Fish Passage and Protection on Flow-Regulated Rivers and Streams

Mike Love explained the engineering concepts behind the design of this bridge for fish passage during the SRF fish passage field schools this fall. (Photo: Dana Stolzman)

Providing upstream fish passage and downstream fish protection on flowregulated rivers and streams is technically challenging. For upstream passage various types of fishways are often used, and screening of water diversions is a common means of protecting juvenile salmonids from injury, stranding, and predation as they migrate downstream. Both fishways and fish screens are based on a hydraulic design approach, which must consider the hydraulic environment, sediment and debris loading, the swimming abilities and behavioral characteristics of the target fish, and the potential for increasing predation or poaching opportunities. Additionally, site and cost constraints frequently make it infeasible to satisfy all existing design criteria over the entire design flow range. In these conditions the objective often becomes one of maximizing the range of flows so that passage or protection can be provided. With all of these considerations, there is a substantial amount of uncertainty concerning the anticipated performance of a particular fish passage or protection project once it is constructed. Given that these types of projects are generally costly to implement, it is critical that we examine and learn from previous projects to maximize the potential for success.

In this session speakers will present recently completed fish passage and protection projects on rivers and larger streams, with a focus on project design, implementation, and lessons learned. Presentations will also emphasize the various elements that were, or should have been, considered in the project design phases.