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Spokane hatcheries get upgrades

Two hatcheries on Little Spokane River renovate its facilities to focus on sustainable practices and phosphorus reduction.

June 10, 2024  By Seyitan Moritiwon

(Photos: Spokane Fish Hatchery, WDFW)

Every building needs a facelift now and then. Spokane Hatchery in Washington State hasn’t had one since it was built in 1934. But now it’s getting one.

The Spokane Hatchery, run by the Washington Department of Fish and Wildlife (WDFW), is one of the major rainbow trout broodstock facilities in the state, producing about nine million rainbow trout eggs each year and six million are shipped to other facilities around the state. 

The primary goal of the renovation is to improve the way the hatchery deals with its wastewater. “So trying to mitigate some or improve solids management generally. And then nutrient management,” said Sarah Welsh, an environmental engineer at the WDFW. 

Currently, discharge from the hatchery goes into a Griffith slew and then flows into the Little Spokane River which has low dissolved oxygen and high levels of nutrients. As one of the point sources on that river, the Spokane Hatchery has been working with the Washington Department of Ecology to figure out the best way for the hatchery to reduce the amount of phosphorus they discharge into it.

Low phosphorus feed
While the hatchery is allowed to discharge 0.51 kg of phosphorus per day, Jordan Bauer, finfish general permit facility manager at Washington Dept. of Ecology said they have been above their discharge levels for some time. To meet this requirement, Spokane Hatchery is introducing low-phosphorus feed into fish diets. In 2023, they did a study to determine how this feed will see lower phosphorus in wastewater and the effect on fish growth and development. 

“From that feasibility study, we saw about a 30 per cent decrease in the amount of phosphorus, both soluble and particulate phosphorus we were seeing in the effluent samples,” Welsh said.

Although it was just one isolated sampling event and not comprehensive, Welsh said, “This might be something that could really help us reduce phosphorus loading without having to pour a bunch of money into more technical treatment, which we’re still doing, but this is a good way to supplement that.” 

This year, they’re doing a longer study, feeding a few different raceways of trout and monitoring their health to see if they’re having higher levels of diseases. They’ll conduct periodic water quality sampling over a long period to see if those lower levels of phosphorus are being maintained in operation samples. 

“We’re looking for any little way to shave off phosphorus in our system. So it’s something that we’re certainly thinking has a place in this hatchery program,” Welsh said.

As a hatchery that’s been in existence since 1934 and had minimal renovations over the past 90 years, a lot of the infrastructure and buildings are starting to fail. There are cracked round ponds and hatchery operators spend a lot of time patchworking different facilities. 

According to Bauer, before this renovation, they made some changes in the early 2000s, putting in raceways instead of round ponds. As part of the renovations, they’re trying to upgrade residences which are also falling apart. 

The plan is to install different drum filters on all their rearing units, new dual drain round ponds that should be more self-cleaning, and a pollution abatement pond so to get the settling of solids. “A lot of the Department of Fish and Wildlife facilities across the state have retention ponds, or pollution abatement ponds that are at the facility, but this one, this one doesn’t have one of those,” said Bauer.

He said polychlorinated biphenyls (PCBs )are also an issue. “The Spokane hatchery, being that it’s an older facility, some of the old caulk and paint and some other things, there has been a discharge for PCBs, but through this renovation, they are going to take those out,” Bauer added will be an improvement.

The Washington State-run hatchery’s current concrete round ponds will be demolished and upgraded to new fiberglass dual-drain round ponds.

Spokane Tribal Hatchery
Another hatchery undergoing renovations is the Spokane Tribal Hatchery, just down the river, but on a much smaller scale.

After an unusual heatwave in Spokane in the summers of 2020 and 2021, which caused an increase in surface water temperature and fish diseases, they started working on ways to alleviate the issues if they occurred again.

