In February, the Washington State Department of Ecology awarded the City of Redmond a grant for $4.9 million and a low-interest loan for $1.63 million to help fund the restoration of Tosh Creek.

The money comes from the department’s Water Quality Financial Assistance, which Steve Hitch, a senior stormwater engineer for the city, said has set aside $100 million to go toward restoring the waters in the greater Puget Sound.

IDENTIFYING THE RIGHT PROJECTS

According to a press release issued by the city, this funding will be used to construct a new stormwater detention vault and stormwater treatment facilities near the 4700 block of 159th Avenue Northeast.

Tosh Creek is one of six streams that are part of the city’s 2013 Watershed Management Plan.

Hitch said Tosh Creek was selected as a priority stream for restoration and is the first one in the plan the city will be tackling. The next one on the list will be Monticello Creek and the remaining four streams are Clise, High School, Bear and Evans creeks.

“Redmond constantly works to make a healthy environment part of our city’s future,” said Redmond Mayor John Marchione. “We prioritized Tosh Creek through our Watershed Management Plan as a waterway that will significantly regain health in the near future. The Washington State Department of Ecology has been a great partner by providing technical and financial support toward meeting this goal.”

In 2014, the press release states, the city received a $250,000 National Estuaries Program grant from the Department of Ecology to help fund a study of the Tosh Creek Watershed. The study was conducted by the city and its consultant team, RH2 and NHC, and Hitch said they just completed the study.

From the study, he said the city produced the Tosh Creek Watershed Restoration plan, which identifies several projects, including the 159th Avenue Vault, to be constructed during a five-year period. Other projects in the plan include modifying a nearby pond for it to hold more water and to address some of its drainage and seepage issues. There is also one more detention vault in the plan.

AN ERODING ISSUE

Roger Dane, a senior planner for the city’s natural resources division, said the location for the first stormwater detention vault underneath 159th Avenue Northeast is very strategic as that is the area that has the most problems.

He and Hitch explained that currently, stormwater runoff is flowing into the creek from existing urban development in the area and causing erosion at a higher rate than they would like. They said as the water rushes into the stream, sides of the stream are sloughed down, causing the water channel to become deeper.

Dane said in a natural (undeveloped) setting, there is some erosion but not as much as that is currently happening with Tosh Creek.

“It’s totally out of whack,” he said about the situation.

As the stormwater rushes in more often, Dane said, it brings in too much sediment such as sand and clay. This sediment will then settle at the bottom of the stream and get packed in between the gravel, making it difficult — if not impossible — for bugs and insects to live there.

“And that’s not good for the stream or the fish,” Hitch said, as the fish eat the bugs and insects.

He said in 2013, the city replaced a culvert — a tunnel carrying a stream or open drain under a road — under West Lake Sammamish Parkway to help with flooding in the area as well as collect some of the sediment. But now, they want to stop that sediment from entering Tosh Creek.

In a healthy stream, Dane said, there should be loose gravel at the bottom, allowing bugs and insects to live there and move freely.

Dane said currently, Tosh Creek contains some fish, including trout and salmon. He added that some salmon do spawn in the stream, making it a higher priority for restoration. Hopefully, Dane said, with the planned improvements, they will see more fish in the creek.

“The 159th Avenue Vault project will restore stream flows and improve water quality in Tosh Creek,” Marchione said. “This, in turn, creates the robust aquatic habitat needed to restart salmon runs and leave a lasting legacy for our community.”

FLOW CONTROL

Hitch said the detention vault — which is basically a big box in the ground — will collect the stormwater runoff from the pavement and release the water back into Tosh Creek slowly to help control the flow of water. The vault will be about 1,000-feet long and hold about 650,000 gallons of water.

After the Tosh Creek Watershed Restoration plan’s five years of projects, Hitch said they will take a look at the stream and its flow to see how they have been affected. In addition, the city will check the water quality to see if there are any chemicals in the stream. They will also be checking the bug and insect levels in the stream.

“If the bugs are happy, the fish are going to be happy,” Hitch said. “Right now, the bugs aren’t happy.”

The city is now in the process of hiring the consultant team that will design the vault, the press release states. This summer, the team will begin outreach to residents who may be impacted by the project. Construction is proposed in 2017. According to the release, building the 159th Vault will put the city on track to reach restoration goals in Tosh Creek.

For more information about the project, visit www.redmond.gov/toshcreek.