WSP03621

• File Number: 8407.600
• Description: Platte River Basin - River Basin General Publications - Kansas General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 10/1/1960
• Author: Kansas Water Resourc
• Title: Kansas Streamflow Characteristics - Part 3 - Flood Frequency - Technical Report Number 3
• Water Supply Pro - Doc Type: Report/Study

22

An extensive search of histOl'ic data established the relative magnitude
of many additional floods and also increased the periods for which the higher
floods Were kno\l,:n to be unsurpassed. .4t 13 stations in region A and 88 stations
in region B there were sufficient data to extend their- individual frequency
Curves beyond the 36-year base period and thereby improve the definition of
the composite frequency cUrves. The individual cur\'(" 5 wer'c dr'awn as the line
of best fit determined visually with consider'alion for the limitations and pecu-
liarities inherent in the data. Ratios to the mean annual flood were computed
for the individual curve discharges at 12.3, 18.5,37, and 50-year I'ccurrence
intervals. The medians of these L'rJ.tios defined the I'cspecthe curves for re-
gions A and B beyond the IO-year recurrence interval. The r'esulting cur'ves,
shown in figur'e 8. indicate the ratio of the 50-year flood to the mean annu8J
flood to be 8.8 for region A and 5,3 for region B. The definition was investi-
gated and verified by plots of the higher' floods by gL'rJ.phical median and by
double median methods. Results were similal' but less reliable.

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RECURRENCE INTERVAL, IN YEARS

Figure

8 .u Composite frequency curves of onnuol floods In Konsos,