MODEL ASSISTED PLANNING OF GROUND WATER 9 DEVELOPMENT

Abstract

A simulation based optimization model has been proposed for arriving at such cropping patterns and the associated pumping pattern that in conjunction with the available canal supplies maximize the stipulated objective functions subject to the assigned constraints. The decision variables invoked in the model comprises areas under various crops that are agronomically feasible in the study area. The model essentially involves stipulating several geographically feasible cropping pattern, i.e. areas under various feasible cropping areas. Geographical feasibility implies that the total cropped area at all times does not exceed the CCA. Subsequently the pumping requirements of the stipulated cropping patterns are computed employing the data of irrigation requirements and the canal water availability. Thereafter using a groundwater flow model the feasibility of the cropping patterns is determined. The objective functions are computed for all cropping patterns found to be feasible. Accordingly the optimal cropping patterns are identified. The model has been illustrated by applying it to Region V of the Sardar Sarovar Command. The twin objective functions invoked in the study are the maximization of the crop intensity and maximization of the net monetary benefit. The net monetary benefit is computed as the net market return minus the costs of water, fertilizer and the labour. The maximization is carried out subject to the constraint of restricting the water table depth ON under the state of dynamic equilibrium with in an acceptable range of 2.5m to 20m. As expected the first objective functions leads to larger crop areas. While the maximization of the first objective function leads to an optimal cropping intensity of 68%, the maximization of the second objective function leads to a net monetary return of Rs 1215.22 /hectare.