Spill

The FCRPS Action Agencies release (or spill) water over the federal dams in the spring and summer to help juvenile salmon and steelhead migrate safely to the ocean. With spill, fish go past the dams in water that flows through spillway openings, rather than traveling through turbines.

The federal agencies have built spill into the 2008/2010 FCRPS Biological Opinion, tailoring it to scientific findings and consulting with the region to meet the FCRPS Biological Opinion performance standards of 96 percent average per-dam survival for spring migrants and 93 percent for summer migrating fish.

The effectiveness of spill to increase fish survival is variable and depends on the configuration at each dam. While spill is effective, by itself it is not a "silver bullet." For example, too much spill can create back-eddies where fish get trapped and become easy prey to predators. Too much spill can also cause gas bubble disease.

Each year, the U.S. Army Corps of Engineers prepares Fish Operations Plans describing operations at each of the eight dams for safe fish passage. During the migration season, state and tribal fish managers work together with the Corps to manage real-time operations decisions for fish.

 

Summary of 2012 Spring Spill at Lower Snake & Columbia River Projects

ProjectPlanned 2012 Spring Spill Operations
(Day/Night)
Comments
Lower Granite20 kcfs/20 kcfsSame as 2011
Little Goose30%/30%Same as 2011
Lower MonumentalGas Cap/Gas Cap
(approximate Gas Cap range: 20-29 kcfs)
Same as 2011
Ice HarborApril 3 - April 28: 45 kcfs/Gas Cap
April 28 - June 20: 30%/30% vs 45 kcfs/Gas Cap
(approximate Gas Cap range: 75-95 kcfs)
Same as 2011
McNary40%/40%Same as 2011
John DayPre-test: 30%/30%
Testing: 30%/30% and 40%/40%
Same as 2011
The Dalles40%/40%Same as 2011
Bonneville100 kcfs/100 kcfsSame as 2011

 

Summary of 2012 Summer Spill at Lower Snake & Columbia River Projects

ProjectPlanned 2012 Summer Spill Operations
(Day/Night)
Comments
Lower Granite18 kcfs/18 kcfsSame as 2011
Little Goose30%/30%Same as 2011
Lower Monumental17 kcfs/17 kcfsSame as 2011
Ice HarborJune 21 - July 13: 30%/30% vs 45 kcfs/Gas Cap
July 13 - August 31: 45 kcfs/Gas Cap
(approximate Gas Cap range: 75-95 kcfs)
Same as 2011
McNary50%/50%Same as 2011
John DayJuly 1 - July 20: 30%/30% and 40%/40%
July 20 - August 31: 30%/30%
Same as 2011
The Dalles40%/40%Same as 2011
BonnevilleJune 16 - July 20: 85 kcfs/121 kcfs and 95 kcfs/95 kcfs
July 21 - August 31: 75 kcfs/Gas Cap
Same as 2011