Water quality targets and maintenance of valued landscape character — Experience in the Axe catchment, UK

摘要

The Water Framework Directive (WFD) (Directive 2000/60/EC) requires new ecological standards for rivers, lakes and coastal waters by 2015. In the United Kingdom the English Catchment Sensitive Farming Initiative has identified 40 catchments which are at risk of failing the European Commission WFD targets for good ecological status of water bodies because of a range of issues. The river Axe catchment situated in south-west England, with a mixture of diffuse and point sources of pollution, is one of these priority sites, as intensive dairy farming and cultivation of high risk crops (maize) cause problems with enhanced suspended sediment, nitrate and phosphorus levels in the river. Much of the Axe is under national and county landscape designations, making land use or management measures taken to achieve river status sensitive to these designations. For the purpose of this research the Soil and Water Assessment Tool (SWAT-2005) was used. The baseline scenario was based on field observation and interviews with the Environment Agency and farmers; it was run with and without point sources. Three different mitigation scenarios, designed to maintain the landscape of the catchment, were then tested. Field buffer strips (FBS), extensive land use management (EXT) and sheep land use management (SHP), were used to assess the effectiveness of the measures in reducing nutrient loads in the river Axe, UK. Management scenarios reduced the average annual loads at the main catchment outlet by 21.2% (FBS), 37.3% (EXT) and 45.0% (SHP), for total nitrogen and 47.7% (FBS), 60.6% (EXT) and 62.4% (SHP) for total phosphorus. The results of this study suggest that there may be a fundamental incompatibility between the delivery of WFD targets and the maintenance of viable agricultural systems necessary to maintain landscapes which are highly valued for their aesthetic, recreational and economic value.