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A continuous record of flows at the USGS Nederland gage, located on Middle Boulder Creek, is available fram 1907 to the present. Significant peak flood discharges and stages during the period from 1945 to 1975 are presented in Table 3. Flow measurements prior to 1945 could not be verified as being either average daily measurements or daily peak measurements. Following U. S. Water Resources Council Bulletin 17, (Reference 45), discharge-frequency relationships in the Middle Boulder Creek Basin were determdned by statistical analysis of the stream gaging records of Middle Boulder Creek at Nederland, using 32 years of record and a weighted skew coefficient of -0.252. For North Beaver Creek, peak discharges for the respective frequencies were determined using USGS Technical Manual No. 1 (Reference 32). The procedure outlined in Technical Manual No. 1 as also used to develop peak discharges at various locations in the Middle Boulder Creek Basin and its subdrainage basin of North Beaver Creek to help define the flow characteristics within both basins. Table 3. Historic Flood Peak Discharges and Stages at Nederland (Recorded on Middle Boulder Creek) Stage Year Date Feet 1949 June 13, 1949 4.66 1951 June 18, 1951 4.75 1953 June 13, 1953 3.98 1957 June 29, 1957 4.25 1965 July 24, 1965 4.25 Maximum Discharge Cubic Feet per Second 674 800 730 745 640 Peak discharge-drainage area relationships for all flooding sources studied by detailed methods are shown in Table 4. 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. For flooding sources studied by detailed methods as part of the previous Flood Insurance Study for the unincorporated areas of Boulder County, hydraulic analyses were developed from the various engineering discussed in Section 7. 0, and have been incorporated into this study of Boulder County. 36