Mill Creek contains ESA listed Snake River summer steelhead, resident rainbow trout and other native
species. The steelhead population is severely depressed from historic levels. Elimination of passage barriers is a high priority action wherever listed species occur. The project site is the McNeill Diversion.
Each year the irrigators enter the stream with heavy equipment to construct a pushup dam to
divert water into the irrigation ditch, disturbing the streambed, creating excessive sediment and
creating a fish passage barrier. Passage is restricted for juvenile steelhead, resident rainbow trout
and other native species after the pushup dam in constructed. The pushup dam remains in place
usually from early-July through the end of October.
The Union Soil and Water Conservation District (SWCD) sponsored the project. BPA funds
were used to install one vortex rock, channel-spanning weir. The weir installation was part of a
larger project the SWCD implemented which rebuilt the diversion headgate structure, installed a
new slide gate, installed a measuring device, installed a new fish screen and piped 1400 feet of
open irrigation ditch. The SWCD acquired funding from the Oregon Watershed Enhancement
Board for all elements of the project except the rock weir.