Diffuse Pollution ‐ What Is the Nature of the Problem?

This paper considers recent developments in the understanding of diffuse pollution, its generation, transport and impacts. The relative importance of diffuse sources to total pollutant loading must be identified in order to develop appropriate strategies for management. Research has indicated that individual diffuse pollutants respond differently to changing flow conditions and that there is a widespread misconception that higher flows are associated with lower pollutant concentrations. Evidence is presented to highlight this discrepancy and a rationale for load assessment is presented. The implications of this for monitoring within the context of the EU Water Framework Directive are discussed as are the implications for the mitigation of diffuse pollution.