FLOOD08868 - Laserfiche WebLink

Home Browse Search

The flood was caused by cloudbursts in the Rocky Mountain foothill region. The swift rise and fall and the unprecedented stage of the flood were remarkable considering the small area the storm covered. The Arkansas River peaked at 103,000 cubic feet per second (cfs), the largest discharge of reliable record at Pueblo. Flooding on June 17, 1965, caused damage in the City of Pueblo and in Pueblo County estimated at $3.7 million. Nonnatural obstructions limited the Fountain Creek channel to a width of 250 feet or less at several locations. Approximately 53 city blocks were inundated to depths of up to 8 feet. A total of 370 residences and 59 busi- nesses was damaged. The cloudburst-type rains that occurred in the vicinity of Colorado Springs on June 17 produced this Fountain Creek flood. The major portion of the floodwater originated from Jimmy Camp Creek near Colorado Springs. The peak discharge from this small, 78-square-mile watershed was 124,000 cfs at the conflu- ence with Fountain Creek. The rainfall was so intense (up to 12 inches in 3 hours) that the entire countryside became a moving lake. The discharge of 47,000 cfs on Fountain Creek is the highest of record at Pueblo. According to CF&I Steel COrporation records, Lake Minnequa overflowed in 1921 and 1965. No documentation of the 1921 flood is available. However, it is known that overflows from the lake on August 22, 1965, did flood the street system below the curb line. This event had an estimated discharge from the lake of 800 to 1.000 cfs. According to National Weather Service records for this date, 2.35 inches of precipitation fell at Pueblo Reservoir located 0.6 mile from Lake Minnequa. The NOAA atlas (Reference 4) cites this as less than a 10-year storm event. In the Bonforte Boulevard Area, flooding occurs when an underground pipe laid in the filled-in stream channel cannot accommodate all of the flow. The excess water spills overland as shallow flooding. Table 1 lists the floods known to have occurred on streams in Pueblo and their discharge. if known. Scenes of flooding and flood damages in Pueblo are shown in Figures 2 through 7. 2.4 Flood Protection Measures The U.S. Bureau of Reclamation constructed Pueblo Dam on the Arkansas River at River Mile 1.293.7. approximately 6 miles upstream from the City of Pueblo. The dam will control Arkansas River flows up to 87.000 cfs. approximately an aOO-year flood (Reference 5). In 1924-25, the Pueblo Conservancy District constructed a concrete- lined floodwall along the north bank of the Arkansas River. It extended through Pueblo from the confluence of Wild Horse-Dry Creek 9