TagSAMP(650)

This document is a First Amendment to an Interlocal Agreement between the cities of Burien, Des Moines, Normandy Park, and SeaTac for the environmental review of the Sea-Tac Airport Sustainable Airport Master Plan (SAMP), originally dated March 6, 2018. The amendment updates Paragraph 7 to clarify that contract management responsibilities — including consultant oversight, invoice coordination, and meeting arrangements — shall be administered by the City of Des Moines. All other terms of the original agreement remain unchanged, and the amendment was signed by authorized representatives of all four cities in 2020.

This document explains the fundamentals of aircraft noise at Seattle-Tacoma International Airport, covering how sound is measured in decibels and A-weighted decibels (dBA) to reflect human hearing sensitivity. It describes how outdoor sound levels decrease with distance due to wave spreading and atmospheric absorption, with noise typically dropping 6 dB each time the distance from the source doubles. A comparative chart of common indoor and outdoor noise levels is included to help put aircraft noise levels in everyday context.

Chapter 6 of SeaTac's Envision SeaTac 2044 Comprehensive Plan outlines the city's Economic Vitality Element, describing SeaTac's vision for growth through 2044 as a major regional job center anchored by Seattle-Tacoma International Airport, which accounts for nearly 25,000 of the city's approximately 43,000 jobs. The plan sets goals around supporting local businesses, diversifying the economy, improving public infrastructure, and enhancing the visitor experience through transit-oriented development and placemaking investments. While focused on economic development rather than noise policy specifically, it references airport expansion under the Sustainable Airport Master Plan (SAMP) as a key driver of future employment and business growth.