IN ORDER TO BUILD its long awaited third runway at Seattle-Tacoma International Airport, the Port of Seattle plans to buy and transport between 15 and 20 million cubic yards of gravel, sand, and miscellaneous dirt: enough to build three Great Pyramids of Giza, with enough leftover for a few little pyramids as well. But the element that the Port’s engineers are losing sleep over these days is not earth but water.

When construction started on what is now Sea-Tac back in early 1943, streams, wetlands, and wildlife were no impediment; old timers remember when the whole plateau where Sea-Tac now stands was known as Bow Lake, but even they have trouble remembering where the lake was. Today, though, Port planners are only too conscious that the whole neighborhood is threaded by streams and dotted with wetlands, all more or less degraded from decades of suburbanization and propinquity to the airport but still functional and hedged off from further damage by a web of local, state, and federal regulations.

The whole third-runway enterprise, approved on July 1, 1996, after years of study and debate by the Puget Sound Regional Council, a group of mayors, county executives, and other politicians from around the region, revolves around water: not just existing streams and wetlands but, even more important, stormwater runoff from another 18,000 feet or so of impervious concrete runway and taxiway. The biggest single challenge facing the third runway’s designers is containing that water and ensuring that it, along with its inevitable lacing of jet fuel, deicing compound, and powdered landing-gear rubber, doesn’t get into the complex network of streamlets that makes up the Miller Creek, Walker Creek, Des Moines Creek, and Gilliam Creek drainage areas.

When the National Marine Fisheries Administration cited Puget Sound Chinook salmon as an endangered species, public pressure to construct a “watertight” stormwater-control system got greater: so great that the state Legislature mandated its own study of the problem, and of the Port’s plans for dealing with it.

That study, by a team of independent consulting firms led by Seattle’s Pacific Groundwater Group, was only published in mid-June of this year, but its results have been the subject of hot and anguished discussion behind the scenes since late last winter. Reduced to their essence, PGG’s findings come to this: The numbers that come out of the mathematical models Sea-Tac planners have are effectively worthless in predicting the impact of runoff from constructing a third runway on Miller Creek and its tributaries, on stormwater disposal, or on the overall water budget of the whole multi-square-mile drainage basin.

Both hydrology and mathematical modeling are arcane subjects difficult for a nonspecialist to comprehend, let alone criticize, but some of the more questionable aspects of the Port’s advance work are understandable even by amateurs.

Christopher Gower, a neighborhood activist whose Normandy Park home overlooks the lower reaches of Miller Creek, provides one vivid example. “Even though the Port is a long way from getting the permits it needs to begin constructing the third runway, they’ve already brought in a couple million cubic yards of fill from various sites around the Sound. We have reason to believe that some of this fill is contaminated with industrial pollutants. But, the Port says, even if the soils were polluted, it wouldn’t matter, because the earth under the spot they have it stored is impermeable to groundwater seepage. The only problem with that is that according to other parts of their study, the same soil layer is permeable. I call it ‘the Port of Seattle’s Incredible Magic Soil’: permeable when you want it to be, impermeable when you don’t.”

By April of this year, it was clear that the inadequacies in the Port’s stormwater projections were not repairable with a software patch or two. The state Department of Ecology, whose go-ahead is necessary for federal approval of the project, mandated a thorough review of the Port’s plan, to be performed by experienced modelers in King County’s Department of Natural Resources already familiar with the soils and streams in the area. Unfortunately for the Port’s construction timeline, county planners are not satisfied with “conceptual” modeling of the kind the Port’s consultants provide. When the Port’s numbers are plugged into the county’s more realistic model, the results are nonsense. The Port says the problem is the county’s model, the county says it’s the Port’s numbers that are at fault. Unfortunately for the Port, it’s the county that holds the cards.

AT THIS POINT, the Port, let down by science, began mobilizing its political artillery. On April 24, the managing director of the Port’s aviation division, Gina Marie Lindsey, e-mailed Martha Choe, now director of the state office of Community, Trade, and Economic Development, to thank her for her “continued willingness to help keep things moving” with the third runway plan.

Choe was no stranger to the third-runway issue—by her own testimony, she had discussed it with Port director Mic Dinsmore on a junket to China last year while she was still serving on the Seattle City Council—and she took up the cause with alacrity. In late April she contacted Ecology director Tom Fitzsimmons to express the Port’s “concern” about expediting the King County stormwater review, suggesting that Fitzsimmons arrange for weekly meetings with the Port to keep the project on track.

In the middle of Choe’s April 25 memo to Fitzsimmons, the reason for the Port’s concern becomes only too clear. “The third runway is part of the metropolitan transportation plan for the Puget Sound region, required for federal funding. Its renewal is slated for later this year and if there is reason to believe the third runway will not happen, [Snohomish County Executive and Puget Sound Regional Council member] Bob Drewel does not count the votes on the [PSRC] for keeping the third runway in.” Should that happen, Choe (herself a onetime PSRC member) opines that “the region would be faced with a repeat of opening up the process to consider another alternate site for an airport.”

That, of course, is exactly what individual activists like Gower and many civic leaders in communities impacted by Sea-Tac expansion would like to see happen. In their opinion, the PSRC’s approval of a third runway at Sea-Tac had little or nothing to do with technology, economics, efficiency, or need, and a great deal to do with regional politics. County executives from both Pierce and Snohomish counties were active in promoting the PSRC’s rejection of airport sites at Everett’s Paine Field and Tacoma’s McChord on their home turf, while King County’s representatives seemed oblivious to the downside of a third runway for their own constituents.

Gower and his like may be unashamed NIMBYs in fighting against more aircraft pollution and noise in their communities. But we shouldn’t forget that there’s also such a thing as ALAIISEBY: the tendency to approve or go along with something “as long as it’s in somebody else’s backyard.” The members of the Airport Communities Coalition—the municipalities of Burien, Tukwila, Des Moines, Federal Way, Normandy Park, and the Highline School District—all suspect that their interests have been sacrificed to those of other more politically potent communities determined to keep the noise and traffic associated with airports out of their area.

But they continue the uphill fight against their immense and powerful neighbor for another, less abstract reason. They claim the Port has never followed through on promised mitigations for the impact of the building of the second Sea-Tac runway in 1970 and therefore cannot be expected to pay more than lip-service to any promises, however appealing, it might make this time around. (Only the airport’s immediately adjacent neighbor, the City of Sea-Tac, has made its peace with the future, its agreement no doubt sweetened by a deal with the Port that one dollar of every parking fee levied—estimated to amount to over $4 million this year—will be deposited in the city’s coffers.)

With so many permits, studies, and negotiations in the mix, it’s easy to overlook a deadline that the Port can’t afford to miss: A little over two months from now, on September 29, the state Department of Ecology must decide on the Port’s application for the so-called 401 permit required for the third runway plan to be sent to the federal agency responsible for giving the ultimate construction go-ahead—the United States Army Corps of Engineers.

“We have been working with the Port on this project now for four years,” says Ecology spokesperson Curt Hart. “The issues we are facing today are the same ones which have been on the table from the beginning: stormwater runoff, stream impacts, wetlands. In that period we have issued permits for literally thousands of other projects. It typically takes four months to a year to approve a project—in the case of a large one like this, as much as two years. For us to be working on one for four years is unprecedented. It’s up to the Port what happens on the 29th of September. Ecology has three options: the Department can approve, disapprove, or waive comment, which would mean we lose any voice in the matter. I can assure you that we are not going to waive.”

Check out the Port of Seattle’s site for further information regarding the need for and progress on the third runway.

And see what the opposition has to say, as well.