TagStormwater(385)

Email chain dated July 30, 2000 from Kelly R. Whiting, PE, King County Department of Natural Resources, Water and Land Resource Division, Drainage Services Section, to David Masters and Tom Luster (WDOE), forwarding water quality specialist Kate Rhoads’ notes on copper (Cu) levels in Seattle-Tacoma International Airport (STIA) runway stormwater runoff. Whiting discusses KCSWDM (King

Email from Kate Rhoads to Kelly Whiting dated July 28, 2000, with attached notes (POS-Cu.doc) on copper levels in Sea-Tac Airport (STIA/POS) runway stormwater runoff and the need for further treatment. Notes discuss total recoverable (TR) copper concentrations (median 37 ug/l) from SEATAC runways versus the acute toxicity standard of 15 ug/l at hardness 100,

Sea-Tac Runway Fill Hydrologic Studies Report (AR 045023, project JE9907) prepared by Pacific Groundwater Group, Ecology and Environment, and Earth Tech Inc. for Washington State Department of Ecology Northwest Regional Office, dated June 19, 2000. Report covers hydrologic and hydrogeologic characterization of the Sea-Tac Airport third runway embankment fill area, including Miller Creek and Walker

This June 2000 report by Pacific Groundwater Group examines the hydrological impacts of proposed runway fill construction at Seattle-Tacoma International Airport. It covers groundwater conditions, surface water management, effects on local wetlands and fish habitat in Miller and Walker Creeks, and reviews stormwater control proposals. The study was prepared for the Washington State Department of Ecology to assess how the Third Runway embankment fill would affect the surrounding hydrologic environment.

These internal deliberative notes from 5/30/00 discuss fill and stormwater management issues related to a construction or development project, covering topics such as soil fill acceptance criteria, Best Management Practices (BMPs) for water quality, spill containment features at Tyee Pond, and monitoring requirements for dissolved metals. The notes reference coordination among multiple regulatory frameworks including Section 401, CZM, and MTCA, and address questions about impervious liner hydrologic impacts and remediation procedures. Key action items include developing an approved stormwater plan, establishing soil sampling protocols for borrow sites, and determining upfront versus incremental BMP implementation strategies.

A professional wetland scientist reviewed the construction plans for a temporary SR509 interchange near Seattle-Tacoma International Airport and concluded that the project would cause harmful sediment-laden stormwater runoff to discharge into nearby Wetland 43. The report found that the wetland boundary was significantly closer to the construction zone than project documents indicated, and that the steep slopes and sparse vegetation of the construction site made sediment runoff unavoidable. The scientist determined that the planned temporary erosion control measures were inadequate to protect the wetland, particularly during unexpected storm events.

A May 2000 environmental science review raised concerns that construction of a temporary highway interchange near Seattle-Tacoma International Airport's third runway would cause direct sediment runoff into the adjacent Wetland 43. The report found that the wetland boundary was up to 50 feet closer to the construction zone than project documents indicated, and that the steep slopes and inadequate erosion controls would fail to prevent sediment-laden stormwater from damaging the wetland's water quality and aquatic habitat.

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

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,

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.