CONJUNCTIVE USE PLANNING OF WATER RESOURCES IN A CANAL COMMAND

Abstract

Agriculture is one of the single largest sectors of most countries economy. It contributes about 35 percent of GDP to some countries, directly accounts for 40 percent of export earnings and employs more than 50 percent of some countries civilian force. The resource of most countries depends on agricultural output. Population explosion has necessitated the need for expansion of agricultural production. Water is evidently the most vital element in the life of plants. However, in recent years, changes in weather pattern have resulted in rainfall being ill-timed and inadequate in some places. Because in some places, the water requirements of crops can not be met by rainfall alone, irrigation schemes incorporating a network of canals and distributaries have been put in place to meet the water requirement of crops. These networks of canals and distributaries also contribute to an increase in groundwater recharge. This recharged groundwater can be used to meet the water needs of crops when rainfall and surface run-off is low. Conjunctive use of surface and ground water is the management of surface- and ground-water resources in a coordinated operation to the end that the total yield of such a system over a period of years exceeds the sum of the yields of the separate components of the system resulting from an.uncoordinated operation. Commonly, conjunctive use involves using surface water supplies in periods of ample rainfall and runoff and groundwater - supplies when surface water is limited or unavailable. The objective of conjunctive use is to increase the yield, reliability of supply, and general efficiency of a water supply system by diverting water from streams and surface reservoirs for conveyance to and storage in ground-water basins for later use when surface water is not available. Conjunctive use model consists of an optimization model and groundwater model. An optimization model is required for conjunctive use planning to obtain optimal cropping pattern and optimal allocation of surface and ground water resources satisfying a series of constraints. A groundwater simulation model is required to know the aquifer response to excitations. The main objective of the present work is to develop a conjunctive use model for optimal planning of surface and ground water resources in the Omkareshwar Canal Command of Khandwa district in Madhya Pradesh, India. A linear programming optimization model is formulated to obtain optimal cropping pattern and the optimal allocation of surface and ground water resources. Different Scenarios of availability of surface and ground water resources are analysed to determine the net benefits and the allocation of water resources