TagACC(1531)

In December 2001, Ann Kenny of the Washington Department of Ecology's Northwest Regional Office drafted a memo requesting that hydrogeologist Ching-Pi Wang review a groundwater and seepage monitoring plan submitted by the Port of Seattle for the proposed third runway at Seattle-Tacoma International Airport. The plan, titled 'Third Runway Embankment Seepage and Groundwater Monitoring Plan,' was submitted on November 16, 2001, and required expert review before Ecology could approve it. Wang was asked to provide written comments on the plan's adequacy and any recommended changes by January 18, 2002.

Port Of Seattle response filed December 6, 2001 to motion to intervene by Citizens Against Sea-Tac Expansion (CASE) in Pollution Control Hearings Board (PCHB) Case No. 01-160, Airport Communities Coalition (ACC) v. Department of Ecology and Port Of Seattle. Port does not oppose CASE intervention if limited under WAC 371-08-420(1): CASE barred from raising new

Airport Communities Coalition (ACC) response to Citizens Against Sea-Tac Expansion (CASE) Motion to Intervene in PCHB No. 01-160, filed December 5, 2001 before the Pollution Control Hearings Board for the State of Washington. ACC does not object to CASE’s intervention but agrees it should not interfere with ACC’s pending Motion for Stay. Respondents are State

Letter dated December 5, 2001 from Sarah Suggs, Wetlands Specialist, Washington State Department of Ecology (Northwest Regional Office) to Grant Beck, Director, San Juan County Permit Center, regarding the Ayer property wetland restoration proposal on Orcas Island. Ecology characterizes the proposal as a wetland conversion (not restoration) under Chapter 90.48 RCW and Chapter 173-201A WAC,

Parametrix, Inc. December 2001 report for Port Of Seattle on Low Streamflow Analysis and Summer Low Flow Impact Offset Facility Proposal for the Seattle-Tacoma International Airport (STIA) Master Plan Update Improvements. Document AR018164, Exhibit 140. Covers HSPF model calibration, embankment modeling, non-hydrologic impacts (cessation of water withdrawals, removal of septic tank discharges), HEC-RAS modeling, vault

This technical report analyzes low streamflow conditions in three creeks near Seattle-Tacoma International Airport (Miller, Walker, and Des Moines Creeks) to assess the potential impacts of airport construction projects on summer water flows. Using a 47-year record of streamflow data and computer modeling tools, analysts determined target streamflow levels for each creek and evaluated how proposed runway and infrastructure improvements might affect seasonal low-flow periods critical to salmon habitat. The study found existing summer low streamflow targets of 0.33 cfs for Des Moines Creek, 0.77 cfs for Walker Creek, and 0.73 cfs for Miller Creek, which were used to guide mitigation planning.

This December 2001 report, prepared by Parametrix, Inc. and several partner firms for the Port of Seattle, analyzes low streamflow conditions and proposes a Summer Low Flow Impact Offset Facility as part of the Seattle-Tacoma International Airport Master Plan Update Improvements. The study examines how planned airport expansion may affect seasonal low-flow water resources in the surrounding area and outlines mitigation measures to offset those impacts. The report is organized across multiple volumes, with Volume 1 containing the main text and Appendices B through J.

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, 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.

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.