Estimation of Crop Evapotranspiration and Irrigation Water Requirement for Dharoi Command Area, India

Abstract

The Sabarmati River basin is one of India's most water-scarce delicate basins as far as water availability is concerned. The major source of water in Dharoi command area is storage of water in Dharoi reservoir. The mean rainfall in the Dharoi command area is 633 mm. Optimal water allocation plays a crucial role in irrigation water management. In this study, crop water requirement and irrigation water requirement of different crops are estimated for Dharoi left bank main canal (LBMC) and Dharoi right bank main canal (RBMC) of the command area using the data of period 2001–2016. FAO Penman–Monteith method is used for estimating reference crop evapotranspiration (ETo) in the command area. The estimated values of reference evapotranspiration (ETo) have been multiplied with crop coefficient (Kc) of respective crops to obtain their crop evapotranspiration (ETc) or consumptive use on daily time scale. Further, effective rainfall is estimated using SCS method on monthly time scale. It is subtracted with ETc of same time scale to obtain the net irrigation requirement (NIR) of the crops in the command area. The results showed that lower ETo values were found in month of August, while maximum values were reported for May month. Maximum monthly NIR of Dharoi LBMC and RBMC command area is found to be 7.63 MCM and 39.34 MCM, respectively.