TagThird Runway(1098)

A September 2000 letter from Northwest Hydraulic Consultants raises concerns about the Stormwater Management Plan for Seattle-Tacoma International Airport's third runway expansion, finding that it fails to demonstrate compliance with the Governor's Certification requirement to protect water flow in Miller and Des Moines Creeks. The letter also identifies serious problems with the airport's plan to manage stormwater through expansions to its Industrial Wastewater System, including unresolved engineering uncertainties and potential conflicts with FAA wildlife safety guidelines that prohibit wastewater facilities within 10,000 feet of runway areas.

This September 2000 letter from environmental reviewers raises concerns about the Seattle-Tacoma International Airport third runway expansion project, specifically arguing that the Port of Seattle's Stormwater Management Plan fails to adequately assess or mitigate reductions in stream base flows and seepage flows to nearby wetlands. The reviewers present hydrological modeling data suggesting that groundwater inputs to Miller Creek could be reduced significantly more than the Port's own estimates indicate, and that the fill embankment's actual drainage behavior contradicts the Port's claims that it would function like natural outwash soil. The letter challenges the Port's assurances that seepage flows to downstream wetlands would be preserved, citing conflicting data within the Port's own documents and questioning the reliability of the analyses used to support those claims.

A September 2000 letter from Northwest Hydraulic Consultants raises concerns that the Seattle-Tacoma International Airport's Stormwater Management Plan fails to adequately assess or mitigate the third runway embankment's impact on stream base flows and seepage flows to nearby wetlands. The consultants argue that the Port of Seattle's own data contradicts its claims that the embankment fill would maintain groundwater recharge, and that independent re-analysis suggests summer groundwater reductions to Miller Creek could be roughly twice what the Port reported. The letter calls for more rigorous and consistent hydrologic modeling before construction commitments are made.

A September 2000 letter from Northwest Hydraulic Consultants, written on behalf of the Airport Communities Coalition, raises serious technical concerns about the Stormwater Management Plan for Seattle-Tacoma International Airport's proposed third runway. The letter highlights findings from King County reviewers showing that multiple stormwater facilities in the plan were unverified, potentially infeasible, or unlikely to meet required flow control performance standards. The consultants argue that the review timeline was insufficient and that the Port of Seattle had a history of failing to deliver promised stormwater mitigation measures.

In September 2000, Northwest Hydraulic Consultants submitted preliminary technical comments on behalf of the Airport Communities Coalition, raising serious concerns about the adequacy of the Stormwater Management Plan for Seattle-Tacoma International Airport's proposed third runway expansion. The letter highlights findings from King County's independent review, which identified numerous cases where proposed stormwater control facilities were unverified, infeasible, or unlikely to meet required flow control performance standards. The consultants warned that the compressed public review timeline was insufficient for thorough evaluation of the plan before Ecology's 401 Certification decision.

A September 2000 letter from environmental consulting firm Azous Environmental Sciences alerts Washington State Department of Ecology officials to an unidentified tributary of Miller Creek that was overlooked in the Port of Seattle's environmental planning documents for Sea-Tac Airport's proposed third runway. The tributary, listed in King County Sensitive Areas records and confirmed to have active water flow, feeds into a Class 2 salmon-bearing stream but was never assessed for potential impacts in the Port's Natural Resource Mitigation Plan. The letter argues this omission—despite four years of environmental analysis—leaves the creek unprotected from planned construction and future aviation operations in the area.

Hart Crowser report prepared for Port of Seattle, dated September 12, 2000 (J-4978-13), evaluating perched groundwater zone interception at Borrow Area 3 for the Sea-Tac Third Runway project. Analyzes shallow perched groundwater flow from northwest to southeast beneath Borrow Areas 3 and 4, its role in sustaining Wetland 29, and the impact of borrow area

Email chain dated September 11, 2000 among Washington State Department of Ecology staff (Chung K. Yee, Kevin Fitzpatrick, Peter Kmet) and ATG’s Joan Marchioro regarding clean fill criteria language for the 401 Water Quality Certification on the Sea-Tac Third Runway. Peter Kmet raises concerns about arsenic limits (proposed 20 vs. background 7-8 in Western Washington),

Email from Peter Kmet to Kevin Fitzpatrick, Washington State Department of Ecology (Ecology), dated September 11, 2000, providing comments on proposed Clean Fill Criteria language for the Section 401 Water Quality Certification for the Sea-Tac Airport Third Runway project. Kmet comments on sections E6, E7, E7a, E7b, E7c regarding Port Of Seattle borrow sites, fill

Email chain dated September 11, 2000 among Kevin Fitzpatrick, Peter Kmet, Chung K. Yee, Joan Marchioro, and Tom Luster of Washington State Department of Ecology (Water Quality Program, NWRO) regarding clean fill criteria language for the 401 Water Quality Certification on the Sea-Tac Third Runway project. Document marked ‘Deliberative Document Currently Exempt From Public Disclosure.’