"MIRSED" towards an MIR approach to modelling hillslope soil erosion at the national scale

This paper reports a new methodology for assessing regional and national pa tterns of hillslope scale soil erosion rates in the UK using a MIR (minimum information requirement) version of WEPP (Water Erosion Prediction Project ) known as MIRSED. WEPP is parameterised using a national coverage, environ mental database containing topographic, soil, land management and climate v ariables for all hillslopes within each grid cell to be modelled. The MIRSE D matrix summarises the behaviour of WEPP in a multi-dimensional parameter space, allowing results to be queried using a subset of key, spatially vari able parameters to produce an averaged hillslope soil erosion response from each 1 km(2) grid cell. The approach is demonstrated for the Great Ouse ca tchment, Cambridgeshire, UK and highlights highest hillslope erosion rates of 2.2 t ha(-1) year(-1) associated with steepest slopes, erodible soils an d management practices that leave the soil exposed for critical times of th e year. A mean soil erosion rate of 0.4 t ha(-1) year(-1) is predicted from hillslopes across the catchment which compares well with observed data col lated at different scales, using contrasting measurement techniques. (C) 20 01 Elsevier Science B.V. All rights reserved.