Hernán Stenta

Simulation of erosion-deposition processes at basin scale by a physically-based mathematical model.

Abstract The development and application of the physically-based and spatially-distributed mathematical model CTSS8-SED is presented. The model simulates hydrologic-hydraulic processes produced by storm events and related soil erosion and sediment transport processes at basin scale in lowland areas. The model simulates (i) storm runoff, (ii) soil detachment by raindrop impact and overland flow (gross sediment yield), (iii) sediment transport by overland flow and associated erosion-deposition processes and (iv) sediment transport by stream flow and riverbed erosion-deposition processes. A quasi two-dimensional representation of water flow and sediment transport routing is made by means of interconnected cells approach. The model is applied to simulate two flooding events in the Luduena Creek basin (Santa Fe, Argentina) occurred in April 1994 and March 2007 due to extraordinary rainfalls.

Grid size effects analysis and hydrological similarity of surface runoff in flatland basins

ABSTRACT The effects of grid-size modification on the derived topographic attributes are analysed and a procedure for scaling model parameters and similarity assessment between flow variables is proposed. Hydrological simulations are performed with a physically-based and spatially-distributed quasi-2D mathematical model. The scaled model parameters are the effective roughness coefficient associated with overland flow (nov) and the transverse slope in the cell (TSC). To scale the selected parameters, the criterion of equilibrium storage conservation between the different grid sizes is applied. Three basins of the central-east region of Argentina are modelled. The spatial variability of basin geomorphology is quantified using the entropy concept. The simulation results show that when grid size is increased, to obtain similar hydrological responses it is necessary to increase the nov or to reduce the TSC. In terms of similarity, the best results are achieved when TSC is scaled, particularly when water depths are considered.