Coleman hatchery undergoes $10M overhaul
By Michael Woodward, Reporter (reprinted with permission)
Wednesday, July 30, 2008

CONSTRUCTION IN BATTLE CREEK:

Battle Creek was diverted during the construction of improvements to the weir and fish ladder at the Coleman National Fish Hatchery Complex.

The Coleman National Fish Hatchery returned in June to its $10 million construction project to improve the control of salmon traffic on Battle Creek, according to Scott Hamelberg, project leader of Coleman National Fish Hatchery Complex. The project coincides with the California Department of Fish and Game restoration efforts of upstream Battle Creek. The DFG has devoted over $42 million to improve the salmon habitat in that area.

The 18-month fish hatchery project will improve the access for salmon to that restored habitat. Although some finishing work will continue past October, the improvements must be functionally complete by October 1, before the salmon arrive, said Hamelberg.

The improvements listed below were not intended to increase the intake of salmon into the hatchery, which regularly makes its quota, Hamelberg said.

"It's less about getting more fish in, and more about restoration," he said. "The improvements are designed to integrate hatchery operations with larger processes on the creek. (The hatchery improvements are) in response to the restoration project, and would not have been done without it."
To begin work this summer, companies Gracon and Portadam first had to divert 150 feet of the creek. Once the original streambed was clear, workers began improvements on the weir, overshot gate and fish ladder.

Stopping salmon
As the salmon swim up Battle Creek, they encounter the weir, a tall cement barrier that the creek flows over, but impedes the salmon from swimming further upstream. The barrier's purpose is to divert salmon into the hatchery's passageway called a fish ladder.

The previous weir design allowed the more athletic salmon to jump over the weir when the flow of the river reached 350 cubic feet per second (cfs). The new design includes a lip on the top of the weir that will hold back the strong jumpers up to a stream flow of 850 cfs.

"This undesired passage of fall Chinook salmon upstream of the weir may potentially hinder efforts to restore . . . spring Chinook salmon," according to hatchery documentation.

The fall run of salmon could spawn the same habitat, effectively digging up and killing the spring run eggs, said Hamelberg.

All traffic merge left
As the creek flows over the weir, the newly designed 10.5-foot overshot gate on top of the weir channels more water to flow to the north side of the creek.

The forceful cascade of water from the gate near the fish ladder entrance would help salmon find the entrance more easily, said Hamelberg.

High volume thoroughfare
The new fish ladder, a term for the watery hallway, will support ten times the volume as the previous design. The extra space will allow for improved fish passage when the creek is full or overflowing its banks at 3,000 cubic feet per second.

The ladder leads to the hatchery holding pond.
The new design does not have the vertical steps of the old design, but instead features vertical barriers. The design will also allow for less viewing for the public during the Return of the Salmon Festival traditionally held in October.