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<br />23 Off-atream aite.- This dam and reservoir site is locat~d
<br />about S ~~~es north of the city limits of Pueblo. The project would
<br />control S03 square m~les of drainage area above the dam. The plan
<br />includes a main dam, diversion channels, and diversion dites. The
<br />do~ and reSerVOlr hove been designed to control the estimated IOO-year
<br />sediment deposit and the volume of the IOO-yearflood. Diversion
<br />Channel-A was deSlgned to accept the standard project flood flow, but
<br />the reservoir lacks capacity to store the volume. The project would
<br />originate with a diversion structure across fountain Creek near the
<br />EI Paso _ pueblo county line. The concrete ogee diversion weir would
<br />be constructed in the streambed to discharge a portion of the spillway
<br />design flood and divert all flows up to the standard project flood
<br />discharge. A low-flow channel would be constructed in Diversion Chan-
<br />nel-A to return normal flows to the Fountain Creek channel about one
<br />mile downstream from the diversion. Thc reservoir capacity at spillway
<br />crest would be 169,000 acre. feet of which 129,000 acre-feet would be for
<br />flood control and 40,000 acre-feet for sediment retention. The spillway
<br />would be cut through a saddle about 0.75 mile east of the cost abutment,
<br />Erosion control would be effected by a long flat slope and a concrete and
<br />riprap weir across the entire width. The outlet works would be located
<br />in the center of the embankment at the low paint.
<br />
<br />24. Since the reservoir would be located ncar the top of the
<br />watershed it would be necessary to construct Chico Dike-F to raise the
<br />water surface above elevation 5J60. To drain the water whiCh would be
<br />trapped above the divide, it would be necessary to construct Chico
<br />Channel-E. All dikes would have a cut-off trench, trapezoidal in
<br />cr05ssectionwithalO-footbottomwidthandlonlsideslol'es,
<br />excavated to shnlc.
<br />
<br />25. The esti~ated costs and engineering features are for a flood
<br />control dam and reservoir only to control the volume of a IOO-year
<br />flood. There are 7.6 roiles of dikes and dam in the proposed project.
<br />A sIight raise in thc hei~ht of the dam would increase the length of
<br />the dlkes out of proportion to the storage gained alld require reloc ....
<br />tion of the D~RGW Railroad alignment.
<br />
<br />26 The estimGted first cost of a project at this 5itc would be
<br />$22,S30,000,allFederal,andthetotlll invescrnent would he $23,SlO,000.
<br />Total annual charges would be $1,283,000> Engineering features are
<br />listed in Table 16 and" detailed cost estimate is given in Table \7.
<br />The plan IS shown on Plate 14.
<br />
<br />l-~~
<br />
<br />i
<br />I
<br />r
<br />I
<br />!
<br />
<br />TABLE 16. -- [nglllcoring reatures, Fountain Creek, Off-strea~ Site
<br />
<br />Contributing Drainage Area, square miles
<br />
<br />RHEIWOIR,
<br />1.lanmurLwatersurface:
<br />Eleva.tion, feet
<br />Capacity, acre_feet
<br />Are.., aCreS
<br />,':atersurface at spillwny creSt:
<br />Elevation, feet
<br />Capacity, acre_feet
<br />Area,acres
<br />Stora~c allocation:
<br />Flo~d control, acre_feet
<br />Sedi~ent, a.cre-feet
<br />
<br />I
<br />I
<br />I
<br />,
<br />
<br />DAN:
<br />---:rype
<br />Ueightabovestrearobed,feet
<br />Top of dam elevation, feet
<br />Top of dam width, feet
<br />Freeboard,feet
<br />Crest length, feet
<br />Side slopes:
<br />Upstr..anl
<br />DownstrealO
<br />Embankment sloro
<br />Upstream
<br />(Jownstrean,
<br />
<br />I
<br />,
<br />I
<br />ISPIl,LWi\Y:
<br />I Locatioo
<br />'>1'0
<br />Maximum design discharGe,
<br />[rest e1ev~tion, feet
<br />Butto", width, f~~t
<br />Side slopes
<br />
<br />20'_
<br />20'-
<br />
<br />10n2.5;
<br />ion2;
<br />
<br />protection:
<br />
<br />I
<br />I
<br />I
<br />i
<br />,
<br />
<br />c.f.s.
<br />
<br />OUTLET lWRKS:
<br />Type
<br />Maximum discharge capacity,
<br />TerlAi"nlcncrgycuntroJ
<br />
<br />c.f.s.
<br />
<br />DIVE~SIOl' ~EI~ AKD OIKE:
<br />'.'eirlength, feet
<br />licight, feet
<br />~ndwalls, height. fcet
<br />Oge.. ~elr, verticnl siJe~
<br />~l:lx i.,,"", des i g ~ d i s charge, c. f, s. ,
<br />Ili vcrs ion to re~crvoir
<br />Spill H) f"''''tain Crl'''', oof.".
<br />
<br />S03
<br />
<br />5187
<br />190,000
<br />4,450
<br />
<br />5182
<br />l6!),OOO
<br />3,150
<br />
<br />129,000
<br />40,000
<br />
<br />Earthfill
<br />'"
<br />5ln
<br />20
<br />,
<br />15,350
<br />
<br />'"
<br />SO'
<br />
<br />I on 3; balance _ 1
<br />I On 2.5; balance
<br />
<br />on 3.5
<br />lon3
<br />
<br />12" riprapon 6"
<br />,..
<br />
<br />gravel
<br />spalls
<br />
<br />Eastnbutmem
<br />Broad crested weir
<br />201,500
<br />5182
<br />2,000
<br />10n2.5
<br />
<br />ll'diameter
<br />spillway crest
<br />
<br />concrete conduit
<br />5,000
<br />Stilling basin
<br />
<br />1,550
<br />,
<br />"
<br />Concrete
<br />
<br />225,000
<br />200,000
<br />
<br />1-36
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