Upper Codornices Creek Fish Passage

Berkeley, CA

Urban Creeks Council
Fall, 2007

Codornices Creek is wedged between private homes and St. Mary’s College High School.  The channel is deeply incised, and the gradient is such that steep drops occur where infrastructure crosses the creek.  Surprisingly, this stream still contains native rainbow trout, and is potential steelhead habitat.  The scope of this project is to restore connectivity below and above the Albina Street bridge, also the entrance to Saint Mary’s High.

The trout in the stream were relocated, and the channel was dewatered using both electric pumps and gravity.  The project was completed late in the dry season, requiring the extra dewatering capacity of a 24” gravity bypass pipe to handle the flashy runoff from an extremely urbanized watershed.  Access to the stream bed required construction of an access road, notched into a nearly vertical bank.  Hanford ARC employed skilled operators, trained in safety under such conditions to construct the rock structures and safely move the equipment in and out of the channel.

The primary component involved installation of a series of 12 rock step pools, connecting to an existing concrete landing under the Albina Avenue bridge.  Due to the confined space, our operator was required to complete the pools and channel bed while working upstream to the access ramp.  We ‘leapfrogged’ rock and gravel past the excavator, using the excavator to both supply and place the material.

A second, independent work area on a downstream reach involved rebuilding a steep slope adjacent to the stream.  The access at this point was so difficult that we opted to excavate and recompact the soil by hand, in benches supported by plywood baffles.  This was effective to rebuild the slope face, which was stabilized with seed and erosion control fabric by UCC crews. The final component of the project for Hanford ARC was to install several large box trees and a drip irrigation system to water plants placed by UCC crews.