The Puget Sound Confined Disposal Site Study:
Background and History
Sediments Can Be Harmful
Many chemicals are flushed into our waterways from industries, storm drains, yards and even undeveloped land. Some of these chemicals tend to bind to and build up in the "sediment" found at the bottom of ocean bays, estuaries, rivers and lakes. When these chemicals build up to high enough concentrations in the sediment, the sediment is considered "contaminated" and can be harmful to aquatic plants and animals. Some chemicals can also accumulate in the tissues of bottom-dwelling organisms, move through the food chain to concentrate in fish and shellfish, and can pose real risks to human health.
There’s A Lot Of Contaminated Sediment, But Few Safe Places To Take It
Officials estimate that as much as 10,000,000 cubic yards of sediment in Puget Sound contain harmful and/or bioaccumulating chemicals and need to be dredged. That’s enough volume to fill about one million dump trucks holding 10 cubic yards each.
Currently, there are few options for effectively confining and isolating these contaminated sediments from the rest of the aquatic environment. Some can be allowed to recover naturally; clean material that is washed in from rivers will eventually cover them. Some can be permanently covered or "capped" in place with lots of imported clean sand, but this isn’t practical in areas where water depth is important to navigation. Other contaminated sediments can be dredged up and taken to an approved landfill, but that is very expensive and takes up valuable space for municipal garbage.
The lack of environmentally protective and cost effective disposal capacity for contaminated Puget Sound sediments can limit navigation and commerce, delay actions on sediment cleanup sites and make developing urban waterfront too costly.
Regional Sediment Management Activities, 1985 – 1995
The Puget Sound Dredged Disposal Analysis Study or "PSDDA" resulted in a comprehensive program to evaluate cleaner sediments, establish open water disposal sites, and implement management and monitoring guidelines for those disposal sites (U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, and Washington State Departments of Ecology and Natural Resources, 1986-1988).
The first Puget Sound Water Quality Management Plan recognized the need to manage and dispose of sediments found unsuitable for open water disposal at PSDDA sites. It directed Ecology to "undertake a needs and feasibility study" of multi-user disposal sites specifically designed to confine and isolate them (Puget Sound Water Quality Authority, 1987). In response to this Management Plan, Ecology prepared a series of "fact finding" reports (1989) and summarized them in "Multi-User Sites for the Confined Disposal of Contaminated Sediments from Puget Sound". The key conclusion was that "such sites are needed and that the urgency will only increase as the volume of dredged materials requiring confined disposal increases" (Ecology, 1991).
At about the same time, the State of Washington adopted the Sediment Management Standards rule (173-204 WAC,) to clean up existing contaminated sediments and prevent more from building up (Ecology, 1991).
The newly formed Cooperative Sediment Management Program focused work on the reuse of cleaner sediments, cleanup of contaminated ones, and feasibility of siting and building a confined disposal facility (1994). A revised Puget Sound Management Plan called for an interagency group to take the next steps in the feasibility study (PSWQA, 1994). This was followed by the Seattle District of the Corps of Engineers preparing a Reconnaissance Study Report that showed there is a federal interest in the feasibility of building such a disposal facility (Corps, 1995).
New Study Of Disposal Alternatives For Contaminated Sediment
The Washington State legislature approved matching funds to work with the Corps on a study that compares the merits of several alternatives for disposing of contaminated sediments (1996). The Corps and the State, represented by the Departments of Ecology and Natural Resources and the Puget Sound Water Quality Action Team, signed a cost sharing agreement that began the The Puget Sound Confined Disposal Site Study (July 1997). The U.S. Environmental Protection Agency and the Washington Public Ports Association are "Cooperating Agencies" in this three-year, $3.5 million project.
This study is sometimes called the "MUDS" project because it examines, among other alternatives, three general designs for Multi-User Disposal Sites that could be used by many private and public entities. These designs are illustrated below.
The first product of the study will be a programmatic environmental impact statement, or "PEIS". The draft PEIS will be released in mid-February 1999 and finalized in the spring. It will describe various general alternatives for safe and cost effective disposal of contaminated sediments. Depending on the conclusions of the final PEIS, public and peer review comments, the agencies may prepare a site-specific EIS. If they do, then this second EIS will likely
The Corps will also prepare a final Feasibility Report to Congress that could lead to authorizing use of federal funds for additional engineering and construction studies.
Getting Involved: Mailing Lists and Upcoming Actions/Events
Interested persons may place their names on the Puget Sound Confined Disposal Site Study or MUDS mailing list by calling or faxing either Steve Martin (Corps @ 206/764-3631, fax 206/764-6602) or Tom Gries (Ecology @ 360/407-7536, fax 360/407-6904). Or visit Ecology’s web site (http://www.ecy.wa.gov/programs/tcp/smu/muds.htm).
Several informational meetings and public hearings will be held after the release of the draft PEIS in February 1999. Formal comments will be accepted for 45 days after the release of the draft PEIS. Issues raised in the public comments will be addressed in the final EIS, to be published spring of 1999.