land surface and from areas of contaminated land, while surface waters are affected by rainfall that washes over and off the land (run-off).

Rivers can also be influenced by the contribution to their flow that comes through springs and seepages from groundwater. Where the groundwater connection with surface waters is high, pollution can pass from one to affect the other.

Run-off has increased as agriculture has intensified and as we have built more roads and houses, particularly where we have degraded the natural permeability of the landscape and reduced its capacity to retain water.

Unlike point source pollution, we cannot easily control diffuse pollution by issuing licences or permits. Regulatory approaches have to be more subtle and in many cases need to be well connected to the land use planning system.

Diffuse pollution tends to arise from sites not directly regulated by the Environment Agency. However, we can only continue to make water quality improvements by addressing diffuse pollution issues and by adopting innovative ways of controlling the risks from diffuse sources. The Water Framework Directive may offer fresh opportunities for this.