ALP 3

Contents
Figure 1. Schematic of the Ridges Basin outlet structure showing the sleeve valve, air bleeder
pipe, and water level in sump well pit.
Figure 2. Inner core of the Pratt energy dissipating axial flow multi jet inline sleeve valve
model 711 and inset showing water jet intersection collision.
Lake Nighthorse is approximately 2.0 miles from the city of Durango, Colorado
http: / /www.google.com /earth/index.html where it will be easily accessible to the public. The
reservoir was filled with water pumped from the Animas River during 2009 -2011 and reached
the normal fill elevation at 6882 feet above mean sea level can Dime 30, 2011. During the filling
process the reservoir was stocked with two types of nonnatiV£O salmonid game fish by the
Colorado Division of Wildlife. As a consequence of Lake Nighthorse becoming a recreational
fishery, stocked nonnative game fish and forage ftsh;(that inhabited Bttsin Creek prior to
reservoir construction) can be entrained into dischai a water. However;.v�ith the discharge water
passing through the sleeve valve it is unfeasible that any fish greater than tfie:diameter of the
sleeve valve nozzle holes will pass through alive: ntrainment,of live fish thra* dam outlet
structures and into the receiving river;is well documented (Cramer and Oligher 194 Bentley
and Raymond 1969, Beamesderfer aiid Rieman 1991, Bye et al. 1996, Coutant and Whitney
2000). Fish smaller in diameter than the sleeve, valve nozzle ltoles which are 0.63 inch or 16
millimeters in diameter can potentially survive passage if they''ca�i.also survive the water jet
intersection collision crested by the design of the sleeve valve (inset picture in figure 2). Live
entrained fish would alS have to survive the.pressure "daf elenees they will experience when
passing through the discharge pifie and sleeve valy, and then inttr ambient atmospheric pressure.
Entrained fish can p6Wmially establish populations downstream of their host reservoir and prey
on native fish as well as tmpete tit favorable habitat, food, and other scarce resources (Rieman
et al. 19-'91).
Animas -La Plata
During 1986, the,V, S., State of Colorado, Ute Mountain Ute Tribe, Southern Ute Tribe,
Colorado Water Resources and'Ptywer Development Authority, Animas -La Plata Water
Conservancy District, New.lw+lrexco Interstate Stream Commission, San Juan Water Commission,
and Montezuma County "(00.), entered into the Agreement to settle Colorado Ute Indian Water
Rights which dated back to 1868. As a primary component of the water rights settlement was the
provision of water to the Colorado Ute Tribes from the Animas -La Plata Project (a water project
added in 1968 to the 1956 Colorado River Storage Project Act), in fulfillment of the Colorado
Ute Tribes' reserved water rights claims from the Animas and La Plata Rivers
hLtp://www.usbr.gov/uL/progact/animp/pdfs/I ALPCostSharingA tg 313 02.pdf.
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