TagPollution Control Hearings Board(1532)

Meeting notes from an October 30, 2001 technical session addressing errors discovered in the low streamflow modeling for Sea-Tac International Airport's Third Runway project. Consultants identified six modeling errors, including a conversion factor mistake that caused embankment flow contributions to be understated by a factor of 24, along with incorrect input files and improper groundwater routing. Representatives from the Port of Seattle, King County, the Department of Ecology, and the Army Corps of Engineers agreed on corrective revisions to be incorporated into a revised Low Streamflow Analysis and Summer Low Flow Impact Offset Facility Proposal required under the 401 Permit.

This technical memo from Hydrocomp, Inc. (authored by Norm Crawford) outlines recommendations for improving hydrological computer modeling of Miller, Walker, and Des Moines Creeks near Seattle-Tacoma International Airport's new runway construction. It describes how rainfall and runoff from the new impervious runway and taxiway surfaces and surrounding pervious grasslands are tracked through a linked series of models (HSPF, Hydrus, and Slice) to estimate groundwater movement and seepage through underlying soil layers. The document identifies several discrepancies in the existing model setup and recommends corrections to better account for water flow paths, drainage areas, and groundwater recharge in the fill areas created by airport expansion.

Memorandum dated October 30, 2001 from Michael Kenrick of Hart Crowser, Inc. to Jim Thomson of HNTB (project number 4978-06), CC Elizabeth Leavitt of Port Of Seattle, regarding wetland hydrology impacts of the Third Runway Embankment Fill at Sea-Tac Airport. Covers depression wetlands, slope wetlands, and riparian wetlands; references FEIS for the Master Plan Update

Memorandum dated October 30, 2001 from Michael Kenrick of Hart Crowser, Inc. to Jim Thomson of HNTB, CC Elizabeth Leavitt of Port Of Seattle, project number 4978-06. Addresses wetland hydrology impacts of Third Runway Embankment Fill construction at Sea-Tac Airport, covering depression wetlands, slope wetlands, and riparian wetlands. References Miller Creek and Walker Creek baseflow,

Port Of Seattle’s submittal of record references in PCHB case No. 01-160 (Airport Communities Coalition v. Department of Ecology and Port Of Seattle), filed October 29, 2001, opposing ACC’s motion for stay. Lists declarations from James C. Kelley Ph.D., Katie Walter, Erik Stockdale, Paul S. Fendt, Joseph Brascher, Donald Weitkamp Ph.D., Ann Kenny, Edward O’Brien,

A October 26, 2001 transmittal from Parametrix, Inc. to the U.S. Army Corps of Engineers (ACOE) provides responses to the ACOE's request for additional information regarding the Seattle-Tacoma International Airport (STIA) Master Plan Update (MPU) Natural Resource Mitigation project. The package includes maps and aerial photographs identifying wetland areas and acreages within Borrow Area 1, submitted on behalf of the Port of Seattle.

Email from Kelly Whiting (King County Department of Natural Resources, Water and Land Resources Division) to Ann Kenny and Raymond Hellwig, dated October 25, 2001, summarizing a pre-meeting briefing on revised low flow hydrologic modeling related to Port Of Seattle airport embankment impacts. Discusses Hydrocomp (Norm Crawford) independent review findings, HSPF modeling errors including incorrect

ACC (Airport Communities Coalition) filing in PCHB No. 01-160 before the Pollution Control Hearings Board, State of Washington, submitting supplemental authorities in reply to ACC’s Motion for Reconsideration and responding to Ecology’s October 22, 2001 submission. Argues AAG statements on a ‘purely legal question’ regarding water rights for the low flow plan fall outside attorney-client

In this October 24, 2001 letter, the Port of Seattle notified the Washington Department of Ecology of a mathematical error discovered in hydrological modeling software used to assess the Seattle-Tacoma International Airport Master Plan's impacts on Miller and Walker Creeks. The error caused stream flow impacts to be overestimated at 1/24th of their actual value, meaning required mitigation facilities could be smaller than originally planned. As a result, the Port requested an extension of the Low Streamflow Analysis submittal deadline from November 5 to November 21, 2001.

Washington State Department of Ecology reply brief filed before the Pollution Control Hearings Board (PCHB No. 01-160) opposing Airport Communities Coalition’s (ACC) arguments against Ecology’s motion to strike attorney-client privileged documents. Ecology argues the privilege is not ‘at issue’ under Pappas v. Holloway (114 Wn.2d 198) and Hearn v. Rhay (68 F.R.D. 574), and that