Efficient Operation of Minipe Left Bank Canal Irrigation Scheme to Satisfy Irrigation Demands

In Sri Lanka, agriculture depends heavily on irrigation, particularly during dry seasons. Despite its importance, the country faces persistent water deficit challenges due to population growth and operational inefficiencies. Water scarcity is especially severe for farmers located at the tail end of irrigation schemes such as the Minipe Left Bank Canal. Despite efforts under the Minipe Left Bank Canal Rehabilitation Project to increase upstream water storage, operational inefficiencies and mismanagement hinder effective water distribution, resulting in continued shortages for tail-end farmers. This study aims to improve water distribution within the Minipe Left Bank Canal irrigation system through reforms in water rotational scheduling and crop diversification. A scenario-based simulation modelling approach using the Water Evaluation and Planning (WEAP) software was employed to optimize water allocation by balancing supply and demand priorities. The research process involved detailed data collection and the estimation of crop irrigation requirements using the CROPWAT 8.0. By simulating the irrigation system’s operation, a water balance framework was applied to develop sustainable water management strategies. The study introduces an efficient operational pattern designed to meet crop water requirements during the Yala and Maha seasons. The findings can contribute to equitable water distribution and sustainable water management in Minipe Left Bank Canal irrigation scheme, thereby increasing the agricultural productivity in Sri Lanka.