Provenance & quality
The methodology is based on [1], [2] and [3] who developed and proved a generic methodology for calculating the impacts of mitigation methods on the control of diffuse pollution. The methodology involves the derivation of a meta-model of export coefficients from the output of more detailed process based models (including NEAP-N, PSYCHIC, IPCC) applied to common descriptions of farm systems that are representative of typical practice. Simulations are carried out for every farm type on a 1 km2 grid across Scotland, using local soil and climate information, and then the results aggregated by WFD waterbody and scaled by data from the June Agricultural Census data for 2010. The impacts of mitigation methods, representing General Binding Rules and the Nitrate Vulnerable Zone Action Programme, were characterised based upon literature, modelling and expert review from the project steering group verification of the modelled pollutant loads was performed by comparison with measured data for 56 large catchments, where data had been recorded for the purpose of reporting to the Oslo-Paris Commission.
[1] Anthony, S., Turner, T., Roberts, A., Harris, D., Hawley, J., Collins, A., and Withers, P. (2008) Evaluating the extent of agricultural phosphorus losses across Wales. Defra project WT0743CSF, Final Report, ADAS UK Ltd, 281 pp.
[2] Anthony, S., Duethman, D., Gooday, R., Harris, D., Newell-Price, P., Chadwick, D. and Misselbrook, T. (2009) Quantitative Assessment of Scenarios for Managing Trade-Off between the Economic Performance of Agriculture and the Environment and Between Different Environmental Media. Final Report, Defra Project WQ0106 (Module 6), 95 pp.
[3] Anthony, S., Jones, I., Naden, P., Newell-Price, P, Jones, D., Taylor, R., Gooday, R., Hughes, G., Zhang, Y., Fawcett, L., Simpson, D., Turner, A., Fawcett, C., Turner, D., Murphy, J., Arnold, A., Blackburn, J., Duerdoth, C., Hawczak, A., Pretty, J., Scarlett, P., Laize, C., Douthwright, T., Lathwood, T., Jones, M., Peers, D., Kingston, H., Chauhan, M., Williams, D., Rollett, A., Roberts, J., Old, G., Roberts, C., Newman, J., Ingram, W., Harman, M., Wetherall, J. and Edwards-Jones, G. (2012) Contribution of the Welsh agri-environment schemes to the maintenance and improvement of soil and water quality, and to the mitigation of climate change. Welsh Government, Agri-Environment Monitoring and Technical Services Contract Lot 3: Soil, Water and Climate Change (Ecosystems), No. 183/2007/08, Final Report, 477 pp + Appendices.
