Business + Industry, United States, North America, Facilities
Safe Passage for Salmon
The Puget Sound Energy Adult Fish Trap
Salmon make amazing journeys. Adults can swim hundreds of miles and climb thousands of feet in elevation—struggling against currents and the odds—to return to their natal stream for spawning. It is an instinctual trip with little to stop them, except the insurmountable natural barriers, walls of concrete and hydroelectric facilities that dam their path. To give salmon runs in the North Cascades’ Baker River basin in Washington, USA, a boost, Puget Sound Energy (PSE) modernized its Lower Baker River adult fish trap (AFT) with new technology and equipment.
CDM Smith teamed with PSE in April 2008 to construct upgrades to the trap-and-haul facility located downstream from the Lower Baker River hydroelectric plant. Built in 1958, the facility captures and transports migrating adult salmon in “fish taxis” upstream around two Baker River dams—too tall for conventional fish ladders—to their spawning grounds. The $18 million renovation not only complies with 50-year relicensing conditions mandated by the Federal Energy Regulatory Commission, but is part of a collaborative, long-range effort by PSE, government resource agencies and local Native American tribes to enhance the watershed fish populations.
Upgrades include an improved attraction water system, which pipes water from above the AFT to below it, to better simulate a flowing stream that encourages fish to swim into the entrance and holding pools. An enhanced crowding system gently moves salmon into a fish lock (or elevator) that lifts them 60 feet to a newly enclosed sorting facility. Here, a programmable logic control (PLC) system helps operators identify, sort, count, record and route species into different pools for sampling and classification, where an electronic data management system records biological information. Salmon are then loaded into water-filled trucks to continue their upstream journey. “This one-of-a-kind facility builds on PSE’s commitment to the environment,” emphasizes Scott Williams, PSE project manager. “We can move many more fish upstream with less manpower and, most importantly, with less stress to the fish.”
Precision, Collaboration and Construction
Central to the project was more than $5 million worth of precisely fabricated components and structural steel, along with precision-poured concrete, designed not to harm the salmon. “This work necessitated high-quality manufacturing and installation,” says Matthew Schultz, CDM Smith principal project manager. “Contractors needed to not only understand how to measure and build with exactness, but possess expertise in accurate field assembly.” Work included custom metal gates and flumes, as well as a brail, fish lock and false weir system to carefully move and handle the fish. Don Clabaugh, CDM Smith principal project director, adds, “Also paramount was effectively conveying engineering specifications to biologists so they would approve components before fabrication. This streamlined installation. The biggest failure would have been to remanufacture equipment.”
The project team was responsive to challenges, providing last-minute design revisions, due to differing site conditions and adjustments. Also, inclement weather, including ice, snow and heavy rains that overtopped a cofferdam, slowed construction. Despite the setbacks, upgrades were completed 2 weeks early, in June 2010—allowing PSE to refine facility operations ahead of the fish runs. The project was also completed with a perfect safety record—CDM Smith logged more than 56,000 work hours without a lost-time injury or recordable Occupational Safety and Health Administration incident during the 14-month working period. According to Don Thompson, PSE project engineer, the project serves as “a model for the completion of complex one-off projects. This facility required considerable collaboration between the owner, design engineer and CDM Smith. We are very pleased with how we all worked together.”
A Salmon's Schedule
Scheduling was critical because “fish couldn’t be left waiting too long for the ‘doors to open’,” states Williams. “Our agreement with the agencies required that we take the existing fish trap out of service for no more than 4.5 months to demolish a portion of the old trap and construct the new one in its place.” Work was completed over two seasons to accommodate two separate fish runs, occurring between June and December. Work outside of the trap’s existing footprint occurred in 2009, allowing the trap to remain operational. In early 2010, the existing trap structures were removed and upgraded.
In-water work was also timed with releases of water for flood control, power generation, fish runs and recreation. However, some work required PSE to shut down its upstream dam operations to keep the river at a safe working level. “Outages affect revenue generation, so CDM Smith and PSE closely coordinated scheduling to reduce shut downs and quickly resume operations,” says Clabaugh. Thompson happily notes, “Excellent construction pre-planning and work execution brought the project in on schedule. The returning salmon didn’t have to wait to enter the trap.”
Following the upgrade, PSE reported a record number of fish—more than 18,000 sockeye—captured and counted at the AFT. Schultz is proud of the new facility. “It was a challenging project and schedule, but provides a major benefit to PSE and the environment.”