Project Details
Client: Southern California Edison
Location: Sequoia National Park, California
Type: Hydroelectric Generation Infrastructure
Completion Date: 2007
Construction Cost: $250,000
Interesting Fact: This project was recognized by the American Council of Engineering Companies (ACEC) with a Engineering Excellence National Honor Award in 2008.
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In early April 2006, Southern California Edison’s Eastern Hydro Division contacted Blair, Church & Flynn Consulting Engineers and asked for their help to improve fish screening at the upstream diversion structure of the Tule River Powerhouse. Fish trapped in the diversion structure were becoming a problem.
Blair, Church & Flynn designed an economical retrofit solution capable of safely returning fish to the Tule River without major disruption to the hydroelectric generation needs of Southern California Edison. Creativity, cooperation and environmental stewardship helped the team overcome the challenges that are synonymous with sensitive, remote locations.
In addition, the project was successfully completed under the watchful eye of regulatory agencies that require zero impact to the Sequoia National Forest, the Federal Energy Regulatory Commission, the U.S. Forest Service, the U.S. Fish and Wildlife Service and the California Department of Fish and Game.
The fish return system is fully sustainable, operating hydraulically without the need for electricity, mechanical components or maintenance needs. And much to the pleasure of Southern California Edison, the project was completed for less than $250,000 – 75% cheaper than the cost of packaged solutions pitched by other consultants. That was because a cost effective, pre-packaged system didn’t exist for this project. The Tule River Fish Return System evolved into a collection of carefully selected components with creative applications, like utilizing a fish ladder, that were all designed to protect fish while returning them to the river.
The system’s components had to be designed in such a way that they could be segmented and hand carried to the site. The project’s remoteness limited the types of tools available to the contractor, which further limited material choices. The new fish return system had to maintain critical flow depth and minimize obstructions, maximize oxygenation and protection of fish. Intense hydraulic modeling efforts successfully produced a design able to provide consistent depth and flow throughout the entire system of pipes, fish ladders and open channels.
Due to rigid powerhouse production schedules, Southern California Edison could afford no more than five days of down time for work to be performed within the diversion structure. Blair, Church & Flynn’s design accommodated this by creating bypass chambers that the contractor could pre-fabricate off-site and easily transport in segments to the site. Material weight, portability and installation methodology were all critical factors in creating the bypass chambers, so that the client could resume power generation operations as soon as possible.