Welcome to the Hidden Lake Dam Removal
Project Online Open House!

The purpose of this Online Open House is to provide a chance for residents to:

• Learn more about this project
• Share what’s important to you and provide comment

Learn more about the proposed design and history of this project below and complete the survey to provide feedback. The online open house and survey will take only a few minutes to complete.

Thank you for your participation!

Project Overview

The City of Shoreline is proposing to remove the existing Hidden Lake Dam in order to improve flood risk and sediment transport conditions for Boeing Creek within the existing lake area. Hidden Lake is an artificially made water body built in 1920 as a private fishing pond. Since that time, the lake has continually dealt with sediment accumulation issues. The initial lake was completely filled in by the 1970’s and has continued to accumulate large volumes of sediment since its latest re-establishment in 1995. The lake can only be maintained through regular removal of these large volumes of sediment (dredging). If the lake is allowed to completely fill itself, it would prevent flows from Boeing Creek to safely pass under NW Innis Arden Way, creating a potentially dangerous flood risk to the roadway and nearby properties. The last time the lake was dredged was in 2013 and shortly after City Council decided to stop dredging and begin this project to remove the dam.

A timeline of Hidden Lake’s history (click the image to enlarge)

The project will include the restoration of Boeing Creek through the existing Hidden Lake area. Removing the lake is expected to improve water quality by reducing the introduction of bacteria from waterfowl and lowering the water temperature. The replacement of the existing stream culverts crossing below NW Innis Arden Way will improve flood control in the area. Additionally, access to the site will be enhanced with the construction of new looped trails within Shoreview Park along the restored creek. 
The existing project site (click the image to enlarge)

Schedule

Construction of the proposed project improvements require in-water work which can only be completed during the summer months. Therefore, a phased approach to the work must be implemented. The first phase of construction will include the removal of the lake and dam, stream restoration, and trail improvements. The second phase of construction will replace the culverts underneath NW Innis Arden Way.

A general outline of the project schedule (click the image to enlarge)

Proposed Site Plan

An illustrative perspective of the Hidden Lake area following construction might look like the following graphic, once plants are fully established.

An illustrative drawing of the Hidden Lake area following construction might look like (click the image to enlarge)

The project will re-establish the natural habitat of the Hidden Lake area by removing the artificially made lake, constructing a defined channel of Boeing Creek in its place that contains natural fish and wildlife habitat and grading to create a connected floodplain which will include planting of native wetland and upland riparian vegetation communities. The vegetation communities are shown the in following illustration.

Vegetation communities (click the image to enlarge)

The proposed plantings will create a wildlife habitat for numerous species shown illustratively in the following graphic.

Wildlife habitat created for numerous species (click the image to enlarge)

Take the Survey

We want your feedback. Please complete the survey to provide your comments. Thank you!