McElroy Slough Tide Gates Replaced
By Alison Studley
In October 2006, saltwater was reintroduced to McElroy Slough thanks to many years of perseverance by project partners and community members to restore tidal function to this small Puget Sound estuary. The project uses an innovative approach for restoring tidal action to the slough, through the installation of a self regulating tide gate. The self regulating tide gate allows saltwater to enter the slough, but only to a predetermined height which will not flood the surrounding landscape at high tide.
McElroy Slough flows through the lowland areas surrounding the Blanchard community and drains into Samish Bay. Three salmon bearing creeks drain into McElroy Slough: Whitehall, Colony and Harrison Creeks. Previous salmon enhancement projects have occurred with landowners on both Colony and Harrison Creeks. The self regulating tide gate restores tidal flushing, fish passage and estuary rearing area for chinook, coho, chum and cutthroat within the McElroy Slough watershed. Restoring the estuary functions to McElroy Slough will greatly enhance the fish and wildlife use of this watershed as well as reduce flood hazards to the Blanchard Community. The project opens 1 mile in length or approximately 9 acres of estuary area for anadromous fish use within the slough. It also improves access to 5 miles of Colony Creek used by anadromous fish, a half mile of Whitehall Creek and 3 miles of Harrison Creek.
The new 6’ x 6’ box culverts and tidegates at Blanchard Road.
The implementation of this project is very exciting, as it has taken years of hard work by many individuals. In 1997 design funds were received for the McElroy Slough project from US Fish and Wildlife Service and a technical advisory committee was formed to develop a preliminary design using a multi-agency collaborative approach. This committee hired a consultant to complete a design report which was used to develop a grant application to the Salmon Recovery Funding Board. By the end of 2001, the project was fully funded and permitted, and ready for construction bidding. A solid monitoring plan was created and baseline information regarding surface and groundwater levels and salinity was being collected. The total project costs at that time were estimated to be $700,000 ($500,000 in grants from the Salmon Recovery Funding Board and US Fish and Wildlife Service and $200,000 from Skagit County road funds). Project partners and Blanchard residents anticipated that project implementation would commence during the 2002 construction season.
However, complications occurred which postponed the implementation of the project for 4 years. In a nutshell, political and engineering issues related to replacing tide gates under a Skagit County road that also served as drainage for the surrounding agricultural fields with a tide gate that allows tidal inundation delayed the project. Monitoring continued over this time, while project partners patiently waited for resolution of these complicated issues through additional analysis, design review and modification.
In 2006 resolution was reached with all interested parties and Skagit County finally put the project out for bid. Total project costs had increased substantially from $700,000 to over $1.1 million due to design changes, inflation and cost increases ($600,000 coming from SFEG’s grants and the rest coming from the Skagit County road fund). The project consisted of replacing three existing McElroy Slough culverts with tidegates at Blanchard Road with four 6’ x 6’ box culverts and tidegates. Three of these tide gates are traditional top hinged gates and one is a side hinged self regulating gate. At the Flinn Road crossing of McElroy Slough two undersized culverts were removed and replaced with a 45 foot long bridge. Construction commenced in August and was completed in October.
Prior to construction, SFEG implemented the remaining elements of the monitoring plan to collect appropriate baseline data both inside and outside of the existing tide gates. Juvenile fish use was documented with the help of the Upper Skagit Indian Tribe, cross sections were taken of the channel, and vegetation plots were established. A high resolution aerial photo survey was taken as well to document baseline conditions. The County restarted the surface and ground water monitoring equipment and prepared it for post construction monitoring. SFEG is committed to working with the community members and Skagit County to insure effectiveness monitoring is conducted as set forth in the monitoring plan.
SFEG staff use nets to document juvenile fish use inside the tide gates prior to construction.
Completing the McElroy Slough Restoration Project represents a concerted and sustained effort by SFEG, Skagit County, Washington Department of Fish and Wildlife, US Fish and Wildlife Service, the Salmon Recovery Funding Board and the residents of Blanchard to make the project a reality. After years of struggle, it is very rewarding to have an agreement reached between the multiple parties involved and see this unique and important project take place. The community and project partners look forward to seeing juvenile salmonids, especially chinook, utilize the newly restored estuarine environment of McElroy Slough in 2007.
