Underground utility exploration, depiction, and planning at Seattle-Tacoma International Airport

Over the next 15 years, the Port of Seattle plans to complete modernization of Seattle-Tacoma International Airport (Sea-Tac), construct a third runway, and add a new terminal, rental car facility, roadways, and other improvements to expand the airport’s capacity from 28 million to 60 million air passengers per year. Since opening in 1942 the airport has gone through a series of expansions and modifications: tenants have moved; concourses and satellites were added; runways were expanded; and underground utilities were installed, expanded, used and abandoned as needs changed. The utility records were filed by year on a project-by-project basis, without the benefit of comprehensive utility system mapping. To gain better control of its utility records, the Port of Seattle recently initiated a project that collated available underground utility information into a single mapping model that can be used for future planning and development of the airport. This paper describes the process applied to create the model and concepts from subsurface utility engineering that were introduced.