Cleanup Sites

Site Summary

The site is located at approximately river mile 15 of the Willamette River, about one mile upstream of downtown Portland. Ross Island Sand and Gravel Co. mined gravel from the lagoon between 1926 and 2001. Beginning in 1980 they were required to reclaim the mined area and, to accomplish this, began importing fill to the site. Some of this fill was contaminated and was required to be capped with clean material. In the late 1990s DEQ required the Port of Portland (primary source of contaminated fill) and RISG to investigate the adequacy of the confinement of the contaminated material and environmental conditions in general. A Record of Decision was signed in 2005 laying out long-term containment, monitoring, and management protocols that RISG must adhere to. This work will be integrated with on-going reclamation activities that RISG is completing under a permit with the Division of State Lands. 


Documents and supporting information

General information


Ross Island reclamation fill evaluation


Cleanup selection/evaluation

​Two basic concerns were identified. The first was to assess whether contaminants have escaped from locations where the Port o f Portland disposed of dredge materials within the Ross Island Lagoon. Between 1992 and 1998, the Port of Portland received state and federal authorization to bury contaminated dredge materials from the Portland shipyard and Port terminals. The Port investigated whether the original disposals were properly handled and whether any contaminants escaped into the environment.

The second concern was potential environmental impacts of upland and in-water disposals at the island complex from sources other than the Port of Portland. Ross Island Sand and Gravel, owner of the islands and lagoon, conducted an assessment to determine what, if any, effects such disposals had. The company also investigated the nature and extent of contaminant releases caused by the breaching of a Port containment cell during gravel mining operations. The Department of Environmental Quality provided oversight and coordinated both efforts to assure that the work met objectives.

    ​The studies used a variety of scientific methods to determine if there had been environmental impacts caused by disposal of contaminated materials within the Ross Island complex. Work included sampling surface and deep sediments, examining the structural integrity of Port disposal cells, testing of ground and surface waters for contaminants.
    ​That was one of the key questions addressed by the investigations. In early 1998, a gravel mining shovel breeched one of the containment cells holding contaminated dredge materials from the Port. Ross Island Sand and Gravel conducted an investigation and determined that material removed from the confined cell ended up in the eastern portion of the main settling pond at the site. The affected portion of the settling pond was closed and filled as part of the Ross Island remedial action.

    The Port of Portland paid for a thorough investigation of the confined aquatic disposal sites. Ross Island Sand and Gravel paid for the broader investigation and continues to pay for cleanup actions under legal documents requiring them to perform necessary work and be responsible for all costs, including time spent by DEQ guiding the assessment process. The Port of Portland and Ross Island Investigation reports are available on this web page.

    The U.S. Army Corps of Engineers guidelines require contaminant testing before disposal of dredged materials. If the material does not test positive for certain contaminants, it may be disposed of at upland locations or returned to a waterway to disperse freely in the current. Contaminated sediment disposal offers fewer options. The material can be placed in properly confined upland areas. Or, it may be placed in holes or cavities under water, then covered with clean material that seals the contaminants in place. This is considered a secure and cost-efficient disposal method.
    ​A land bridge connecting Ross and Hardtack islands closes the Ross Island lagoon at the upriver end of the joined islands. The lagoon opens on the down-river end with an outlet into Holgate Slough. Fish, including salmon may use the lagoon as they travel between the ocean and spawning locations upstream.  Ross Island Sand and Gravel Company is required to monitor turbidity during fill placement to ensure against increases that could harm aquatic species.

    Depending on work being performed, Ross Island Sand and Gravel operates under three separate, but closely related, regulatory systems. The Oregon Division of State Lands (DSL) regulates placement of clean fill within the island complex. Fill operations are also covered by the federal Clean Water Act section 404 permit process administered by the U.S. Corps of Engineers. The Department of Environmental Quality plays a decisive role in the Corps section 404 process through state authority to issue or deny a section 401 certification. A 401 Certification from DEQ puts the state on record that certain in-water activities will not violate water quality standards.

    In addition, DEQ also regulates discharges from the company's gravel processing facility through a National Pollution Discharge Elimination System (NPDES) permit. This permit process also operates under authorization of the federal Clean Water Act.

    ​The Ross Island Sand and Gravel Company owns the majority of Ross and Hardtack islands, and the lagoon created between them. The islands have been under private ownership since the early part of this century. A portion of Ross Island on the northeast side (45 acres) was deeded to the City of Portland in 2007.  The Port of Portland owns 6.5 acres at the northern tip of Ross Island.

    The planned reclamation of the islands is described in Ross Island Sand and Gravel's permit with the Division of State Lands. The plan specifies creation of wetland and shallow water habitat within the lagoon. It also includes a re-vegetation plan for the islands.

    Ross Island Sand and Gravel Co. no longer mines sand and gravel from Ross Island lagoon, but imports this material from a site near Klickitat, WA via barge to be processed at the plan on Hard Tack Island.

    Dredge material meeting Class A criteria established in DSL’s reclamation permit can be placed in Ross Island lagoon without any long term controls. Class A standards were established by DEQ to reflect contaminant concentrations and/or testing results that indicate the fill will not pose a risk to human health or the environment at Ross Island. RISG submits Annual Report documenting fill source and quality to DSL as part of the reclamation permit requirements.
    ​The contamination in the lagoon is primarily located 30 feet or more below the mean water level of the river and has now been covered by a minimum of 3 feet of clean fill. The cap over contaminated material in the lagoon gets thicker each year as reclamation progresses. People using the lagoon for recreational purposes will not come into contact with contaminated sediment. Because the contaminants present in the sediment are not mobile and are sequestered beneath clean material, fish and other aquatic organisms will not be impacted.
    ​Environmental Cleanup Site Information Number (ECSI):   2409 
    County Multnomah 
    City:  Portland
    Region: Northwest  


    Project Manager:  Jennifer Sutter Phone: 503-229-6148