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as having special significance for flood plain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and SOO-year floods, have a 10, 2, 1, and 0.2 percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long-term average period between floods of a specific magnitude, rare floods could Occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood which equals or exceeds the 100-year flood (1 percent chance of annual exceedence) in any 50-year period is approximately 40 percent (4 in 10), and, for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding potentials based on conditions existing in the community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes. 3.1 Hydrologic Analyses Hydrologic analyses were carried out to establish the peak discharge- frequency relationships for each flooding source studied in detail affecting the community. Peak discharge-frequency relationships for streams studied in Colorado Springs were developed from one of four sources: (1) material prepared by the COE (Reference 6), (2) existing flood plain reports designated by the State of Colorado for flood plain regulation, (3) from new hydrologic data developed by CDM, or, (4) from existing hydrologic reports by private firms. The fOllowing discussion summarizes the hydrologic analysis and results for each stream studied. The hydrologic analysis used for this Flood Insurance Study for FOuntain Creek was obtained from COE reports (References 6 and 7). The hydrologic analysis in each was reviewed by the study contractor, and the reports were found to show a good correlation in peak dis- charges at common points on Fountain Creek in Colorado Springs for all recurrence intervals. This hydrologic method, utilized in Reference 6 and 7, consists of gage station analysis, whereby stream gaging data have been analyzed to es~imate peak flows for the various recurrenc~ intervals. ~ Peak discharges for Monument Creek from its confluence with Fountain Creek to the northern Colorado Springs study limit were obtained from a COE Flood Plain Information report (Reference 8). A regional gage station analysis was utilized to develop the selected recurrence interval peak flow rates. The hydrologic results contained in this report correlated well with Reference 6 and the FOuntain Creek study discussed above (Reference 7). 13