Relation Between Runoff Curve Number and Irrigation Water Requirement

Abstract

This paper proposes a relationship between Soil Conservation Services runoff curve number (CN) and crop water requirement/irrigation water requirement (IWR) for Seonath river basin (area = 30,860 sq km) falling in Chhattisgarh State (India) considering rain-fed irrigation. It is derived empirically from long-term (30 years, 1960–1989) rainfall–runoff data and validated on the remaining data of 20 years from 1990 to 2010. The relationship was derived with coefficient of determination (R2) of 0.970 for monsoon season and 0.926 for post-monsoon season. It was validated with R2 of 0.957 and 0.954 for monsoon and post-monsoon seasons, respectively, indicating the existence of a strong CN–IWR relationship.