TagMiller Creek(260)

Natural Resource Mitigation Plan for Seattle-Tacoma International Airport (STIA) Master Plan Update, November 2001, document reference 556-2912-001 (03). Table 1.3-1 lists all proposed Master Plan Update improvement projects including: third parallel runway 16X/34X (8,500 ft), Runway Safety Areas (RSAs) for 16R/34L and 16L/34R, South 154th Street relocation, South Aviation Support Area (SASA) for cargo/maintenance, embankment

Report prepared by Parametrix, Inc. for Port Of Seattle regarding the Miller Creek Riparian Corridor and Instream Enhancement Project and Wetland A17 Restoration, part of the Seattle-Tacoma International Airport Master Plan Update Improvements. Document AR 052286 covers wetland mitigation design, Army Corps of Engineers requirements, buffer averaging, hydrology, soils, vegetation, grading, landscape plan, performance standards,

Port of Seattle Natural Resource Mitigation Plan figure (AR017604, Exhibit 46, dated 12-20-01) showing Master Plan Update Improvement Projects at Seattle-Tacoma International Airport (STIA). Map depicts Third Runway construction area, Runway Safety Areas (RSAs), MSE retaining walls used to avoid and minimize wetland impacts, relocated section of Miller Creek, Miller Creek Detention Facility, Lora Lake,

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

These draft meeting notes from October 30, 2001 document a technical review session in which Port of Seattle consultants disclosed and explained several errors found in the low streamflow modeling for the Sea-Tac Airport Third Runway project. The key errors included a 1/24th magnitude conversion factor mistake in embankment fill data input, incorrect input files used for embankment modeling, and an overlap in which approximately 8 acres of the Walker Creek embankment appeared to be counted in both the Hydrus embankment model and the HSPF stream model. The meeting outlined corrective steps to be taken by the Port's consulting team to fix these errors before finalizing the revised Low Streamflow Analysis required under 401 Permit conditions.

Final meeting notes from October 30, 2001 Low Flow Analysis meeting regarding Port Of Seattle’s revisions to the Low Streamflow Analysis and Summer Low Flow Impact Offset Facility Proposal per 401 Permit conditions for Sea-Tac Airport Third Runway. Attendees included Ann Kenny (Dept. of Ecology), Kelly Whiting and David Masters (King County), Lisa Scott (Corps

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.

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.

Declaration of Amanda Azous filed in Pollution Control Hearings Board (PCHB) cases No. 01-133 and No. 01-160, Airport Communities Coalition (ACC) v. State of Washington Department of Ecology and Port Of Seattle. Azous argues Port Of Seattle’s wetland hydrologic monitoring is inadequate for Section 401 Certification No. 1996-4-02325 and CZMA concurrency statement. Document addresses Wetlands

Declaration by Amanda Azous filed in PCHB Case Nos. 01-133 and 01-160 (Airport Communities Coalition v. State of Washington Department of Ecology and Port Of Seattle) in support of ACC’s reply on motion for stay of Section 401 Certification No. 1996-4-02325 and CZMA concurrency statement. Azous asserts scientifically substantiated harmful impacts to Miller Creek, Walker