Quantifying soil erosion by water in the UK: a review of monitoring and modelling approaches

Abstract

The role of erosion by water in the UK is considered. A summary of available data describing water erosion is presented providing insights into rates of erosion from the hillslope scale to the large catchment scale. Evidence suggests that soil erosion rates in excess of acceptable thresholds occur on a wide range of soils and under a wide range of land uses throughout the country. Given the recent shift towards erosion modelling and away from erosion monitoring, discussion of the quality of existing available observed data in the context of model evaluation is made. Much quality data exist in the UK to describe erosion by water, but it is argued here that few datasets provide the necessary detail with which to evaluate model performance accurately, especially when the description of the spatial heterogeneity of soil loss is a goal. Furthermore, the paradox between data collection (to improve models) and erosion modelling (to replace data collection) is highlighted as an issue that must be addressed within the discipline if full use of datasets and improvement of models is to be made.

Effects of the largest daily events on total soil erosion by rainwater. An analysis of the USLE database

“…Models are the most powerful tool to predict soil erosion, and hence to serve as the basis for designing correction measurements, but models need fi eld data of high quality to be validated (Brazier, 2004), since they will never be more than analogies (Kirkby et al, 1993). Within this context, long-term studies are scarce and data poorly understood (Burt, 1994), and this issue is particularly relevant under the present global climate change conditions (Williams et al, 2001;Michael et al, 2005).…”

Scaling Soil Erosion Models in Space and Time

“…temporal support. Erosion measurements emphasize the high degree of spatial variability (see discussion in Brazier, 2004), but for the reasons previously discussed, simple statistical approaches are not valid.…”

Evaluation of modelled spatially distributed predictions of soil erosion by water versus field-based assessments

“…There is a great need to integrate the work of modellers with that of researchers assessing erosion in the field (Boardman, 1998b;Brazier, 2004). In that way theory and reality, as reflected in assessments of potential and actual erosion, are brought together.…”

“…There is information available in England and Wales to make comparisons between data obtained by modelling erosion and that obtained by field monitoring. It is probably only in Britain that such comparisons can be made, yet few (if any) models have been rigorously evaluated in the light of such data, which is seen to be a crucial step towards improving erosion predictions in the UK (Brazier, 2004).…”