SEATTLE, Wash, Dec. 10, 2001 — Salmon habitat in estuaries of the Snohomish River grew by 19 high-quality acres, thanks to a new environmental strategy developed by the state and put into action by the Port of Everett.
Working with consultant Pentec Environmental, the natural resources division of Seattle-based Hart Crowser, Inc. the Port restored a large tidal salt marsh and mudflat on land that had been diked and farmed since the early 1900s. Using a new state-sanctioned approach called mitigation banking, the Port dedicated 12 of the restored 19 acres as mitigation for about 9.5 acres of lower-quality shallow water habitat lost to recent development. The remaining 7 acres of new marine habitat have been "banked" by the Port for mitigation on future projects.
Mitigation banking helps owners and regulators formulate the long-term strategies that not only remove some of the uncertainties associated with development, but also improve outcomes under federal state and regional programs to create and retain habitat. The State of Washington has only recently developed guidelines for mitigation banking that are compatible with federal regulations administered by the U.S. Army Corps of Engineers and the U. S. Environmental Protection Agency. These new guidelines are making it easier for industry and public entities to take advantage of the mitigation banking strategy, with the Port of Everett among the first.
In the Port's case, a pressing need for expanded terminal space, combined with the need to dredge and dispose of sediments clogging existing berths, led to plans for a near-shore fill that would contain the dredged material while also providing acreage for a container terminal. The Port asked Pentec Environmental to evaluate the project site, an intertidal area dedicated to industrial uses for the past 90 years. Pentec used the Snohomish Estuary Wetland Integration Plan (SEWIP) to define the impacts of filling the site and to calculate the mitigation needed to compensate for loss of the area, which had only marginal value as habitat.
At the same time, the Port identified a sizeable parcel near Union Slough, former farmland that was now diked and zoned for industrial uses. The owner had plans to fill the land for development, but the Port was able to purchase the property for about $1 million. Working with Pentec and a third-party engineering firm, the Port then set out to develop a 19-acre salt marsh that looked and functioned as much as possible like a natural marsh.
To minimize construction impacts, a new central channel and smaller feeder channels were excavated inside the existing dikes, which were then breeched to restore tidal circulation to the site. Above the high-water line, native plant species were installed to improve the riparian zone. Below the high-water line, native wetland plants are self-seeding. Two months after the dikes were breeched in early 2001, juvenile salmon were seen in the marsh. Pentec will continue monitoring for 10 years to verify that the mitigation project functions as intended to provide habitat for salmon, shorebirds, waterfowl, and crab.
Graham Anderson, environmental planner for the Port of Everett, believes that mitigation banking will allow the Port to plan more comprehensively for both development and mitigation—and that it also works better for the fish. "We can build one large mitigation project," says Anderson, "which is much more cost-effective for us than mitigating project by project. The fish get large contiguous areas, providing them with good, new habitat to use before there's a loss of habitat elsewhere."
Jon Houghton, Pentec's principal in charge of the project, points out that mitigation banking promotes better long-range planning. "Over the years, the Snohomish estuary has lost seventy-four percent of its mudflat and salt marsh habitat," Houghton said. "Now we can focus on preserving those areas that will have the greatest positive effect on threatened species, using clear formulas and policies that help clients and regulatory agencies define impacts and mitigation needs, so both know what to expect."
Dedicating 12 acres of the 19-acre habitat to mitigation for its container terminal/near-shore fill project leaves the Port of Everett with 7 acres of high-quality marine habitat "in the bank." That deposit will make it easier for the Port to plan for future development. Meanwhile, fish and wildlife are earning interest—in the form of both immediate and long-lasting benefits—on all 19 acres.
Pentec Environmental, a division of Hart Crowser, Inc, has been creating and enhancing habitat in the Snohomish estuary for more than 15 years. Located in Edmonds, WA, Pentec specializes in aquatic biology, fisheries biology, geomorphology, hydrology, marine ecology, and aquatic toxicology.
Founded in 1974, Hart Crowser is an environmental consulting and remediation engineering and design firm headquartered in Seattle, WA, with offices in Portland, OR; Anchorage, AK; Long Beach, CA; Denver, CO; Boston, MA; and Jersey City, NJ. Corporate offices are located in Seattle. The company's web site offers information about the firm's service areas, www.hartcrowswer.com.
