A Chinook salmon migrates up Battle Creek at the Coleman National Fish Hatchery Barrier Weir. (photo: USFWS)

by Jess Newton, Red Bluff FWO
In a landmark agreement between the Pacific Gas and Electric Company and government agencies, a large-scale restoration project was established in 1999 to recover imperiled Chinook salmon and steelhead trout in northern California's Battle Creek. But large-scale restoration projects take time to plan and execute and immediate action was needed to sustain threatened fish populations until restoration efforts could be implemented.  It was this immediate need for action that led to the Interim Flow Agreement. 

The Restoration Project:

The Battle Creek Salmon and Steelhead Restoration Project is estimated to cost more than $100 million and will restore 42 miles of habitat in Battle Creek, a tributary to the Sacramento River that runs through Shasta and Tehama counties. The restoration project includes the removal of five dams, construction of new state-of-the-art fish screens and fish ladders at three remaining dams, and large increases in stream flows.  The project will help restore winter- and spring-run Chinook and Central Valley steelhead, all of which are critically imperiled.

Interim Flow Agreement:

The Interim Flow Agreement was initiated in 1995 with the goal of immediately increasing stream flows to a minimum of 30 cubic feet per second in both the North Fork and South Fork Battle Creek.  These flows were intended to maintain current populations of critically imperiled fish, especially spring-run Chinook salmon, until a restoration project could be implemented.  The FWS’s Red Bluff Fish and Wildlife Office has monitored the Battle Creek population of spring Chinook since 1995.  Monitoring results indicate that, on average, the population of spring Chinook has been increasing at the moderate rate of nine fish per year over the last 14 years.  Although the increase is small, it indicates that the goal of the Interim Flow Agreement is being achieved.

Monitoring data also suggests that the consequences of not providing interim flows could be devastating to the spring Chinook salmon population.  In two years (2001 and 2002), interim flows were not provided in the South Fork Battle Creek due to limitations in funding.  The lack of interim flows led to unsuitably high water temperatures and a large reduction in spawning habitat.  The population of adults returning to Battle Creek in 2004 and 2005 (i.e., progeny of the 2001 and 2002 year classes) were reduced by 19% and 67 % respectively.

It is estimated that the Battle Creek Restoration Project will lead to a spring Chinook population that is 19 times larger than its current average size.  The Interim Flow Agreement is playing a key role in realizing this potential.