NATIVE SALMONID CONSERVATION FACILITY
Usk, Wash.
BEST PROJECT, WATER/ENVIRONMENT
KEY PLAYERS
Sent by: HDR
OWNER: Seattle city light
LEADING DESIGN COMPANY: HDR
GENERAL CONTRACTOR: Obedient construction
CIVIL ENGINEERING: HDR
STRUCTURAL ENGINEERING/MEP: HDR and Womer & Associates
CONSTRUCTION MANAGER: HNTB
Located on the Pend Oreille River north of Metaline Falls in Washington state is Boundary Dam, a 340-foot high concrete arch hydroelectric dam first built in 1967 that can generate 1,117 MW of power When the facility’s license with the Federal Energy Regulatory Commission (FERC) was renewed in 2009, owner and operator Seattle City Light (SCL) agreed to review impacts related to endangered or threatened species of termination as part of the re-license agreement for the new facility. License of 42 years.
As part of this effort, SCL worked with HDR and Lydig Construction to design and build a state-of-the-art $27 million facility that now helps protect and establish the self-sustaining, naturally-produced, and threatened population of cutthroat trout from the west slope in the Pend Oreille River watershed. To do this, the facility captures genetically pure fish from the basin’s tributaries, breeds them, and returns their offspring to their native streams. It also eradicates non-native species.
The scope of work included a major underground utility facility along with eight facility structures including a new store and storage building, an administration building, truck filling and disinfection station, pumping station, pollution reduction pond, water treatment building and discharge structure. The facility also has a barracks for visiting scientists and two residences for full-time staff.
Interior view of the Westslope Salvage Building, which houses many of the facility’s breeding tanks.
Photo by Chris Thompson Photography
Underground challenges
West Slope cutthroat trout numbers have plummeted by about 90% across the region, nearly qualifying the fish for extinction. Species restoration is the sole focus of this conservation facility, where advanced aquaculture techniques will help keepers rescue and feed trout from local streams.
The native salmonid conservation facility relies on real-life stream conditions and careful attention to population genetics to produce the highest quality fish possible. The hatchery features two steel-framed fish rearing buildings, each with circular fiberglass tanks, which are maintained in optimal conditions for the trout through all stages of their life cycle. A third building will eventually be constructed to help restore the area’s bull trout populations as well.
“The water supply is very cold, which is not very suitable for a typical sport fish production hatchery, but [it] it’s perfectly suited for West Slope cutthroat trout,” says Mark J. Hassebrock, project manager at HDR.
“The water supply is very cold, which is not very suitable for a typical sport fish production hatchery, but [it] it’s perfectly suited for West Slope cutthroat trout.”
—Mark J. Hassebrock, Project Manager, HDR
Skookum Creek provides cold water, which is diverted to the facility’s piping and control vault. It is then mixed with spring water from an underground collection pipe system to create the ideal temperature for the fish. To prevent contamination, the water is purified before entering the nursery tanks, and after passing through the facility, the water is returned to the stream. During periods of low flow, a system of pumps will return diverted water to the withdrawal point to limit impacts.
This site was home to an older nursery, demolished to make way for the new structures, which used a small concrete dam to impound spring water. However, with no as-built drawings available, its depth remained a mystery. Crews quickly realized when they began work on the spring collection pipe that the tip of the dam was a few feet below ground, making the structure unstable. To solve the problem, the team collaboratively designed and built a 20-foot-deep pile replacement dam, which allows the structure to capture much more spring water than before. This enhanced capacity will also provide the facility with ample water resources in the future, should the area face groundwater loss as a result of climate change.
With shallow groundwater to contend with as well, the team faced some difficulties during the installation of both the foundation and two large firefighting storage tanks. Constant pumping was necessary to maintain subsurface conditions during excavation. With the help of their geotechnical consultant, the team stabilized the excavations using a combination of quarry rock and geotechnical fabric.
The Washington Department of Fish and Wildlife helped support habitat restoration and management as part of the project. Native plantings will help replenish sensitive areas and buffer.
