TagACC(1531)

Technical memorandum dated September 5, 2000 from Elizabeth Leavitt (Port Of Seattle) to Ray Helwig (Washington State Department of Ecology), cc’d to Erik Stockdale, Nancy Groves (Ecology), Jim Kelley and Paul Fendt (Parametrix), Project No. 556-2912-001(03). Addresses CWA Section 401 permit issues for Seattle-Tacoma International Airport Master Plan Update projects involving wetlands and streams. Topics

Draft subsurface conditions data report prepared by HartCrowser for HNTB regarding the Third Runway Embankment at Sea-Tac International Airport, project numbers J-4978-23, -26, -27, and -31. Covers additional field explorations and advanced geotechnical testing including auger borings, standard penetration tests (SPT), Shelby tubes, pocket penetrometer, test pits, piezocone penetrometer probes, cone penetration tests (CPT), and

This September 2000 preliminary design report, prepared by Kennedy/Jenks Consultants for the Port of Seattle, outlines a plan to augment water flow in Des Moines Creek near Seattle-Tacoma International Airport. The report covers facility configuration, process components such as backflow prevention, dechlorination, and aeration systems, as well as an evaluation of chemical dechlorination alternatives. The project was designed to improve creek water quality by treating and releasing water in a controlled manner.

A September 2000 report by Azous Environmental Sciences, commissioned by the Airport Communities Coalition, critically analyzes the Port of Seattle's wetland mitigation plan for the SeaTac Third Runway construction project. The report identifies numerous errors in wetland acreage accounting, inadequate mitigation ratios, and flaws in the proposed compensatory measures, including out-of-basin mitigation that fails to replace lost wetland functions in the affected Miller, Walker, and Des Moines Creek watersheds. The author concludes that the Port's plan falls short of Washington State Department of Ecology standards and the regulatory goal of no net loss of wetland functions.

Reinforced Earth Company (job number 8079, designer MJB, dated 09/01/00) design calculations for Port Of Seattle Sea-Tac International Airport, West Wall 181+25. Document covers internal and external stability analysis for a Mechanically Stabilized Earth (MSE) retaining wall structure including design parameters (select backfill φ=37°, γ=0.140 kcf, Ka=0.24858; random backfill φ=35°, γ=0.140 kcf, Ka=0.27269; foundation φ=35°,

AR017487. Email from Chung K. Yee (Ecology, NWRO Water Quality Program) to Kevin Fitzpatrick dated August 24, 2000, commenting on draft clean fill criteria language for the 401 Certification for the Third Runway at Sea-Tac Airport. Comments address sections E6, E7c.2.(b), E7c.2.(e), and E7c.3, covering inappropriate fill, EPA databases, Confirmed & Suspected Contaminated Sites Report,

Internal email chain from Chung K. Yee to Kevin Fitzpatrick (Supervisor, Industrial Permit Unit, Water Quality Program, NWRO, Washington Department of Ecology) dated August 24, 2000, commenting on draft clean fill criteria language for the 401 Certification for the Third Runway at Sea-Tac Airport. Comments address sections E6, E7c.2(b), E7c.2(e), E7c.2(f), and E7c.3, covering issues

A fisheries biologist assessed the Port of Seattle's plan to use City of Seattle drinking water to boost summer flows in Miller and Des Moines Creeks when levels drop below 1.0 cubic feet per second. The report concludes that chlorine and fluoride in drinking water are toxic to fish and other aquatic life at very low concentrations, and that mixing drinking water into these small streams would far exceed Washington State water quality standards even with dilution. The biologist recommended against the plan and suggested that treated well water from within the local watersheds might be a less harmful alternative.

A fisheries biologist, writing on behalf of the Airport Communities Coalition, assessed the Port of Seattle's plan to use City of Seattle drinking water to boost low summer flows in Miller and Des Moines Creeks near Sea-Tac Airport. The report concludes that the drinking water's chlorine and fluoride content would be highly toxic to fish and other aquatic life, far exceeding Washington State water quality standards even after dilution in the streams. The biologist recommends against the plan and suggests that well water from within the local watersheds may be a less harmful alternative.

Draft memorandum dated August 21, 2000 from Jamie Beaver, Mike Bailey P.E., and Barry Chen P.E. of Hart Crowser, Inc. to Jim Thomson at HNTB (project J-4978-30) providing geotechnical design information for RECo for MSE wall and reinforced embankment fill design for the Third Runway Embankment at Sea-Tac Airport. Document includes minimum factors of safety