Mowitch Restoration Project (Formerly Wasser-Winters)

Location: Hylebos Creek, Commencement Bay, Washington.

Funding source: Port of Tacoma settlement.

Design Objectives

• Enhance fish habitat for juvenile salmonids.
• Establish backwater pools.
• Establish areas for salt marsh vegetation.
• Protect the site for natural resources.

Following a solicitation for proposed restoration project site names from students at a tribal school, and in consultation a Puyallup tribal linguist, the Puyallup tribal representatives proposed names for five projects. One of those sites, the Wasser-Winters site, has been renamed "Mowitch," which in the Salish language means "deer."

The project site is located along the lower reach and mouth of Hylebos Creek and is adjacent to the industrial shoreline of the Hylebos Waterway Upper Turning Basin. As with the adjacent areas, the project site was filled to its present elevation, channelized, and straightened in the early 1960s when the Hylebos Waterway Upper Turning Basin was dredged to its current configuration.

Onsite industrial uses varied little from the early 1960s through the mid-1980s, with log storage and log sorting being the primary onsite activities. During this time, the site was routinely maintained with crushed rock and Asarco slag as groundcover for the large log handling equipment. As a result of using Asarco slag, the Washington State Department of Ecology required that the Port of Tacoma, the landowner, take remedial actions to address the elevated levels of arsenic, copper, lead, and zinc found in the soils and storm water on the project site.

The project site is vacant. The site is generally clear of most significant vegetation except for scott's broom (Cytisus scoparius), sapling red alser (Alnus rubra) and a few douglas fir trees (Pseudotsuga menziesii). Other plant species such as Himalayan blackberry (Rubus procera), Pacific blackberry (Rubus ursinus), and Canadian thistle (Cirsium arvensis) have invaded the open areas of the project site.

The shoreline area of Hylebos Creek is steep and exhibits indications of erosion and bank sloughing. Rooted vegetation is lacking below approximately +10 mean lower low water (MLLW). The project site includes a portion of Hylebos Creek where the channel has been highly modified by past dredging, straightening, and filling activities. Along the project area, Hylebos Creek is tidally influenced, with the ordinary high water mark (OHWM) established physically and biologically in relationship to tidal elevations. The city of Tacoma has identified this aquatic community as meeting the regulatory definition of a stream.

Restoration Activities

Volunteer planting activities occur in the spring and fall as needed. Please contact the CB restoration manager for information about future volunteer planting activities.

Two conceptual designs were presented at an April 1999 public briefing: Alternative A and Alternative B. The restoration technical staff, public, and design contractors evaluated the potential environmental impacts and feasibility of the proposals and selected Alternative B as their preferred design. This alternative is discussed below in more detail.

The character of the straight stream channel has been modified and diversity has been added to the habitat. Three backwater pools with base elevations near mean low water (MLW) have been sculpted from the present upland buffer area. A secondary stream mouth has been added in the area of the site that was a historical log ramp. The backwater area should become flooded the majority of the year. The pools and adjacent terraces include horizontal logs as habitat features. In addition, the area between the pools has been regraded to an elevation between mean high water (MHW) and mean higher high water (MHHW) (10.96 to 11.84 on a MLLW datum). A minimum of 25 feet next to the fence is to remain vegetated.

The planting designs are based on plants native to Commencement Bay. The upland plants are being selected based on their tolerance for dry conditions, which are anticipated on the riparian bank. The emergent plant species will be similar to those found elsewhere in Commencement Bay and will use the freshwater component from Hylebos Creek. Plantings in the downstream (northern) area are dominated by salt grass to accommodate the more saline conditions expected from the tidal flood patterns on the site. The area between elevations 11.32 and 14.32 are extreme high-tide areas and will be planted with emergent plants. The site design plans include provisions for regular watering during the time when the plants are becoming established.

The Common Names of Plants To Be Established at the Mowitch Restoration Project Site

Salt marsh plants: Lyngby's sedge, saltgrass, pickleweed, American threesquare rush, seaside arrowgrass.

Riparian plants: Red alder, paper birch, black cottonwood, douglas fir, red osier dogwood, Oregon grape, Pacific ninebark, nootka rose, hooker's willow, scouler's willow, snowberry.