Seattle's Sound Transit is responsible for planning, building, and operating the area's regional transit systems and services, thus improving mobility for the citizens and visitors of the Central Puget Sound. One facet of the complex system is the Link Light Rail, which will serve as a vital link between downtown Seattle, southeast Seattle, Seattle-Tacoma International Airport, and other important parts of the city. An estimated 1.6 miles of the light rail, which opened in August 2003, already connects downtown Tacoma with the new Tacoma Dome Station, while other major lines are currently being constructed.
Since 2002, CDM has provided environmental support services during construction of the new light rail from downtown and the airport. Construction spans an estimated 15 miles of a mix of underground, at-grade, and above-grade alignment, and includes construction of an operation and maintenance facility, replacement of existing utilities under the alignment, replacement of impacted roads, and installation of approximately 13 stations.
Services include remediation oversight, inspection, and documentation of underground storage tank and oil-water separator removals. The project also includes stormwater monitoring, inspections of temporary erosion and sediment control best management practices, hazardous materials abatement, oversight of contaminated soil and groundwater remediation, and assistance with stabilizing lead-contaminated soil. For example, the operations and maintenance facility is constructed over the top of an old landfill, and CDM provided assistance in remediating the most contaminated portion-one that contained high levels of leachable lead and petroleum hydrocarbons.