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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />The peak flow rates calculated for the Master Drainage Plan for Breckenridge <br />(Ref. 3) were compared to the peak flow rates from the previous FIS - Hydrology <br />Report (Ref. 2) as shown in Tables 2.4 and Tables 2.9 of Reference 3. Although <br />the peak flow rates for the Blue River as well as for French Gulch and Illinois <br />Gulch showed a good agreement, discrepancies were found in the analysis of Lehman <br />Gulch and Sawmill Gulch. On Lehman Gulch, the FEMA (Ref. 2) value is nearly <br />double the HEC 1 (Ref. 3) value and on Sawmill Gulch the HEC 1 value is nearly <br />double the FEMA value. Furthermore, upon comparing the FEMA results for the two <br />gulches, a large difference in peak flow rates exist even though the two drainage <br />basins have similar areas, shapes, topography and geology. Since neither basin <br />is a part of this study, research to determine the reasons for the disparity was <br />not performed. <br /> <br />Further corre 1 at i on checks were performed whil e research; ng the val i dity of <br /> <br />previous reports. Table 1, Hydrology Summary, contains descriptions of the <br />checks and cross-referencing performed. <br /> <br />VI. DETERMINATION OF PEAK FLOW RATES <br /> <br />The peak flow rates used in this study were (1) taken directly from previous FIS <br /> <br />or other studies, (2) derived from other frequencies using log-probabil ity plots, <br /> <br /> <br />(Fig. 6), or (3) calculated using regression equations from previously referenced <br /> <br />studies (for small basins regression lines were adjusted to consider rainfall <br /> <br />effects). The descriptions in the Hydrology Summary (Table 1) outline the method <br /> <br />used to achieve peak flow rates for each study reach. <br /> <br />8 <br />