TagThomas/Lane(5)

A April 1997 memo and progress report from Hellmuth, Obata + Kassabaum, Inc. (HOK) summarizes the near-complete Sea-Tac Area Mitigation Study, which assessed environmental, traffic, and socio-economic impacts related to Sea-Tac Airport. The memo outlines scheduling recommendations for a series of public and stakeholder meetings planned for May 1997 in Burien, Washington, including suggestions to consolidate citizen meetings and limit City Council sessions. As of the report date, all major project tasks were at 100% completion except the Mitigation Plan, which stood at 99%, with the consultant team preparing to present final findings to the community.

This 1997 draft study assessed the potential environmental, transportation, and socioeconomic impacts of a proposed third runway at Seattle-Tacoma International Airport on five neighboring communities—Burien, Des Moines, Federal Way, Normandy Park, and Tukwila—as well as the Highline School District and Highline Community Hospital District. Funded by a Washington State grant administered through the City of Burien, the study was conducted by a team of consultants and aimed to develop mitigation strategies and funding mechanisms to address impacts on affected jurisdictions. The report reviewed the Port of Seattle's Environmental Impact Statement and proposed independent mitigation measures, while expressly prohibited from being used to oppose the runway's construction.

This document outlines a Neighborhood Impact Matrices framework used to assess environmental, transportation, and socio-economic effects of a proposed airport-related project on communities surrounding Seattle-Tacoma International Airport, including cities such as Burien, Des Moines, Federal Way, Normandy Park, and Tukwila. Each matrix evaluates impacts across four columns — Measure, Impact, Mitigation, and Cost — covering issues such as aircraft noise (DNL and SEL contours), air quality, surface and groundwater quality, wetlands, and floodplains. Proposed mitigations range from neighborhood buyouts at $760,000 per acre for areas within the 65 DNL contour to easement and insulation programs, stormwater management plans, and flight track modifications.