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<br />DAM MiD RESERVOIR PRO.,'f.CTS, FOiill'I'I.I!.' CREU, ,rCDlfTY OF PUfBW
<br />
<br />21 Pir~n Site.~ thiS site is located near th~ tOWn of PlnOn,
<br />Colorado, about 8 miles north of the eity limits of Pueblo. The dam
<br />would control 852 square ~iles of Fountain Creek drainage area above
<br />the dam There would be 6S square miles of uncontrolled drainage area
<br />below the dam. The west abutment of the dam would be located immediate-
<br />lybelow the confluence of Young Ilollow Arroyo with Fountain Creek . The
<br />alig~.ent would then generally follow the Denver and Rio Grande Western
<br />Railroad for about 3-4 ",des to the south, theneegenerally eastward to
<br />high ground at the east abutment. Minor modifications would be required
<br />at the crossing of the AT&SF Railway and the O~RGW Railroad. The reser-
<br />voir...'ouldcontain169,OOOaere-feetat spillway crest, ofwhic h129,000
<br />acre-feet would be for IOO-year flood protection and 40,000 acre-feet
<br />for 100-year sediment retention. The outlet works would he located in
<br />the stream thalweg and the sl'illwaywouldbe located around the east
<br />abut",ent. Flows OVer the spiHwaywould follow an existing arroyo and
<br />return to the Fountain Creek channel, The estimated first cost of a
<br />project at this site would be $27,766,000, all Federal, and the total
<br />investment would be $29,000,000. Total annual charges would be
<br />$1,543,000. EngineeriTlg features are listed in Table 14 and a Jetailed
<br />cost estiJllate is given in Table 15. The plan is shown on plate 13.
<br />
<br />22. Several other alignments were investigated for a dam and
<br />reservoir at the Pinon site, including one straight across the Valley,
<br />in an effort to increase the Jegree of protection. The slope ef
<br />Fountain Creek is such that any railroad relocation around the reSer-
<br />voir site weuld have to begin at Pueblo to maintain an acceptable
<br />gradient This plus the rc1ocation of lnterstat.e Highway 25 past the
<br />site woulJ increase the cost of a dam and reservoir with a larger
<br />StOrage capacity beyonJ the rang" of feasibility.
<br />
<br />1-3.
<br />
<br />TABLE 14. __Engineering Features, Pinon Dam an<l Reservoir
<br />
<br />C"ntributingDrainageArea, sq. mi.
<br />
<br />852
<br />
<br />RESERVOIR;
<br />Maximum water surface:
<br />Elevation, feet
<br />Capacity,acre-fcet
<br />Area,acres
<br />Water surface at spiIlway crest:
<br />Elevation, feet
<br />Capacity, acre-feet
<br />Area, acre~
<br />Stora~e allocation:
<br />Floo control,acre-feet
<br />Sediment, acrc4feet
<br />
<br />5120
<br />250,000
<br />5,450
<br />
<br />5103
<br />169,000
<br />3,900
<br />
<br />129,000
<br />40,000
<br />
<br />OM!:
<br />Typ'
<br />Heightabovestreambed,feet
<br />Top of dam elevation, feet
<br />Top of dam width, reet
<br />Freeboard, feet
<br />Crestlength,fcet
<br />Embankment slope protection;
<br />Upstreallt
<br />Oownstrea",
<br />
<br />EurthfilI
<br />130
<br />5125
<br />"
<br />,
<br />29,550
<br />
<br />12" riprap On 6" gravel
<br />SO'spalls
<br />
<br />I
<br />I
<br />I
<br />I
<br />
<br />SPILLWAY:
<br />Location
<br />Type
<br />Ma~imum design di~charge, c.f .s.
<br />CreSt elevation, feet'
<br />Basewidth,feet
<br />Side slopes
<br />
<br />Ea~t abutment
<br />Broad crested weir
<br />400,000
<br />5103
<br />2,000
<br />lon2.S
<br />
<br />OUTLET ~.ORKS;
<br />Type
<br />Elevationatintakc
<br />~la.x imum d i s charge capac i ty ,
<br />Tcrninal energy control
<br />
<br />11' diameter concrete conduit
<br />4990
<br />c.f.s., spillway crest 5,000
<br />5tillingbasin
<br />
<br />1_32
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