Posted: February 2, 2025
By Bill Derry
Edmonds resident Bill Derry is the president of the Pilchuck Audubon Society and a member of the Edmonds Marsh Estuary Advocates. He previously served six years on the board of directors for People for Puget Sound.
Part 2 of a 5-part series. You can read part 1 here.
In the first article on Edmonds’ waters, I discussed what happens when old growth forests are replaced by development and rain becomes contaminated stormwater runoff. This article looks specifically at Edmonds’ streams and how our choices are changing them.
Edmonds has four streams that could support salmon, in addition to several smaller streams (see map below). The four salmon streams are Willow, Shellabarger, Shell and Perrinville Creeks, all of which drain toward Puget Sound.
The eastern portion of Edmonds’ drains to Hall’s Creek, then to Lake Ballinger and then to McAleer Creek (a salmon-bearing stream) and Lake Washington.
The streams are fed by rainfall that is filtered by soils but also by runoff from rooftops, streets and parking lots, which reaches streams and Puget Sound without detention or treatment.
Each of the four primary streams have man-made barriers to salmon passage. Perrinville Creek’s sediment trap, stream diversion structure and culvert under the railroad were installed (without permits) by the City of Edmonds (city) in the 1990s. A private owner dammed Shell Creek, just south of Caspers Street and west of 7th Avenue. The watershed for Willow Creek flows to Puget Sound, but is confined by a pipe along Edmonds Way (SR-104) installed by Washington State Department of Transport (WSDOT). Shellabarger Creek flows into the Edmonds Marsh, which connects to Puget Sound through a 1,600-foot city pipe. Both the WSDOT and city pipes are impassable for salmon.
None of the streams in Edmonds meet state water quality standards for multiple parameters. Untreated stormwater is, as discussed earlier, often highly toxic and any fish who succeed in passing barriers struggle to survive.
Each of the creeks are subject to more frequent and more extreme high flows created by runoff from pavement and rooftops. The creeks are also subject to lower “low flows” in between storms. The effects of increased runoff and decreased low flows are shown in the graphics below. (Kim Stephens and I developed these graphics while working on watershed planning projects in British Columbia 25 years ago.) With high flows, channels erode and widen flushing out salmon eggs. With low flows, there is little refuge habitat left for young salmon.
The problems are complicated by management practices. For example, the science is clear that a 200-foot buffer, or setback, on each side of a stream is necessary to provide adequate shade and insect life to sustain fish populations. The city lacks both consistent requirements for buffers and enforcement of ordinances created to protect critical areas. As a result, water temperatures are too high for fish and there is not adequate cover or food for fish.
The funds for stormwater management come from the City’s stormwater utility but the funds are primarily used for street maintenance. So, little is left for stormwater treatment, stream protection or restoration.
In summary, we routinely cause serious damage to the streams and wetlands: We change their flow, ignore the chemicals our activities flood into the water, and do not provide 200 feet of clearance when building around them. But there are steps we can take to reduce our impact, and create an Edmonds where streets, roads and salmon runs can co-exist.
Future articles will focus on the marine waters off Edmonds and the state of the Edmonds Marsh and Estuary. In the final article I will discuss realistic ways we can reduce our impact, while recognizing we cannot eliminate it.