TagPCHB(607)

This section of Sea-Tac International Airport's Comprehensive Stormwater Management Plan outlines proposed Master Plan Update (MPU) improvements and their likely stormwater management requirements. It describes how land use changes — including increases in impervious surfaces across various airport development phases — were analyzed using GIS and hydrologic modeling to assess drainage impacts. The document also notes that projects such as the relocated Airport Surveillance Radar required specific flow controls to manage stormwater runoff on the west side acquisition area.

This document describes the Integrated Water System (IWS) stormwater management configuration at Seattle-Tacoma International Airport (Sea-Tac), detailing storage lagoons totaling 76.9 million gallons and a treatment rate of 4.0 million gallons per day across approximately 435 acres. Simulations over a 50-year period confirmed zero overflow events under proposed conditions, with overflows only beginning to occur if treatment rates dropped below 3.1 million gallons per day. The system experienced only one historical overflow during an extreme rain-on-snow event in December 1996–January 1997, with no petroleum hydrocarbons detected downstream.

Port Of Seattle memo opposing Airport Communities Coalition (ACC) motion for stay in PCHB No. 01-133, Volume 2 of 3, containing Declaration of Paul S. Fendt and SMP Volume 3 materials. Includes preface to the Comprehensive Stormwater Management Plan (SMP) for Seattle-Tacoma International Airport Master Plan Update Improvements, July 2001, with replacement pages developed in

Final meeting notes prepared by Kate Snider of Floyd & Snider Inc. for the 401 Permit Decision-Making process for the Sea-Tac International Airport Third Runway project, covering Low Flow Analysis discussions held June 25, 2001. Attendees included representatives from Washington State Department of Ecology (Ann Kenny, John Drabeck), King County (Kelly Whiting), Port of Seattle

These are meeting notes from a June 25, 2001 technical meeting regarding the 401 Permit Decision-Making process for the Sea-Tac International Airport Third Runway project, focused on analyzing low stream flow impacts. Participants from the Department of Ecology, King County, Port of Seattle, and various consulting firms discussed methodologies for evaluating water flow modeling results, vault filling estimates, and potential mitigation requirements for affected streams. Modeling results were not yet available at the time of the meeting, and a follow-up meeting was scheduled for July 9, 2001 to review completed modeling output and determine any required mitigation measures.

A biologist from Columbia Biological Assessments submitted a rebuttal in June 2001 challenging the Port of Seattle's environmental justifications for proposed construction improvements at Seattle-Tacoma International Airport. The letter argues that the Port failed to adequately assess impacts on Miller Creek, particularly regarding fish habitat, water temperature, and dissolved oxygen levels in a relocated section of the creek. The author contends that no proper baseline survey of fish and aquatic life was conducted, making regulatory approval of the project scientifically premature.

Final meeting notes from June 14, 2001 (1:00–4:00 PM) prepared by Kate Snider, Floyd & Snider Inc., for the 401 Permit Decision-Making process for the Sea-Tac Airport Third Runway. Attendees included Ann Kenny and John Drabeck (Dept. of Ecology), Kelly Whiting (King County), Keith Smith (Port Of Seattle), Paul Fendt (Parametrix), Alan Black (HNTB), and

These draft meeting notes from a June 14, 2001 technical meeting cover the low flow stream analysis conducted as part of the 401 Permit Decision-Making process for Sea-Tac International Airport's Third Runway project. Attendees from the Department of Ecology, King County, Port of Seattle, and consulting firms identified five additional technical tasks, including verifying groundwater basin calibration parameters for Walker Creek and Des Moines Creek, documenting embankment infiltration rationale, and assessing water availability for proposed low stream flow mitigation measures.

A June 13, 2001 email from Kate Snider of Floyd Snider McCarthy, Inc. notifies project team members of a conference call scheduled for 3:30 PM that day. The agenda covers two technical topics: an updated approach to scaling up recharge rates (rather than precipitation) for an HSPF hydrological model run used to generate inputs for the Hydrus groundwater model, and a concern raised by one team member about potential upward groundwater flow. The email was sent to consultants and staff involved in what appears to be a groundwater modeling study related to the Sea-Tac Airport area.

These draft meeting notes from June 12, 2001 document a technical status meeting between the Washington Department of Ecology, King County, and the Port of Seattle regarding low stream flow analysis for the Sea-Tac International Airport Third Runway project. The group reviewed progress on hydrological modeling efforts, including HSPF and Hydrus modeling used to assess how runway embankment construction might affect nearby stream flows. Discussions also covered planned mitigation measures such as stormwater retention vaults, upcoming modeling deliverables, and a follow-up conference call that confirmed the Port team's modeling methodology was acceptable and conservative for evaluating embankment seepage.