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1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long- term averajite 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 one 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 by detailed methods affecting the community. Hydrology for Clear Creek and South Clear Creek was obtained through methods described in the Manual for Estimating Flood Characteristics of Natural-Flow Streams In Colorado (Reference 4). There are no flood control reservoirs upstream from the town on either creek, nor any detention reservoirs. Hydrology for Clear Creek at the northern corporate limit of Georgetown (downstream from its confluence with South Clear Creek) was derived through a statistical analysis of annual peak flows at USGS gage 06716500, Clear Creek near Lawson (period of record: March 1946 to present). This information was then transferred to the subject location using a weighting of the computed flood peaks at .he gage with flood peaks calcula.ed with regional regression equations (Mountain Region equations). Drainage area ratios are also employed in this method. Data used in establishing peak flows were as follows: 38 years of annual peak flows from the Lawson gage data; drainage area at the gage; drainage area at Georgetown's northern corporate limit; and mean annual precipitation above .he gage. A s.atistical analysis of 38 years of gage data using log-Pearson Type III fitting of data was conducted. Hydrology for South Clear Creek and for Clear Creek upstream from its confluence with South Clear Creek was based on the Mountain Region regression equations. Parameters used in establishing peak flows were: drainage area of Clear Creek upstream from its confluence with South Clear Creek; mean annual precipitation upstream from this point; drainage area of South Clear Creek; and mean annual precipitation from the mouth of the creek. 5