TagThird Runway(1068)

This August 2001 letter from Northwest Hydraulic Consultants, submitted on behalf of the Airport Communities Coalition, raises technical concerns about the Port of Seattle's Low Streamflow Analysis for the proposed Sea-Tac Airport third runway project. The letter argues the Port's document is incomplete, inconsistent with the Stormwater Management Plan, and lacks critical design details needed to demonstrate that impacts to low streamflows in Walker, Des Moines, and Miller Creeks will be adequately mitigated. Key issues identified include missing sections in the analysis report, unaddressed impacts from airport expansion activities, conflicting information about proposed storage facilities, and failure to account for water transit losses during dry periods.

Draft memorandum dated 8/6/01 from Ray Hellwig, Director, Washington State Department of Ecology, to Tom Fitzsimmons, Director, recommending approval of a 401 Water Quality Certification for the Port Of Seattle’s Sea-Tac International Airport Third Runway project. Document covers 8,500-foot parallel third runway, Runway Safety Areas (RSAs), South Aviation Support Area (SASA), impacts to approximately 700

A technical review letter from Northwest Hydraulic Consultants, written on behalf of the Airport Communities Coalition, raises serious concerns about the Port of Seattle's Low Flow Analysis related to the proposed 3rd runway at SeaTac Airport. The letter identifies the July 23, 2001 document as incomplete and inconsistent with other project plans, citing missing sections, absent facility drawings, and unresolved questions about how water storage and release systems would function in practice. Key technical issues flagged include inadequate accounting for water transit losses, potentially impractical small-orifice flow controls, and poor calibration of streamflow models for Walker Creek.

A August 6, 2001 letter from Water Resources Consulting L.L.C. on behalf of the Airport Communities Coalition critiques the Port of Seattle's 'Low Flow Analysis - Flow Impact Offset Facility Proposal' submitted in support of its Section 404/401 permit application for SeaTac Airport expansion. The letter argues that the Port's plan fails to provide reasonable assurance that the airport's stormwater management will meet water quality standards in Miller Creek, Walker Creek, and Des Moines Creek. Key concerns include an incomplete and unfinished proposal, insufficient stormwater storage capacity, unproven water quality treatment methods, and reliance on vague future 'adaptive management' rather than concrete, enforceable designs.

Email from Ann Kenny (Washington State Department of Ecology) dated August 5, 2001, distributing a revised Draft 401 Water Quality Certification for the construction of a Third Runway and related projects at Seattle-Tacoma International Airport (STIA) in the Miller, Walker, and Des Moines Creek watersheds and wetlands in SeaTac and Auburn, King County, Washington. The

Email from Ann Kenny (Washington State Department of Ecology) dated August 5, 2001, circulating a revised Draft 401 Water Quality Certification for the Port Of Seattle’s Third Runway construction at Seattle-Tacoma International Airport (STIA). Recipients include Gordon White, Raymond Hellwig, Erik Stockdale, Kevin Fitzpatrick, John Drabek, Dave Garland, Ching-Pi Wang, Katie Walter, Kelly Whiting, Joan

In this August 3, 2001 email, Andrea Grad, a paralegal at Helsell Fetterman, submits a Public Disclosure Act (PDA) request to Ann Kenny at the Washington State Department of Ecology. Grad notes that several sections of the Port of Seattle's two-volume Low Flow Analysis — including the Introduction and the section on Determination of Impacts to Streamflow — were either incomplete or entirely missing from the copy provided by Ecology. She asks Ecology to confirm whether the Port had submitted the missing sections, and requests copies of any such materials.

In August 2001, King County's Department of Natural Resources submitted a technical review letter to the Washington Department of Ecology evaluating the Port of Seattle's Low Flow Impact Analysis and proposed offset facilities for stormwater management near Sea-Tac Airport. The review found the proposal goes well beyond the basic requirements of the King County Surface Water Design Manual and represents substantial mitigation for low flow impacts in affected drainage basins, including Miller and Walker Creeks. Reviewers noted several inconsistencies and data gaps in the documentation and recommended that a final consolidated document be prepared incorporating all corrections and technical memoranda.

This August 2001 draft document outlines Water Quality Certification conditions for Sea-Tac International Airport (STIA), requiring the Port of Seattle to implement a Comprehensive Stormwater Management Plan covering treatment, flow control, and retrofitting of stormwater facilities. Key requirements include obtaining Ecology approval before discharging operational stormwater to state waters, conducting a Water Effects Ratio Study, and ensuring all runoff from impervious surfaces is treated using all known available and reasonable treatment methods. The Port must also retrofit existing stormwater facilities at a rate proportional to new impervious surface construction, with progress documented in quarterly reports.

In August 2001, King County's Department of Natural Resources wrote to the Washington Department of Ecology confirming that the Port of Seattle's Comprehensive Stormwater Management Plan for Sea-Tac International Airport Master Plan improvements met the technical requirements of the 1998 King County Surface Water Design Manual. The review found that the plan demonstrated a feasible conceptual strategy for managing stormwater from proposed airport construction projects. Reviewers noted that while the plan showed compliance with design standards, additional oversight and monitoring would be needed as individual projects moved from planning into construction.