The project area is located just north and east of the Lake Sammamish State Park boat launch and ELSP. In the 1800s, this area was deforested (including the creek path), the creek was channelized, wetlands near the lake shore were converted to farmland, and a railroad was constructed along the east side of Lake Sammamish to serve the numerous lumber mills along the lake shore. The earliest arial photograph of the area, taken in 1936 (see gallery), shows a still-mostly deforested landscape, the channelized creek, and farmlands, while the railroad is gone, indicative of the demise of the local timber industry following areawide deforestation. Some land has been restored to wetland, with the notable exception of the boat launch area and the adjacent private properties to the north.
- East of ELSP: Laughing Jacobs Falls drops down from the Plateau to Hans Jensen State Park (the project’s eastern border). Here the creek runs through mature forest, but the corridor is narrow and restricted by its proximity to ELSP. There is some armoring of the creek channel. A second tributary, Many Springs Creek, flows from the north. Many Springs Creek is also considered potentially good habitat for kokanee. (Note: it currently crosses under ELSP via a separate, adjacent culvert.)
- ELSP: Laughing Jacobs Creek flows under ELSP via a 48″ pipe culvert. While kokanee have been observed on the upstream of this culvert, migration is highly dependent on flow, and is therefore considered a significant barrier.
- West side of ELSP: Laughing Jacobs Creek is joined by Many Springs Creek, and flows through three private lots on its way to the lake. (The mouth is potentially good rearing habitat for juvenile Chinook.) These lots were once farm land. The creek in this reach has not been allowed to recover, having the following characteristics:
- Lawn and landscaped fields
- Little riparian cover or shade
- Some areas are choked with invasives
- Armored banks
- To replace the 48″ pipe culvert at ELSP with a fish-passable culvert, and
- To restore reaches of Laughing Jacobs Creek upstream of ELSP (WILL THERE BE ANY RESTORATION OF MANY SPRINGS CREEK???) for spawning kokanee, coho and cutthroat trout.
Future goals: work with private landowners on the west side of ELSP to restore riparian and in-stream habitat, including the mouth of the creek at Lake Sammamish.
The Kokanee Work Group evaluated three “alternatives” and selected Alternative 3. The restoration plan will:
- Replace the two existing culverts for Laughing Jacobs Creek and Many Springs Creek with a single, 25-foot wide box culvert passage with fish-friendly features.
- Relocate the confluence of Many Springs Creek and Laughing Jacobs Creek to the east side of ELSP — to within the boundaries of Washington State Parks.
- Realign (relocate) a significant section of Laughing Jacobs Creek, away from the east side of ELSP, and further into mature-forest State Park land. This will:
- Provide a much larger riparian buffer along both sides of the channel.
- Allow for better long-term natural “recruitment” of fallen wood from the existing forest. (Fallen wood, over time, creates stream diversity, cover for fish, depressions in the stream bed, and helps retain spawning gravels.)
Highlights of the proposed creek channel:
It is intended to create a “mini floodplain within the stream corridor.”
- It will be wider, allowing the creek to naturally migrate and sort sediment and gravel.
- It will be a “two-stage channel” consisting of:
- a low flow channel and
- thin benches a foot above the channel bottom on each side, in order to spread higher flows across a wider area.
The Issaquah School District is constructing three schools within one mile upstream of the project area: a high school, a middle school and an elementary school. These projects will include a significant amount of impervious surface, thereby contribute additional flow to the creek during storm events, while reducing groundwater recharge, depriving the creek of that water during the summer. Increased flow during storm events will contribute to scouring of the creek bed and spawning beds. The City of Issaquah and the Kokanee Work Group should consult the school district on what additional stormwater measures can be taken to protect Laughing Jacob Creek salmonids. Additionally, the planned artificial turf football field should be reviewed for its potentially lethal effect on coho salmon attributable to rubber infill derived from recycled tires.