Runoff estimation of machhu and watrak rivers basins of gujarat india using SCS-CN Method and GIS

Main objective of the study is to estimate the runoff of Machhu and Watrak river basins of Gujarat for the planning and management of catchments. The Soil Conservation Service (SCS) -Curve Number (CN) method was used to estimate runoff. For Machhu river basin threshold value of rainfall is 250 mm and for Watrak river basin 400 mm. This difference of threshold values is due to different topography, geology and soil conditions of these two catchment areas. Regression analysis of observed rainfall and simulated runoff of these two river basins indicated good correlation (R² : 0.85 and 0.735). The present rainfall-runoff study of the two widely separated river basins suggestsapplicability of simple SCS-CN method in different areas having different geo-environmental conditions.