As explained by Brent Nichols, fisheries and water resource director for the Spokane Tribe, the Spokane tribe used to subsist primarily on Chinook salmon, steelhead, and sockeye, but Chinook was the most prominent component of their culture. When Grand Coulee Dam was constructed, in 1939, it completely blocked all movement of salmon to the Spokane Tribe of Indians. In 1980, Congress enacted the Power Act, which is what created the mitigation for the Pacific Northwest for all the construction of hydro systems dams.

“Our hatchery was designed and is operated still as partial mitigation for the construction of those dams on the Columbia River in Spokane rivers,” said Nichols. “Rainbow trout is our focal species for the tribe.”

Rebecca Cook, fisheries biologist for the Spokane Tribe said currently, the hatchery doesn’t reuse its water. She said they have a flowthrough system. “We wanted to see if there are ways to turn our flowthrough hatchery into a partial reuse so that if there were low water times throughout the year, the hatchery wouldn’t be scarce, and have problems with the fish capacity that they currently maintain and need to maintain,” she said.

Partially recirculating
Nichols said right now, the effluents of the tribal hatchery go into a settling pond. “Part of this renovation and the ability to recirculate this water and reuse this water will be to at the point at the hatchery where it flows into the settling pond it will be diverted into a containment system where they will have the biological filters in place to help break down the ammonia and nitrogen,” he said.

It’ll then go through drum filters to remove particulate material, and through the UV filters to remove any bacteria or viruses anything before that water is pumped back up for reuse. They’re targeting 80-83 per cent reuse.

 Like the tribal hatchery, the state-run Spokane Hatchery wants to install a partial recirculating aquaculture system (PRAS) to help mitigate low water years when there isn’t much spring water. They’ve designed six banks of these round ponds to recirculate up to 75 per cent of flow. So they use less water to raise the same amount of fish. 

These new ponds will be a partial recirculating aquaculture system designed to reuse up to 75 per cent of its water.

A lot of new technology that will be installed has a higher power demand, so they’re adding in solar panels. “Spokane is a really sunny area compared to Western Washington. So we’re trying to take advantage of the sunlight so that they don’t have a massively higher power bill after this project,” Welsh said.

The tribal hatchery renovations are estimated to cost US$2.2-2.6 million and have gotten funding from the Bureau of Reclamation and Bureau of Indian Affairs.

On the other hand, the Spokane Hatchery project is going for about 23 times that amount. The project is divided into three phases and is estimated to cost around US$55-60 million. It is expected to last six years and the first phase will kick off in the winter of 2024 with construction beginning in the summer and lasting two summers.

“Our first phase is really supposed to test if we’re going to be able to meet that waste load allocation with the strategies we are currently planning. And if not, we have some land set aside for other options if we need to continue to explore that. But we’re hoping that kind of strategy we’ve come up with at this point is going to be enough,” said Welsh, who’s also project manager for the technical side of this project.

Welsh has been working at the WDFW for two years. After growing up in a family that loved the outdoors and fishing, together with her interest in STEM, Welsh studied Environmental health engineering at Havard University. “It’s cool to be an engineer, but not just be in a room full of engineers talking math and nerdy things. So there’s a lot of public and, within the agency interaction in this job,” he said.

Welsh emphasizes that water treatment is difficult. She said they’re doing a lot of learning about low phosphorus feed at the WDFW that they hope to publish.

“We are trying our best to clean up our wastewater from this facility because the people who run this facility are also the ones going out and fishing in Lake Spokane and live on Little Spokane River.”

“We’ve talked to a number of other hatcheries that are trying to do similar things and all of them are having similar issues of the traditional wastewater treatment technology doesn’t seem to work well, when it comes to some of these applications.”

She said while low phosphorus feed might be the answer for some, it has its drawbacks, and it is more expensive. “It’s not necessarily mass-produced in all the same feed manufacturers we currently use. So there are a number of challenges with this project.” 

Correction: The story was originally published in the July/August 2024 issue with a quote from Sarah Welsh stating there was a study that measured a 400 to 600 per cent decrease in phosphorous. The source has since corrected their statement to say about “30 per cent decrease”. Hatchery International regrets its error.

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