Reaney, S. M. and Heathwaite, A. Louise and Lane, S. N. and Buckley, C. (2007) Spatially based management of agricultural phosphorus pollution from diffuse sources : the SCIMAP risk based approach. EOS, Transactions American Geophysical Union, 88 (52): H53J-07. ISSN 0096-3941
Full text not available from this repository.Abstract
Pollution of rivers from agricultural phosphorus is recognised as a significant global problem and is a major management challenge as it involves processes that are small in magnitude, distributed over large areas, operating at fine spatial scales and associated with certain land use types when they are well connected to the receiving waters. Whilst some of these processes have been addressed in terms of water quality forecasting models and field measurements, we lack effective tools to prioritise where action should be taken to remediate the diffuse pollution problem. From a management perspective, the required information is on ‘what to do where' rather than absolute values. This change in focus opens up the problem to be considered in a probabilistic / relative framework rather than concentrating on absolute values. The SCIMAP risk management framework is based on the critical source area concept whereby a risk and a connection are required to generate a problem. Treatments of both surface and subsurface hydrological connectivity have been developed. The approach is based on the philosophy that for a point to be considered connected there needs to be a continuous flow path to the receiving water. This information is calculated by simulating the possible flow paths from the source cell to the receiving water and recording the required catchment wetness to allow flow along that route. This algorithm gives information on the ease at which each point in the landscape can export risk along surface and subsurface pathways to the receiving waters. To understand the annual dynamics of the locational diffuse P risk, a temporal risk framework has been developed. This risk framework accounts for land management activies within the agricultural calendar. These events include the application of fertiliser, the P additions from livestock and the offtake of P in crops. Changes to these risks can be made to investigate management options. The SCIMAP risk mapping framework has been applied to 12 catchments in England as part of the DEFRA / Environment Agency's Catchment Sensitive Farming programme. Result from these catchments will be presented.