Streamflow Forecasting and Reservoir Model for the Payette River, Idaho

Riverside Technology, inc. (RTi) developed and implemented an enhanced forecasting system based on the National Weather Service River Forecast System (NWSRFS) for the Payette basin in southwestern Idaho. Project subtasks conducted for the Idaho Power Company (IPCo)

Black Canyon Dam on the Payette River

included historical data collection, analysis and time series processing; basin delineation; watershed runoff modeling that included calibration of snowmelt, soil moisture accounting, consumptive use, channel routing, and unit hydrograph models, reservoir modeling and software modifications to address reservoir operating issues in the Payette Basin; and implementation of a real-time forecasting capability. System installation and training of IPCo staff also were completed as part of the scope of work.

RTi enhanced the RES-J reservoir model to simulate the joint operations of Cascade, Deadwood, and Black Canyon Reservoirs for flood control based on a seasonal water supply forecast. The system was configured to produce a seasonal water supply forecast that subsequently could be used by RES-J to determine reservoir releases. The deterministic system component has the capability of forecasting end-of-period streamflows, reservoir volumes, and reservoir releases for up to ten weeks, with a minimum six-hour time step. This component uses Quantitative Meteorological Forecasts (QMF) and/or a user-selected historical year’s data as input. The deterministic component is coupled with an Ensemble Streamflow Prediction (ESP) Component to provide information up to 2 years into the future. The system provides information to support short-term operations as well as long-term planning.

Payette River Basin Forecast Points and Subareas

2290 East Prospect Road, Suite 1, Fort Collins, Colorado 80525  (970) 484–7573  (970) 484–7593 Fax www.riverside.com   info@riverside.com