Optimal Water Management Strategies for Salinity Control

Abstract

Multi‐objective linear programming models have been formulated to evaluate the water management strategies for salinity control. The water management strategies essentially aim at minimizing irrigation return flow (IRF) through structural rehabilitation of the irrigated system. The models have been applied to a part of the area irrigated by the Bhakra Canal System (BCS) in Haryana, India. The optimal management strategies at a 70% reduction in IRF include: (1) Improving surface water application methods through precision land leveling and better design of irrigation layout (46%); (2) groundwater pumping by shallow tubewells from fresh and marginally saline aquifers (28%); (3) the lining of government controlled canals in Stage I (14%); and (4) the introduction of a combination of surface and sprinkle irrigation methods in the ratio 75:25% (12%). Appreciable increase in benefits from IRF reduction up to 70% is possible, without any increase in investment, if cost‐minimizing strategies are substituted by those maximizing benefits under the constraint of minimized cost. However, for the complete elimination of irrigation return flow, capital investments will have to be substantially enhanced. The sensitivity analysis in respect of cost $\left(c_i\right)$ and benefit $\left(B_i\right)$ coefficients indicated that the optimal plan was not very sensitive to changes in the range of $\pm 20\%\text{.}$