EVALUATION OF CROP WATER REQUIREMENT AND CROPPING PATTERN OF MAHAKALI IRRIGATION PROJECT

Abstract

Mahakali Irrigation Project (MIP) is a large irrigation project in Kanchanpur district of Nepal. Its development plan consists of three stages namely Stage-I with Net Command Area (NCA) of 4800 hectare (ha), Stage-II with NCA of 6800 ha and Stage-III with NCA of 33520 ha. Stage-I and Stage-II are at operation and Maintenance stage while Stage-III is under construction. -Stage-I is considered in the present study. Joint Irrigation Management (PJM) has been successfully implemented in Stage- I of this project. MIP Stage-I is divided into four blocks with each block having a Water Users' Associations (WUA). There is an apex committee which is called Water Users' Association Co-ordination Committee (WUACC). As per Memorandum of Understandings (MOUs) the WUAs will look after the tertiary canals in their jurisdiction. Irrigation Department will look after the main canal, branch canals, distributaries, minors and sub-minors. In addition to the operation and maintenance of tertiary canals Water Users' Association Co-ordination Committee will collect water tax from WUAs. The collected amount will be deposited to Irrigation Department and WUACC will receive its part according to the prevailing Irrigation Rules and Regulations as management grant. Now the farmers .are organized through WUAs, they are interested to optimize the cropping pattern to maximize their return by using their land and water resources optimally. In this dissertation an attempt has been made to evaluate the water requirement of crops grown in the study area and to find out optimal cropping pattern to maximize net returns, satisfying the energy (calorie) and nutrients requirement of the inhabitants of the study area. The study has been done on both full irrigation and variable irrigation basis for various crops. FAO Penman-Monteith method has been used to determine the reference crop evapotranspiration (ET,), Quadratic function has been utilized as the production function in variable irrigation model and Linear programming technique has ° been utilized for optimization in the present 'study.