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recommendation of 5.3 cfs. The winter flow recommendations, which meet 2 of 3 criteria and are within the accuracy range of the R2CROSS model range from 3.0 cfs to 2.1 cfs (See Table I). Averaging the winter flow recommendations within the accuracy range of the model results in a winter recommendation of 2.6 cfs. It is our belief that recommendations that fall outside of the accuracy range of the model, over 250% of the measured discharge or under 40% of the measured discharge may not give an accurate estimate ofthe necessary instream flow required. Hydrologic Data After receiving the cooperating agency's biologic recommendation, the CWCB and BLM staff, conducted an evaluation of the stream hydrology to determine if water was physically available for an instream flow appropriation. Although there is a substantial amount of streamflow gage data available for the Uncompahgre Plateau and Glade Park, most of this data is severely impacted by diversions and irrigation use. This situation makes it difficult to estimate the natural flow regime for the watersheds on the Plateau. Without specific gage data to evaluate, the next best approach is a regional equation that estimates annual flow characteristics. The USGS has developed regional equations (Estimation of Natural Streamflow Characteristics in Western Colorado. Water Resources Investigations Report 85-4086.1985) that apply to the Uncompahgre Plateau and Glade Park based on basin drainage area, mean annual precipitation, mean basin elevation and mean basin slope. The report "Uncompahgre Plateau and Glade Park Annual Hydrograph Estimation" in Appendix C, explains staffs water availahility analysis in more detail. Table 2 below displays the estimated stream flow of Spring Creek. Table 2: Spring Creek estimated streamflow. Januarv Februarv March ADril Mov June J"1v Auaust September October November December 0.87 1.9 2.7 41 150 69 3.' 1.3 1.1 1.1 1 0.96 Spring Creek Estimated Stream Flow 6 5 _..._oo_...._____ 4 -{l3 .. . '" 2 ---- ./'" "- 1 .. .. .. .. .. .. .. .. . .. .. .. .. .. .. .. .. .. .. .. .. .. 0 JAN Fa! MAR A'" MAY JLN JIL ALG 5B' OCT """ IlEC Month Table 2 shows that the summer flow recommendation of 5.3 cfs is available from April 1st through June 30th. Table 2 also shows that the winter flow recommendation of 2.6 cfs is only available from July 1st through July 31st. The winter flow recommendation was further reduced to 0.9 cfs for the time period of August 1st through March 31st based on limited water availability. -4-