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Developing a field tool kit for ecological targeting of agricultural diffuse pollution mitigation measures - WQ0223

Agricultural diffuse pollution has been recognized as one of the factors affecting the ecological quality and biodiversity of rivers, lakes and ponds and a range of mitigation measures has been identified to reduce this pollution. However, where these have been implemented, a corresponding improvement in the ecological quality has generally not been seen. Reasons for this include lack of understanding of ecological sensitivity, dominance of non-agricultural pollutant sources, impact of river channel engineering, inability to reduce pollutant levels to the required amounts and lack of local ecological refuges for recolonisation. In order to provide best value for money, there is a need to identify those areas which are most likely to show ecological benefit whilst minimizing the burden on farm businesses and productivity. This project aims to develop methods for screening out catchments where the mitigation of agricultural diffuse pollution is unlikely to achieve any ecological benefit. This will be based on modelling the pollution loads (covering nutrients, sediment and pesticides) from both agriculture and non-agricultural sources. These will be used to provide estimates of concentrations during times of the year when the ecology is particularly sensitive. Additional screening layers describing the long-term release of nitrate from groundwater, the recycling of phosphorus attached to deposited sediment and degradation of river channels and flow regimes will also be provided. Alongside these developments, existing ecological data will be collated and used to improve our understanding of sensitivity. This will focus not on individual stressors but on how the sensitivity changes with different stressors acting simultaneously. Additional evidence on the threshold levels of nutrients above which there will be no impact of mitigation will also be gathered through the deployment of small experimental channels. The potential for ecological recovery will also be explored through existing datasets and field monitoring to provide new biologically-based screening. The scientific evidence provided in this project will form the basis of both a national screening tool and a field toolkit. These will be developed in partnership with stakeholders to enable them to provide better advice and targeting of mitigation measures to achieve best value for money.
1.9 Sub-
The aim of the project is to provide a national screening tool and field toolkit to enable mitigation measures for agricultural diffuse pollution to be targeted in those catchments and farm practices where it is most likely to lead to an improvement in ecological status. WP1 and WP2 are focused at the national scale with WP1 providing evidence relating to abiotic factors at the WFD catchment scale and WP2 providing evidence on the biotic factors for both rivers and lakes. Taken together, they provide the essential screening for targeting mitigation. Once the scope for effective mitigation has been defined, WP3 takes it forward into practice at the local farm scale.
WP1 National screening tools
Task 1.1 Pollutant load, concentration and effect of agricultural mitigation (ADAS/CEH/Wallingford HydroSolutions Ltd)
Task 1.2 Site-specific seasonal screening of sewage domination (CEH)
Task 1.3 Nitrate legacy from groundwater (BGS)
Task 1.4 Phosphorus legacy in lake and stream sediments (CEH)
Task 1.5 Hydromorphological constraints (CEH)
WP2 Ecological Sensitivity, Resilience and Recovery
Task 2.1 Existing evidence and biological indices (CEH)
Task 2.1 Broad-scale analysis identifying sensitivity to multiple stressors (CEH)
Task 2.3 Ecological recovery (CEH)
Task 2.4 Nutrient thresholds for rivers and lakes (CEH)
WP3 Development of field toolkit (ADAS/Westcountry Rivers Trust/CEH terrestrial ecologist)
Time-Scale and Cost
From: 2012

To: 2015

Cost: £817,291
Contractor / Funded Organisations
A D A S UK Ltd (ADAS), Centre For Ecology and Hydrology (CEH)
Decision Support              
Diffuse Pollution              
Water Framework Directive              
Water Quality