Water is at a premium in the West. Every drop of it matters to the multiple end users, ranging from Tribes to towns, and farmers to fish.
Nobody appreciates the value of water more than the staff at the U.S. Fish and Wildlife Service’s Leavenworth National Fish Hatchery.
Built in 1940 to make up for salmon loss after the construction of Grand Coulee Dam, Leavenworth National Fish Hatchery draws water from Icicle Creek to raise 1.2 million of Chinook salmon annually. Icicle Creek is an iconic cold-water stream in central Washington that runs through the heart of the Okanogan-Wenatchee National Forest into the Wenatchee River, providing life-giving resources to the surrounding communities.
Leavenworth NFH is just one of many stakeholders sharing the vital resource of Icicle Creek.
“Water connects us all,” says Mathew Maxey, manager for Leavenworth National Fish Hatchery. “We and our federal, state, Tribal, and community partners have a vested interest in conserving Icicle Creek while serving the fish and people who rely on it in this time of changing climate.”
This watershed is so important that Chelan County and Washington Department of Ecology’s Office of Columbia River co-convened the Icicle Work Group in December 2012 to find collaborative solutions for water management within the Icicle Creek watershed. The Icicle Work Group includes Chelan County, City of Leavenworth, Icicle-Peshastin Irrigation District, Yakama Nation, Colville Confederated Tribes, the Washington State Department of Ecology, Leavenworth National Fish Hatchery, Bureau of Reclamation, and numerous other federal agencies, local citizens and non-profit organizations.
Protecting this limited resource is particularly timely for the area.
According to the Leavenworth NFH Climate Change Vulnerability Report released in January 2022, will alter the flow, temperature, and composition of Icicle Creek and impact the surrounding landscape significantly over the next 20 years. The hatchery is using that information to develop and implement proactive strategies for resource management. Here is what data projections show is in store for Leavenworth National Fish Hatchery and the Icicle Creek in the next two decades:
- Warmer water: Surface water temperatures of Icicle Creek are expected to be warmer in all months.
- More rain, less snow: More precipitation will fall as rain and substantially less precipitation will fall as snow. This would result in a decreased snowpack, which would result in lower water flow in the summer.
- Higher flows in winter, lower flows in the summer: High flows will most likely occur in late fall and winter, with lower peak runoff in June and consistently lower flows in summer.
- Late summer water shortage: Water releases from Snow Lake in August and September would be barely sufficient in the 2040s to meet the hatchery’s water rights.
- Increased fire risk: Reduced snowpack and less precipitation during the summer in the 2040s are expected to increase fire risks to Leavenworth NFH.
- Increased flood risk: A significant increase in the magnitude of 100-year peak water flows.
- Increased disease risk for fish: Higher water temperatures during the summer are expected to increase disease risks for salmon.
While the vulnerability report may look dire, Leavenworth NFH staff and our partners are already working on an innovative project designed to raise fish differently while conserving water.
Getting around the problem
Leavenworth hatchery is one of three mitigation hatcheries established by the Grand Coulee Fish Maintenance Project to compensate for anadromous fish losses above Grand Coulee Dam. The U.S. Fish and Wildlife Service-operated Leavenworth NFH is funded by the Bureau of Reclamation and Bonneville Power Administration.
Together, the Service and Reclamation developed a plan to make better use of the water needed to raise salmon. They did it by thinking outside of the raceway.
Typically, once salmon have hatched and reached the “fry” stage, staff transfer them into long, straight concrete channels known as raceways. These 44 raceways are where the salmon spend 11 months growing before their release into Icicle Creek. From there, their migratory journey begins as they spend two months making their way to the Pacific Ocean before returning home to spawn two to four years later.
While the raceway system is efficient at propagating healthy Chinook salmon, it isn’t the most efficient use of the precious water.
“Raceways are effective for rearing large numbers of fish and have served us well for many decades,” said Hayley Muir, fish biologist at the Service’s Mid-Columbia Fish and Wildlife Conservation Office. “Yet we have data showing that changing from a raceway to circular tanks may increase fish health while decreasing our water usage and increasing discharge water quality.”
The Service, with the financial support of Reclamation, has installed four state-of-the-art fish-rearing circular tanks. Known in the fisheries world as Partial Recirculating Aquaculture Systems (PRAS), these circular tanks move water around in a whirlpool-like motion allowing for most of the solid waste to be removed from a drain in the center of the tank. Cleaner water is removed from a drain on the side of the tank, filtered, stripped of carbon dioxide, UV treated to remove pathogens, re-oxygenated, and then returned to the tank.
Rearing fish in circular tanks is not new to the fish hatchery community. However, rearing the notoriously finicky spring-run Chinook salmon in a PRAS system is new territory.
The ability to recondition and reuse the water makes the circular tanks more efficient in terms of water conservation, which could lead to a 50% decrease in the amount of water needed to raise salmon at Leavenworth.
“This project would not be possible without the collaborative efforts between many Tribal, federal, and state partners that worked together to make this state-of-the-art facility happen,” said Bureau of Reclamation Regional Director Jennifer Carrington. “The relationships built during this project will continue to stay strong as we pursue additional projects and upgrades here at the hatchery in the future.”
The Leavenworth staff used the tanks for the first time in early June.
So far, it is going swimmingly.
“The fish in the circular tanks are growing very similar to the fish outside in the raceways. We knew there would be challenges, and we’re trying to work through those,” Maxey said. “We did see slightly warmer temperatures in the circular tanks compared to the raceways, so we had to supplement with ground water. But the system is designed for that, so there was no problem. We were able to keep ick (a fish disease) out of the system, so that was a benefit. The UV system appears to be working. So we’re still getting preliminary data three months into it, but right now it appears to be working as designed.”
The PRAS pilot project will have a five-year evaluation period, where staff will compare PRAS to the traditional raceways. The evaluation will address if PRAS can rear smolts as well as the conventional raceways, maintain high water quality, mitigate disease risk, sufficiently reduce water usage, and meet effluent requirements. If the answer is “yes” to these metrics, the hatchery will move forward with rearing all of the salmon in a PRAS setting — meaning the continued production of millions of fish and massive water savings for Icicle Creek.