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A dam has been constructed on the White River at the Taylor Draw Reservoir approximately 7 miles upstream of the Town of Rangely. The reservoir was not constructed for flood protection purposes. The reservoir storage volume is 13,800 acre-fe~t, as compared with an average annual runoff of 550,000 acre-feet for the approximately 3,000 square mile drainage area, and has no significant affect on the 100- and SOO-year floods. Construction of the dam was completed in the spring of 1984. Though not intended to provide flood protection, it is expected that the dam will indirectly serve to lessen or eliminate flooding problems caused by ice jams in the town. It is believed the dam will provide flood protection since it will collect ice flows and fluctuate discharg~s in the river, causing existing ice accumulations to break up and thus preventing blockages. 3.0 ENGINEERING METHODS For the flooding sources studied in detail ln the community, standard hydrologic and hydraulic study methods were used to determine the flood hazard data required for this study. Flood events of a magnitude which are expected to be equaled or exceeded once on the averag~ during any 10-, 50-, 100-, or 500-year period (recurrenc~ interval) have been selected as having special significance for floodplain 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 avera2e 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 lOO-year flood (i-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 frequency intervals affecting analyses were carried out relationships for floods for each flooding source the community. to establish peak discharge- of the selected recurrence studied by detailed methods Peak f100df10ws on the White River were computed from a statistical analysis of 73 years of gaged data. A log-Pearson Type III frequency distribution was used in the analysis and three sets of discharges were computed from a station skew, a regional skew, and a weighted skew coefficient. For further compari sons, a set of discharges was computed from a Gumbel extreme value distribution and Hazen plotting positions for the 66-year period of record from 7