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2.3 . . qrasses, ...ith Gamhel oak and ponderosa pine trees. The tablelands vegetation is mainly western wheatgrass, junigrass, mountain meehley, and Gambel oak. ~rincipal Flood Problems Douglas County is located in an area that is prone to very intense rainfall, sometimes of cloudburst magnitude. Floods have resulted from storms covering large areas with heavy general rain- fall as well as from storms covering small areas with extremely intense rainfall. Floods generally occur from May through August. The upland areas are characterized by dissected topographic relief ...ith steep stream slopes. Floods are characterized by rapid rises, hiqh maximum discharges, short durations, and comparatively low volumes of total runoff. The road...ays that cross the streams and obstruct floodflows are the most significant factor affecting flooding in the area. Other manmade objects, such as buildings, cars, and fences, as well as the natural vegetation of the flood plains, cause flow obstruc- tion. The following accounts of flooding on the South Platte River, Plum Creek, and Cherry Creek area are representative of typical floods for which information is available. Three separate floods occurred during May and June 1864. The first originated in the Cherry Creek and Plum Creek basins, occurring during the night of May 19-20, 1864, and "as caused primarily by a cloudburst in the upper part of those basins. On the morning of May 20, the flood inundated the lower portions of Denver at a depth of 1 to 5 feet, leaving great deposits of sand and gravel. Records indicate that 2.08 inches of rain occurred during a 2-hour period on July 14, 1912. The heaviest precipitation occurred be- tween Franktown and a point approximately 5 IlIiles north of Denver; the center was located near parker. The rainfall started around 3 p.m. and continued until around 5 p.m. Cherry Creek crested around 10 p.m. and had a peak discharge of 25,000 cubic feet per second ICfs) in Denver. The Cherry Creek Flood Commission estimated that runoff occurred from an area of approximately 200 square miles. Flood damages in the reach between Franktown and the site of the existing Cherry Creek Dam and Reservoir totaled $554,000. In June 1921, the rainfall.extended east of the mountains for a considerable distance, and the plains tributaries as well as those in the mountains contributed flow into the south Platte River. No gaging stations were being maintained at the mouths of the trib- utaries. This flood caused the South Platte River to rise approx- imately 7 feet in Denver. The local press estimated that approxi- mately 500 houses were inundated and many f~lies were forced to 9