The Middle Waterway (Simpson/Trustees) site is a 3.3-acre nearshore area, on property owned by Simpson Tacoma Land Company and situated in a highly industrialized area in Commencement Bay, at the southeast end of the Middle Waterway. The project is located in proximity, and functionally related to, the intertidal habitat constructed in 1988 as part of the St. Paul Waterway Area Remedial Action and Habitat Restoration Project conducted by Simpson and Champion International Corporation (now International Paper Company) at the north end of the Tacoma Kraft mill, as well as other intertidal and subtidal areas near the Puyallup River delta. Under the St. Paul Waterway Natural Resource Damage settlement agreement, Simpson and Champion funded the completion of the Middle Waterway Shore Restoration Project. The Project was selected and proposed by a project planning group consisting of Simpson, Champion, the Trustees, and other cooperating federal and state agencies.
The primary objective of the project was to provide estuarine habitat, in perpetuity, that is adjacent to one of the largest remaining areas of original Commencement Bay intertidal mudflat. Under the original settlement agreement, monitoring at the site was initiated in 1994, prior to site construction, and continued through the summer of 2000. Site construction was initiated in early 1995 and planting was undertaken between October 1995 and May 1996. In the summer of 1999, the Trustees assumed management responsibilities for the site and, in the fall, conducted additional adaptive management activities to promote the establishment of intertidal vegetation by regarding a portion of the site and by organic soil amendment, followed by supplemental planting in the spring of 2000.
Lower elevations at the site are functioning as mudflat habitats with patchy but extensive cover of microalgae, macroalgae, and a few species of vascular plants. These species generate primary production and organic matter (detritus) that are consumed by bacteria and primary consumers (herbivores and detritivores) which, in turn, provide food for secondary consumers such as benthic invertebrates, juvenile salmon, flatfish, and shorebirds. Buffer and riparian vegetation planted at the site is surviving but physical and biological stresses including high salinity, sandy soils, wave action, and herbivory by geese have hampered the establishment of mid- and upper-intertidal vegetation. Adaptive management measures have been undertaken by the Trustees to ameliorate some of these stresses.