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<br />on meeting 3 of 3 hydraulic criteria and the winter flow recommendation based upon 2 of 3 <br />hydraulic criteria. <br /> <br />Table I: Data <br /> <br />Partv Date 0 250% -40% Summer (3/3) Winter (2/3) <br />USFS 06/02/2004 5.81 14.5 - 2.3 2.6 1.4\') <br />USFS 06/02/2004 7.15 17.9 - 2.9 3.6 1.1 "~I <br /> <br />BLM = Bureau of Land Management DOW = Division of Wildlife <br />(1) Predicted flow outside of the accuracy range of Malll1ing's Equation. <br /> <br />USFS = United States Forest Service <br />? = Criteria never met in R2CROSS Staging Table. <br /> <br />Biologic Flow Recommendation <br />The summer flow recommendations, which meet 3 of 3 criteria and are within the accuracy range <br />of the R2CROSS model, range from 3.6 cfs to 2.6 cfs (See Table I). The winter flow <br />recommendations, which meet 2 of 3 criteria but are outside the accuracy range of the R2CROSS <br />model, range from 1.4 to 1.1 cfs (See Table I). Averaging the two summer flow <br />recommendations within range, results in a 3.1 cfs recommendation. Averaging the two winter <br />flow recommendations outside the range, results in a 1.25 cfs recommendation. It is our belief <br />that recommendations that fall outside of the accuracy range of the model, over 250% of the <br />measured discharge or under 40% of the measured discharge may not give an accurate estimate <br />of the necessary in stream flow required. In these cases, CWCB staff relies upon the biological <br />expertise of the cooperating agencies to develop a biologic in stream flow recommendation. The <br />USFS has indicated that this is a high priority stream segment, however, because the winter <br />recommendation falls outside the accuracy range of the R2CROSS model, staff has consulted <br />with the recommending agency. Staff and the recommending agency believe the winter flow <br />recommendation of 1.2 cfs would be sufficient to protect the natural environment to a reasonable <br />degree (See Table I). <br /> <br />Hydrologic Data <br /> <br />After receiving the cooperating agency's biologic recommendation, the CWCB staff conducted <br />an evaluation of the stream hydrology to determine if water was physically available for an <br />instream flow appropriation. The hydrograph below was derived from data collected by the <br />USGS stream gage for Escalante Creek near Delta, CO (ID #09151500), which has a drainage <br />area of 209 square miles (See Gage Summary in Appendix C). The total drainage area of this <br />segment of the Middle Fork Escalante Creek is approximately 33.7 square miles. The period of <br />record for this gage was 1976 to 1989, the period of record used by staff in their analysis was <br />1976 - 1989, or 14 years of record. Since this gage is heavily impacted by upstream diversions, <br />the estimated average flow was derived by adding average diversion records for the irrigation <br />season (March through October). Table 2 below displays the estimated average flow of Middle <br />Fork Escalante Creek. <br /> <br />Table 2: Estimated Stream Flow on l\1iddle Escalante Creek: <br /> <br />Jan <br /> <br />Feb <br /> <br />Mar <br /> <br />Jun <br /> <br />Jul <br /> <br />Oct <br /> <br />Nav <br /> <br />Dee <br /> <br />-4- <br />