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Ratin Curves g A rating curve is the relationship between river stage and discharge at a given cross section station. By surveying the water surface elevation when a discharge measurement is collected, the discharge Q can be expressed as a power function of the river stage as follows: Q = a (stage)b where a is a coefficient and b is a exponent determined by a least squares fit power regression. The stage at each level logger was measured above assigned reference elevation. This regression relationship plots as straight line on a log-log graph. The regression relationships are presented in Table 2 with the correlation coefficients and the Canyonlands rating curve is plotted on Figure 2. Tahle ?. R~itn ; ~Gurve Relationships 1.~~~ci tx7g~cr~~tc. l:~ru~ti«,z . it~t~eence E,1e~<~ttcin R' Mitten Park Q = 2749.2 (stage)eeez 80 0.98 Ouray Wildlife Refuge O = 163.85 (stage)1815 4650 0.98 Below Ouray O = 1296.3 (stage)1-2789 90 0.98 Desolation Canyon O = 33.17 (stage)2J91 80 0.995 Canyonlands Q = 210.68(stage)1 B18 3940 0.997 Green River Discharge Ilydrographs The level logger data includes date, time, pressure head, and temperature. The data is recorded at prescribed interval of either 15 minutes, 30 minutes or 1 hour. The data is reduced with a Fortran program called Logger which was written to convert the pressure head data to a river stage. The discharge is then computed using the derived rating curve. In addition, the program also computes an average daily discharge. The Logger program was applied to each level logger data base to produce a daily discharge hydrograph. The discharge hydrographs at the level logger sites are presented in Figures 3a through 3d. The discharges at the USGS Jensen and Green River gages along with the Flaming Gorge release data are also plotted for comparison. It should be noted that the USGS gage discharge data is provisional at the time this report was prepared. There may be adjustments in the USGS gage data prior to final publication. Green River Temperature Plots of the Green River temperature at three of the levee logger recording stations are shown ' in Figure 4 as function of the date. The temperature throughout the system increases significantly during the period from June 1 to June 7, then levels off until approximately July 1. The rate of rise 8