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f , '. The IOO-year flood discharge at most of the surveyed cross sec- tions was calculated using methods shown In the "Manual for Estimating Flood Characteristics of Natural-Flow Streams In Colorado," by McCain and Jarrett (1976) and Is shown on the flood-prone-area maps. Sample discharge values were then compared with those obtained by using the U.S. Soil Conservation Service (1975) method. This procedure verified that the results were reasonable. Also, consulting engineering firms have prepared detailed flood reports for the towns of Kiowa, Elbert, and El izabeth; areas covered by these reports are out I ined on the en- I arged maps. 4 Swmla:l'Y of extreme j'Zood disaharges for streams bJhieh j'ZObJ bJithin and near EZbert County, CoZo. [Data for sites 1-12 from Matthai (1969, p. 37); and for site 13 from Snipes and others (1974, p. 35] t " Site Drainage area, Discharge. in No. Stream and location County in square cubic feet Year miles per second 1 Kiowa Creek at K-79 Reservoir EI Paso 3,20 5,250 1957 near Eastonville , 2.370 1955 2 Kiowa Creck Subwatershed EI Paso 1.12 2,600 1965 No. J-33 near Eastonvi I I e 3 Kiowa Creek Subwatershed Elbert 2.82 6,880 1965 No. R-3 near Elbert 4 Kiowa Creek Subwatershed Elbert ,59 1,350 1955 No. a-51 near Elbert 5 Kiowa Creei, at Elbert Elbert 28.6 43,500 1935 41,500 1965 5 West Kiowa Creek at Elbert Elbert 35.9 20,000 1965 7 Kiowa Creek at Kiowa Elbert 111 19,700 1955 8 Kiowa Creek at Bennett Adams 236 75,300 1935 24,900 1965 9 East Bijou Creek at Deer Trail Arapahoe 302 25,000 1935 274,000 1955 10 Middle Bijou Creek near Arapahoe 190 143,540 1935 Deer Tra i I 145,000 1955 11 West Bijou Creek near Kiowa Elbert 85,7 67,200 1955 12 West Bijou Creek at Byers Arapahoe 277 164,670 1935 75,500 1965 13 Big Sandy Creek near Calhan EI Paso 49.0 60,700 1955 Hydrology Heavy, intense rainfall anywhere in Elbert County's long, narrow and rather steep drainage basins will cause flooding. The flational Weather Service (1973) determined that the 100-year. 6-hour rainfall for EI bert County Is 3.4 Inches. However. as. much as 12 inches fell in about 3 hours southeast of the town of Elbert. on June 17, 1965. The probable maximum 6-hour precipitation for a given 10-square-mile area in Elbert County is about 22 inches (Matthal, 1969). Flooding also can result from lesser amounts of rainfall on successive days or when storm cells move along already swollen creeks.