Application of a distributed 2D overland flow model for rainfall/runoff and erosion simulation in a Mediterranean watershed

C Juez,J Fernández-Pato,R.J Batalla,A Tena,P García-Navarro

doi:10.18172/cig.3320

Abstract

Soil erosion has reemerged as an environmental problem associated with climate change that requires the help of simulation tools for forecasting future consequences. This topic becomes even more relevant in Mediterranean catchments due to the highly variable and irregular rainfall regime. Hence, an approach that includes the rainfall/runoff and erosion phenomena is required for quantifying the amount of soil the catchments are transferring to the rivers. As the calibration process of the infiltration and erosion parameters can become cumbersome in terms of iterations to the optimal values to fit experimental data, a Simplified Catchment Model (SCM) is introduced as a first approach. The set of tuning constants that provides the best fit are used as input for re-calibrating the parameters by means of the simulation of the real catchment. The modeling effort here presented opens its application to the analysis of the hydro-sedimentary processes at larger temporal and spatial scales.

Highlights

In the last decades, the scientific interest in soil erosion has increased due to the growing awareness of its associated impacts
The catchment hydrosedimentary response to a characteristic rainfall event in the Western Mediterranean region has been simulated by means of a distributed surface flow model together with empirical infiltration and erosion laws
Rainfall/runoff losses have been estimated by means of a spatially distributed SCS model as an additional source term for the 2D shallow water model

Summary

Introduction

The scientific interest in soil erosion has increased due to the growing awareness of its associated impacts. Whilst soil erosion and redistribution in tropical and semiarid areas is still a significant issue, in temperate areas it is being increasingly recognized as a hazard. These issues are of particular importance for Mediterranean areas, because of the irregular or torrential rainfall regime. Mullan et al, 2012) It is well known the sensitivity of the Mediterranean region to environmental changes (e.g. Conacher and Sala, 1994), there is still the need of sediment transport studies tackling the effects of these changes on hydrological and erosional processes; this type of studies are often difficult to carry out due to the difficulty of studying infrequent erosional events in temporary rivers Despite the series of studies done so far, there is a significant gap in our understanding of soil erosion processes and the associated sediment yield in this region

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Conclusion