Situational and sustainability assessment of irrigation systems to Nepal from the Koshi Barrage

Abstract The Koshi Barrage was constructed in the Nepalese territory as per the Kosi Agreement signed between Nepal and India in 1954 and amended in 1966. Two irrigation systems, viz. the Koshi Distributary System and the Koshi Pump Lift Irrigation System, starting off from the Koshi Western Main Canal in India, are irrigating 11,300 and 13,180 ha of land in the Saptari District of Nepal, respectively. The average annual amount of water available in the Koshi Pump System and Koshi Distributary System is found to be 60.28 and 136.97 million cubic meters (MCM), respectively. The existing cropping intensity of these two systems is 170 and 190%, respectively. The sustainability of these irrigation systems was assessed using the Multi Criteria Analysis (MCA). The Koshi Pump Irrigation System is found to be a Sustained but At-Risk Project, whereas the Koshi Distributary Irrigation System is found to be a Not Sustained Project. Furthermore, the study concluded that these irrigation systems have low crop productivity and the conditions of the existing infrastructures are poor.