V - Missouri Department of Natural Resources

FLOODS OF JULY 18-23, 1965 IN
NORTHWESTERN MISSOURI
by
James E. Bowie
and
E. Eugene Gano
ABSTRACT
The disastrous floods of July 18-23, 1965 in northwestern Missouri were of a frequency
greatly in excess of the defined 50-year flood. Recurrence intervals of both rainfall and
runoff were extremely high.
Rainfall totaled more than 20 inches in the towns of Rockport and Edgerton during the
period July 17-20. Rainfall recorded at Edgerton, in a 24-hour period, was 2.5 times the
IOO-year point rainfall for northwestern Missouri. The average rainfall that occurred over
a 400 square mile area, in 24 hours, was almost double the amount expected for the IOO-year
rainfall.
Peak discharges at 23 flood measuring sites exceeded the 50-year flood discharge. At
10 of these sites the peak discharge was from 2 to 6 times as large as the discharge for the
50-year flood. The highest known unit rate of runoff ever recorded in Missouri, 6,690 cubic
feet per second per square mile, was experienced at Boney Branch at Rockport. The record
flood of June 1947 was exceeded in the downstream portions of the One Hundred and Two, Platte,
Little Platte, and Fishing River basins. The frequency of the flood in the Fishing River
basin increased with increasing size of drainage area.
Four lives were lost during the flood, 729 residences were damaged or destroyed, and
433,700 acres of agricultural lands were flooded. The total flood damage amounted to
$24,292,900.
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