ALP 3

Contents
The 1968 Animas - La Plata Project was considerably scaled down to the current project to
include the Durango Pumping Plant, Ridges Basin Inlet Conduit, Ridges Basin Dam, and the
Navajo Nation Municipal Pipeline. The purpose of the Project was also scaled back to provide a
municipal and industrial source of water for both Indian (Colorado Ute Tribes and Navajo
Nation) and non -Indian entities in Colorado and New Mexico and no longer included water for
irrigation purposes. Construction for the scaled down version of the Animas -La Plata Project did
not begin until 2001. Ridges Basin Dam is a zoned earthfill dam composed of six distinct earth
material types totaling approximately 5.25 million cubic yards ofMaterial. The impervious
earthen core was constructed from clay material obtained from the future reservoir site and large
rock boulders collected locally were used as rip rap on the face of the dam
httl2://www.usbr.gov/uc/progact/animas/index.html.
The most important feature of the Animas - La Pat
The reservoir is located inside of Ridges Basin tt
Animas River. Ridges Basin Dam impounds Batii
whereas the Animas River is a large free - flowing
thousand cubic feet per second (cfs) during spring
the Animas River were set at 571000 BCPe-et >ann
spring runoff high flow period. The Durango-1 t n
foot (ft) conduit about 2.1 miles before reaching t
maximum pumping amity is 280 cfs but the pla
of Lake Nighthorse is Y 0,000 -feet whdte 90,
30,000 acre -feet is in4dive storag+ (minimum pcx
streambed of Basin Creek and has a.Frest length o
Niahthorse-is 1;490 acres at:full i�ool i ttt:l www.i
x
ism
t1
W
a Project is that it is a off- stream reservoir.
is filled by water pumped uphill from the
Creek which is a small intermittent stream,
ve whero, flows typically reach =several
unoff(fll re 3). Pumping depiet ions from
ally and can be mostly achieved during the
zing Plant pumps water uphill through a 4
ke.'Al ghthorse.:The pumping plant's
t can perate at lesser rates. The total volume
acre =f.i- considered active storage and
1. Ridges Basin Dam is 217 ft above the
1.670 ft. The total surface area of Lake
USGS 09361596 ANWAS RIVER AT DURANGO, CO
mt .- W ar opt J- Wr M mt .r W A& .t&
IM as as as a ate au M0 an au = M un
—M-MM — 11WMA.i We"d*.0
— r.u..e.e a..Um
Figure 3. Animas River flow (2009 — 2011 water years) during Lake Nighthorse filling period
hLtp://waterdata.usgs.gov/co/nwis/rt.
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