Conventional and unconventional alternatives for water supply management

A computer simulation of the Potomac River basin system run under conditions projected for the year 2010 has been used to test the performance of three water supply systems proposed for the Washington, D.C., metropolitan area. Two of the systems offered additional storage capacity on the Potomac River. These systems were found to meet average daily water withdrawal requirements. A third system, the minimum storage plan, offered no new storage capacity but was found feasible if used in conjunction with pumping from the Potomac River estuary and/or accepting drought adjustment. The minimum storage plan was the least costly system in real terms. However, the most costly reservoir systems are favored by local water planners, because most of the reservoir costs would be shared by the federal government. Although the real costs of the minimum storage plan are less than those of the reservoir plans, it is not favored, because none of the costs are borne by the federal government. This study illustrates the inefficiencies that can be generated by current cost‐sharing policies.