For many decades, utilities, engineers, tribes and scientists have worked together to restore salmon to the upper reaches of Washington State’s Baker River.
The Baker River is the site of Puget Sound Energy (PSE)’s largest hydroelectric development, which includes two dams that block access to the upstream spawning grounds. Engineers developed an unconventional fish-passage system at this location.
Instead of using a traditional fish ladder or fishway, the fish are collected in the reservoirs behind the dams and then transported around the barriers using a trap-and-haul system.
In a single year, nearly 1.5 million juvenile sockeye salmon and approximately 67,000 juvenile coho salmon were transferred around PSE’s Baker River dams prior to release back into the river system.
The river once lost almost all of its sockeye
In order to allow salmon to migrate up and down the Baker River, a trap-and-haul system was developed and implemented on the river.
Adult salmon traveling upstream to spawn are trapped below the reservoirs and hauled over the dams to their spawning habitats. Juveniles migrating downstream to enter saltwater are also aided during their migration.
Prior to the implementation of a trap and haul system on the river, the run fell to a low of just 99 returning sockeye in 1985.
Since that time, numerous restoration efforts, including fishery improvements and fish passageway enhancements, have contributed to significant population growth within the Baker River System.
Recent years have seen record returns of sockeye to the Baker River system during multiple recent migration seasons.
Millions of young salmon still face the same obstacle
Many millions of young salmon still require some form of passage to get past the dams.
According to Puget Sound Energy, there are currently millions of sockeye salmon and tens of thousands of coho salmon being raised and released into Baker Lake and Lake Shannon.
Once these young fish begin their migration downstream, they will encounter another barrier – the dams. To aid in this situation, the young fish are intercepted prior to reaching the dams.
A new record for juvenile fish passing through the Baker Lake and Lake Shannon floating surface collectors was set recently when 1.5 million fish migrated through the collectors.
The National Marine Fisheries Service has referred to this technology as a model for other high-reservoir dam operators. Utility personnel from all over the world have visited the Baker River Project to study its innovative fish-passage system.
It is how the young fish are collected and transported that differentiates this method from others.
Most fish bypass the dams entirely
While the floating surface collectors capture the vast majority of migrating juveniles to transport them around the barriers, collection is not 100 percent. The floating surface collectors are structures placed in the reservoirs behind the dams.
According to Puget Sound Energy, these collectors utilize powerful pumps that create strong surface currents that draw in juvenile salmon.
Upon entering the facility, the fish are safe and may be evaluated prior to being transported downstream.
One of the structures located at Baker Lake is a 130-foot x 60-foot floating facility equipped with pumps, submerged screens, holding chambers, evaluation stations, and truck-loading facilities. Fine-mesh guide nets help funnel migrating fish toward the collector.
Next comes the fish taxi
Following collection, fish are transported around the dams in specialized transport trucks.
These vehicles carry juveniles downstream and adults upstream to habitat areas that would otherwise remain off-limits due to the dams.
Without the use of either floating collectors or fish taxis, millions of salmon would be unable to navigate two large concrete barriers in order to complete essential aspects of their life cycles.
At the Baker River location, engineers helped them complete their journeys by transporting them around the dams rather than directing them through the structures.
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