Jimmy,
The Cougar Dam on the South Fork of the McKenzie River in Oregon has either recently been, or is in the process of being retrofitted with multi-level intakes. The e-mail sent to me from Oregon today actually said "multi-level outlets", but I think they meant intakes to the turbines (and thus outflow to the river). The South Fork below the dam (impassable) is the "last best place" for Threatened wild spring chinook in the Willamette Basin, and they weren't doing too well. Turns out after construction of the dam, the river was warmer in the winter than in the summer, because of a hypolimnetic release. Oops, sort of messed up their life-histories a tad!! You might be able find more information on a COE website.

-- Rick