Assessing Stormwater Harvesting Potential in Dehradun City Using Geospatial Technology

Assessment of surface runoff using Natural Resources Conservation Service-Curve Number (NRCS-CN) method is the most extensively globally adopted method. With the availability of geospatial techniques, the surface runoff can be estimated accurately. In this study, effort has been made to assess the applicability of NRCS-CN method by incorporating the geospatial tools on the study area. The land-use maps are generated by supervised classification, and soil map is prepared by applying this method. Land-use map and soil group map are integrated, and the CN values are assigned to form reclassified image from NRCS Standard tables. The runoff curve number (CN), thus assigned to different subareas, was utilized to estimate monthly runoff for the city of Dehradun. The paper also looks into the gap between runoff and precipitation for different months in a year, and this subsequently helps identifying the need for harnessing rainwater or surface runoff during these critical months. Considering the demand patterns along with runoff generated can be helpful in dimensioning storage tanks in available utilized patches in the city.