Prediction Models for Water Erosion Risk Management: A Review

Abstract

In order to estimate the potential soil erosion hazard of an area, erosion prediction models are needed. Various models have been used by researchers, which ranges from mathematical and conceptual simple approaches to complex models that try to include the complexities of the real world. Six (6) models are reviewed in relation to their suitability for use. The KINEROS, CORINE and EUROSEM were best suited for water erosion risk prediction in cultivated soils. On the other hand, the KINEROS, PESERA, CORINE and EUROSEM were found to be applicable in all sectors (Agronomy, water resources management and road construction) highlighted. The GLASOD had the least applicability with respect to this study. Keywords: Water Erosion, sediment transport models, Model structure and suitability for use Soil erosion by water has been a major environmental threat to the sustainability and productivity of agriculture, available data suggests that arable land is lost at a rate of more than 10 million ha per year (Pimentel et al, 1995). Information on soil erosion and its effects on water and land resources on plot or catchment scales are increasingly sought by land resource managers and stakeholders. This has led to continuous researches which focus on soil erosion processes as well as its modelling (Merritt et al., 2003). Majority of the Water Erosion Risk Prediction Models (WERPM) that were earlier developed to provide information on erosion and water quality processes are inappropriate for providing catchment scale, event-based predictions of sediment loads. They have shortcomings which includes over-parameterization, unrealistic input requirements, unsuitability of model assumptions, and inadequate documentation of model testing and resultant performance (Merritt et al., 2003). Development in the use of computer programming over time has led to rapid increase in the estimation of erosion soil loss, transport and sediment through the use of computer models. These models have differences such as complexity, the kind of processes considered, and the data required for measurement. There is no perfect model for all applications; rather, the model to be used will depend on the intended use and the characteristics of the area of focus. In general, models fall into three main categories: Empirical or statistical, conceptual and physics based models. The categorization of models depends on the physical processes simulated by the model, the model algorithms describing these processes and the data dependence of the model. This paper is essentially, a simplified review of soil erosion risk prediction models majorly drawn from the work of Merit et al. (2003) with an infusion of other models not covered in their review. There are many models available but more often than not, their strengths and weaknesses are unknown. Therefore, the aim of this paper is to showcase and compare the characteristics of the current water erosion prediction models available in literature.