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Effects of Seasonal/Monthly Variation on Runoff Curve Number for Selected Watersheds of Narmada Basin

2013; National Environmental Science Academy; Volume: 3; Issue: 6 Linguagem: Inglês

0976-4534

Sarita Gajbhiye, Sumeet Mishra, Ashish Pandey,

Flood Risk Assessment and Management

This study examined seasonal and monthly effects on the runoff Curve Number for four watersheds of Narmada basin. The periods between April-June and October-December were defined as the Pre-Monsoon and Post-Monsoon seasons, respectively. The Curve Number method was used to determine Curve Numbers using these observed rainfall and runoff values. Based on the date that rainfall and runoff volume were observed, the Curve Number values were grouped to their respective seasons for statistical analysis. The results from all watersheds showed monthly Curve number indicates a homogeneous pattern of variation in all the four watersheds in the basin. The monthly curve number has peak (during July) and valley (during August). However, at Shakkar watershed the peak is during August instead of July in other watersheds. The maximum monthly curve number is recorded during the month of September with the average value of 97.96 in Mohgaon watershed and the minimum Curve Number is recorded during the month of September with the average value of 17.88 in Bamhani watershed. Pre-monsoon contributes the major portion of the curve number with the average value range 25.70–27.76% for all watersheds. However, Post-monsoon curve number is almost negligible in Bamhani watershed (3.46%). The average maximum and minimum curve number is 97.43 and 95.74 for Manot and Bamhani watershed respectively. Because the Cultivated lands to exhibit higher CN values than Forest land.