Over the next two months starting Wednesday, March 6, small sections of Gas Works Park will be closed to the public as environmental crews continue an ongoing investigation of sources of contamination along the park on Lake Union.
The State Department of Ecology (Ecology) oversees the work under a March 2006 legal agreement between Ecology, the City of Seattle and Puget Sound Energy (PSE). The soil and groundwater study will help in the cleanup of contaminated lake sediments by gathering information on the effect of underground contamination from the upland (on-shore) area on sediment (lake bottom mud) in Lake Union.
Details on this project and other cleanup work at Gas Works Park are available on Ecology’s website at https://fortress.wa.gov/ecy/publications/SummaryPages/1309163.html.
Contractors hired by PSE will perform soil borings and install monitoring wells to study soil and groundwater conditions 10 to 50 feet below the ground surface. Preliminary field activities have begun and drilling activities are scheduled to begin on March 18, 2013.
Park users can expect to see track-mounted drilling rigs that will push probes into the ground in up to 80 locations in the park. A 50-foot area around each drilling location will be closed to the public while drilling takes place, then reopened. An area for staging equipment will be signed and fenced.
A half acre field just north of the park’s Play Barn will remain closed to the public until late spring to allow new turf grass to take root.
Once the sampling and monitoring work is completed, the results will be analyzed and incorporated into a Draft Remedial Investigation/Feasibility Study Report (RI/FS). The RI/FS will describe the findings and outline potential cleanup options, and will be available for public review and comment.
BackgroundGas Works Park is a 20-acre park located at the north end of Lake Union. From the early 1900s until 1956, gas companies operated a plant at the site that converted coal and oil into manufactured gas. A tar refinery also operated at the site, refining materials obtained as a byproduct of the gas manufacturing process and producing tar-based coal products.
The Park underwent an environmental cleanup in 2000-01 and in 2005, when most of the park was covered with two feet of clean topsoil placed over a protective barrier. The historic gasification plant metal structures were preserved in place. And groundwater remediation was conducted from 2001 through 2006.
Investigation of the sediments offshore of the park in Lake Union has indicated the presence of contaminants. The upcoming work includes evaluation of the upland areas for impacts on the sediments. The results of the work will identify the nature and extent of impacted soil, groundwater and sediment and help identify potential cleanup solutions.