PCHB09016647

401 Certification of the Third Runway construction project and related projects at the Seattle- Tacoma International Airport (STIA). My testimony will focus on the likelihood that ground water contamination at various sites at STIA will migrate to the Third Runway project area via preferential pathways. 2. It is my opinion that multiple lines of evidence indicate that the existing ground water contamination is contained to areas of the major release sites near the STIA aircraft operations and maintenance area (AOMA) and will not migrate to the Third Runway project area via perched groundwater zones, regional groundwater aquifers, utility trenches or via any other mechanisms. It is also my opinion that construction dewatering activities associated with subgrade improvements at the Third Runway project area will not alter the fate and transport of ground water contaminants at the AOMA area. Supporting conclusions for my opinion include: • The major contamination source areas are located over one-half mile (2800 feet) from the Third Runway project area and this distance provides a more than adequate buffer. • Ground water contamination is contained within the AOMA, the area of the airport where most aircraft fueling and maintenance operations have been performed. Extensive environmental investigations have been performed in the AOMA to define the nature and extent of soil and ground water contamination. • The environmental data does not support the allegation by the appellants that contaminated ground water is migrating preferentially within backfill of subsurface utility lines such that it would impact the Third Runway…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]