What are the main sources of nutrient inputs to Ireland's aquatic environment?

Where rivers and lakes are impacted by excess nutrients, we need to understand the sources of those nutrients before mitigation measures can be selected. In these areas, modelling can be used in conjunction with knowledge from local authorities and information gained from investigative assessments to identify significant pressures that contribute excessive nutrients to surface waters. Where surface waters are impacted by excess nutrients, understanding the sources of those nutrients is key to the development of effective, targeted mitigation measures. In Ireland, nutrient emissions are the main reason that surface waters are not achieving the required Good Status, as defined by the Water Framework Directive (WFD). A model has been developed in order to predict the sources of nutrients contributing to these emissions and to assess future pressures and the likely effectiveness of targeted mitigation scenarios. This Source Load Apportionment Model (SLAM) supports catchment managers by providing scientifically robust evidence to back-up decision-making in relation to reducing nutrient pollution. The SLAM is a source-oriented model that calculates the nitrogen and phosphorus exported from each sector (e.g. pasture, forestry, wastewater discharges) that contribute to nutrient loads in a river. Model output is presented as maps and tables showing the proportions of nutrient emissions to water attributed to each sector in each sub-catchment. The EPA has incorporated these model results into the multiple lines of evidence used for the WFD characterisation process for Irish catchments.