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<br />Table 1 - Estimated Runoff of Cow Creek At Overland Reservoir (acre-feet)
<br />1950-1967
<br />
<br />YEAR OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP TOTAL
<br />1950 246 164 130 108 98 128 310 2,575 3,690 1,317 386 258 9,410
<br />1951 178 118 94 78 71 92 223 1,860 2,660 948 278 180 6,780
<br />1952 331 220 175 145 131 172 416 3,450 4,970 1,770 518 342 12,640
<br />1953 211 140 111 93 84 110 265 2,200 3,160 1,127 330 219 8,050
<br />1954 177 117 93 77 70 91 221 1,845 2,640 942 276 181 6,730
<br />1955 211 140 111 93 84 110 265 2,200 3,160 1,127 330 219 8,050
<br />1956 189 126 99 83 75 98 237 1,970 2,830 1,008 296 199 7,210
<br />1957 356 237 188 156 141 185 447 3,720 5,340 1,902 558 370 13,600
<br />1958 282 188 149 124 112 146 354 2,945 4,230 1,505 442 293 10,770
<br />1959 162 108 85 71 64 84 203 1,690 2,430 865 254 164 6,180
<br />1960 217 144 115 95 86 113 276 2,270 3,250 1,160 340 227 8,290
<br />1961 138 128 110 98 89 98 144 2,145 2,156 259 172 442 5,979
<br />1962 497 257 186 142 119 154 522 2,373 6,150 2,542 304 195 13,441
<br />1963 162 128 98 76 80 87 355 3,163 1,580 282 174 96 6,281
<br />1964 76 87 53 53 82 121 165 2,059 3,213 616 586 213 7,324
<br />1965 142 91 87 75 51 87 179 1,378 5,245 3,274 690 392 11,991
<br />1966 353 215 185 153 119 160 353 2,833 2,104 319 209 131 7,134
<br />1967 169 163 170 151 108 138 140 2,002 4,585 1,298 488 252 9,664
<br />AVG 228 154 124 104 92 121 282 2,387 3,522 1,237 368 243 8,862
<br />
<br />The above data indicates that, during the 18 year study period, there was sufficient runoff volume to
<br />fill a 7,171 acre-foot reservoir 13 of those years. During 3 of the 5 years in which there was not
<br />sufficient volume to fill a 7,171 acre-foot reservoir, the runoff exceeded the existing capacity of the
<br />Overland Fteservoir (6,200 acre-feet).
<br />
<br />Also included in Appendix B is a tabulation of historic flows in the Overland Ditch. This data was
<br />obtained from the local water commissioner and the Colorado HydroBase database. These records
<br />include a 35 year period from 1970 through 2004. However, only 12 of these years include complete
<br />records. The average diversion for all years (including those with incomplete records) is about
<br />13,000 ac-ft/yr. However, for the years with complete records, the average is 15,839 ac-ft/yr. It also
<br />turns out that, during the years with complete records, the average diversion from Leroux Creelc was
<br />about 5% less than the average diversion amount for the period of record from Leroux Creek Even
<br />though, without a detailed evaluation of the Leroux Creelc water availability, it would be difficult to
<br />justify a direct relationship between total ditch diversions and diversions from Leroux Creelc, this
<br />does indicate that the years with complete records may have been somewhat drier than the average
<br />for a longer period. It seems reasonable that the average diversion volume deteIlIlined from the years
<br />with complete records should be inflated by at least 5 percent to 16,679 ac-ft/yr (rounded to 17,000
<br />ac-ft for the purposes of this report). This is not much different from an estimate of 18,000 ac-ft/yr
<br />made by the ODFtC manager.
<br />
<br />PROJECT DESCRIPTION AND ALTERNATIVES:
<br />
<br />The purpose of this project is to provide a means to store the balance of a conditional storage water
<br />right that will supply supplemental irrigation water as well as, possibly, augmentation water. Three
<br />alternatives have been considered:
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