Surface Runoff Model Formulation

Abstract

Hydrologic and environmental processes are distributed in space and time. Simulation of these processes is made possible through the already well-developed spatial data analysis and management techniques of a GIS. Digital maps of soils, land use, topography, and rainfall are used to compute rainfall runoff in each grid cell in the drainage network. In principle, runoff generation caused by rainfall rates exceeding infiltration rates or soil profile saturation can is simulated in this scheme. Runoff losses due to infiltration in channels can account for runoff processes typical of alluvial fans in more arid climates or due to karstic geology where fractures permit runoff arriving from upstream to percolate into the subsurface or aquifer as recharge. The objective of this chapter is to explore the model formulation and the geospatial data used to define topography, land use/cover, soils, and precipitation input within a physics-based distributed framework.