Photo by Chris Thompson Photography
A lot of water
While the main goal of the fish propagation facility to restore native aquatic species is sustainable, one of the biggest costs for such a facility is all the energy required to pump the fish supply. water through the different stages of the process. Thanks to the site’s natural slope, the team was able to adopt gravity flow when designing the stream and water supplies, eliminating the need for continuous pumping and associated energy.
But another water consideration was to ensure that full-time site staff had access to a domestic water supply, permits for which were difficult to obtain at this site. Doing so was a bit of a catch-22. To meet sanitary standards for domestic water, the team had to demonstrate that the site’s well was not hydraulically connected to nearby Skookum Creek. However, the team had to go ahead and drill the well in order to find out if there was even a deep enough water table for the well to not be hydraulically connected to the stream.
These facilities can also sometimes adversely affect other wild fish. The old hatchery was based on a small wooden dam on the Skookum Creek channel that moved water to the facility, but the Washington Department of Fish and Wildlife (WDFW) identified that dam as a barrier to the no fish For the native salmonid conservation facility, crews removed the old dam and used a stabilized natural channel design to restore about 260 feet of stream habitat. WDFW also helped support habitat restoration and management as part of the project, with native plantings that will help replenish sensitive areas and buffers.
In addition to helping the fish, this project also included the scope to help some creatures above ground. One of the smaller former structures on the site was a maternal roost for the endangered Townsend’s big-eared bat. One of the goals of the project was to move the bedroom to the north end of the property, where it would not be disturbed by nursery operations. After consulting with chiropterologists about the best mitigation strategies, the team built a new shed dimensionally identical and oriented as the old structure, which has already been observed using bats.
All about collaboration
One of the team’s biggest challenges “was trying to implement a project during the height of the COVID restrictions and supply chain issues,” says Harry Rich, fisheries biologist and SCL project manager.
Working together with SCL, the HNTB and Lydig team focused on finding solutions with greater constructability in the field, while maintaining the original design intent. Spotting potential problems early allowed crews to resolve problems quickly, saving time and rework costs.
“The contractor, design consultant, owner and construction management teams came together in a strong combined team that developed a high level of open communication and respect for the wide range of knowledge, expertise and experience valuable things that individual members brought to the team,” Hassebrock. he says “Creative problem solving became commonplace.”
Lydig also prioritized safety and placed more emphasis on injury prevention because the remote location of the underdeveloped site would make it difficult to seek medical attention. To keep workers safe during extreme weather conditions on rugged terrain, the contractor used Yaktracks gripper traction devices to prevent slips and falls over two long winters. To combat muddy conditions in the spring and fall prior to paving, ramps were covered with wire to stabilize the surface. Efforts like this helped the team achieve 67,298 hours of work with no lost time or recordings.
“Building strong relationships […] it allowed everyone on the team to trust each other, overcome challenges and deliver an incredible project.”
—Harry Rich, Fisheries Biologist, Project Manager, Seattle City Light
An extensive stormwater pollution prevention plan helped protect native areas and streams from impacts related to heavy construction on the site. A Certified Erosion and Sediment Control Consultant (CESCL) worked alongside Lydig’s CESCL staff to help the project meet stormwater pollution prevention requirements.
On May 29, SCL and other stakeholders including WDFW, the Kalispel Tribe of Indians, the US Fish and Wildlife Service and the Pend Oreille Public Utility District celebrated the grand opening of the facility.
“The greatest reward [on this job] it was building strong relationships between the owner, the design/engineering firm, and the contractor that allowed everyone on the team to trust each other, overcome challenges, and deliver an incredible project,” says Rich.
SCL expects to operate the new hatchery for decades, and the facility is already breeding and rearing trout. Initially, it will have the capacity to produce up to 12,000 trout eggs, fingerlings or fingerlings per year and spawners of various age classes.
“Previously it wasn’t very well known whether wild-caught westslope cutthroat trout would feed in captivity,” says Hassebrock. “Now that the facility is operational with live fish, operators are having success with live feed consisting of worms and insect larvae that are being grown at the facility.”
