(2014-056 Jan. 22) Loup Loup Bridge SEPA 2013-12

(2014-056 Jan. 22)

Loup Loup Bridge

SEPA 2013-12

The proposal intends to enhance groundwater fed surface flows and in channel habitat complexity features within a high flow conveyance side-channel of the Methow River. To accomplish this they will install an approximately 725 linear foot gravity fed groundwater collection gallery buried within the floodplain at depths appropriate to contact static groundwater elevation as low flow conditions. The groundwater collection gallery will feed into a 2100 foot long conveyance pipe also buried at depths ranging from 6 to 12 feet fellow existing surface grade that will outlet into an enhanced section of the existing 1890’s side channel (approximately 4,500 linear feet of enhanced channel. The ground water gallery is expected to produce flows near 4 cubic feet per second during low flow conditions resulting in a bypass reach on the Methow River for just over one mile. Diverted water will return to the Methow River at the downstream end of the side channel. An assortment of wood structures will be added to the enhanced channel as habitat complexity elements, and the channel bottom and banks will be contoured to contain pool/riffle habitats and wetland and riparian vegetation. There will be approximately 9 acres of area where spoils from deepening the side channel will be placed. Approximately 41,000 cubic yards of alluvial spoils will be excavated from the side channel and placed within an adjacent existing pasture. 5,200 cubic yards of top soil obtained from a local commercial source will be imported to restore the vegetated pasture on top of the channel excavated material and to create new wetlands in the side channel enhancement area.

The site is accessible through private lands off of driveways connecting to Peters Road and State Highway 20 on the northern boundary of the Town of Twisp, WA (530 Peters Rd), Sections 6, 7, and 8, T33N, R22E, Willamette Meridian, Okanogan County. The comment period for this determination ends at 5pm on February 5, 2014. Comments must be submitted in writing. Direct questions and comments to: Charlene Schumacher, Natural Resource Senior Planner, Okanogan County Office of Planning & Development, 123 5th Ave. N, Suite 130, Okanogan, WA 98840, (509) 422-7113. Published by Omak-Okanogan Chronicle.


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