TagStormwater(385)

A 1999 internal technical memo from Parametrix, Inc. evaluates three alternative water-quality dilution modeling methods for assessing whether proposed stormwater outfalls at the Port of Seattle could exceed Washington State water quality standards. The methods range from a static single-event approach based on Ecology's Permit Writer's Manual to a dynamic continuous simulation using HSPF hydrologic models and a probabilistic EPA-funded model developed by researcher Dominic Di Toro. The memo recommends continuing with the continuous simulation approach while considering budget, Ecology's involvement, and the nature of ambient and effluent pollutant concentration data.

This document is a section of Washington State's Permit Writer's Manual covering Water Effect Ratio (WER) methodology for water quality permitting. It outlines procedures for determining how receiving water conditions affect the toxicity of discharged effluents, including required toxicity testing species, sampling schedules at critical and non-critical flow conditions, and guidelines for freshwater and saltwater discharge situations. The document is unrelated to Sea-Tac Airport noise policy.

A 1999 draft assessment prepared by Parametrix, Inc. for the Port of Seattle outlines best management practices (BMPs) for managing stormwater runoff at Seattle-Tacoma International Airport as part of its Master Plan Upgrades. The document describes how the Port plans to implement water quality treatment measures—including filter strips, bioswales, and wet-vaults—across existing and newly developed stormwater drainage subbasins to meet Washington State Department of Ecology redevelopment requirements. Note that while archived alongside airport planning documents, this report focuses on stormwater and water quality compliance, not noise policy.

Technical memorandum prepared by HNTB Corporation for the Port of Seattle and Parametrix, Inc. (June 15, 1999) analyzing temporary wetland impacts during Seattle-Tacoma International Airport Third Runway embankment construction. AR 042490. Covers storm water management during construction, temporary fill in wetlands west of runway embankment toe, impacts to Wetland 37 (Miller Creek basin) and Wetland

Exhibit 2110, AR 033718. Internal Washington State Department of Ecology email chain dated May 14, 1999, among Kevin Fitzpatrick, Tom Luster, Raymond Hellwig, Paula Ehlers, Erik Stockdale, Wendy Bolender, Lisa Austin, John Glynn, and Bill Moore regarding the 401 Certification and NPDES permit matrix for the Sea-Tac Airport Third Runway project. Key issues include stormwater

Email chain dated April 30, 1999 from Ronald Lavigne (ATG) and Ann Kenny to Washington State Department of Ecology staff including Sandra Manning, Kevin Fitzpatrick, and others, raising legal concerns about agreements reached at a Wednesday meeting regarding 401 certification and 402 permit policy. Lavigne raises issues including: the state’s one-year waiver deadline for 401

This is a Procedure Manual for stormwater monitoring at Sea-Tac International Airport, developed by Port of Seattle Environmental Services to comply with NPDES Permit WA-002465-1. It outlines sampling locations, monitoring schedules, deicing event protocols, and quality assurance procedures for collecting and reporting stormwater data. The manual covers topics ranging from automatic and manual sampling methods to laboratory accreditation and discharge monitoring report requirements.

A March 30, 1999 follow-up phone call was made to Kevin Fitzpatrick of Ecology regarding a WER (Waste Equivalency Ratio) work plan renewal and a mixing zone study approach for a project near Sea-Tac Airport. Fitzpatrick indicated that Gary Bailey would assist with the WER work plan alongside Randy Marshall, and Norm Glen would review the mixing zone approach, but Kevin wanted to wait until after an April 1, 1999 meeting before proceeding. Key outstanding questions included whether existing outfalls already meet treatment standards and whether the Puget Sound Stormwater Manual technology standards would apply to existing outfalls at the site.

This document consists of a fax transmission from Parametrix, Inc. to Scott Tobiason at the Port of Seattle, dated March 29, 1999, transmitting water quality data logs and flow weighting calculation worksheets for WGR (water quality) samples collected from receiving streams on February 22, 1999. The attached field data logs record measurements such as pH, temperature, dissolved oxygen, and water levels at a site designated 'WC,' along with observations of rain, sheen, and water color during sampling. A flow weighting calculation worksheet for the 'Walker' site summarizes subsample volumes and calculates a total storm flow of 33,030 units for a 30-inch pipe.

This 1999 email chain between Washington State Department of Ecology staff discusses the challenges of applying water quality standards to stormwater discharges related to the proposed Sea-Tac Airport third runway project. Officials from the Water Quality and Shorelines/Environmental Assistance programs agreed that strictly enforcing numeric water quality criteria on stormwater is scientifically and legally difficult, and recommended an 'adaptive management' approach requiring monitoring and ongoing improvements rather than immediate full compliance. The correspondence also highlights resource limitations, the relationship between Section 401 and 402 Clean Water Act permits, and the need for a consistent statewide policy on stormwater review.