Water and Sediment Discharges Simulations via Hydrologic and Channel Modelling Approaches

Hydrossedimentologic models are generally used for investigating mathematical representation of catchment processes, being the surface flow, soil erosion, and sediment transport the main goal. The surface total flow discharging through the drainage system is a consequence of hydrologic processes occurring in the catchment (e.g., precipitation, interception, infiltration, percolation, interflow, groundwater), and is affected by the catchment changes. This implies that infiltration decreases as impervious areas increase and as a consequence peaks of water discharge increase. Moreover, erosion decreases at impervious areas. Land use changes are important for the modelling and simulation of water and sediment discharges for practical purposes. Peaks of runoff are applied for the design of drainage systems, while the runoff corresponding to the limit of sediment deposition into the channel is the criterion used to avoid sedimentation and reduction of channel convey. In this research the distributed hydrologic model MOSEE, a MOdel for Soil Erosion Estimation, was used to simulate water and sediment discharges at a small catchment subjected to changes via process and catchment modelling, and observed values. Model results were compared with simulations carried out with MOSTG, a MOdel for Sediment Transport in Galleries, which was coupled on to the hydrologic model, and designed for simulating water and sediment discharges at the limit of sediment deposition. The hydrologic model flow depths were taken as input to the channel model, and the simulated water and sediment discharges compared. The results showed to be consistent, and suggest that the models are viable for simulating the discharges in areas of interest considering the limit of deposition of sediments.