Application of a numerical model designed for integrated watershed management

The present research is concerned with the latest developments and practical application of a physically-based numerical model MELEF (Modele d’ELEments Fluides, in French) that incorporates a finite elements solution to the steady/transient problems of the joint ground/surface fresh/salt water flows in inland and coastal regulated watersheds. The proposed model considers surface and groundwater interactions to be 2-D horizontally distributed and depthaveraged through a diffusive wave approach. Infiltration rates, overland flows and evapotranspiration processes are considered by diffuse discharge from surface water, non-saturated subsoil and groundwater table. Recent developments also allow for the management of surface water flow control through the capacity of diversion on river beds, spillways and outflow operations of floodgates in weirs and dams of reservoirs. The application regards the actual hydrology of the Mero River watershed, with two important water bodies mainly concerned with the water resources management at the Cecebre Reservoir and the present flooding of a deep coal mining excavation. The model was adapted and calibrated during a period of five years (2008/2012) with the help of hydrological parameters, registered flow rates, water levels, precipitation, water uses and water management operations in surface and groundwater bodies. The results presented predict the likely evolution of the Cecebre Reservoir, the flow rates in rivers and the flooding of the Meirama open pit.