TagMiller Creek(254)

Memorandum from Brian Pippin (Parametrix, Inc.) to Linda Logan (cc: John Brooker), dated August 14, 2000, Project Number 556-2912-001, Port of Seattle WERs. Discusses critical conditions for Water Effect Ratio (WER) sampling per the Permit Writers Manual for the third runway treated stormwater discharge into Miller Creek. Uses HSPF hindcasting over 49-year period to evaluate

The Port of Seattle submitted a Joint Aquatic Resources Permit Application (JARPA) in August 2000 for the Miller Creek Project, part of Master Plan Update Improvements at Seattle-Tacoma International Airport. The application, prepared by Parametrix, Inc., seeks permits related to work affecting Miller Creek, Walker Creek, and associated wetlands in the City of SeaTac. The project required approvals from multiple agencies, including the Washington Department of Fish and Wildlife for a Hydraulic Projects Approval (HPA).

A fisheries biologist hired by the Airport Communities Coalition reviewed a Washington State Department of Ecology hydrologic study of the Sea-Tac runway fill project, concluding that the study significantly underestimated impacts on local fish and wetland habitats in Miller, Walker, and Des Moines Creeks. The reviewer found that the study failed to accurately document fish species present, overlooked key wetlands supporting salmon and cutthroat trout, and inadequately assessed the consequences of relocating nearly 1,000 feet of Miller Creek to accommodate runway expansion. The letter argues that the Ecology department accepted the Port's claims of habitat improvement without requiring a thorough analysis of the substantial fish and invertebrate communities that would be destroyed.

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

A fisheries biologist hired by the Airport Communities Coalition assessed the potential environmental impacts of a temporary SR-509 interchange construction project near Seattle-Tacoma International Airport, concluding that the project posed serious risks to fish and wetland resources in Walker Creek. The report found that proposed erosion control measures, such as silt fences and whattles, were grossly inadequate given the steep terrain (slopes of 40–60%) adjacent to Wetlands 43 and 44, and that sediment-laden stormwater runoff containing metals and polycyclic aromatic hydrocarbons would likely reach these sensitive areas. The biologist also criticized the Port of Seattle and its contractor, Parametrix, Inc., for failing to conduct fish species inventories and for providing little documentation to support their claim that no significant wetland impacts would occur.

A June 2000 letter from Azous Environmental Sciences to the US Army Corps of Engineers raises concerns about the incorrect mapping of Wetland 44a near the proposed SR509 temporary interchange in SeaTac, Washington. A field review found that the wetland may be 20 to 40 feet closer to the construction zone than shown in project plans prepared by HNTB Corporation, potentially exposing it to significant sediment runoff during construction. The letter also highlights an overlooked creek system connecting Wetland 44a to Walker Creek and Miller Creek, warning that construction impacts could affect a broader network of wetlands and waterways.

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.

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.