TagEcology(788)

Email chain (Exhibit 2061, AR031718-AR031720) dated February 26, 2001, from Jerald LaVassar (Ecology Dam Safety Office) to Ann Kenny (Ecology), responding to Andrea Grad (Helsell law firm, representing ACC/Airport Communities Coalition). LaVassar explains why the Mechanically Stabilized Earth (MSE) wall at Sea-Tac Airport’s third runway project does not qualify as a dam under WAC 173-175-020,

Letter dated February 22, 2001 from Pam Bissonnette, Director, King County Department of Natural Resources, to Ann Kenny, Senior Permit Specialist, Washington State Department of Ecology Northwest Regional Office, regarding King County’s technical review of the Port Of Seattle’s Comprehensive Stormwater Management Plan (SMP) for Master Plan Improvements at SeaTac International Airport. The letter references

Letter dated February 22, 2001 from Pam Bissonnette, Director of King County Department of Natural Resources, to Ann Kenny, Senior Permit Specialist at Washington State Department of Ecology (DOE) Northwest Regional Office, regarding King County’s technical review of the Port Of Seattle’s Comprehensive Stormwater Management Plan (SMP) for Master Plan Improvements at SeaTac International Airport.

In February 2001, GeoSyntec Consultants submitted a technical review letter to the U.S. Army Corps of Engineers and Washington State Department of Ecology on behalf of the Airport Communities Coalition, raising serious concerns about the proposed Third Runway expansion at Seattle-Tacoma International Airport. The letter identified significant deficiencies in the geotechnical investigation, analysis, and design of the planned embankment fill and West Mechanically Stabilized Earth (MSE) Wall, warning that the project's foundations involved weak peat and liquefiable sands in a highly seismic area. GeoSyntec concluded that the available data was insufficient to confirm the safety of what would be the tallest MSE wall in the world, and that approval should not be granted without a more thorough geotechnical review.

A February 2001 technical review letter from Northwest Hydraulic Consultants, submitted on behalf of the Airport Communities Coalition, raises serious concerns about the stormwater management plans for Seattle-Tacoma International Airport's proposed third runway expansion. The review identifies multiple technical deficiencies in the project's hydrology and drainage designs, warning that they could cause significant adverse impacts to local streams and wetlands, particularly Miller Creek and Des Moines Creek. The letter also criticizes the lack of clearly defined stormwater control standards, absence of independent design review processes, and failure to provide financial guarantees for implementing the stormwater management plan.

In February 2001, Northwest Hydraulic Consultants submitted technical review comments to the U.S. Army Corps of Engineers and Washington State Department of Ecology on behalf of the Airport Communities Coalition, raising concerns about the stormwater management plan for the proposed third runway at Seattle-Tacoma International Airport. The letter identified multiple deficiencies, including dam safety issues, vault structures that violated King County depth requirements, inadequate methods for assessing standing open water durations, and insufficient erosion and sediment control planning. These issues, the consultants warned, could pose risks to both structural safety and safe airport operations if not addressed prior to project approval.

Handwritten notes from an Ecology informational meeting with Erik and Ann dated February 14, 2001 (AR 018355-018357). Topics include stormwater plan analysis from Kelly Whiting and John Drybeck (water quality staff), Vasen Farm farmed wetland ratios (1:1 in-basin acreage, 2:1 out-of-basin replacement), enforcement vs. restoration, prior converted designation, Corps of Engineers wetland determinations, 509 overpass,

A declaration by geologist John J. Strunk of Associated Earth Sciences, Inc. (AESI) submitted to Washington State's Pollution Control Hearings Board describes groundwater contamination studies conducted at Seattle-Tacoma International Airport (Sea-Tac) in connection with the proposed Third Runway project. The studies found that while contamination exists in shallow groundwater zones within the Airport's Aircraft Operations and Maintenance Area (AOMA), it is isolated and located approximately 2,800 feet from the Third Runway site, with water flow predominantly directed away from that area. AESI concluded that subsurface utility lines do not appear to be a significant pathway for contaminant migration toward the Third Runway construction zone.

WAC 173-340-740 from the Model Toxics Control Act (MTCA) Cleanup Regulation, published February 12, 2001, establishing unrestricted land use soil cleanup standards. Covers Method A, Method B (standard and modified), and petroleum mixture cleanup levels including Equations 740-1 through 740-3 for noncarcinogens and carcinogens. Specifies default exposure parameters: soil ingestion rate 200 mg/day, average body

This Washington State regulation (WAC 173-340-747) establishes methods for determining safe soil contamination levels that protect groundwater quality at cleanup sites. It outlines several scientific approaches, including three-phase and four-phase partitioning models, leaching tests, and empirical demonstrations, to calculate the maximum allowable concentration of hazardous substances in soil before they risk contaminating groundwater. The regulation requires that soil concentrations not cause groundwater cleanup level exceedances and not result in the buildup of nonaqueous phase liquids in or on groundwater.