GIS-Based Fully Distributed Rainfall-Runoff Model for Suggesting Alternate Land Use Patterns

Abstract

A GIS based fully distributed rainfall-runoff model has been developed on the basis of SCS-CN method for computing daily runoff at grid level. Grid map preparation for the study area with a square grid size of 1 km x 1 km has been carried out in GIS environment. The study area has been divided into 2785 number of grids. The average yearly runoff was estimated for the period from 1996 to 2006 as 40.12% of rainfall for the study area. Maps pertaining to runoff, Geomorphology, Soils, Groundwater Potential, Slope and Land use/Land cover spatial maps have been integrated in GIS environment and the Composite Land Unit map has been derived. It provides an effective summary of the characteristics or attributes related to topography, hydro geomorphology, soil, drainage and land use. By careful examination, decision rules were applied through the model on each grid element of the integrated coverage taking into account the existing land use practices, the suitability of soils and the availability of surface and ground water potential in order to create the action plan suggesting alternate land use practices of the study area. The alternate land use practices such as Agro-horticulture, Horticulture, Intense agriculture, Silvipasture and Forest gap plantations have been suggested at grid level. These recommendations will result in better information and coordination activities essential for successful implementation of sustainable water resources development and management activities.