Clearwater Coho Acclimation Pond

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The proposed pond modifications would occur at the existing Nez Perce Tribal Hatchery facility known as the North Lapwai Valley (NLV) acclimation site. NLV is operated by the NPT with funding from Bonneville Power Administration, and is located approximately 0.75 miles upstream of the confluence of Lapwai Creek and the Clearwater River in Nez Perce County, Idaho. The NLV is currently used to acclimate fall Chinook salmon subyearling smolts, which precludes the use of existing facilities for the acclimation of coho salmon. The NLV satellite currently has two ponds, with approximately 13,150 cfs of rearing space each, with both a surface and groundwater supply system that can be mixed to control water temperature. The ponds are located in the higher elevation area of the site with discharge entering Lapwai Creek near the State Highway Route 95 bridge crossing. The site was designed for additional pond construction and has adequate living quarters for personnel to occupy during acclimation. The following modifications are proposed at this site: • Excavate a pond to acclimate up to 550,000 coho salmon down slope from the existing ponds (Attachement 1). The proposed pond would be 23,000 cubic feet, allowing the acclimation of 550,000 coho smolts at a density index (Piper et al. 1982) of 0.3. • Tap into the existing pond overflow, well, and surface water head tank. • Construct a first pass water supply through the overflow of the existing head tank, and allow for diversion of second pass water through the overflow from existing ponds. • Construct small check dams to impound a series of small pools along the existing overflow ditch leading to Lapwai Creek.

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