Evaluation of knowledge gained from the National Demonstration Test Catchment

The Demonstration Test Catchment (DTC) project was commissioned in 2009 through Defra’s Agriculture and Water Quality team to test the hypothesis that ‘it is possible to cost-effectively reduce the impact of agricultural diffuse water pollution on ecological function while maintaining food security through the implementation of multiple on-farm mitigation measures’. The project was established as a research platform in four catchments (Eden in Cumbria, Wensum in Norfolk, Avon in Hampshire and the Tamar in Devon/Cornwall) where water quality was known to be compromised by diffuse pollution. These catchments provide good national coverage and representativeness of different physical and socio-economic factors relevant to diffuse pollution. The primary aim of this review is to evaluate the knowledge gained, on intervention effectiveness for water quality and farmer engagement, from the DTC programme by undertaking a Rapid Evidence Assessment (REA) of the available, published evidence. Secondary aims were included to evaluate the broader physical and social science methodologies that were adopted and the approach for generalising the findings.