This paper summarizes the Interim findings of the second phase of the HEC-PRM Columbia River application. The HEC-PRM represents the Columbia system as a link-node network and uses network-flow programming to optimize, in time and space, flow and storage in the system. The representation of operational goals in HEC-PRM is accomplished through flow, storage, and energy economic penalty functions. Operational purposes represented by penalty functions included hydropower, water supply, flood control, navigation, recreation, and anadromous fish. The application was based on fifty year period-of-record with a monthly time interval. The HEC data storage system, HEC-DSS, was utilized extensively for data management and analysis of results. System analysis, Reservoir modeling, Operations research, Network-flow programming, Operation studies, Reservoir operating rules.

Report documenting the development of the HEC-Prescriptive Reservoir Model and its application of analyzing the operation of the Columbia River reservoir system. The model represents the system as a network and uses network- flow programming to allocate optimally the system water. Two applications are documented: (1) a validation test to determine the applicability of the model for the system, and (2) analysis of the critical period. The applications are performed using the best-currently-available estimates of flow data and penalty functions.

Development and implementation of viable operating rules are among the most important aspects of decisions made in reservoir system management. Hydrologic Engineering Center's Prescriptive Reservoir Model (HEC-PRM) is used to suggest reservoir system operations optimized explicitly for quantitative statements of system operating objectives. Previous studies tested the feasibility of applying HEC-PRM to aid the System Operation Review and analyzed and compared three system operation alternatives. This study improved the model1s representation of the Columbia River system, analyzed and developed strategic operating rules for the system, and explored the application of HEC-PRM to seasonal operations.

Report documenting the application of the HEC-Prescriptive Reservoir Model for evaluation of three operation scenarios of the Columbia River system. The evaluation was performed to optimize the operation of: (1) existing policy with existing Canadian Treaty; (2) hydropower objectives were omitted; and (3) additional Canadian water is provided by Mica Reservoir. Conclusions include: HEC-PRM analysis performed successfully for the Columbia River System; three alternatives specified by CENPD were evaluated and compared; penalty functions were successfully used; using more storage at Mica does not significantly improve system performance; omitting the hydropower objective enhances system fish protection, navigation and recreation at the expense of system hydropower.