FLOOD03996

• County: Statewide
• Basin: Statewide
• Title: Magnitude and Frequency of Floods in the United States
• Date: 1/1/1968
• Prepared By: USGS
• Floodplain - Doc Type: Educational/Technical/Reference Information

PART 6-B

APPLICATION OF THE METHOD 13
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FIGURE l1.-Relation of selected flood frequencies to distance above mouth,
South Platte River.

fore the frequency relations were not detennined, but discharges
for the other seven streams for selected recurrence intervals can
be obtained directly from the curves in figures 9-14.

Storage affecting the Missouri River downstream from Sioux
City, Iowa, became significant after storage began in December
1952 in Fort Randall Reservoir. Additional storage started in
Garrison Reservoir in 1953, in Lewis and Clark Lake in 1955,
and in Oahe Reservoir in 1958; therefore, the curves plotted in
figure 9 are for the period 1929-52 when flow from a large part
of the area upstream from Sioux City was not controlled.
The North Platte River is regulated by Seminoe, Pathfinder,
Alcova, Glendo, and Guernsey Reservoirs and by Lake McCon-
aughy. Flood-frequency relations upstream from Seminoe Res-
ervoir can be computed from curves for hydrologic area 1 and
region A. Data plotted in figure 10 for station above Pathfinder
Reservoir are for the period 1914-38, prior to completion of
Seminoe Reservoir; therefore, these data plus adjustments for
storage provide frequency infonnation for the reach of the North
Platte River between Seminoe and Pathfinder Reservoirs.

nee above mouth,

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