EPA Region 10 just released its Record of Decision (ROD) for the Duwamish River Superfund Site. This is the next step in the cleanup process for the Lower Duwamish River, and documents EPA’s selected remedy for the site. It comes on the heels of EPA’s Proposed Plan for the Duwamish, issued in February 2013.
The selected remedy is projected by EPA to cost $342 million. It applies active remediation to 177 of the 441 acres that compose the Lower Duwamish River Superfund Site. Of those 177 acres:
- approximately 105 acres are slated to be dredged (960,000 cubic yards of material);
- approximately 24 acres will be capped;
- approximately 48 acres will be capped with a thin layer of material to enhance natural recovery of those sediments; and
- in areas of structural or access restrictions, location-specific technologies will be applied.
EPA anticipates that these activities, in conjunction with upland source control, will result in removal of 90% of the total contaminants in the waterway. You can view the areas where these remedial technologies are anticipated to be applied by clicking on the above thumbnail. The “active” portion of the remediation is anticipated to take 7 years, although this time frame does not include remedial design activities (discussed below). Concentrations of toxics in fish and shellfish are predicted to achieve the lowest levels 17 years after commencement of construction of the remedy, so ten years after the end of active construction of the remedy.
Changes from the Proposed Plan
Overall, the selected remedy looks a lot like “Alternative 5C Plus” outlined in the Proposed Plan, with some notable changes. The summary of these changes begins on page 116 of the ROD. Some of those changes include:
- Revisions of cleanup levels to reflect changes made to Washington’s Sediment Management Standards.
- Confirmation that the ROD does not establish cleanup levels for fish tissue. This is a technical but important point because the Proposed Plan contained a Preliminary Remediation Goal (“PRG”) for fish and shellfish, and a PRG usually is converted to a cleanup level in a ROD. But, in the ROD, EPA acknowledged that fish tissue receives contaminants from a variety of sources besides the sediments in the River, and as a result the PRGs for fish tissue will be used by EPA to assess performance of the selected remedy and source control activities that are meant to address non-sediment sources of contaminants to fish tissue.
- Updated dredge volumes and cost estimates. The remedy in the Proposed Plan was estimated by EPA to cost $305 million. As mentioned above, the Selected Remedy is projected to cost $342 million. The difference looks to be a combination of updated costs related to dredging sediments (EPA is relying on newer data in the ROD as compared to the Proposed Plan), and increased dredge volume.
- Dredging of contaminated shoaled areas in the navigation channel. For those of you not familiar with the river, the middle is a federally-authorized navigation channel. The Army Corps of Engineers periodically dredges this portion of the river to maintain navigation depths. In response to Corps comments on the Proposed Plan, EPA identified areas of the channel that are relatively shallow, so subject to propeller scour from vessels, and included those areas in the areas designated for dredging. The total area is 21 acres, accounting for the increased dredge area as compared to the Proposed Plan (which designated 84 acres to be dredged). This increase in dredge area is a big driver in the $37 million increase in estimated costs.
My Initial Reactions
One of the challenges with the Lower Duwamish is that the risk-based cleanup levels calculated for the site are, in many cases, below the “background” concentrations of those contaminants flowing into the site from upstream (via the Green River) or from lateral inputs such as stormwater runoff. EPA acknowledges this challenge in the ROD, and makes the point in many places that this is a sediment cleanup, with these other sources being better addressed through other statutory regimes, like the Clean Water Act. The issuance of the ROD came with the release of a Memorandum of Agreement between EPA and Ecology that gives EPA lead agency status for implementing the in-water work under the ROD, with Ecology as lead agency for source control activities such as Clean Water Act compliance and enforcement. For many businesses that operate in the Duwamish/Green River watershed, these source control activities have already resulted in more regulatory scrutiny with respect to their operations, and it is likely that these activities will continue to be what most businesses experience as a result of the efforts to clean up the River.
This agreement between Ecology and EPA also provides some information on how the remedy will be implemented, and is worth reviewing for that insight alone. For instance, Ecology and EPA will be closely coordinating source control and in-water work, with the in-water work starting at the upper part of the River and working downstream. The agencies anticipate that a technical impracticability (“TI”) waiver for achievement of water quality requirements would occur, at the earliest, ten years after remedy construction completion. This TI waiver is anticipated because of the issue I discuss above regarding cleanup levels for the site being below background concentrations and potentially not achievable under any scenario. In addition, the agencies will coordinate in the use of all relevant environmental laws to address recontamination risk after construction of the remedy (potentially trying to avoid the recontamination issues already seen in the River), and the agencies are planning on cooperating in developing the Pollutant Loading Assessment for the Green-Duwamish watershed (i.e., evaluating upstream source of contaminants to the Lower Duwamish site).
As I mention above, the Selected Remedy is about what I expected based on the Proposed Plan. But, one of my initial reactions is that the ROD states in more explicit detail how uncertain we are about the actual scope and cost of the remedy. While the ROD may provide a framework for selecting and applying particular remedial technologies, it is important to recognize that the final scope (and cost) of the remedy may be more or less than the estimate put together by EPA in the ROD. This is because much of the data relied upon in making the decisions regarding scope of dredging, capping, and other remedial technologies is more than a decade old, and the sampling density is too low to properly characterize or delineate actual areas to be dredged. EPA acknowledges this point in the ROD, and states that the implemented remedy will involve resampling of all 441 acres of the entire site. It looks like remedial design for this site will be more than the usual engineering considerations, and will instead consist of what is essentially a second, focused, remedial investigation. This potentially massive remedial design effort raises interesting questions with regards to who will perform that work (the LDWG parties were signed up to perform the RI/FS work only) and the timing of that work with respect to remedy implementation. The original RI work took many years of effort, and presumably the remedy design sampling will be similar or greater in scope, so I wouldn’t be surprised if that effort is equal to the work on the original RI in terms of cost and time.
Finally, if you want an overview of the political and community issues in play at this site, it is worth reviewing EPA’s responses to the more than 2,300 comments received on the Proposed Plan. This document highlights the many different views of stakeholders, including businesses, environmental and community organizations, and the tribes that fish in the area.
EPA is in the process of scheduling a series of stakeholder meetings, with the first scheduled for January 6th at noon at Town Hall in Seattle.