Alan Dyer (WSDOT, Urban Corridors Office; 21851 84th Ave South; Kent, WA 98032-1958)

is seeking coverage under the Washington Department of Ecology's NPDES General Permit for Stormwater Discharges Associated with Construction Activities.

The proposed 5.234 acres project, known as SR 509/518 Safety Improvements Project is located at SR 509/518 Interchange, in King County within the City of Burien (Section 20, T23N, 6R04E). Approximately 2.034 acres will be disturbed for construction of safety improvements. These safety improvements include:

Re-channelization of SR 518 westbound (WB) direction in the interchange area with SR 509, from mile post (MP) 0.0 to 0.1.

Widening SR 509 southbound (SB) off-ramp to accommodate current and future traffic storage needs.

Widening SR 509 SB on-ramp to accommodate dual design vehicle left turning movements from WB SR 518 to the ramp.

New and replaced signing and illumination on the ramps and interchange areas.

Constructing new water quality facility (Ecology Embankment) on the west side of SR 509 SB On-Ramp at the Interchange

Landscaping in the interchange area between MP 0.0 and 0.1 to give a visual transition from an urban freeway to surface streets in the City of Burien.

Anticipated construction equipment includes backhoes, excavators, front loaders, pavement grinders, jack hammers, and grading and paving equipment. Construction is scheduled to take place in January of 2007 and last approximately 25 months. The project will result in:

A net loss of 4,285 square feet of paved surface. The project will add 33,500 square feet of new pavement and remove approximately 37, 785 square feet of existing pave surface (associated with traffic islands, asphalt lined ditches and ramps). The previously paved areas will be landscaped with native vegetation.

Enhanced treatment will be employed to treat all new and approximately 6,400 square feet of existing pavement

Clearing of approximately 0.42 acre of upland vegetation (roadside grass/shrub) as part of construction activities. No large trees or riparian vegetation will be cleared. Temporarily cleared areas will be replanted with native vegetation. There is no sensitive area (wetland) within the project limits.

Best Management Practices and controls to mitigate erosion and sediment transport during construction will be used, and a Stormwater Site Pollution Prevention Plan (SWPPP) will be prepared and implemented during construction. Temporary Erosion and Sediment Control (TESC) devices will include scheduling to minimize earthwork activities during the wet season, limiting soil exposure and using and using sediment control devices such as sodding, silt fences, check dams and erosion control mats. Construction stormwater will be subject to these TESCs before being discharged from the site. Stormwater will be treated via ecology embankments prior to discharging to closed conveyance system traveling south and emptying into Miller Creek. Miller Creek is approximately one half mile from the project area.

Any persons desiring to present their views to the Department of Ecology concerning this application may notify Ecology in writing within 30 days from the last date of publication of this notice.

Comments may be submitted to: Washington Department of Ecology Water Quality Program Stormwater Unit - Construction

PO Box 47696 Olympia, WA 98504-7696

Published in the Highline Times/Des Moines News on NOVEMBER 22 & 29, 2006.

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