TagACC(1531)

Draft memorandum dated 8/6/01 from Ray Hellwig, Director, Washington State Department of Ecology, to Tom Fitzsimmons, Director, recommending approval of a 401 Water Quality Certification for the Port Of Seattle’s Sea-Tac International Airport Third Runway project. Document covers 8,500-foot parallel third runway, Runway Safety Areas (RSAs), South Aviation Support Area (SASA), impacts to approximately 700

In August 2001, GeoSyntec Consultants submitted technical comments to the U.S. Army Corps of Engineers and Washington State Department of Ecology raising serious concerns about the geotechnical safety analyses for the proposed Third Runway expansion at Seattle-Tacoma International Airport. The firm identified multiple flaws in the design work performed by the Port of Seattle's consultants, including underestimation of earthquake risk, incorrect seismic stability analyses, and overestimation of post-earthquake soil stability. GeoSyntec concluded that the Port's consultants had not adequately demonstrated that the embankment fill and retaining wall structures would perform safely under anticipated seismic loads over the facility's lifetime.

A technical review letter from Northwest Hydraulic Consultants, written on behalf of the Airport Communities Coalition, raises serious concerns about the Port of Seattle's Low Flow Analysis related to the proposed 3rd runway at SeaTac Airport. The letter identifies the July 23, 2001 document as incomplete and inconsistent with other project plans, citing missing sections, absent facility drawings, and unresolved questions about how water storage and release systems would function in practice. Key technical issues flagged include inadequate accounting for water transit losses, potentially impractical small-orifice flow controls, and poor calibration of streamflow models for Walker Creek.

This August 2001 letter from Northwest Hydraulic Consultants, submitted on behalf of the Airport Communities Coalition, raises technical concerns about the Port of Seattle's Low Streamflow Analysis for the proposed Sea-Tac Airport third runway project. The letter argues the Port's document is incomplete, inconsistent with the Stormwater Management Plan, and lacks critical design details needed to demonstrate that impacts to low streamflows in Walker, Des Moines, and Miller Creeks will be adequately mitigated. Key issues identified include missing sections in the analysis report, unaddressed impacts from airport expansion activities, conflicting information about proposed storage facilities, and failure to account for water transit losses during dry periods.

Email from Katie Walter (KLW@shanwil.com) to Ann Kenny (Ecology), forwarded to Erik Stockdale, dated August 6, 2001, marked ‘Do not Disclose Deliberative’ (AR 018322, DOE 8/13/01 0251). Discusses outstanding issues in a draft permit or approval for Port Of Seattle wetland mitigation, including mitigation ratios, construction oversight team, web site/CD-ROM for document availability, restrictive covenants

A water resources consultant, writing on behalf of the Airport Communities Coalition, argues that the Port of Seattle's July 2001 Low Flow Analysis for Sea-Tac Airport expansion fails to provide reasonable assurance that the project will meet water quality standards in Miller, Walker, and Des Moines Creeks. The letter criticizes the submission as incomplete and rushed, noting missing figures, unfinished sections, and an unresolved plan to store the required 46 acre-feet of stormwater across the three watersheds. The consultant contends that the Port's proposed water quality protections—including filtration, aeration, and biofiltration swales—are unproven, inadequately designed, and fall short of the regulatory standard required for Section 401/404 permit approval.

A biological scientist hired by the Airport Communities Coalition reviewed the Port of Seattle's plan to store airport stormwater in detention vaults and release it into Miller, Walker, and Des Moines Creeks during summer low-flow periods. The review found that the plan could worsen water quality in those creeks, because stored sediments may release toxic levels of copper and zinc, and potentially harbor human pathogens from airplane wastewater. The scientist concluded that regulators lacked sufficient information to approve the proposal without further testing, modeling, and independent scientific review.

A August 6, 2001 letter from Water Resources Consulting L.L.C. on behalf of the Airport Communities Coalition critiques the Port of Seattle's 'Low Flow Analysis - Flow Impact Offset Facility Proposal' submitted in support of its Section 404/401 permit application for SeaTac Airport expansion. The letter argues that the Port's plan fails to provide reasonable assurance that the airport's stormwater management will meet water quality standards in Miller Creek, Walker Creek, and Des Moines Creek. Key concerns include an incomplete and unfinished proposal, insufficient stormwater storage capacity, unproven water quality treatment methods, and reliance on vague future 'adaptive management' rather than concrete, enforceable designs.

Email from Ann Kenny (Washington State Department of Ecology) dated August 5, 2001, distributing a revised Draft 401 Water Quality Certification for the construction of a Third Runway and related projects at Seattle-Tacoma International Airport (STIA) in the Miller, Walker, and Des Moines Creek watersheds and wetlands in SeaTac and Auburn, King County, Washington. The

Email from Ann Kenny (Washington State Department of Ecology) dated August 5, 2001, circulating a revised Draft 401 Water Quality Certification for the Port Of Seattle’s Third Runway construction at Seattle-Tacoma International Airport (STIA). Recipients include Gordon White, Raymond Hellwig, Erik Stockdale, Kevin Fitzpatrick, John Drabek, Dave Garland, Ching-Pi Wang, Katie Walter, Kelly Whiting, Joan