TagStormwater(373)

AR027061. Two letters dated December 2001 regarding NPDES Permit WA-002465-1 for Seattle-Tacoma International Airport. First: Washington Department of Ecology (Tricia Miller, Permit Coordinator, Northwest Regional Office) acknowledges receipt of a waste discharge permit application from Michael Feldman, Director of Aviation Facilities, Port Of Seattle, received December 21, 2001; contact Ed Abbasi at (425) 649-7227. Second

Letter dated December 27, 2001 from Keith R. Smith, Water Resources Manager at Port Of Seattle Seattle-Tacoma International Airport, to Ms. Ann Kenny at Washington State Department of Ecology (Bellevue, WA 98088-5452), transmitting construction stormwater monitoring reports for September, October, and November 2001 under Section K.6 of Water Quality Certification No. 1996-4-02325 (Amended-1) and NPDES

This document is a deposition of Edward O'Brien, taken on December 21, 2001, as part of a Pollution Control Hearings Board case in Washington State involving the Airport Communities Coalition challenging the Department of Ecology and the Port of Seattle. O'Brien discusses stormwater management techniques, including infiltration facilities, which can be used to treat stormwater quality and mitigate low-flow impacts on surface water systems connected to groundwater. He explains that while infiltration can delay and filter stormwater flows through soil profiles, precise control over timing and flow rates is limited and depends on site-specific soil and hydrological conditions.

Declaration of Kelly Whiting, Senior Engineer at King County Department of Natural Resources, filed before the Pollution Control Hearings Board (PCHB No. 01-133) in Airport Communities Coalition v. State of Washington Department of Ecology and Port Of Seattle. Whiting reviewed the Port Of Seattle’s Comprehensive Stormwater Management Plan (SMP) for Master Plan Update Improvements at

A December 2001 technical letter from Northwest Hydraulic Consultants, written on behalf of the Airport Communities Coalition, identifies inconsistencies in the Port of Seattle's stormwater management plans for Sea-Tac Airport expansion. The letter argues that the Port's hydrologic modeling failed to account for the planned commercial redevelopment of borrow pit areas by 2006, and that the Natural Resource Mitigation Plan reverted to an outdated stormwater approach relying on regional detention facilities to be built by others. These gaps, the consultants contend, prevent a full assessment of the airport Master Plan Update's environmental impacts.

Northwest Hydraulic Consultants (NHC), retained by ACC (Airport Communities Coalition), wrote to Colonel Ralph H. Graves, Ms. Muffy Walker, and Ms. Gail Terzi of the U.S. Army Corps of Engineers Seattle District (Corps Ref. No. 1996-4-02325) identifying inconsistencies in Port Of Seattle proposals for site development and stormwater management at Sea-Tac Airport Master Plan Update

Report prepared by Parametrix, Inc. with Aqua Terra Consultants, Earth Tech, Inc., Foster Wheeler Environmental Corporation, HNTB, and Pacific Groundwater Group for Port Of Seattle regarding Sea-Tac Airport Master Plan Update Improvements. Analyzes summer low streamflow impacts to Walker Creek and Des Moines Creek from planned airport projects and proposes an offset facility using underground

This December 2001 technical report analyzes low streamflow conditions in Miller, Walker, and Des Moines Creeks near Seattle-Tacoma International Airport, assessing the hydrologic impacts of the proposed third runway embankment as part of the airport's Master Plan Update. The study found that the runway construction would reduce summer stream flows, requiring mitigation of 0.11 cfs in Walker Creek and 0.08 cfs in Des Moines Creek during the annual low-flow period (late July through October). To offset these impacts, the Port of Seattle proposed collecting and storing excess winter stormwater in underground vaults—approximately 18.5 acre-feet for Walker Creek and 13.5 acre-feet for Des Moines Creek—for controlled release during dry-season low-flow periods.

This December 2001 technical report, prepared for the Port of Seattle, analyzes low streamflow conditions around Seattle-Tacoma International Airport and proposes a facility to offset the impact of airport Master Plan construction on summer low flows in nearby creeks. It includes hydrologic modeling, water quality design considerations, and an operation and monitoring plan for a stormwater storage and release system intended to maintain stream levels during dry summer months. Note that while archived alongside airport planning documents, this report focuses on water resources and stream impact mitigation rather than noise policy.

Third declaration of William A. Rozeboom, professional civil engineer with Northwest Hydraulic Consultants, filed before the Pollution Control Hearings Board (PCHB), Case No. 01-160, Airport Communities Coalition (ACC) v. State of Washington Department of Ecology and Port Of Seattle. Declaration concerns Section 401 Certification No. 1996-4-02325 and CZMA concurrency statement. Rozeboom identifies significant technical deficiencies