A creek identified as viable for future kokanee salmon populations seems to be coping with recent harsh winter weather, even after heavy rains and a November washout upstream.

The most recent storm last week carved out a clear path of Zaccuse Creek, just upstream from known kokanee advocate Wally Pereyra’s property off of Eastlake Sammamish Parkway.

Sammamish residents Mary Ellen Stone and Gary Mahn, who overlook Pereyra’s property midway up the creek, have kept a watchful eye on its health.

Back when the Plateau was part of unincorporated King County, a development above Stone’s and Mahn’s property improperly dumped runoff water down the stream. The runoff caused serious flooding and considerable damage to the creek and their property, the couple said.

The county restored the creek by mitigating runoff from development, bringing in large tree trunks, rocks and native vegetation, to stop the water from eroding the creek.

Stone and Mahn say the heavy rains did not affect the restored portion of the creek on their property. But just past it, they’ve seen “major changes to the stream bed,” Mahn said.

Using a photo from a couple of years ago for comparison, the increased flows clearly defined a path creating a new channel about 3 feet deep and growing, Mahn estimated.

Tawni Dalziel, a senior stormwater program manager with the city, said the increased flows and defined channel are to be expected after a heavy rainstorm. Still, she said the development probably warranted a site visit from city staff.

“Streams don’t stay constant,” Dalziel said. “I would expect some erosion after a heavy rain storm. What we want to do is try to manage changes that we make on the landscape through the building of homes or expansion of things that can cause increased flows.”

Currently, the city’s keeping an eye on the creek near Louis Thompson Hill Road Southeast, where heavy rains caused the road to wash out into the creek during a Nov. 15 storm.

“It was kind of the result of all the heavy rains that came down those steep roads and it overwhelmed our drainage system,” Dalziel said.

A geotechnical firm working with the city said the road is safe to pass, she said. They are working on solutions to prevent such a failure in the future.

Zaccuse Creek begins near Louis Thompson Road Southeast and 210th Place Southeast and extends down to Lake Sammamish. It does not currently support the rare kokanee population, but residents and the city are looking to change that in the near future.

“We hope that with some grant money available in the next couple of years, we will be able to make all of these improvements to Zaccuse Creek that will help kokanee salmon get into the creek, at least the lower portion,” she said. “The creek is definitely on our radar, even before the rains occurred and the washout.”

Dalziel, who walked the upper portion of the creek after the November storm, said the sediment that washed down the road did not appear to move into Pereyra’s property.

Pereyra, who said Nov. 17 there did not appear to be a “residual siltation problem” from the slide, is still concerned about the longterm effects associated with not having a functioning culvert under Eastlake Sammamish Parkway that would allow sediment and other debris off of the Plateau.

While this washout may not have fogged the creek’s crisp waters, Pereyra’s concerned about the possibility that other rain storms and increased runoff from up the hill could ultimately cause a backup of sediment in the wetland on his property.

That, he said, is why the Parkway culvert needs to be replaced with a properly functioning box culvert.

For now, it’s a matter of time and money.