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0 <br />0 <br />• 1.54 cfs is recommended for April 1 through August14. This flow is <br />required to maintain the three principal criteria of average depth, average <br />velocity and percent wetted perimeter; <br />• 0.79 cfs is recommended for August 15 through March 31. This flow is <br />required to maintain two of the three principal criteria, specifically average <br />velocity and percent wetted perimeter. <br />Water Availability. There is one known diversion on Severy Creek. The U.S. Forest <br />Service holds the right to divert 0.005 cfs through the Barr Camp Springs & P/L. This <br />water is used by Barr Camp, a special -use permittee. The camp is a stopping point for <br />many climbers, some of whom stay the night and shower. The Forest Service describes <br />the use as minimal. No conflict between these senior rights and the instream <br />appropriation is anticipated. Additionally, there is an aqueduct that appears to cross the <br />watershed near its confluence with Cascade Creek. TU and CDOW recommend that the <br />terminus for the proposed instream flow right be established immediately above this <br />aqueduct. <br />Because there are no stream gages on Severy Creek, TU recommends using paired <br />watershed approach to estimate daily flows on Severy Creek. Briefly, this approach <br />estimates discharge in an ungaged watershed from the discharge records of neighboring <br />watersheds. This approach works best for watersheds that are in close proximity have <br />similar aspects, slopes, elevations, areas, and vegetation. It assumes that watersheds with <br />similar physical characteristics will have similar hydrologic properties and thus <br />differences in discharge result from differences in watershed area. Based on this <br />assumption, discharge in the ungaged watershed on any given day can be estimated from <br />the discharge in the gaged watershed as follows: the area of the ungaged watershed <br />divided by the area of the gaged watershed multiplied by the discharge of the gaged <br />watershed. <br />Colorado Springs Utilities has maintained flow gages for both North Cascade Creek <br />(1116) and South Cascade Creek (1117) since 1949. Although both North Cascade Creek <br />and South Cascade Creek were somewhat smaller than Severy Creek, they were <br />otherwise quite similar. Consequently, both North and South Cascade Creek were used <br />to provide independent estimates of the daily discharge in Severy Creek for the period of <br />record using the synthetic hydrology approach described above. The mean of these two <br />estimates provided the best estimate of a given day's flow. Because neither North <br />Cascade Creek nor South Cascade Creek appear to have any diversions above their <br />respective gages, no adjustment for withdrawals was necessary. <br />This analysis showed that, regardless of the watershed used to estimate discharge in <br />Severy Creek, throughout the year both the average daily flow and the monthly 50% <br />exceedences were typically greater than the recommended flows. This held even when <br />the Barr Camp Springs rights were subtracted from estimated flows through Severy <br />Creek. The only exceptions were on April 1 and 2 when estimates of Severy Creek flows <br />