Sea-Tac International Airport: Third Runway Project

  • By Walt Crowley (with research by Daryl McClary and Paula Becker)
  • Posted 6/21/2003
  • Essay 4211
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The development of a third "dependent" runway at Seattle-Tacoma (Sea-Tac) International Airport, the state's largest airport, was one of the largest and most sensitive public works projects in regional history. The need for an additional runway for bad-weather operations was first recognized in 1988 when the Port of Seattle (which owns and operates the airport), the Federal Aviation Administration, and regional planners predicted that the airport could reach its maximum efficient capacity as early as 2000. The Puget Sound Regional Council and Port of Seattle launched a "Flight Plan" study in 1989 to determine how best to meet regional airport needs, and the Washington State Air Transportation Commission later examined the problem from a statewide perspective. After a public involvement program of unprecedented scale, regional planners ultimately concluded that development of a new regional airport and other alternatives were infeasible and that the addition of a third runway at Sea-Tac was the only viable solution to meeting regional air service needs. The Port formally launched the project in 1992, but encountered substantial opposition from cities and communities neighboring the airport, which won a two-year state moratorium on the runway and challenged necessary environmental permits. As a result, the runway's completion date slipped from 2000 to 2008, and its cost rose from a preliminary estimate of $217 million to more than $1 billion. It opened on November 20, 2008.

Landing at Bow Lake

On March 7, 1942, three months after Japan attacked Pearl Harbor, the Port of Seattle undertook development of Seattle-Tacoma International Airport at the urging of the federal government. A new airport was desperately needed to help relieve pressure on Seattle’s Boeing Field and Tacoma’s McChord Field, which were commandeered for warplane production and military use in World War II. After rejecting a site on the Sammamish Plateau as unsafe, the Port chose a sparsely populated plateau near Bow Lake, roughly midway between Seattle and Tacoma.

Sea-Tac’s first runway was completed in 1944 at a final cost of $4.2 million (covered by the federal government), and limited civilian operations began in 1947. The airport’s first permanent terminal and administration building was dedicated by Governor Arthur Langlie (1900-1966) on July 9, 1949.

Although hailed as the "state of the art" of airport design at the time, Sea-Tac was quickly overtaken by technological change and air-traffic growth in the 1950s. The first modern jetliner, the Boeing 707, born in Seattle in 1954, could not land at Sea-Tac until the airport’s main runway was lengthened to 8,500 feet in 1956 (it now stretches nearly 12,000 feet).

Catching Up With the Jet Age

In anticipation of new generations of faster and larger jetliners such as a planned supersonic transport and the Boeing 747 Jumbo Jet, the Port undertook a major construction program in 1968 to expand the terminal and add a second runway parallel to and 800 feet west of the first. This narrow separation would later create major problems because it prevents the simultaneous use of both runways when fog or low clouds limit visibility, which occurs about 44 percent of the year at Sea-Tac.

As the national and regional economy recovered from the "Boeing Bust" recession of the early 1970s, air traffic at Sea-Tac began to climb at double-digit rates. Complaints over growing aircraft noise led to Sea-Tac’s first noise abatement and environmental mitigation programs in 1973 to relocate affected residents or to sound-proof affected structures. The Port later joined with local cities and governments in preparing an award-winning "Sea-Tac Communities Plan" to limit and offset airport impacts on neighboring areas.

Commercial air traffic at Sea-Tac took a steep dive after the federal government deregulated airlines in 1978, but the industry reorganized in the 1980s and airport use began to soar anew as Sea-Tac became a central “hub” for airline service between the Pacific Rim and the nation. The Port of Seattle responded in 1985 to local concerns with one of the nation’s most ambitious noise reduction programs, costing $140 million, and later limited flights by older, louder "Stage 2" aircraft during evening hours.

