US Army Corps of Engineers
Seattle District Website

Dredged Material Management Office (DMMO)

        

The Seattle District DMMO is the main point of contact for the interagency Dredged Material Management Program (DMMP). The DMMP brings together agencies with roles in management and regulation of dredged material to streamline testing and decision-making.  Together the DMMP agencies manage a network of multiuser open-water disposal sites in Washington State.

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Contact the DMMO

Seattle District (CENWS)
Dredged Material Management Office
PO Box 3755
Seattle, WA 98124-3755

CENWS-DMMOTeam@usace.army.mil

206-764-6083
206-764-6945
206-764-6550
206-764-6713

USACE Seattle

USACE Seattle

News and Updates

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32nd SMARM was held VIRTUALLY on September 30th, 2020

The first ever fully virtual SMARM was successfully held on September 30th.  Presentations will be posted on the SMARM page soon and draft clarification papers are available here.  Comments can be submitted to CENWS-DMMOTeam@usace.army.mil and will be accepted through November 30th.

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Now Available: Dredge Year 2020 Highlights Flyer

Click on the image below to see the PDF flyer discussing the evaluation, disposal and monitoring highlights of the Dredged Material Management Program during Dredge Year 2020.

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DMMP Project-Specific Issue Resolution Process

In response to the recommendations made by the 2016 Ecology and DNR Management Review of the Dredged Material Management Program, DMMP agency managers and staff developed a process for elevating individual project decisions before the management of all four DMMP agencies.  The issue resolution process may be used to address issues or disagreements with DMMP determinations before or after decision documents are signed.  This issue resolution process was presented at the 2019 SMARM and is now in effect and available for use by project proponents.  Detailed information on the project-specific issue resolution process is available on the User Manual page.

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FAQs

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The Dredged Material Management Program (DMMP) consists of four agencies that work collaboratively to make sure that material proposed for dredging in Washington State is appropriately tested and managed. The DMMP agencies are the U.S. Army Corps of Engineers, Seattle District (USACE); the U.S. Environmental Protection Agency, Region 10 (EPA); the Washington Department of Ecology (Ecology); and the Washington State Department of Natural Resources (DNR).

The federal government, ports, marinas and other entities dredge to maintain navigational waterways and berth depths when those areas are filled in by natural sediment deposition. The DMMP agencies oversee testing for contaminants to determine what material can be disposed of at open-water disposal sites. The state-owned sites are managed by DNR. The DMMP does not manage contaminated sediment cleanups--those are managed by cleanup programs within Ecology and EPA.
Dredging affects the lives of nearly every Washington State citizen and visitor.  Maintenance and navigation dredging is done frequently in harbor areas, ports and marinas. These areas naturally silt in. Dredging is performed to maintain the depths needed for boats to operate, and to develop new areas or achieve increased depths for boat access. A significant component of Washington's economy depends on navigation and commerce, which in turn depends on dredging the state's waterways; between 2000 and 2015, over 50 million cubic yards of dredged material have been dredged and disposed of at the open-water disposal sites.

An extensive analytical, public process was used to define open-water sites for dredged material disposal, and to define the guidelines for dredged material that can be disposed at these sites. There are two types of sites:  dispersive and non-dispersive.

Dredged material placed at non-dispersive sites remains on-site and is the subject of long-term monitoring.  Non-dispersive sites are managed to allow minor adverse effects such as sub-lethal effects to some species after long-term exposure.

Dredged material placed at dispersive sites--which are located in areas with strong tidal currents--disperses quickly. No adverse effects are allowed at dispersive sites, so dredged material must meet more stringent evaluation guidelines to be eligible for disposal at these sites.

There are eight dredged material disposal sites around Puget Sound (three dispersive and five non-dispersive) and two dispersive estuarine sites each in Grays Harbor and Willapa Bay. The DMMP agencies collectively evaluate the suitability of dredged material for disposal at these sites. As owner of the state's aquatic lands, DNR manages the disposal sites and is responsible for environmental monitoring of all nondispersive disposal sites.

RSET (Regional Sediment Evaluation Team) is a multi-agency, multi-state umbrella organization whose role is to provide a consistent regional framework for the evaluation of dredged material in the Pacific Northwest.  RSET developed the Sediment Evaluation Framework (SEF 2016) as a guide to regional sediment testing. The RSET is tasked with maintaining and updating the SEF based on customer feedback and changes in science and national policy. 

The DMMP agencies ensure that the content of the DMMP User Manual is aligned with the regional SEF through agency participation in regular RSET meetings and involvement in SEF updates.

RSET (Regional Sediment Evaluation Team) is a multi-agency, multi-state umbrella organization whose role is to provide a consistent regional framework for the evaluation of dredged material in the Pacific Northwest.  RSET developed the Sediment Evaluation Framework (SEF 2018) as a guide to regional sediment testing. The RSET is tasked with maintaining and updating the SEF based on customer feedback and changes in science and national policy. 

The DMMP agencies ensure that the content of the DMMP User Manual is aligned with the regional SEF through agency participation in regular RSET meetings and involvement in SEF updates.

The DMMP User Manual is the implementation manual for dredged material evaluations in the state of Washington.  For projects within the geographic jurisdiction of the DMMP, use the DMMP User Manual for dredging project evaluations.

The DMMP User Manual applies to projects in Puget Sound, on the Washington Coast, for non-port projects on the Washington side of the Columbia River, and to all other water bodies within the state of Washington.  Questions regarding sediment evaluation for DMMP projects should be directed to the DMMO team.

Port projects on the Washington side of the Columbia and ALL projects on the Oregon side are evaluated by the Portland Sediment Evaluation Team (PSET). PSET is headquartered at the USACE Portland District, and functions similarly to the DMMP for Oregon projects. The PSET agencies include the Portland District, Environmental Protection Agency, Oregon Department of Environmental Quality, Washington Department of Ecology, U.S. Fish and Wildlife Service, and National Marine Fisheries Service.  The SEF should be used for Portland District projects.  Questions regarding dredged material testing and evaluation procedures for Portland District projects (including Corps dredging permits) should be directed to the PSET Lead.