TagSR509(120)

A June 2000 letter from Azous Environmental Sciences to the US Army Corps of Engineers raises concerns about the incorrect mapping of Wetland 44a near the proposed SR509 temporary interchange in SeaTac, Washington. A field review found that the wetland may be 20 to 40 feet closer to the construction zone than shown in project plans prepared by HNTB Corporation, potentially exposing it to significant sediment runoff during construction. The letter also highlights an overlooked creek system connecting Wetland 44a to Walker Creek and Miller Creek, warning that construction impacts could affect a broader network of wetlands and waterways.

A professional wetland scientist reviewed the construction plans for a temporary SR509 interchange near Seattle-Tacoma International Airport and concluded that the project would cause harmful sediment-laden stormwater runoff to discharge into nearby Wetland 43. The report found that the wetland boundary was significantly closer to the construction zone than project documents indicated, and that the steep slopes and sparse vegetation of the construction site made sediment runoff unavoidable. The scientist determined that the planned temporary erosion control measures were inadequate to protect the wetland, particularly during unexpected storm events.

A May 2000 environmental science review raised concerns that construction of a temporary highway interchange near Seattle-Tacoma International Airport's third runway would cause direct sediment runoff into the adjacent Wetland 43. The report found that the wetland boundary was up to 50 feet closer to the construction zone than project documents indicated, and that the steep slopes and inadequate erosion controls would fail to prevent sediment-laden stormwater from damaging the wetland's water quality and aquatic habitat.

Memorandum dated May 3, 2000 from Jim Kelley (Wetland Ecologist, Parametrix Inc.) to Jonathan Freedman (U.S. Army Corps of Engineers), cc Elizabeth Leavitt (Port of Seattle), analyzing indirect impacts to wetlands from the temporary SR-509 interchange at South 176th Street near Seattle-Tacoma International Airport. Concludes no significant indirect impacts to Wetland 43 or Wetland 44

Handwritten notes from a BEATAC meeting at the Port on April 20, 2000, AR018447, involving City of Des Moines personnel including Tom Walsh, Tacie Borden, John Marchiloro, Jim Kelly, and others. Topics include: stormwater review at FCC starting 5-5-00; SR-509 temporary interchange issues (ESA/BA review, Jonathan Freedman indirect impacts, erosion/sediment control, no federal nexus); LWS#3

SEPA Addendum dated January 24, 2000, Port Of Seattle, POS SEPA No. 00-02, addressing modifications to the Master Plan Update Development Actions for the Third Parallel Runway at Seattle-Tacoma International Airport. Addendum covers: (1) increased wetland acreage affected by the project, revised from 12.23 acres to 18.33 acres, with 15.41 acres affected by the runway

Email forwarded by Erik Stockdale to Tom Luster, originating from Gail Terzi, regarding SR509 proposal conflicts with Sea-Tac Airport third runway (SASA). Key issues include wetland fills in overlapping areas, moving Des Moines Creek for SR509 while Port Of Seattle spends millions bridging the creek at Tyee, and FAA telling WSDOT they CAN mitigate habitat

HNTB-prepared Final Draft Phase I study (November 1996) for Sea-Tac Airport Third Runway fill material alternative delivery methods. Evaluates transport corridors including Corridor 1 (Des Moines Creek barge transfer and land conveyor), Corridor 2 (SR 509 conveyor, truck, rail), and Corridor 3 (SR 518 conveyor, truck, rail). Covers technical viability, construction/environmental permitting (local, state, federal),