Racing Against Time

In the late 1980s, planners at the Port of Seattle, the Federal Aviation Administration (FAA), and the Puget Sound Council of Governments (which reorganized as the Puget Sound Regional Council [PSRC] in 1991) took a fresh look at Sea-Tac’s air traffic trends as part of the process of updating the Regional Airport System Plan (RASP) for Puget Sound. Extrapolating recent rates of air-traffic growth, they predicted that Sea-Tac could reach its maximum efficient capacity of 380,000 annual “operations” (takeoffs and landings) with no more than a five minute average delay as early as the year 2000.

As operations exceeded this capacity measure, bad-weather delays would begin to increase dramatically, costing airlines and passengers millions of dollars annually as well as causing major inconvenience and logistical problems. The prospect of chronic delays also raised the risk that airlines might shift their hubs to other West Coast airports and thereby reduce Puget Sound’s direct connections with the Pacific Rim and the rest of the world. Thus, Sea-Tac’s physical limitations in handling projected growth in air traffic were an issue of regional and statewide importance.

Given the amount of time required for major airport development projects, this forecast sounded regional alarm bells. At the same time, the Port Commission and other local officials recognized that undertaking a major Sea-Tac expansion or construction of a major new airport demanded a regional discussion and, they hoped, consensus.

All Options on the Table

On this basis, the Port and regional Council of Governments agreed on May 23, 1989, to empanel an independent and broadly representative 39-member Puget Sound Air Transportation Committee (PSATC) to lead a thorough review of all of the options for meeting Puget Sound’s airport needs through 2020. The process was dubbed “Flight Plan” and $693,000 was budgeted for an unprecedented program of public outreach, citizen participation, and technical analysis.

Guided by its citizen chair, Eastside developer Bob Wallace, PSATC implemented an extensive program including 26 public working sessions, six open houses, and four public hearings (not counting 11 public hearings conducted by the Port Commission during the same period). The committee began with a full menu of options including:

  • Construction of a second major regional airport in the Puget Sound region;
  • Development of one or more “supplemental airports” in the region;
  • Commercial airline use of existing runways at Snohomish County's Paine Field in Everett, Tacoma’s McChord Air Force Base, and an existing general aviation airport in Arlington;
  • Diversion of Sea-Tac’s air cargo, private plane traffic, and regional commuter flights to other airports;
  • Development of high-speed interurban rail service to reduce intraregional air traffic;
  • Linking the large Moses Lake airport (used chiefly for Boeing training and military flights) in Eastern Washington to Puget Sound via a fast "bullet train" line through the Cascades;
  • New operational and "demand management" approaches to improve Sea-Tac’s efficiency;
  • Expansion of Sea-Tac with a new "dependent" runway for foul weather operations; or
  • Some combination of these approaches.

Ironically, in light of future controversy, the attendees at the first Flight Plan public hearings loudly endorsed expansion of Sea-Tac, and communities near alternative airports such as Paine Field quickly rallied opposition to their increased use. In 1990, not long after the Flight Plan process began, the Washington State Legislature mandated the Air Transportation Commission (AIRTRAC) to examine the issue from a statewide perspective. It would review many of the same options identified by PSATC (and reach similar conclusions), with special attention to the idea of linking Sea-Tac with an existing Moses Lake airfield via a high-speed rail line through Stampede Pass.

Advise and Dissent

In its Draft Report and its detailed Environmental Impact Statement (EIS), both published on January 7, 1992, the PSATC concluded that the region’s future air service needs could be met best by the addition of a third "dependent" runway for use during bad weather at Sea-Tac, commercial airline use of Paine Field, and pursuit of existing or new sites for a future "supplemental" airport in Pierce or Thurston Counties. (An Environmental Impact Statement is a detailed analysis of the likely effects of a proposed plan or project, including reasonable alternatives, on the natural and social environment. The federal requirement for EIS preparation was established by the National Environmental Policy Act of 1970, which has since been emulated by most states and local governments. The findings of an EIS do not necessarily dictate final policy decisions, but the "adequacy" of its analysis can be challenged by opponents in court to delay and/or modify a project.)

