The Variability of Alternative Decisions in a Water Resources Planning Problem

Abstract

Optimization models do not perfectly represent the real world. Therefore the mathematically optimal solution is not necessarily the “best” decision to implement. Water resources planning models tend to have many solutions that are nearly optimal in terms of objective function value, but which are significantly different decisions. Methods for generating nearly optimal solutions to linear programming models have been devised. The use of such methods is illustrated with an example problem involving the sizing of reservoirs and hydroelectric power plants and demands for municipal water supply and irrigation. The results show that the interactions among the decision variables and the economics of the system determine the range of choice among nearly optimal decisions. The examination of these interactions yields insight into the basic structure of the decision problem.