Integrated Watershed Modeling Using a Finite Element Method and GIS Approach

Abstract

A watershed is a hydrological unit that can be used as a physical and biological unit and socio-economic-political unit for the planning and management of natural resources. For the appropriate management of a watershed, it is essential to calculate the runoff from a particular watershed for the given rainfall. Hence watershed modeling is very important in water resources impact assessment and watershed management. Due to the complexity of the hydrological processes, watershed modeling requires advanced computational techniques and data management tools, such as the Finite Element Method (FEM) and Geographic Information Systems (GIS). In this research study, the features of FEM have been added to a GIS to take into account the spatial variations of the data of the watershed considered. Effort has been made to integrate these two modeling tools to provide more efficient assessment procedures in watershed modeling. In the watershed modeling procedure, initially overland flow is simulated using the mass and energy balance approach facilitated by GIS. Subsequently the channel flow is simulated by the finite element method, using the kinematic wave model based on the continuity and momentum equations. Finally, both the overland flow model and channel flow model are coupled together to evaluate the runoff. The developed model is applied to an un-gauged watershed for the runoff simulation and the results are found to be satisfactory.