Citizens and local officials from areas neighboring both Paine Field and Sea-Tac criticized the Flight Plan findings. In the Sea-Tac area, the cities of Normandy Park and Des Moines, Highline Community College, and Highline Hospital organized an ad hoc Regional Commission on Airport Affairs (RCAA) and hired environmental attorney Richard Aramburu to challenge the third runway plan. Also that year, the State Legislature imposed a two-year moratorium on new runway construction at Sea-Tac and other Puget Sound airports pending the findings of AIRTRAC.

On June 17, 1992, after several public hearings, PSATC voted 29 to 6 to approve its final report without major changes, and dissolved. The PSRC published the final Flight Plan EIS on October 6.

Outreach and Backlash

Based on this policy framework, on November 3, 1992, the Port of Seattle Commission unanimously approved Resolution 3125, which authorized a "Master Plan Update" for Sea-Tac and preparation of a new Environmental Impact Statement for its expansion. This represented the Port’s formal commitment to planning for a third runway, then estimated to cost $217 million.

Sensitive to local concerns engendered by the concept of a third runway at Sea-Tac, the Port launched a new public information and involvement program, including an ongoing "Sea-Tac University" to engage citizens in detailed discussion of airport plans. The Port also invited third-runway critics from the Regional Commission on Airport Affairs and newly formed Airport Communities Coalition (ACC) to join planners and officials on a special Technical Advisory Committee.

These overtures did not mollify third-runway foes. New opposition groups, Citizens Against Sea-Tac Expansion (CASE) and Washington Alliance of Taxpayers and Travelers (WATT) were organized. The Highline School District and cities of Burien, Federal Way, and Tukwila joined the anti-runway coalition. The new City of SeaTac, which incorporated in 1990, negotiated its own interlocal agreement with the Port in September 1997 to minimize and mitigate airport impacts, and Des Moines withdrew from the Airport Communities Coalition in a controversial City Council vote in late 2002 after spending $5 million to fight the runway.

On April 29, 1993, an 89 percent majority of the Puget Sound Regional Council’s General Assembly voted to adopt resolution A-93-03, which affirmed "that the region should vigorously pursue, as the preferred alternative, a major supplemental airport and a third runway at Sea-Tac" subject to PSRC’s final approval by April 1, 1996. The resolution made the final decision contingent upon reviews by up to three Expert Arbitration Panels to be appointed by the Secretary of the Washington State Department of Transportation (WSDOT). A panel was appointed to examine the ability to expand Sea-Tac’s effective capacity through better “demand and system management,” but it never met because this option was soon found to be inadequate to meet air travel needs. The other panel focused on the effectiveness of Sea-Tac’s noise mitigation programs.

The subsequent quest for a supplemental airport site pared down an initial list of 41 candidates to 19 and then to 12 before concluding there were no viable sites in the region. This conclusion was affirmed on October 27, 1994, with PSRC Executive Board Resolution EB-94-01. A related study found in July 1996 that improved "demand and system management" of existing Sea-Tac's facilities also could not effectively absorb its projected air traffic growth.

Meanwhile, the State’s AIRTRAC submitted its final report a year ahead of schedule in November 1993. It also could not find ready alternatives to Sea-Tac expansion, but added that "the third [Sea-Tac] runway alone does not solve the region's long-term capacity problem." Regardless, the moratorium on Sea-Tac’s expansion expired and the Legislature rebuffed proposals to curtail the Port Commission’s authority or to interfere with its airport planning. (Interestingly, AIRTRAC staff director Kenneth Reid took the helm of the anti-runway Airport Communities Coalition in January 1995.)

