Development of GIS based Decision Support System for Estimation of Watershed Surface Runoff

Abstract

Runoff from rainfall is an important component of the hydrological cycle. Estimation of runoff is critical for the design of hydrological structures and drainage systems in watersheds. Different soils, land use and water management practices affect runoff differently. In real watersheds, land use, soils and weather conditions vary spatially over the geographical area of the watershed leading to spatial variations in runoff. Also, most watersheds form a part of larger drainage basin or a large watershed consisting of several such sub-watersheds. Each sub-watershed is hydrologically connected to the other sub-watersheds of the basin. A comprehensive Geographical Information System (GIS) based decision support system (DSS) for estimation of runoff that includes the spatial variations in rainfall and natural resources is presented. A DSS is a computer-based information system which serve the management, operations, and planning levels of an organization and help people make decisions about problems that may be rapidly changing and not easily specified in advance. The DSS is developed as a deployable application by integrating independent GIS layers of watershed features created in ArcGIS with MapObjects in Visual Basic software, as a case study for the KK3 watershed in Mahaboobnagar district of Telangana state, India. The DSS generates thematic maps of spatial variations in runoff on individual rainy days for the sub-watersheds.