Surface Runoff Depth by SCS Curve Number Method Integrated with Satellite Image and GIS Techniques

Abstract

The existing scenario of groundwater recharge potential around the corner is one of the most talks about topic in today's world. And in the case if groundwater recharge scenario is primarily concerned, surface runoff is a prime factor to be quantified since it affects to the potential of groundwater recharge. Surface runoff also supports to the information required for groundwater recharging efficiency by providing the behavior of surface water flows for certain geographical terrain. The study area, Bhandara district (Maharastra, India), semi-arid region having geographical area of about 4090 Km2 (24 watersheds)normally receives average annual rainfall of 1300 mm and is very much concerned about the existing groundwater recharge scenarios. So, in this study an attempt has been made to quantify the annual average surface runoff depth of each watershed so that the potential groundwater recharge could be revealed indirectly. Soil Conservation Services (SCS) curve number method has been employed for the estimation of surface runoff depth integrated with remote sensing (RS) and Geographical Information System (GIS) techniques. SCS curve number method is basically defined by the curve number (CN) derived from landuse/landcover and hydrological soil groups of the particular geographical area. Landuse/landcover and hydrological soil group have been derived from satellite image (LISS III) using GIS techniques. The watershed-wise results of surface runoff depth were classified into six classes (very low, low, medium low, medium high, high and very high) in the range of 700--1000 mm with 50 mm difference between the classes. The study area is mostly covered by low to medium low runoff depth indicating for medium groundwater recharge potential. These results were re-examined with the average groundwater level fluctuation. Both the results were shown similar conclusion of having moderate groundwater recharge potential in this area.