Moving Mountains

The Port of Seattle and Federal Aviation Administration issued their draft Environmental Impact Statement for the third-runway project on April 27, 1995. It proposed a new runway of up to 8,500 feet in length located 1,700 feet west of the existing second landing strip. This would require the westward extension of the airport plateau atop some 17 million cubic yards of fill dirt, to be secured on the north, south, and west by retaining walls averaging between 27 and 74 feet. The Draft EIS identified the need to acquire about 400 homes and cited potential effects on nearby creeks and wetlands. Among other mitigation measures, it proposed to restore about 80 acres of wetland habitat and buffer land along Miller Creek, 30 acres along Des Moines Creek, and 34 acres along Green River in Auburn, augmented by the creation of 30 acres of new wetland.

Under this plan, the Port proposed to restore or create five acres of habitat for each single acre potentially affected by the expansion. Despite the project’s scale, the EIS concluded that all of its construction and operational impacts could be reduced or compensated for with sensitive design and development of replacement wetlands. The cost estimate for the runway now penciled out at $430 million, excluding other airport and terminal improvements, to be financed by federal aid, the airlines, and fees -- not by new or higher taxes.

After extensive public comment, the Port and FAA published a final EIS, numbering 5,500 pages in seven volumes, on February 1, 1996. The following month, the Expert Arbitration Panel on noise abatement issued its report. While praising the Port’s "impressive array" of noise mitigation efforts, a two-member majority wrote on March 27 that Sea-Tac had “not shown a reduction in real on-the-ground noise impacts sufficient to satisfy the noise-reduction condition” set by PSRC Resolution A-93-03.

Runway opponents predicted the project’s demise. WATT spokesperson Susanne Albright declared, "It’s a big win for us," and Airport Communities Coalition attorney Peter Kirsch warned, "It would be the height of audacity for the Port to even attempt to move forward at this point." State Secretary of Transportation Sid Morrison (b. 1933) agreed that it was "a setback for the third runway," but the Port took heart in the panel’s overall praise of its noise program. Aviation Division director Gina Marie Lindsey observed, "They have already said we are the best there is, that we’re doing a terrific job. The issue ... is whether that’s enough or not" (The Seattle Times, March 28, 1996).

Holding Patterns

In response to the Expert Panel findings, the Regional Council concluded that the Port could do more to reduce noise but that its record to date was not a fatal flaw for the runway project. With passage of Resolution A-96-02 on July 11, 1996, the PSRC gave the third-runway project its official blessing by formally adding it to the federally mandated Regional Transportation Plan. At the same time, it imposed new noise abatement standards on Sea-Tac.

The Port Commission accepted these conditions with passage of Resolution 3212 on August 1, 1996, and officially adopted its Sea-Tac Master Plan Update. This moved the runway closer to reality by authorizing detailed planning and engineering, acquisition of needed properties, and preparation of applications for environmental permits from local, state, and federal agencies.

The Port promptly undertook an aggressive "Acquisition Communications" program to contact owners and residents of properties it needed to purchase on the airport’s fringes. It held 35 community meetings, established an independent ombudsman program, and went door to door to inform affected property owners, residents, and businesses through 1999.

Meanwhile, the acceleration in actual air-traffic growth at Sea-Tac and other issues related to third runway development led the FAA and Port to announce on December 27, 1996, that they would prepare a Supplemental Environmental Impact Statement (SEIS) to revisit and refine earlier analyses. The Final SEIS was issued on May 13, 1997, following public comment, and the Port Commission adopted Resolution 3245 two weeks later to reaffirm its Sea-Tac expansion plan.

The FAA issued a "record of decision" on July 3, 1997, finding that the project posed no insurmountable environmental challenges. That same year, Sea-Tac operations reached 385,000 takeoffs and landings, exceeding its maximum efficient capacity three years ahead of initial projections.

The Permit Phase

Simultaneously in 1997 and in response to PSRC conditions, the Port launched a new “Part 150 Noise Exposure and Land Use Study” under FAA regulations. The Port’s three-year effort far exceeded requirements for citizen involvement and was approved in 2000. In a related initiative dubbed "Sound Environment for Education," the Port and federal government ultimately agreed to pay half of a 10-year, $200 million noise insulation and mitigation program for the Highline School District, with the State of Washington and Highline district splitting the balance. The latter’s contribution was financed by passage of a new school levy in 2002, although the district remained an official opponent of the third runway.

