TagThird Runway(1084)

SEPA Addendum (April 27, 2000) prepared by Port Of Seattle and FAA as addendum to the Final Supplemental Environmental Impact Statement for the Proposed Master Plan Update Development Actions at Seattle-Tacoma International Airport (STIA), and to the SEPA Environmental Checklist for the Auburn Wetland Mitigation Project (August 1998). Documents modification to Master Plan Update wetland

A February 2000 draft memo from environmental consultants Parametrix summarizes testing and monitoring data concluding that stormwater runoff from Seattle-Tacoma International Airport (STIA) does not harm aquatic life in nearby Miller and Des Moines Creeks. Three lines of evidence are presented: whole effluent toxicity tests showing most outfalls are non-toxic, water effect ratio studies demonstrating that creek water significantly reduces copper toxicity, and metals monitoring confirming that copper concentrations in the creeks fell below water quality standards. The one outfall found to be toxic (SDN1) was traced to zinc leaching from galvanized rooftops, with the Port of Seattle pursuing corrective measures.

A February 2000 draft memorandum from Parametrix, Inc. outlines a scope and budget for range-finding Water-Effect Ratio (WER) studies using receiving water from Miller and Des Moines Creeks, intended to help determine whether copper discharge standards at a Port facility could be adjusted through site-specific water quality criteria. The studies involve acute toxicity tests comparing copper-spiked site water to copper-spiked laboratory water, with estimated costs ranging from $2,110 for one site to $2,650 for two sites. Results from earlier 1999 range-finding tests suggested WERs high enough to potentially justify more definitive studies, but new tests without mixing zone assumptions were recommended to better assess achievable permit limits.

Email from Erik Stockdale (Ecology NWRO) to Raymond Hellwig and Tom Luster, dated February 17, 2000, summarizing a February 15 meeting with Jim Kelley of Parametrix regarding public comments on the Sea-Tac Airport third runway project (AR 018438–018440, Exhibit 173). Issues raised by commenters Sarah Cooke and Andy Castelle concerned incorrect wetland mitigation ratio calculations

A February 2000 email from hydraulic consultant Bill Rozeboom argues that the proposed expansion of Sea-Tac Airport's Integrated Wetlands System (IWS) lagoon—tripling its storage capacity—is primarily driven by the airport's Master Plan Improvements, including the proposed third runway, rather than being a routine water quality project. Rozeboom notes that the planned increase in impervious drainage area (roughly 521 additional acres) closely mirrors the proposed increase in IWS storage volume, supporting his conclusion that the third runway is the primary driver of the expansion. He also raises concerns that the environmental documents fail to adequately assess the impact of large-scale out-of-basin water transfers on aquifer recharge and stream base flows in the Miller Creek and Des Moines Creek basins.

A February 2000 draft memorandum from environmental consultants to Keith Smith summarizes efforts to develop a site-specific water quality criterion for copper in Miller, Walker, and Des Moines Creeks near Seattle-Tacoma Airport, in anticipation of stormwater runoff from a proposed third runway. The memo outlines two technical approaches—the Water-Effect Ratio (WER) and the site-specific metals translator—for potentially raising copper discharge permit limits, and describes toxicity screening and range-finding studies conducted in 1999. The phased study approach was designed to avoid unnecessary costs if the WER method proved infeasible or if the Washington Department of Ecology would not permit its use in adjusting permit limits.

A February 2000 internal draft memorandum from environmental consultants to Port of Seattle staff summarizes efforts to develop a site-specific water quality criterion for copper in Miller, Walker, and Des Moines Creeks, in connection with stormwater runoff anticipated from a proposed third runway at Sea-Tac Airport. The memo evaluates two technical approaches—the Water-Effect Ratio (WER) and the site-specific metals translator—for potentially raising copper discharge permit limits, and outlines initial toxicity screening and range-finding study results. It also describes ongoing negotiations with the Washington State Department of Ecology regarding unresolved issues such as mixing zones, AKART requirements, and critical sampling conditions.

Email chain dated February 8, 2000 among Washington State Department of Ecology staff (Roger Nye, Raymond Hellwig, Steve Alexander) regarding fill criteria compliance for the Third Runway at Sea-Tac Airport. Roger Nye describes the 401/404 permit fill acceptance policy developed with Port Of Seattle governing contaminant criteria for borrow sources used in Third Runway construction

Internal forwarded email chain dated January 28, 2000, from Erik Stockdale to Tom Luster (copying Sarah Suggs original), forwarding a SEPA register entry (Ecology File# 200000524, LA File# 00-02) for an Addendum EIS issued by the Port of Seattle as lead agency. The addendum EIS covers Third Runway Wetland Fill and Temporary Construction at Sea-Tac

SEPA Addendum dated January 24, 2000, Port Of Seattle, POS SEPA No. 00-02, addressing modifications to the Master Plan Update Development Actions for the Third Parallel Runway at Seattle-Tacoma International Airport. Addendum covers: (1) increased wetland acreage affected by the project, revised from 12.23 acres to 18.33 acres, with 15.41 acres affected by the runway