Multiobjective analysis of multireservoir operations

Abstract

The objective of the study reported herein is to develop practical procedures for the analysis of a multiple purpose, multiple facility reservoir system to guide real time decisions concerning the optimal operation of the system. Application is made to the California Central Valley Project (CVP). The five purposes (benefits), treated as objectives here in the multiobjective optimization, include (1) hydropower production, (2) fish protection, (3) water quality maintenance, (4) water supply, and (5) recreation. The constraint method is used to develop the trade‐offs while a specially modified linear programing and dynamic programing algorithm is used for optimization. Noninferior sets can be obtained with each benefit parameterized singly and in various combinations. Two sets of monthly historical streamflows, one set corresponding to a drought year and the other set to an excess water year, are used to develop the corresponding noninferior sets. These procedures provide guidance for allocating the total benefits derived from a region's water resources and for operating the available system within all statutory, contractual, and other applicable constraints. A very high degree of decomposition of the typically large multiple purpose, multiple facility operation problem is made possible by the above technique, resulting in a rapid delineation of the noninferior policy set. The decision maker participates at various stages of the analysis and can request more or less detail with regard to the noninferior set. In our opinion, information is best presented to him via a series of two dimensional plots representing various cross sections of the noninferior set. Tabular presentations are not conducive to a good appreciation of the consequences of alternative benefit allocation policies.