Keywords

Nutrient Load Apportionment Modelling; Phosphorus; Nitrogen; Integrated Catchment Management; Water Framework Directive

Location

Session D4: Water Resources Management and Planning - Modelling and Software for Improving Decisions and Engaging Stakeholders

Start Date

11-7-2016 3:30 PM

End Date

11-7-2016 3:50 PM

Description

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 remains the top suspected cause of surface waters not achieving the required Good Status, as defined by the Water Framework Directive (WFD). Hence, a toolbox has been developed 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 & phosphorus exported from each sector (e.g. pasture, forestry, wastewater discharges) that contribute to nutrient loads in a river. The SLAM was built as a modular framework in ArcGIS ModelBuilder to encourage continuous development by a range of scientific experts without the need for programming skills. Model output is presented as maps and tables showing the proportions of nutrient emissions to water attributed to each sector in each sub-catchment. Results for the Suir catchment, in the South East of Ireland, indicate that diffuse losses of nutrients from pasture are the dominant source of nitrogen and both wastewater discharges and losses from pasture are dominant for phosphorus. The Irish EPA has incorporated these model results into the WFD characterisation process for Irish catchments.

 
Jul 11th, 3:30 PM Jul 11th, 3:50 PM

Development of a Nutrient Load Apportionment Modelling Toolbox

Session D4: Water Resources Management and Planning - Modelling and Software for Improving Decisions and Engaging Stakeholders

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 remains the top suspected cause of surface waters not achieving the required Good Status, as defined by the Water Framework Directive (WFD). Hence, a toolbox has been developed 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 & phosphorus exported from each sector (e.g. pasture, forestry, wastewater discharges) that contribute to nutrient loads in a river. The SLAM was built as a modular framework in ArcGIS ModelBuilder to encourage continuous development by a range of scientific experts without the need for programming skills. Model output is presented as maps and tables showing the proportions of nutrient emissions to water attributed to each sector in each sub-catchment. Results for the Suir catchment, in the South East of Ireland, indicate that diffuse losses of nutrients from pasture are the dominant source of nitrogen and both wastewater discharges and losses from pasture are dominant for phosphorus. The Irish EPA has incorporated these model results into the WFD characterisation process for Irish catchments.