DESCRIPTION
The project site is located on the former Kenco Marine Services property at the western upstream boundary of the maintained navigation channel (Turning Basin No. 3) where the Duwamish Waterway is formed from the Duwamish River. The upland portion of the site was composed of fill material and is covered with asphalt and concrete pads, in addition to an office/warehouse structure, small storage sheds and a house. A commercial pier extended 125 feet into the Turning Basin. Barges and other vessels moored in the intertidal and subtidal area. Portions of the area had already been restored to natural wetlands by federal agencies, including the National Oceanic and Atmospheric Administration (NOAA), the U.S. Fish and Wildlife Service (FWS), and the Port of Seattle, under a Coastal America Partnership. The Elliott Bay/Duwamish River Restoration Program Panel funded the purchase of additional land to increase estuarine habitat in this area, to be held under the trusteeship of the Muckleshoot Tribe. Over one acre of mudflat has been day-lighted by the removal of derelict vessels at the site. The commercial pier and shoreside structures were removed and the area was recontoured and revegetated to provide an enhanced intertidal wetland area. Summary taken from the NOAA Northwest Region DARRP website (http://www.darrp.noaa.gov/northwest/elliott/tb3.html).
Project implementation includes:
- Removal and prohibition against moorage of barges and other vessels at the site allowed
- 18,000 square feet of intertidal and subtidal mudflats to become permanently exposed (1998).
- Demolition and removal of former commercial structures, concrete foundations, paved areas, including the dock structure and creosoted wooden supporting piles (2005).
- Recontouring and revegetating the area created an enhanced intertidal wetland area consisting of three habitat benches at various elevations:
- A 'lower bench" at +2 to +6 feet at a 10:1 slope of sand over 3/4" gravel substrate created 6,500 square feet of intertidal habitat. Bank stabilization was accomplished by using 'soft" substrates (wood) in lieu of riprap at the transition to the emergent zone bench.
- An 'emergent zone bench" at +9.5 to +11 feet at 20:1 slope was planted with native intertidal vegetation and random rock placement to create 6,050 square feet of marsh habitat.
- A 'groundcover and shrub zone bench" at elevation +14 to +17 feet at a 3:1 slope planted with native riparian vegetation created 1,850 square feet of riparian habitat.
- Monitoring for intertidal habitat success is being conducted under the Elliott Bay/Duwamish Restoration Program's monitoring plan through 2015.
Description taken from the NOAA Northwest Region DARRP website (http://www.darrp.noaa.gov/northwest/elliott/tb3.html).
NOTES
Goals: NOAA reports only 1,850 square feet of riparian area planted during installation in 1995, but GIS data collected on site in 2007 by People For Puget Sound suggests 0.33 acres of riparian area (including upland to the road). Was this area planted with additional natives by People For Puget Sound sometime after initial construction'
Budget:
Land Acquisition cost: Panel provided $479,200 toward the total; the remainder was a grant to the Muckleshoot Tribe
Planning and Design: $166,043.03
Construction: $544,744.11 (actual construction only, does not include NOAA's project management/contracting costs which were not tracked separately from other NOAA activities)
Duwamish Tier 1