Meanwhile, the Port began preparing applications for a crucial "401" water quality permit from Washington State Department of Ecology (WSDOE) and a “404” permit from the U.S. Army Corps of Engineers to allow filling wetlands. Both processes created new opportunities for administrative appeals and legal challenges by Sea-Tac expansion opponents. (The numerical designations of these permits derive from sections of the Federal Clean Water Act.)

The Port filed its first applications in December 1996, and the first of many public hearings were convened in April 1998. The Port soon recognized that the third-runway project would affect more wetlands than initially anticipated and requested that state and federal authorities halt their reviews. The Port submitted revised applications one year later, but withdrew them in September 2000 to address remaining technical issues.

The Port reapplied the following month, and Washington State Department of Ecology and the Corps of Engineers convened joint public hearings on January 26 and 27, 2001. The State approved the Port’s 401 permit in August of that year, but project opponents promptly appealed to the Washington State Pollution Control Hearings Board.

Clear Skies Ahead?

The Hearings Board ultimately approved the permit on August 12, 2002, but added 16 additional conditions, which proved too onerous for both the Port and State Department of Ecology. They, and runway opponents, filed various appeals to the Board’s rulings. The Port and the state Department of Ecology objected in particular to the Board’s imposition of unprecedented testing standards related to contaminants in needed fill dirt. The State Legislature overruled this condition in April 2003.

On December 13, 2002, the U.S. Army Corps of Engineers issued its 404 permit, directing the Port to restore or preserve 14 acres of wetlands, enhance another 77 acres, and create 30 new acres of wetlands near Auburn, essentially as proposed by the Port. Runway opponents also appealed this permit.

While these various political and regulatory maneuvers were fought on the ground, air traffic at Sea-Tac soared beyond its maximum efficient capacity to nearly 446,000 operations in 2000, leading to significant delays. Traffic then declined to 365,000 operations in 2002, due to the regional recession and national decline in air travel following the attacks of September 11, 2001. If nothing else, this temporary decline bought the airport and the region time in preparing for the inevitable resumption of air traffic growth.

In May 2004, the State Supreme Court largely cleared the way for construction to resume, and on August 19, 2004, the Airport Communities Coalition dropped litigation. The coalition had spent $15 million over 10 years campaigning and litigating against the third runway. Although they failed to stop the runway project, former opponents noted they had won major environmental benefits, including improved quality of fill dirt, state-of-the-art stormwater treatment, relocation of a salmon-spawning stream, and creation or enhancement of wetlands.

Construction resumed after the Supreme Court ruling but controversy did not end.  Airlines, whose fees pay some of Sea-Tac's capital expenditures, balked at cost estimates that had risen to $1.2 billion by 2003, prompting a short-lived 2005 proposal by Southwest and Alaska airlines to shift operations to Boeing Field.  The actual cost by the time the runway opened in 2008 turned out to be $116 million less than the $1.2 billion estimate.

But even as the runway was finally finished, two highly critical reports suggested that nearly $100 million of the cost had been wasted or lost to fraud.  First, State Auditor Brian Sonntag used new powers, given to his office by a 2005 initiative sponsored by professional ballot-measure promoter Tim Eyman, to undertake a performance audit of the Port. His report, released in December 2007, said the Port had wasted $97 million in construction contracts and called its construction management "vulnerable to fraud, waste and abuse" (Young, "Third Runway About to Open..."). The state audit triggered a federal criminal investigation that lasted two years but did not lead to any charges being filed.

Port management initially disputed the audit charges but the Port Commission hired former United States Attorney Mike McKay to conduct an internal investigation of Port construction management practices. McKay's report, released in December 2008, weeks after the new runway opened, was as damning as Sonntag's earlier audit.  It found that Port employees repeatedly broke state law or Port policy and committed civil fraud at least 10 times, with most instances connected to the third runway project. Within days of the report's release, John Rothnie, project manager for the third  runway, resigned as disciplinary action against him began. Seven other employees were suspended or reprimanded for their role in misleading the commission about the actual cost of one of the runway contracts.

