Integrated Simulation-Optimization Framework for Water Allocation Based on Sustainability of Surface Water and Groundwater Resources
Iman Chakraei, Hamid R. Safavi, Graeme C. Dandy, Mohammad H. Golmohammadi
Abstract
The aim of this study is to develop a framework for the optimal conjunctive use of surface and groundwater in a case study of the Zayandehrud river basin in Iran. The basis of the framework is an integrated simulation-optimization model that can be used to optimize a number of decisions, including (1) the operation of a reservoir, (2) allocations of water to irrigation canals, and (3) withdrawals from the river and groundwater sources. A water evaluation and planning system (WEAP) model is coupled with the nondominated sorting genetic algorithm II (NSGA-II) optimization algorithm to optimize the following two criteria: (1) a fuzzy sustainability criterion, and (2) the normalized shortfall of supply compared to demand. Each point on the generated Pareto front corresponds to a set of releases from the reservoir and allocations from surface and groundwater resources to the various agricultural regions. A compromise solution is selected from the Pareto front using an established method. The total sustainability of the compromise solution is 26% higher than that obtained previously by using the simulation model alone. It also represents an increase in the sustainability of the reservoir by 37% and the sustainability of the aquifers by 16%.