Southern Water: Low cost catchment modelling approaches

Since its inception in 2000, the EU Water Framework Directive has fostered a transformation in river basin management. In order to meet the Directive's need for holistic River Basin Management Plans, hydrological catchment models are increasingly used to predict the impact of environmental change on the flow characteristics and water quality of European rivers.

The Water Framework Directive seeks to prevent the deterioration of ground and surface water bodies, and achieve good ecological and chemical status in water courses. This requires the management of a range of chemical contaminants, including pesticides, and their supply to water courses. Metaldehyde (a synthetic aldehyde pesticide used globally in agriculture) has been identified as an emerging contaminant of concern. Metaldehyde is of particular problem because it is highly stable in water, can be very mobile in the environment, and is ineffectively removed by drinking water treatment processes.

This project considered how low-cost catchment modelling approaches (e.g. ArcSWAT) might help to predict where and when water quality issues are most likely to arise, and was a collaboration with Southern Water.

This research aimed to integrate large existing data sets with the Soil and Water Assessment Tool (SWAT) in order to establish a transferable protocol for mapping and predicting aquatic pollutants. SWAT is an open source catchment-scale hydrological model originally developed in the US.

This research modelled metaldehyde in a pilot catchment (the Medway catchment) in order to better assess risk and to establish a transferable protocol for mapping and predicting future emerging aquatic contaminants. As such, the approach allowed the development of more effective mitigation strategies and will provide the water sector with much needed resilience to future climate change.