Understanding nutrient connectivity at the landscape scale: The use of the SCIMAP approach in the UK and Ireland

Many approaches to understanding diffuse pollution risk at the landscape scale have focused on its 'sources' and 'mobilisation' with a basic representation of the effect of connectivity between the landscape the receiving waters. Connectivity will determine whether source areas become critical source areas and create problems in the receiving waters. It is the landscape position of a source, both in terms of its upslope contributing area and its downslope flow path, that determine the likelihood of a connection being made. The SCIMAP approach, developed at Durham and Lancaster Universities with the Environment Agency, has taken a strongly connectivity driven approach, set within a risk based framework. SCIMAP aims to predict the location in the catchment that is most likely to be the source of an in stream water quality problem derived from diffuse pollution. The predictions are generated at a 5m-pixel level, to give within field estimates of risk and connectivity, and applied to whole landscapes (from 1 to 2000 km2 +) to give a broad overview of the issues. Recent work has shown that there is significant value in adding a detailed connectivity treatment when predicting measured patterns of water quality. The SCIMAP approach to diffuse pollution risk mapping has been applied by: the Environment Agency under the Catchment Sensitive Farming program; the Teagasc 'Agricultural Catchments' program; the Defra funded 'River Eden Demonstration Test Catchment'; and various river and wildlife trusts in the UK. This poster shows an overview of the SCIMAP approach and the results from both the Teagasc 'Agricultural Catchments' and the EdenDTC projects.