TagStormwater(373)

Email from Raymond Hellwig to Thomas Fitzsimmons dated May 19, 2000, regarding the SeaTac Third Runway permitting process and July 2000 decision-making timeframe. Discusses King County review of Port Of Seattle stormwater management plan requiring up to 10 more weeks, internal staff meetings to develop a definitive issues list, drafting 401 language for resolved issues,

Email dated May 19, 2000 from Raymond Hellwig (City of Des Moines) to Thomas Fitzsimmons regarding the SeaTac 3rd Runway permitting process. Discusses tight July 2000 decision-making timeframe, King County review of Port Of Seattle stormwater management plan requiring up to 10 more weeks, development of a definitive issues list for the proposed runway, drafting

Northwest Hydraulic Consultants submitted follow-up technical comments in May 2000 raising serious concerns about flawed stormwater modeling used to assess the impact of a proposed third runway at Seattle-Tacoma International Airport. The consultants identified major inconsistencies in soil-type assumptions and runoff parameters in the hydrologic models, concluding that the Stormwater Management Plan's predictions of detention facility performance were unreliable and required a complete overhaul. The letter also flagged a lack of adequate local regulatory oversight to ensure that Port of Seattle stormwater designs complied with King County surface water standards.

A technical review by Northwest Hydraulic Consultants, submitted to the U.S. Army Corps of Engineers and Washington State Department of Ecology in May 2000, raises serious concerns about the stormwater management plan for Seattle-Tacoma International Airport's proposed third runway. The report identifies major flaws in the hydrologic modeling used to assess drainage impacts, including inconsistent soil-type assumptions and unreliable flow predictions for Miller Creek. The consultants call for a complete overhaul of the modeling process, independent technical review, and clearer regulatory oversight of the Port of Seattle's stormwater design work.

Final report prepared by Scott Tobiason, Aviation Environmental Programs, Port Of Seattle, documenting Stormwater Whole Effluent Toxicity (WET) testing at Seattle-Tacoma International Airport (STIA), May 2000. AR 044473. Covers WET testing background, sampling methods, STIA storm drainage subbasins, source-tracing of SDN1 outfall, chelation testing, synthetic runoff WET test results, field investigations, and NPDES stormwater discharge

A draft memorandum dated April 2000 summarizes range-finding water-effect ratio (WER) toxicity tests conducted for the Port of Seattle to measure copper levels in streams receiving stormwater runoff from Seattle-Tacoma International Airport (STIA). Water samples were collected from five sites — including Miller Creek and Des Moines Creek — during a storm event on April 15, 2000, and tested using Daphnia magna organisms to compare copper toxicity in site water versus clean laboratory water. The results were intended to determine whether more expensive definitive WER studies would be warranted, and to help establish site-specific water quality standards for copper.

This April 2000 draft memorandum from the Port of Seattle summarizes range-finding toxicity tests conducted to evaluate water-effect ratios (WERs) for copper in streams receiving stormwater runoff from Seattle-Tacoma International Airport (STIA). Water samples were collected from five sites—including Miller Creek and Des Moines Creek—during a storm event on April 15, 2000, and tested using Daphnia magna to measure how site water chemistry affects copper toxicity compared to clean laboratory water. The results were intended to help determine whether full definitive WER studies were warranted, which could support the establishment of site-specific water quality standards for copper in receiving streams.

In an April 2000 email, Port of Seattle executive Gina Marie Lindsey updates a Washington State Department of Ecology contact about the status of the Port's stormwater permit application related to a Comprehensive Stormwater Master Plan. She explains that while the environmental work quality was deemed strong, the submittal needed to be reformatted to meet King County's review standards rather than DOE's, with a revised package due May 5 and a County final review expected by mid-June. Lindsey also addresses concerns about potential 'piecemealing' of the permit process and expresses concern about the lengthy timeline given the County reviewer's limited weekly hours for the project.

Handwritten notes from a BEATAC meeting at the Port on April 20, 2000, AR018447, involving City of Des Moines personnel including Tom Walsh, Tacie Borden, John Marchiloro, Jim Kelly, and others. Topics include: stormwater review at FCC starting 5-5-00; SR-509 temporary interchange issues (ESA/BA review, Jonathan Freedman indirect impacts, erosion/sediment control, no federal nexus); LWS#3

Draft memorandum dated April 20, 2000, authored by Doug Henderson and Linda Logan (job number 556-2912-001) for Port of Seattle project files, summarizing range-finding water-effect ratio (WER) toxicity tests for copper in streams receiving Seattle-Tacoma International Airport (STIA) stormwater. Tests used Daphnia magna as indicator species; copper was spiked into site water and synthetic laboratory