That’s a photo sent recently by John, showing a beaver along Longfellow Creek, which parallels much of Delridge Way. In some areas along the creek, beavers are just part of the ecosystem – but Seattle Public Utilities says their work is posing a potential problem in one area, and is pursuing this project, announced in a recent Land Use Information Bulletin (note that the same notice covers the West Seattle proposal and a similar one elsewhere in the city):
Beavers have recently constructed dams immediately upstream of the pedestrian footbridge over Longfellow Creek … and dams in SPU’s Meadowbrook Pond Stormwater Detention and Flood Control Facility in the Meadowbrook neighborhood.
The dams may lead to localized flooding of nearby residential properties during the rainy season. This proposal would deploy beaver dam management interventions at the dams at both sites. Specifically, the proposed work would install four pond levelers by notching the dams and then installing exclusion fences. The fencing would extend 16-feet upstream from the top of the dam. Notching assists in
preventing beavers from detecting stream flow through the dam and the fencing prevents them from effectively plugging the notch.
These interventions are intended to control water levels and flows in Longfellow and Thornton creeks and are preferred alternatives to relocating the beavers or removing or breaching an established beaver dam that maintains hydrology of a nearby wetland or pond. The proposed design provides unimpeded fish passage while preventing beavers from constructing effective dams at the pedestrian \ bridge at the Longfellow Creek site and in Meadowbrook Pond at the Thornton Creek site.
The Project includes the following major work elements:
1. Creating a notch in the beaver dam
2. Installation of metal t-posts and welded-wire fencing with a mesh size of 4 inches by 6 inches to create a box in the notch of the beaver dam.
3. Extend the wire fencing box 16-feet upstream from the beaver dam.
This is in/near the 2500 block of SW Graham [map], according to the city notice. What the city published, specifically, is a Determination of Non-Significance, meaning it doesn’t believe a formal environmental-impact study is needed for this. Here’s the full-length “checklist” document, below and here:
You can comment by June 3rd by emailing Kevin Buckley at SPU, email@example.com; you can also formally appeal the Determination of Non-Significance, deadline June 10th, as explained in the notice.