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I I I I I I I I I I I I I I I I I I I Station Number Name Period of Record 09095500 09093700 Colorado River near Cameo Colorado River near De Beque 1934 to present 1967 to present The Cameo gage is 13 miles downstream of the dam site and has a drainage area of 8,050 square miles; whereas, the De Beque gage is at the dam site. The annual gaged flow at the Cameo gage averages 3,653 cfs (2,640,000 ac-ft) and ranged from 1,937 cfs to 5,825 cfs, for the 30-year study period of 1950-1979 selected for evaluation of the Project. The average annual gaged flow at the De Beque gage since 1967 is 3,515 cfs (2,540,000 ac-ft). A linear correlation analysis of average monthly flows produced a synthetic record of the 1950-1979 gaged flows at the dam site shown in Table II-1. The correlation equation for monthly flow volumes in ac-ft between the two gaging stations was determined to be as follows: Gaged flow at De Beque gage = 1.01249 x (gaged flow at Cameo gage) - 9,730. The resulting estimated 30-year average annual gaged flow at the dam site for 1950-1979 is 3,540 cfs. The distri bution of daily gaged flows at Cameo for the period 1934-1980 is illustrated in the flow-duration curve, Fig. II-3. The median flow is 2,000 cfs and the 15 percentile exceedance flow is 6,200 cfs. The monthly average virgin flows for the period 1950-1979 at the Una dam site as shown in Table II-2 were obtained by adding the appropriate upstream depletions from the synthetic flow record tabulated in Table II-1. The procedures for and the derivation of the virgin flow are summarized in Appendix C, Water Rights Evaluation and Storable Flow Analysis, prepared by Leonard Rice Consulting Water Engineers, Inc. (LRCWE). The average annual virgin flow is estimated to be 4,320 cfs and is equivalent to an average annu- al runoff of 7.94 inches over the basin. These monthly virgin flows are util- ized to develop tables of monthly storable flows for the Project as described in Section III. II-5