This WSDOT discussion document from November 2021 shows a planning map for the SR 509 Puget Sound Gateway Program's new expressway project, spanning from 24th Ave S to S 188th St near Des Moines Creek Park in the City of SeaTac. The map highlights the proposed highway alignment (shown in red) running adjacent to Des Moines Creek Trail Park, identifying wetland areas, contour elevations, and nearby features such as an Amazon warehouse and the Lake to Sound Trail. The project represents a major infrastructure expansion in the SeaTac area that would affect the Des Moines Creek Park corridor and surrounding natural resources.Open full document
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A WSDOT Puget Sound Gateway Program discussion map showing the proposed SR 509 new expressway project near Des Moines Creek Park in the City of SeaTac. The map depicts the project alignment, wetland areas, Des Moines Creek Trail, and surrounding features including an Amazon warehouse and existing roadways. The document is marked ‘For Discussion Purposes Only’ and dated November 4, 2021.