In spite of the proliferation of computer technologies for decision support, classical simulation and optimization models have remained at the heart of most water resources DSSs. Ironically, these widely used analytical tools have also brought about the need for other technologies to be integrated into DSSsūtheir often unwieldy input files and cryptic output files made them useful only to technical analysts. Since some of these simulation and optimization models will be discussed in other reviews (e.g., Wagner, [1994]), we will focus here only on computerized water resources planning systems comprised of integrated systems of simulation and optimization models, databases, expert systems, geographic information systems, and the like, which can be characterized as systems which sacrifice modeling at the scale of physical processes for the sake of remaining useful for decision-making.
Wurbs [1993] reviewed a wide array of reservoir simulation and optimization models and evaluated the usefulness of each approach for different decision-support situations. He hoped that his paper would help practitioners choose the appropriate model from the overwhelming number of models and modeling strategies which currently exist.
Yeh [1992] reviewed optimization techniques for groundwater supply planning and management. A key advancement in this field has been the development of a single systematic procedure for experimental design, parameter identification, and the management decision. However, nearly all of the groundwater planning models found in the literature have addressed only the management decision.