GIS-based spatially-distributed overland flow modeling

A GIS-based spatially-distributed hydrologic overland flow model which uses DEM (digital elevation model) and TIN (triangulated irregular network) to represent watershed topographic features is presented. The tools include a hydrologically ordered cell-to-cell flop sequence which is subsequently used to dictate the order of overland flow computations. Watershed characteristics are simulated according to digitized thematic maps. Combining the digital watershed flow algorithm with the hydrologic model for a sloped-land watershed and using kinematic-wave based finite-difference method to solve the system equations, a runoff hydrograph was produced