GIS BASED RAINWATER HARVESTING THROUGH HYDROLOGIC MODELLING OF A WATERSHED

Abstract

Surendranagar in Gujarat is characterized by erratic rainfall and high evapotranspiration. Annual rainfall is sufficient for crop production, but frequently threatened by the highly variable distribution in time and space and contributes to food insecurity. Rainwater harvesting (RWH) as supplementary irrigation is being considered by the Indian government as an alternative to mitigate the dry spells and thus large numbers of different RWH practices have been implemented throughout during the last decade. A systematic identification of areas which are suitable for RWH and the RWH methods are essential to ensure its effectiveness and better target investments in RWI-l. However, the identification of potential areas for RWH on a large scale presents great challenges. Efficient techniques for RWH have evolved with the advent of powerful and high-speed personal computers, through which GIS is of great significance. The objective of this study is to identify potential areas for RWI-I amongst the sub-watersheds of Surendranagar, Gujaral. using Geographic Information Systems (GIS) techniques. This study presents a methodology to find the sites suitable for rainwater harvesting (RWH) easily through the use of freely available remote sensing data and GIS soliware. Historical and near real time data has been used for hydrologic modeling in GIS alongwith analytic hierarchy process (AHP) using spatial multi criteria evaluation (SMEC) model for decision making. Erdas Imagine 2013 and Arc Map 9.3 are used to derive all the key input layers which are required for various analysis. Rainfall, slope, soil groups, landuse/landcover, drainage, CN are the various layers which has been used as inputs. Soil Conservation Service (SCS) has been used for runoff modeling at pixel scale.