By Greg Glass (gglassenviro@comcast.net)
Phase I of the Lower Yard Interim Actions is nearing completion. Chevron convened a stakeholders meeting on March 12th to provide a status update and a description of all of the cleanup activities already performed and the still-pending Phase II activities. I attended along with Frances Murphy on behalf of ECAC (Duane Uusitalo was out of town). Other groups represented included Chevron and its primary cleanup consultant, ARCADIS; Ecology; the Port of Edmonds; the City of Edmonds; and the Washington State Department of Transportation (WASHDOT).
I have continued to visit the site approximately weekly to observe onsite activities. After the record storm and high rainfall period earlier in the year, the last six weeks or so have provided lower-than-normal precipitation and near-optimal winter working conditions.
Almost all of the areas planned for soil excavation have now been addressed, including extensions laterally and vertically to remove contaminated soils as they were observed during the excavations. The primary exception is an area at the far southeast corner of the Lower Yard, close to Willow Creek, where concerns about possible releases to the creek during wet weather excavations led to a decision to defer final excavations there until later this summer during Phase II. A few small areas at the margins of excavation areas along the western site boundary next to Willow Creek will be addressed as part of the planned sediment cleanup activities in Phase II. The extensive areas excavated during Phase I have been backfilled, restoring the Lower Yard to close to original grade.
The excavations planned for the southeast Lower Yard were for three discrete, separated areas, based on the available information from previous site investigations. As things turned out, however, excavations were extended to cover essentially all of the open areas where historic airphotos showed ground disturbance. A few crushed drums and some debris have been uncovered so far; the southernmost portion of the southeast Lower Yard, as noted above, still awaits excavation later this summer. The uncertainties resulting from limited site history information and limited site investigation data for this portion of the Lower Yard have thus been largely resolved through extended soil excavations.
Of the many soil samples collected from the final sidewalls and bottoms of excavation areas, only a handful have exceeded the remedial action criteria for total petroleum hydrocarbons (TPH) or selected multi-ring polynuclear aromatic hydrocarbons (PAHs). One area of note where this occurred is in the central Lower Yard adjacent to the WASHDOT storm drain line along the former site access road. Excavations were limited there because of concerns about damaging the storm drain line. A temporary liner has been placed to isolate the remaining contaminated soils from clean backfill. Chevron will be coordinating with WASHDOT as it reviews options for how to address this remaining contamination.
The total amount of soils excavated and taken offsite during Phase I was reported by ARCADIS to be approximately 140,000 tons. The few small remaining areas to be addressed as part of Phase II may add around 10,000 tons to this total. Considering all of the earlier Lower Yard Interim Actions, as well as the extensive cleanup of the Upper Yard, the total amount of soil removed is around 320,000 tons (!). This required on the order of 10,000 truck trips over all the years of cleanup actions.
As local residents know, great blue herons frequent the marsh. By early March a number of herons had returned to their nesting sites, which happen to be located in the tree line just north of the southeast Lower Yard. Chevron and ARCADIS are coordinating with the resource agencies to determine what timing restrictions, if any, the heron nesting and chick-rearing activities may pose for onsite equipment operations and cleanup actions through the rest of the Lower Yard cleanup.
The final activities for completion of Phase I include installation of a storm drain system throughout the Lower Yard, some final grading to route runoff to the storm drain system, and hydroseeding or otherwise protecting the surface from erosion. Subsurface soil samples will also be collected and analyzed from the southwest Lower Yard areas where excavations occurred in an earlier Interim Action. Those samples will characterize the bottom of the previous excavation; only sidewall samples were collected previously. Chevron has expressed confidence that those subsurface soils will not exceed the current excavation criteria. The sampling results should be available by May. All of these Phase I completion steps should be done within about a month. At that point equipment will be taken offsite - except for the water treatment system – and the site will be in “stand-down” mode until the start of Phase II, which is expected to occur around July or early August. Phase II will include the remaining minor soil excavations and the required cleanup of sediments in Willow Creek along the western boundary of the site, and is expected to be finished around September. ARCADIS is currently obtaining all of the required permits for the proposed cleanup activities in Willow Creek.
The original Interim Action schedule called for additional ground water monitoring wells to be installed in the Lower Yard for two monitoring programs (in the interior of the Lower Yard and along the perimeter of the property) at the end of soil excavations, in the Fall of 2007. Chevron has requested, and Ecology has approved, a delay in the installation of those additional monitoring wells until after the physical cleanup activities in Phase II are completed. WASHDOT was consulted by Ecology and agreed, stating that the overall delay of about one year in starting the ground water monitoring programs will not affect the schedule for the Edmonds Crossing multi-modal transportation hub. This delay will eliminate the potential for damaging the newly-installed wells as heavy equipment continues to traverse the site during completion of the cleanup activities. Ground water conditions will also have more time to stabilize after the large-scale disturbances from soil excavations during cleanup. Well installations should now occur around October 2008.
Chevron will be providing more information to residents on the scope and schedule for Phase II activities as the starting date approaches. The level of onsite activities, and the length of Phase II, will both be smaller than for Phase I. All of the cleanup activities and sampling results will be documented in “As-Built” reports; those reports for Phase I and Phase II are now scheduled for submittal around December 2008 and April 2009, respectively. In addition to making periodic site visits during cleanup, I will be reviewing those As-Built reports and all ground water monitoring data collected after physical cleanup actions are completed.
Soil excavations in the current and previous Interim Actions have been extensive and cover most, but not all, areas of the Lower Yard. To address potential data gaps that could possibly result in some areas of contamination being missed, Chevron will be preparing a plan for any proposed additional site assessment investigations. That plan will be submitted to Ecology in May. I will coordinate with ARCADIS as this plan is being prepared to discuss our views on possible data gaps and additional site investigations to address them. In any event, I will review the plan as submitted to Ecology.
Feel free to contact me via e-mail ( HYPERLINK "mailto:gglassenviro@comcast.net" gglassenviro@comcast.net) if you have comments or questions.
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