ESTIMATION OF SURFACE RUNOFF BY NRCS CURVE NUMBER METHOD USING GIS AND REMOTE SENSING IN YAREHALLI MICROWATERSHED OF DAVANAGERE DISTRICT.
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Date
2021-12-03
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University of Agricultural Sciences, Bangalore
Abstract
The relationship between rainfall and runoff for a watershed is important in various activities of a water resources development and management. The transformation of rainfall to runoff is highly complex, dynamic, nonlinear & exhibits temporal and spatial
variability. A Geospatial technique was used for surface runoff estimation in Yarehalli micro-watershed which lies between 75° 51' 38" to 75 ° 53' 30" E longitudes and 13° 58' 59’ to the 140 01' 04" N latitudes in Davanagere district of Karnataka, India. The study
reveals that, drainage pattern is dendritic with trunk order 2. The area, maximum length and width of the micro-watershed are 761.47 ha, 3.96 km and 2.92 km respectively. The mean value of bifurcation ratio is 14, it indicates micro-watershed has suffered less structural disturbance and the value of formfactor indicates micro-watershed is approaching towards elongated shape. The value of drainage density is 1.64 km km-2 which indicates the region is having permeable sub-soil material. NRCS Curve Number method was used to estimate the surface runoff which uses watershed characteristics & 5-day antecedent rainfall. This method estimated the runoff as 255.56 mm and the total volume of runoff is 194.6 ha m in the year 2020, which is 18.66% of total volume of rainfall. These results help in planning, development and management of available water resources in the Yarehalli micro-watershed. November,