The third runway finally opened to traffic on November 20, 2008, as an Alaska Airlines flight took off for Denver following a dedication ceremony.  The completed runway is a vast strip of concrete 8,500 feet long, 150 feet wide, and 17 inches deep.  To make it level with the other two runways, it sits on a plateau built up with 500,000 truckloads of fill dirt held in place by a 1,430-foot-long, 130-foot-high retaining wall.


“Regional Airport System Plan, 1988-2020,” Puget Sound Council of Governments, September 29, 1988; Port of Seattle and Puget Sound Council of Governments Interagency Agreement for Long Term Air Carrier System Planning, May 23, 1989; “The Flight Plan Project, Final Environmental Impact Statement,” Puget Sound Council of Governments, October 6, 1992; Port of Seattle Commission Resolution 3125 Amended, November 3, 1992; Washington State Air Transportation Commission (AIRTRAC) newsletters and reports, September 1992-December 1993; Puget Sound Council of Governments General Assembly Resolution A-93-03, April 29, 1993; “Major Supplemental Airport Feasibility Study,” Puget Sound Regional Council, March 23, 1995; “Final Environmental Impact Statement for Proposed Master Plan Update Actions at Seattle-Tacoma International Airport,” Port of Seattle and Federal Aviation Administration, February 1, 1996; Puget Sound Regional Council General Assembly Resolution A-96-02, July 11, 1996; “General Chronology Related to Regional Commercial Aviation Development in the Central Puget Sound Region,” Puget Sound Regional Council memorandum, May 9, 2002; “Detailed History of the 3rd Runway Planning Process,” Port of Seattle memorandum, October 3, 2002; “Regional Air Capacity -- Public Involvement History,” Port of Seattle memorandum, February 5, 2003; Roger Downey, “Risky Runway,” Seattle Weekly, September 28, 2000; The Seattle Times, July 27, 1988, April 22, 1990, March 21, June 15, 1992; January 15, 1993; February 14, 1994; January 27, April 27, 1995; March 28, June 25, June 28, August 2, 1996; July 4, 1997; July 24, 1998; March 24, 1999; September 29, October 31, 2000; May 24, August 10 and 11, December 20, 2001; August 13, September 19, December 13 and 21, 2002; March 16, 2003; Seattle Post Intelligencer, January 27, March 24, June 19, 1999; January 26, May 26, September 29, October 21 and 27, 2000; May 21, June 13, July 25 and 27, August 10 and 24, October 17, November 5, December 19, 2001; January 3 and 14, March 17, August 13, August 26, September 10, December 14, 2002. Port of Seattle Website accessed on March 21, 2003 (; Regional Commission on Airport Affairs Website accessed on March 21, 2003 (; Airport Communities Coalition website accessed on March 21, 2003 (; Tim Klass, "At Last -- $1B Third Runway Dedicated at Sea-Tac," Seattle Post-Intelligencer, November 20, 2008 (; Kristen Millares Young, "Third Runway About to Open, but Will It Fly?" Ibid., November 13, 2008; Young, "Third Runway Opponents See Victory in Concessions," Ibid.; Larry Lange and Jeffrey M. Barker, "You Know That Third Runway? Sea-Tac's Really Getting It," Ibid., August 20, 2004; Kristen Millares Young, "Port's Own Inquiry Finds Employee Fraud," Seattle Post-Intelligencer, December 4, 2008;  Bob Young, "Port Forces Out 2 Managers, Disciplines 7 Others," The Seattle Times, December 10, 2008; Mike Carter, “Investigation of Port of Seattle Fraud Ends Without Indictments,” Ibid., January 22, 2010.
Note: This essay was updated and corrected on August 30, 2004, and again on December 5,  2008. It was updated on February 5, 2009, and again on January 30, 2010.

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