TagThird Runway(1092)

A July 1, 1998 memorandum from Parametrix, Inc. summarizes the results of a Reasonable Potential Analysis (RPA) conducted for the Seattle-Tacoma International Airport (STIA) Third Runway project, assessing stormwater runoff quality against water quality criteria for Miller Creek and Des Moines Creek. The analysis found that most pollutant concentrations after treatment with best management practices (BMPs) such as bioswales, sand filters, and wet ponds would meet criteria, with the exception of copper, which remained above acceptable levels. The memo also notes that during storms, pollutant concentrations already present in the receiving waters exceeded criteria and were higher than those predicted from Third Runway stormwater runoff.

A 1998 internal memo from Parametrix, Inc. summarizes the results of a Reasonable Potential Analysis (RPA) conducted for the Seattle-Tacoma International Airport (STIA) Third Runway project, assessing whether stormwater runoff from the new runway could exceed water quality criteria in Miller Creek and Des Moines Creek. The analysis found that most pollutant concentrations after treatment with best management practices (BMPs) such as bioswales, sand filters, and wet ponds would meet criteria, with the exception of copper, which remained above acceptable levels. The memo also notes that existing pollutant concentrations in the receiving waterways during storms already exceeded criteria, even before accounting for Third Runway runoff.

Draft Stormwater Quality Management Plan (Appendix F) prepared by Parametrix, Inc. for Port Of Seattle, July 1998, as part of the Preliminary Comprehensive Stormwater Management Plan for Sea-Tac Airport Master Plan Improvements. Covers existing drainage conditions including Storm Drain System (SDS) and Industrial Waste System (IWS), Miller Creek and Des Moines Creek receiving systems, existing

A July 1, 1998 internal email from Ken Ludwa to Paul Fendt outlines preliminary cost estimates for a StormFilter stormwater treatment system, based on a discussion with a VP of Stormwater Management. A 100 cfs system handling approximately 4,700 cartridges would cost roughly $2.3 million to design and build, while an 80 cfs system would cost approximately $1.8 million to build with $150,000 annually for cartridge replacement. Cartridge costs vary depending on total suspended solids (TSS) levels and rainfall, as cartridges are replaced on an as-needed basis.

A June 30, 1998 email from John Rogers of CH2M to Thomas Hubbard and Ken Ludwa provides a website link (www.stormwatermgt.com) for a compost filter vendor, noting the company had recently changed its name. Rogers mentions that the vendor would be sending additional product information by overnight mail and water quality data by fax the following day. The correspondence relates to stormwater management and water filtration research being conducted in connection with Port of Seattle operations.

A June 1998 internal email from Ken Ludwa to Jim Kelley includes spreadsheet data comparing removal efficiency percentages for various pollutants—including solids, phosphorus, nitrogen, BOD, iron, lead, zinc, copper, bacteria, and total petroleum hydrocarbons—across multiple published studies from the 1980s and 1990s. The tables compile findings from sources such as Marselek et al. (1996), Metro (1992), and the UW Short Course, and conclude with recommended removal efficiency values for each pollutant category. This document appears to relate to Best Management Practices (BMPs) for stormwater treatment, likely in the context of environmental review for airport-related runoff management.

Port Of Seattle response to public and agency comments on Army Corps of Engineers Public Notice Permit Reference No. 96-4-02325 for Master Plan Development Actions at Seattle-Tacoma International Airport. AR035118/AR035119. Addresses six major concerns: EPA/COE MOA wetland impact sequencing and compensatory mitigation; justification for out-of-watershed mitigation (Auburn wetland) for wildlife habitat; South Aviation Support Area

A 1998 letter from Fisheries Consultants to the U.S. Army Corps of Engineers concludes that SeaTac Airport's proposed Third Runway will have an overall neutral effect on aquatic habitat and fish populations in Miller Creek. Minor benefits are expected from new storm flow detention facilities, which will reduce peak flood flows by 5–20%, and from a planned 100-foot-wide stream buffer created through residential buyouts along the creek. Adverse impacts are limited to the temporary disruption of a quarter-mile creek relocation and an approximate 8% reduction in late-summer low stream flows due to increased paved surfaces and wetland fill.

Comment Binder A compiled by Port of Seattle for Sea-Tac Airport (Seattle-Tacoma International Airport) third runway project, containing letters submitted to the U.S. Army Corps of Engineers during the initial comment period (December 19, 1997 to January 20, 1998) and comments from the joint Corps/Ecology public hearing held April 9, 1998. Includes a January 15,