Salmon Habitat Restoration Efforts in Rainier Beach

At Rainier Beach's Be'er Sheva Park, fish ecologist Ashley Townes stands in Mapes Creek wearing a red hard hat as cranes carefully lower massive logs. From the outside, it may look perplexing — why is large wooden debris being strategically placed in the water? But for Townes, these logs are one part of a habitat restoration project she's been working on for several years.

The beginnings of the project go back to 2019, when Townes learned that a previous restoration project from 2014 revealed and exposed buried streams of about 427 feet of Mapes Creek spanning from Kubota Gardens to Be'er Sheva Park. This project brought the stream to the surface and allowed for it to drain into the southern end of Lake Washington, and post-monitoring surveys from 2015 to 2017 found that the habitat was increasingly used by juvenile Chinook salmon.

But Townes felt there was more work to be done.

"That's incredible that this has been here for a few years, but what else can we do to enhance the habitat in the area to, again, [increase the number of] juvenile Chinook salmon that come and rest and get bigger to go on their journey to the Puget Sound?" Townes said. "It was so cool to see the effect of restoration on that level back then. We thought, let's do some more restoration, and let's be more creative on how we can focus on the fish, focus on the other wildlife — like the birds — and also focus on water quality."

In 2022, Townes worked with Rainier Beach Link2Lake — a neighborhood organization of which Townes is a member that focuses on restoring shoreline in Rainier Beach — and Seattle Parks Foundation to conduct a pre-monitoring survey where she observed the salmon's behavior in the creek by snorkeling and using a remotely-operated vehicle (ROV).

During that survey, Townes observed enough juvenile Chinook salmon along Be'er Sheva Park's shoreline to conclude that the region may serve as a potential feeding ground for the fish during the day and a resting location at night. But there were several factors that kept them from thriving. Some invasive plant species were established there, heavy silt accumulation covered the lake bottom, and suspended sediment clouded the water, which isn't good for young salmon — it can alter their behavior and physiology and lead to stress. The riverbed also lacked rocks and gravel essential for young salmon to grow.

In addition, Townes found something she wasn't expecting: litter. And a lot of it.

"I noticed with my own eyes and also with my devices … so much debris, urban debris," Townes said. "I saw chairs and ottomans and a cabinet, 28 plus tires that were removed by a dive team after eight months of advocating saying, 'Hey … if we ever get this project off the ground with the installation of the logs and the floating structures, we need to clean up shop first.'"

After those eight months of advocating, Townes and Link2Lake collaborated with Seattle Parks and Recreation to remove the trash — which included several tires that were deeply embedded in the lake bed.

The pre-monitoring survey informed the design of the habitat structures now being installed at Mapes Creek. Their ultimate purpose is to increase salmon numbers.

First, six 40-foot logs were positioned on the shoreline to protrude out into Lake Washington. Rootwads on the logs give the juvenile fish places to hide from predators, and also attract invertebrates that serve as a rich food supply for the salmon. They also stabilize sediment, maintain water quality, and moderate water temperatures.

"We know from studies, especially here in Washington and the Puget Sound region, that [the logs are] very effective in increasing juvenile Chinook salmon," Townes said. "We want them to make it … This is a very critical stage."

In addition to the logs, the restoration involves a more innovative component: floating plant structures. The purpose of the structures is to reestablish the native plants; duck potato, also known as wapato, and hardstem bulrush, which provide shade for the salmon, improve water clarity, and reduce erosion. According to Lizzie Zemke, an environmental botanist and wetland scientist with the engineering, planning, and surveying company DOWL and the designer of the floating plant structures, there is very little native aquatic vegetation in the Rainier Beach area, but historically, those plants provided habitat for the salmon. Zemke also found the plants at Lake Sammamish, which is somewhat similar to Lake Washington in that it's another large freshwater lake in the western part of the state.

Initially, Zemke planned to establish the plants along the lakeshore, but after some research, she learned that wouldn't work for the plants due to Lake Washington's unnatural water regime. "At Lake Washington, the water is high in the summertime and relatively lower in the winter," Zemke explained, "and that's an artificially imposed water regime … [because of] the [Ballard] Locks, so getting these plants started in the springtime when the water is high was going to be difficult, because the plants that we were looking at — the duck potato and the hardstem bulrush — need to be in relatively shallow water in the summertime, in the growing season. Then, they can deal with deeper water in the winter." The floating plant structures should help mitigate the effects of the water regime by creating offshore mounds to help the new plants remain mostly out of water when levels are at their highest in the summertime.

Construction will be completed by the end of the year, and Townes and her team start monitoring the area in January, right around when salmon are expected to arrive. The project is funded through 2027, which is when Townes will determine if the restoration was effective with new data.

In addition to making a temporary home for the juvenile Chinook salmon during their long journey, Townes hopes the project will be educational — especially for young people.

"We're right in front of Rainier Beach High," Townes said. "[The students] can do experiments. They can [volunteer]. They can learn about salmon ecology. To get these awesome kids that live next door to me into the sciences — I see it that way too. I'm trying to think about the future of what this is going to do, besides what it's going to do for the fish and the wildlife, but also the people too."