Due to the modification of the Coleman National Fish Hatchery (CNFH) barrier weir, construction activities required fish rescues on Battle Creek. On June 5 and 6, 2008, biologists from the U.S. Fish and Wildlife Service's (FWS) Red Bluff Fish & Wildlife Office conducted fish rescues to remove fish from dewatered sections around the barrier weir. During this phase of construction, Gracon (the construction contractors for the project) needed to drain the water around the barrier weir so they could make modifications and finish construction of the downstream end of the new fish ladder. The primary focus of the fish rescue effort was to remove threatened or endangered fish (spring or winter Chinook salmon and steelhead), but all species captured were safely relocated. Fish rescues were performed above the barrier weir on June 5 and below the barrier weir on June 6.

On June 5, Gracon excavated out the downstream and upstream berms to the diversion channel letting water from the main-stem of the creek pass around the barrier weir. At that point, Gracon assembled the cofferdam in the area above the barrier weir. At 1320, the cofferdam was sealed and water was slowly drained down through the old fish ladder. Initially seines were used to recover fish but boulders and general unevenness of the bottom made this method difficult. Subsequently electro-fishing was used to recover fish. Gracon used three pumps to drain the pool, covering the hose ends with net pens. The FWS constructed the net pens with a 1/8 inch mesh to prevent entrainment of fish during pumping. Electro-fishing was an effective fish capture method. As the water level dropped, some fish were stranded but many of them were collected using dip nets and buckets.

On June 6, Gracon assembled a cofferdam below the barrier weir to dewater that area. The rescue area had large boulders and uneven ground, and the largest pool area had depths greater than eight feet. After Gracon sealed the cofferdam, they placed three pumps in the deepest part of the pool. These pumps also had their hose ends covered by net pens to prevent entrainment of fish. As the water drained, FWS staff rescued fish using seines, electro-fishers, and dip nets. Fish rescued downstream of the barrier weir included two adult Pacific lamprey, one adult Chinook salmon, many rainbow trout, and several other species.

During the two-day fish rescue effort, FWS staff relocated 1 adult Chinook, 8 juvenile Chinook, 49 rainbow trout, and 1175 non-salmonids. Non-salmonid species included Sacramento sucker, Sacramento pikeminnow, Pacific lamprey, riffle sculpin, tule perch, threespine stickleback, hardhead, California roach, green sunfish, and speckled dace.

Fish rescue area upstream of Barrier Weir

Fish rescue area downstream of Barrier Weir

Old barrier weir at Coleman National Fish Hatchery

Metal supports were erected and a bladder dam was lowered to block off the main-stem flow
The enclosure was snorkeled to see if there were any T and E species trapped in the area:
FWS staff seined the upstream enclosure prior to dewatering
Electrofishing was used to rescue fish during dewatering of the upstream enclosure.

Pumps with the hose ends covered with net pens helped the water drain, but most flowed out the old fish ladder

The barrier weir with no water flowing over it
Installation of the portable cofferdam to dewater the area downstream of the barrier weir

Seines and nets were used to capture fish. When no more fish could be caught by seine and net, electrofishing was used.
Lamprey

Coleman NFH Barrier Weir Modification Evaluation Plan Overview

For progress updates on the Coleman NFH Fish Barrier Weir and Ladder Modification Project, please refer to "Green Sheets" on the Greater Battle Creek Watershed Working Group page.