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outside of the accuracy range of the model, over 250% of the measured discharge or under 40% <br /> of the measured discharge may not give an accurate estimate of the necessary instream flow <br /> required. <br /> Hydrologic Data <br /> After receiving the cooperating agency's biologic recommendation, the CWCB and BLM staff, <br /> conducted an evaluation of the stream hydrology to determine if water was physically available <br /> for an instream flow appropriation. Although there is a substantial amount of streamflow gage <br /> data available for the Uncompahgre Plateau and Glade Park, most of this data is severely <br /> impacted by diversions and irrigation use. This situation makes it difficult to estimate the natural <br /> flow regime for the watersheds on the Plateau. Without specific gage data to evaluate, the next <br /> best approach is a regional equation that estimates annual flow characteristics. The USGS has <br /> developed regional equations (Estimation of Natural Streamflow Characteristics in Western <br /> Colorado, Water Resources Investigations Report 85-4086, 1985) that apply to the Uncompahgre <br /> Plateau and Glade Park based on basin drainage area, mean annual precipitation, mean basin <br /> elevation and mean basin slope. The report "Uncompahgre Plateau and Glade Park Annual <br /> Hydrograph Estimation" in Appendix C, explains staff's water availability analysis in more <br /> detail. Table 2 below displays the estimated stream flow of Little Dolores River, <br /> Table 2:Estimated flow Little Dolores River. <br /> January February March April May June July August September October November December <br /> 1.4 1 3 I 4.3 I 65 1 240 I 110 I 5.5 I 2.1 I 1.8 I 1.7 I 1.6 I 1.5 <br /> Little Dolores River Estimated Stream Flow <br /> 10 - <br /> 8 <br /> 6 <br /> 4 <br /> - -- -- -- -- -- - - -- -- -- - <br /> JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC <br /> Month <br /> Table 2 shows that the summer flow recommendation of 2.4 cfs is only available April 15t—July <br /> 315t. The summer flow recommendation was further reduced to 1.6 cfs for the time period of <br /> August 15t through October 315t based on limited water availability. Table 2 also shows that the <br /> winter flow recommendation of 1.0 cfs is available from November 1st through March 31st. <br /> - 4 - <br />