Modelling sediment export, retention and reservoir sedimentation in drylands with the WASA-SED model

Abstract

Abstract. Current soil erosion and reservoir sedimentation modelling at the meso-scale is still faced with intrinsic problems with regard to open scaling questions, data demand, computational efficiency and deficient implementations of retention and re-mobilisation processes for the river and reservoir networks. To overcome some limitations of current modelling approaches, the semi-process-based, spatially semi-distributed modelling framework WASA-SED (Vers. 1) was developed for water and sediment transport in large dryland catchments. The WASA-SED model simulates the runoff and erosion processes at the hillslope scale, the transport and retention processes of suspended and bedload fluxes in the river reaches and the retention and remobilisation processes of sediments in reservoirs. The modelling tool enables the evaluation of management options both for sustainable land-use change scenarios to reduce erosion in the headwater catchments as well as adequate reservoir management options to lessen sedimentation in large reservoirs and reservoir networks. The model concept, its spatial discretisation scheme and the numerical components of the hillslope, river and reservoir processes are described and a model application for the meso-scale dryland catchment Isábena in the Spanish Pre-Pyrenees (445 km 2 ) is presented to demonstrate the capabilities, strengths and limits of the model framework. The example application showed that the model was able to reproduce runoff and sediment transport dynamics of highly erodible headwater badlands, the transient storage of sediments in the dryland river system, the bed elevation changes of the 93 hm 3 Barasona reservoir due to sedimentation as well as the life expectancy of the reservoir under different management options.

lumpR 2.0.0: an R package facilitating landscape discretisation for hillslope-based hydrological models

“…As hydrologic connectivity of the landscape can be represented in a realistic manner, the model has been used for a number of studies investigating runoff redistribution and erosion processes (e.g. Güntner and Bronstert, 2004;Mueller et al, 2010;Medeiros et al, 2010;Bronstert et al, 2014).…”

“…It has been frequently employed in semi-arid areas such as northeastern Brazil (including the Benguê catchment; for references see Sect. 4.1), India (Jackisch et al, 2014) and Spain (Mueller et al, 2009(Mueller et al, , 2010Bronstert et al, 2014). The model incorporates the Shuttleworth-Wallace approach for evapotranspiration calculation over sparsely vegetated surfaces and an infiltration approach based on Green-Ampt accounting for Horton-type infiltration.…”

Seasonal drought prediction for semiarid northeast Brazil: About the added value of a process-based hydrological model

“…Reservoirs can be simulated by treating large strategic reservoirs in an explicit manner while representing smaller ones as lumped water bodies of different size classes to efficiently account for water retention of many small reservoirs in a study region . The model was developed for and successfully applied in the semiarid areas of northeastern Brazil (Medeiros et al, 2010;Krol et al, 2011;de Araújo and Medeiros, 2013;Medeiros et al, 2014) and used for other dryland regions, such 10 as in India (Jackisch et al, 2014) and Spain (Mueller et al, 2009(Mueller et al, , 2010Bronstert et al, 2014).…”

“…More information are given in Delgado et al (2017). Mueller et al, 2010). Reservoirs can be simulated by treating large strategic reservoirs in an explicit manner while representing smaller ones as lumped water bodies of different size classes to efficiently account for water retention of many small reservoirs in a study region .…”

Water and sediment fluxes in Mediterranean mountainous regions: comprehensive dataset for hydro-sedimentological analyses and modelling in a mesoscale catchment (River Isábena, NE Spain)

“…Sediment connectivity for two sub-catchments of the Isábena basin was analysed based on digital elevation models obtained from airborne lidar data and surface cover fractions obtained from airborne hyperspectral imagery , while sediment origins were traced back by spectral fingerprinting, based on measured spectra of suspended sediment samples and soil samples of potential sediment sources (Brosinsky et al, 2014a, b). Furthermore, for the process-based, spatially semi-distributed model WASA-SED developed for water and sediment transport in dryland catchments (Bronstert et al, 2014;Mueller et al, 2010), a framework for studying the effect of model enhancements was tested using parts of the dataset presented here . Table A1 of Appendix A for station IDs).…”