U.S. Army Corps of Engineers issues a permit for filling wetlands in connection with Sea-Tac International Airport's third runway on December 13, 2002.

  • By Paula Becker (with research by Daryl McClary and Walt Crowley)
  • Posted 6/24/2003
  • HistoryLink.org Essay 4210
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On December 13, 2002, the United States Army Corps of Engineers issues to the Port of Seattle a Section 404 Permit to begin filling wetlands within the area designated for Seattle-Tacoma (Sea-Tac) International Airport’s third runway. The Port had halted processing of an earlier application after determining that more wetlands were potentially impacted by the project than originally estimated.

A “404 Permit” was issued in compliance with Section 404 of the 1972 federal Clean Water Act regulating the filling of wetlands. Under this Act, the U.S. Army Corps of Engineers is charged with weighing protection for U.S. waters and wetlands against the public benefits of each development proposal. Section 404(b)(1) requires that the Army Corps of Engineers ensure that projects to which it issues permits are the least environmentally damaging of all available options, and, after mitigation, will not significantly degrade affected aquatic ecosystems. The permitting process involves extensive public notice and time for public comment and hearings.

The Port initially applied for both the 404 permit from the Army Corps of Engineers and a 401 permit from the Washington State Department of Ecology in December 1996. The 401 permit refers to Section 401 of the federal Clean Water Act relating to water quality. These two permits were essential for construction of a third runway at Sea-Tac International Airport to proceed.

Mitigation Measures

The Port of Seattle and Federal Aviation Administration issued their draft Environmental Impact Statement for the third runway on April 27, 1995. It proposed a third runway of up to 8,500 feet in length located 1,700 feet west of the existing second runway. This in turn would require the westward extension of the airport plateau atop some 17 million cubic yards of fill dirt secured by retaining walls averaging 74 feet high on the west, 54 feet high on the north, and 27 feet high on the south. The Draft Environmental Impact Statement identified the need to acquire about 400 homes and cited potential effects on nearby Miller Creek and on several acres of wetland habitat.

In September 1998, the Port withdrew both permit requests when it was discovered that the wetlands area involved was more extensive than had been thought originally. The Port had also acquired new properties containing wetlands not assessed in previous environmental studies. The Port resubmitted the updated permit applications in September 1999 but withdrew them again a year later in order to address lingering issues and to provide more time for analysis by permitting agencies.

Public hearings accompanied all steps of the application process. The Airport Communities Coalition, an organization comprising six communities surrounding Sea-Tac International Airport, strongly opposed issuance of both the 401 and 404 permits. Upon the news that the Army Corps of Engineers had issued a 404 permit to the Port, the Airport Communities Coalition immediately filed an appeal in federal court.

In announcing its approval of the 404 permit, Corps district commander Col. Ralph Graves spoke of the need to balance protecting some 20 acres of wetlands with the air-safety concerns which prompted third runway planning. Under the 404 permit the Port was required to restore 80 acres of buffer and wetlands along Miller Creek and 33 acres of buffer and wetlands on Des Moines Creek. In Auburn, the Port had to create 30 acres of new wetlands and restore 34 acres of buffer and wetlands, among many other environmental improvements and investments in the greater Sea-Tac area.

In August 2004, the Airport Communities Coalition dropped its appeals following an adverse State Supreme Court decision. Construction resumed on the third runway, which was completed in 2008 at a cost of more than $1 billion.


“USACE Regulatory Program: Section 404 of the Clean Water Act,” United States Army Corps of Engineers Website (http://hq.usace.army.mil/cepa/pubs/wetland.htm); “Clean Water Act, Section 401 Certification,” under "Wetlands," United States Environmental Protection Agency Website (www.epa.gov/OWOW/wetlands/regs/sec401.html); “Sea-Tac Gets Key Third-Runway Permit, But It’s Quickly Challenged,” The Seattle Times, December 14, 2002; “Port Gets Permit For Third Sea-Tac Runway,” Seattle Post-Intelligencer, December 13, 2002; “Port Withdraws Request For Third Runway,” The Seattle Times, September 29, 2000; “Setback For New Runway: Port Drops Application For Wetlands Permit,” Seattle Post-Intelligencer, September 29, 2000; Larry Lange and Jeffrey M. Barker, "You Know That Third Runway? Sea-Tac's Really Getting It," Seattle Post-Intelligencer, August 20, 2004, p. A-1.
Note: This essay was updated on August 31, 2004, and again on November 20, 2008

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