Implementation and Evaluation of Mitigation Strategies for Pollution Control at a Farm Scale (PEPFAA into Practice).

This project aimed to establish, within catchments vulnerable to water pollution, 'Good Practice Farms' to evaluate pollution mitigation measures for diffuse, land-based pollution in accordance with codes of practice such as the recently updated "Prevention of Environmental Pollution from Agricultural Activities (PEPFAA)". On these farms, a range of measures which were expected to reduce water pollution from farm wastes, agrochemicals and sediments, were introduced or investigated by model simulations. <P>
Mitigation measures such as the use of buffer strips and fencing of watercourses, retention bunds for sediment, off-stream watering of livestock, farm ponds, nutrient budgeting and use of waste management plans, have been considered. The evaluation has included, where feasible, initial benchmarking, feasibility, acceptability and cost of mitigation measures, technical measures of water quality improvement, and socio-economic and environmental health impacts. This project has considered a range of intensive land uses, focusing particularly on water quality standards for microbiological contamination of bathing waters and eutrophication from phosphorus in agricultural runoff. <P>

A farm system model has been developed to evaluate the water quality benefits of specific mitigation measures for E. coli, ammonium and phosphorus. A simple model of catchment response to faecal pollution of bathing waters has been linked to an evaluation of public good benefits, through epidemiological risk assessment and public "willingness to pay" for avoidance of health risk. <P>

The assessment of cost effectiveness of BMPs investigated showed that the general order of cost effectiveness was:
<ul> <LI>
retention bund (for hotspots of erosion) > buffer strips > nutrient budgeting > in-line ponds (for sediment and particulate P pollution from arable farms);
<LI>
Steading separation of clean and dirty water > in-line ponds > prevention of soil compaction > prevention of access to water courses = buffer strips > access to off stream drinking without fencing ( for faecal indicators from dairy farms);</UL>
The assessment of cost:benefit of BMPs on the specific catchments studied showed :
<UL> <LI>

A benefit: cost ratio >1 for buffer strips and retention bunds for hotspots of soil erosion in the Loch Leven catchment.
</ul>
A benefit:cost ratio >1 for measures which achieve 85% removal of FIOs during critical flow periods will only if average annual costs are <£1k or capital costs <£11k per dairy farm in the Irvine catchment. However, this figure only takes into account health benefits, not any fines imposed or ecological effects of nutrient loading from animal excreta.