Federal Columbia River Power System Water Management
FCRPS Reservoirs are managed to provide beneficial flow conditions and dams are operated to provide safe passage, to allow migrating juveniles to reach the Columbia River estuary and the Pacific Ocean.
FCRPS Reservoirs are managed to provide beneficial flow conditions and dams are operated to provide safe passage, to allow migrating juveniles to reach the Columbia River estuary and the Pacific Ocean. During the juvenile migration season (~April through August), water and dam operations are cooperatively managed with states, tribes, and federal parties through the Technical Management Team.
Resevoir Operations
Some FCRPS reservoirs are used to manage flow and water temperature to benefit migrating juvenile salmon. These include:
- Libby Dam
- Hungry Horse
- Dworshak
- Grand Coulee Project/Lake Roosevelt
- Upper Snake reservoirs
Seasonal Use
There are two management seasons for the use of this water: Spring (April - June 22) and Summer (June 23 - August 31). Reservoirs are managed to be as full as possible going into the spring season, while maintaining flood control objectives. This is accomplished by having the reservoirs as full as flood control allows by April 10. The concept is to pass the spring freshet (i.e., the flood of a river from heavy rain or melting snow) downriver to aid salmon migration, rather than filling empty reservoir space (passing it rather than keeping it). The summer season is managed by assuring reservoirs are full going into the summer, and then drafting (taking water out of) them within specified limits before the end of the season.
Summer Flow Management Volumes
| Storage Reservoir | Draft Limit from Full (feet) | Draft Volume (kaf) |
|---|---|---|
| Libby | 10 | 455 |
| Hungry Horse | 10 | 246 |
| Grand Coulee | 10 | 789 |
| Banks Lake | 5 | 130 |
| Dworshak | 80 | 1,200 |
| Upper Snake | 487 | |
| Canadian water | 1,000 - 2,000 | |
| Total | 4,307 - 5,307 |
Run-of-River Operations
Most of the FCRPS projects have very little active storage. Those projects within the migratory corridor are managed to reduce the travel time for outmigrating juvenile salmon. This increases juvenile survival. This concept called "minimum operating pool" applies to the following projects:
- Lower Granite
- Little Goose
- Lower Monumental
- Ice Harbor
- John Day (minimum irrigation pool)
These projects are drawn-down approximately 5 feet from full pool levels during the juvenile migration season (April-August). The lower pools (measured in elevation) result in shorter travel times for fish.
Additional measures to avoid fish passage through the turbines and to improve survival are to provide spill or to transport fish around the dams. Learn more about spill and transport.
Water Quality
- Spill & Total Dissolved Gas
- Temperature