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<br />Acknowledgments <br /> <br />Jhe cooperation and assistance of L. Scott Tucker, Executive Director, <br />Urban Drainage and Flood Control District, and Dominick J. Gianola, Staff <br />Engineer, are greatly appreciated. Thanks are also extended to Glen Brees <br />and staff, Colorado Division of Water Resources, who provided basic stream- <br />flow data at eight stations on the South Platte River and major tributaries. <br /> <br />STORM PRECIPITATION <br /> <br />Detailed precipitation records were collected at 5-minute intervals <br />during the storm at 16 rainfall-runoff data collection stations throughout <br />the Denver area. Figure 6 shows the distribution of recorded storm precipi- <br />tation totals. Table 1 provides a sample format of the computer printout <br />available for each of the 16 stations and these data may be obtained by <br />contacting the Executive Director, Urban Drainage and Flood Control District, <br />181 E. 56th Ave., Denver, Colorado 80216. The cost is $5.00 per set, which <br />includes all available precipitation and runoff data as collected by the <br />operational rainfall-runoff data collection stations. <br /> <br />Rainfall data, as shown in table 1, consists of a computer printout <br />showing a tabulation of 5-minute incremental precipitation during the storm. <br />The tabulation of precipitation intervals does not begin until the precipi- <br />tation in a 5-minute interval exceeds 0.015 inch. Thus, it is possible to <br />show a daily total of precipitation that is larger than a storm total that <br />occurred in the same day. This is due to the accumulation of rainfall incre- <br />ments of less than 0.015 inch per 5-minute interval prior to the initiation <br />of the storm detail tabulation. Details of duration, time, depth, and inten- <br />sity are provided whenever a storm equals or exceeds 0.50 inch. The storm <br />tabulation is terminated when 2 hours elapse and no incremental precipitation <br />is recorded. <br /> <br />Table 2 provides a tabulation of the approximate lOa-year, 24-hour dura- <br />tion rainfall depths and 2-year, I-hour duration rainfall depths for each of <br />the 16 stations as derived from rainfall frequency maps (Wright-McLaughlin <br />Engineers, 1969). Also included is a listing of 24-hour and I-hour depths of <br />May 6, 1973, for comparison purposes. A comparison of 24-hour depths shows <br />that the May 6 values range from about 0.4 to 1.1 times the laO-year values, <br />indicating a rainstorm of statistical significance based on 24-hour totals. <br />However, examination of the I-hour duration rainfall depths shows that the <br />May 6 values range from about 0.3 to 0.6 times the 2-year values, indicating <br />the storm was not significant when considering short duration precipitation <br />totals. <br /> <br />7 <br />