Monitoring and modelling diffuse pollution from agriculture for policy support: UK and European experience

The need to understand and mitigate diffuse water pollution from agriculture (DWPA) using a range of monitoring or modelling techniques and abatement methods has never been greater. In response to the widely reported detrimental environmental impacts of such pollution and the desire to safeguard water resources, a number of important legislative drivers have been introduced, including the Water Framework Directive (WFD) for EU member states. Efforts to commission research and introduce policy options that address the key requirements of over-arching legislation, increasingly point to a number of common and important issues for policy makers. Whereas our understanding of, and ability to predict, pollutant loadings is reasonably well developed, coupling such pressures to ecological impacts remains a difficult task due to the limited functionality of available toolkits. It is important for mitigation programmes to consider multiple pollutants especially given the risks of pollution swapping and to support the uptake of abatement options that are economically and socially acceptable to the stakeholders involved. Appropriate spatial targeting of mitigation methods will continue to come under scrutiny, especially in the context of additional environmental pressures like climate change. Given its key role in governing the transfer and fate of priority nutrients and contaminants and its well-documented negative habitat impacts, sediment must be given a higher profile in diffuse pollution policy. The latter does, however, require further investigation of background sediment loads necessary for healthy habitats and associated sediment standards or thresholds, in order that catchment compliance can be more reliably assessed. Delayed water quality response to the mitigation of DWPA must be assessed and understood, as a means of informing stakeholders and policy options. A further challenge is posed by the need to place DWPA in the context of pollution from alternative sectors so that a more holistic approach to understanding and managing pressures and impacts and engaging stakeholders can be encouraged.