The capability exists within the Corps to evaluate the water quality impacts of alternative proposals for river and/or reservoir projects. The capability and example applications of the various water quality models available from the Hydrologic Engineering Center are described. (Author).

Several example applications of water quality models were discussed to provide background into the development of a comprehensive mathematical model capable of evaluating water quality conditions in any river-reservoir system. A need exists for a river-reservoir water quality model which can be continuously updated and maintained with the best available concepts. The 'Water Quality for River-Reservoir Systems' (WQRRS) model was developed by the Hydrologic Engineering Center (HEC) to meet these needs. The HEC continuously updates the WQRRS based on the advantages of water quality research work brought to their attention. (Author).

Several state-of-the art models are available for analyzing water quality conditions in complex reservoir systems for a given set of operational conditions. Some of these models can even make operational decisions regarding proper gate regulations to obtain a desirable water quality condition at a dam site for a given set of flow conditions. HEC-5Q, Simulation of Flood Control and Conservation Systems (Including Water Quality Analysis) computer model, has the unique capabilities to accept user-specified water quantity and quality needs system-wide and to decide how to regulate the network of reservoirs. The decision criteria are programmed to consider flood control, hydropower, instream flow (municipal, industrial, irrigation, water supply, fish habitat) and water quality requirements. The HEC-5Q program was first applied to the Sacramento River System in California and a report was published in July 1985. Two other applications are in progress the Kanawha and Monongahela River systems, and are expected to be completed by September 1986. Keywords: Reservoir System Analysis, Water Quality, Case Study, Stream System Analysis, Computer Model.

The Corps' Hydrologic Engineering Center (HEC) has developed a generalized simulation model capable of analyzing complex river-reservoir systems. The development of the model, 'HEC-5, Simulation of Flood Control and Conservation Systems' (Eichert, 1974, 1975) has been paced by the changing mission of the Corps as well as the evolution of computer systems. HEC-5 development and management, including code development, testing, documentation, training and field application experience, is discussed. (fr).