TagWater Quality(478)

Dissolved Oxygen Deicing Study prepared by Cosmopolitan Engineering Group for Port Of Seattle Sea-Tac International Airport (AR042698, August 1999), examining impacts of de-icing agents from airport stormwater runoff on Miller Creek and Des Moines Creek, including BOD5 discharges to NW Ponds and Lake Reba. Accompanied by Washington State Department of Ecology (NWRO) response letter dated

In this October 1999 letter, the Washington State Department of Ecology reviewed a study by the Port of Seattle examining how de-icing chemicals used at Sea-Tac International Airport affect water quality in Miller and Des Moines Creeks. Ecology found significant deficiencies in the study, including incorrect water quality classifications, too few de-icing events sampled, and inadequate monitoring methods, concluding that dissolved oxygen levels in both creeks frequently failed to meet applicable standards. The agency requested that the Port resubmit the study with corrections before a determination could be made about whether de-icing operations were being properly managed to protect local waterways.

In this October 1999 internal memo, Washington State Department of Ecology staffer Tom Luster describes a meeting with his supervisor Paula regarding the agency's water quality review of Sea-Tac Airport expansion. Luster explains that he cannot yet provide 'reasonable assurance' that the Port of Seattle's proposal will meet water quality standards for Des Moines Creek, citing inadequate stormwater treatment plans and the Port's removal of flow augmentation measures from its mitigation plan. He expresses concern that management pressure to approve the project quickly could compromise the integrity of the regulatory review process.

Internal email from Tom Luster (Ecology) to Raymond Hellwig, Kevin Fitzpatrick, Erik Stockdale, and Paula Ehlers, dated September 16, 1999, regarding SeaTac Airport 401 certification and compliance with water quality standards under the Clean Water Act. Discusses non-attainment of water quality standards in Des Moines Creek and Miller Creek, antidegradation requirements, Level 2 detention requirements,

Internal email from Tom Luster (Washington State Department of Ecology) to Raymond Hellwig, Kevin Fitzpatrick, Erik Stockdale, and Paula Ehlers dated September 16, 1999, outlining unresolved stormwater issues in the 401/CZM review of Port Of Seattle’s Sea-Tac Airport Master Plan Expansion. Topics include: definitions of ‘modified Level 1’ and ‘Level 2-type flow control’; role of

Fax transmittal dated 9/16/99 from John Strunk of Associated Earth Sciences, Inc. (Bainbridge Island, WA) to Roger Nye at Ecology, transmitting a map showing proposed well locations for measuring groundwater levels at Seattle-Tacoma International Airport (STIA). The attached map titled ‘Proposed Groundwater Level Monitoring Well Network, STIA Groundwater Study’ (September 16th, 1999) shows on-site and

A 1999 technical memorandum from Parametrix, Inc. analyzes whether stormwater discharged near Des Moines Creek meets Washington State dissolved copper water quality criteria, using a Monte Carlo simulation model. The analysis finds that copper levels in the stormwater effluent consistently exceed water quality standards regardless of background ambient concentrations, with dilution factors generally less than 2. The study evaluates several potential remedies, including increased onsite detention, expanded mixing zones, and water effect ratio adjustments, finding that the Water Effect Ratio (WER) is the most influential factor in achieving compliance.

This is the Annual Stormwater Monitoring Report for Seattle-Tacoma International Airport, covering the period from July 1, 1998 through June 30, 1999, prepared by the Port of Seattle. The report documents water quality sampling results from airport storm drainage systems, including measurements of petroleum hydrocarbons, metals, fecal coliforms, and the effects of aircraft and ground deicing activities on runoff. It includes data summaries, outfall inspections, and source tracing studies aimed at tracking and managing stormwater pollution from airport operations.

Annual Stormwater Monitoring Report for Seattle-Tacoma International Airport (Sea-Tac Airport) covering July 1, 1998 through June 30, 1999, prepared by Port Of Seattle, September 1999 (AR 026459–AR 026461). Includes stormwater quality data tables for outfalls SDE4, SDS3, SDN1, and SDN4 with copper (CAS No. 7440-50-8) concentration measurements in micrograms per liter, hardness-dependent freshwater acute water

Annual stormwater monitoring report (AR018047) prepared by Port Of Seattle for Seattle-Tacoma International Airport (STIA) covering the period July 1, 1998 through June 30, 1999. Documents NPDES stormwater sampling results across STIA storm drainage subbasins including grab and composite samples for total petroleum hydrocarbons (TPH), fecal coliforms, suspended solids (TSS), turbidity, biochemical oxygen demand (BOD5),