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OOlJJ3 I I I I I I I I I I I I I I I I I I I flooding due to the high volume of runoff associated with this type of event. However, the threat to human life is minimal because of the long lead time available for dissemination of flood warning information. (a) Annual Streamfl ow Annual streamflow measurements have been made at the U.S. Geological Survey's streamgaging station in the Cherry Creek near Melvin starting in 1939 and discontinued in 1969. The gage was located one mile downstream from Arapahoe Road until October 1960 and moved to Araphaoe Road thereafter. These annual flows are plotted in Figure-4. . The average for the 30-year period of record is 11.8 cubic feet per second. The largest annual streamflow was in 1942 when the average for the year was 51.5 cubic feet per second. The lowest was 1954 with only 0.62 cubic feet per second. The mean annual streamflow record is not homogeneous. Prior to 1950, streamflow was much larger. From 1940 to 1949, the annual mean was 22.6 cubic feet per second. Thereafter, the mean dropped to 6.33 cubic feet per second, only 28 percent of that of the prior 10 years. (b) Monthly Streamflow The average monthly streamflow in the Cherry Creek near Melvin for the period 1939 to 1969 is as follows: AVERAGE MONTHLY STREAMFLOW (UNITS ARE FT3/S AND % OF ANNUAL) OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP ANNUAL 2.98 3.49 3.14 3.73 14.7 29.7 20.2 17.6 13.7 11.5 18.8 2.55 11.8 2.1 2.4 2.3 2.7 9.6 21.3 14.0 12.6 9.5 8.2 13.5 1.8 100.0% March has the most streamflow on the average. The highest monthly stream- flow was in April 1942, for which the average was 204 cubic feet per second. The lowest monthly streamflow was zero in many months in many years. The averages for all months are ploted in Figure-4. -11-