TagStormwater(385)

Final draft technical meeting notes from May 14, 2001 (1:00–4:00 PM) for the 401 Permit Decision-Making process for Sea-Tac International Airport Third Runway. Prepared by Kathryn Snider, Floyd & Snider Inc. Attendees included Ann Kenny and John Drabek (Dept. of Ecology), Kelly Whiting (King County), Keith Smith (Port of Seattle), Tom Atkins (Parametrix), Alan Black

Final draft meeting notes from a 401 Permit Decision-Making technical meeting on May 1, 2001, regarding Sea-Tac International Airport Third Runway, prepared by Rachel McCrea of Floyd & Snider Inc. Attendees included John Drabek and Ann Kenny (Dept. of Ecology), Keith Smith (Port Of Seattle), Kelly Whiting (King County), Paul Fendt and Tom Atkins (Parametrix),

In this April 2001 letter, Northwest Hydraulic Consultants raised technical concerns on behalf of the Airport Communities Coalition regarding a proposed NPDES permit modification for Seattle-Tacoma International Airport. The firm identified two key issues: a lack of clear, enforceable design criteria for stormwater overflows from the airport's integrated wastewater system (IWS), and an inconsistency between the permit's stormwater detention standards and the stricter standards sought under Section 401 Certification for the Third Runway and Master Plan Update projects. The consultants recommended that the permit be revised and republished for public comment to address these gaps and ensure consistent, enforceable stormwater management requirements.

Final draft meeting notes from April 17, 2001 management meeting on 401 Permit Decision-Making for Sea-Tac International Airport Third Runway, prepared by Rachel McCrea of Floyd & Snider Inc. Attendees include Ray Hellwig, Ann Kenny, Kevin Fitzpatrick (Dept. of Ecology), David Masters (King County), Michael Cheyne, Elizabeth Leavitt, Keith Smith (Port Of Seattle), Kate Snider

In an April 2001 letter to the Washington State Department of Ecology, Northwest Hydraulic Consultants raised serious concerns about the adequacy of a low streamflow analysis conducted for the proposed third runway expansion at Seattle-Tacoma (Sea-Tac) Airport. The firm argued that Ecology's March 2001 review memo effectively endorsed the study's methods and conclusions without addressing significant technical flaws, including the use of future rather than existing basin conditions and the failure to account for impacts from gravel mining, lagoon lining programs, and embankment seepage. The consultants, representing the Airport Communities Coalition, requested that Ecology revisit its review, consider all submitted technical comments, and require the airport's applicant to formally respond to outstanding concerns before any regulatory certification was granted.

Revised draft meeting notes from April 9, 2001 technical meeting on 401 Permit Decision-Making for Sea-Tac International Airport Third Runway, prepared by Rachel McCrea of Floyd & Snider Inc. Attendees included John Drabek and Ann Kenny (Dept. of Ecology), Keith Smith (Port of Seattle), Kelly Whiting (King County), Alan Black (HNTB), Paul Fendt and Tom

A 2001 internal email from King County staff puts stormwater storage volumes for the Third Runway project (3RW) into everyday perspective. It compares proposed retention ponds and vaults to familiar landmarks: Pond D would hold the equivalent of over 12 Olympic-size swimming pools, and the largest vault considered (88 acre-feet) would cover a football field with 80 feet of water—roughly an 8-story building. The email also notes that 0.1 cubic feet per second of water flow is equivalent to about five garden hoses running at full pressure.

Final draft meeting notes prepared by Rachel McCrea of Floyd & Snider Inc. from a April 4, 2001 technical meeting on low streamflow impact analysis for the Sea-Tac Airport Third Runway 401 Permit Decision-Making process. Attendees included representatives from Washington Dept. of Ecology (Ann Kenny, Kevin Fitzpatrick, Dave Garland), King County (Kelly Whiting), EarthTech (Rick

This 2001 draft report by Parametrix, Inc. describes a water quality study conducted for the Port of Seattle to assess the feasibility of meeting state water quality standards following construction of a third runway at Seattle-Tacoma International Airport. The study focused on developing a site-specific water-effect ratio (WER) for copper in Miller, Walker, and Des Moines Creeks by conducting toxicity bioassays on stormwater samples collected during storm events. The report summarizes results from initial screening and range-finding phases, with the final site-specific water quality standard still pending completion at the time of publication.

A 2001 internal memo from Parametrix, Inc. summarizes a conversation with the Washington State Department of Ecology (WADOE) about water toxicity testing procedures. The memo reports that WADOE opposes adjusting lab water hardness to match site water, recommending instead that storm water tests target the hardness of the receiving water body, typically 40–60 mg/L as CaCO₃. It also notes that low water hardness (around 10 mg/L) may cause chronic reproductive effects in certain test organisms but not acute toxicity.