FLOOD05519

• County: Statewide
• Community: Eastern Colorado/South Platte River Basin
• Stream Name: South Platte River
• Basin: South Platte
• Title: Report on the Floods of June 1965 South Platte River Basin Colorado and Nebraska
• Date: 1/1/1967
• Prepared For: CWCB
• Floodplain - Doc Type: Flood Documentation Report

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8. DRAINAGE AREAS

The South Platte River watershed drains 24,300 square miles, of
which'19,450 square miles lie in Colorado, 2,050 square miles lie in
southeastern W;yoming, and 2,800 square miles lie in southWestern
Nebraska. A tabulation of drainage areas at selected locations in
the .basin is provided in table 1. A tabulation of stream lengths is
given in table 2.

9. PHYSIOGRAPHIC FEATURES

Approximately 23 percent of the drainage area is high mountainous
terrain in the Rocky Mountain range. The mountainous regions lie on
the western portions of the basin. Toward the northeast and east,
the basin's features change from the rougher, steeply sloping terrain
of the high plains region to the broadly terraced plains lands of the
lower basin. The stream valleys begin as narrow valleys and canyons
in the mountainous regions and increase progressively in width toward.
the lower regions of tributary stresms. The valley of the South Platte
River begins to broaden at metropolitan Denver and increases progressively
in. width from Denver to its mouth near North Platte, Nebraska. Basin
elevations range from 14,200 feet m.s.l. at the Continental Divide
to approximately 2,800 feet m.s.!. at the mouth.

10. STREAM FLOW

The U. S. Geological Survey in cooperation with the Colorado
State Engineer's office has maintained stream gaging stations in the
South Platte River basin since 1895. Comparative pes.Jt, discharges
for the June 1965 flood and previous recorded lIl8XimumS are given for
selected locations in table 3.

11. ECONOMIC CHARACTERISTICS

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a. Population. In 1960, the estimated population of the South
Platt.e River basin was 1,184,000 persons, of which about 78 percent
resided .in metropolitan Denver. In 1960, the basin's population
density averaged 48.7 persons per square mile. However, population
densities are.concentrated principally in the upper portions of the
basin (average population density of 61.5 persons per square mile)
and primarily in the Denver metropolitai1 region. In 1964, the popula-
tion density within the Denver metropolitan region averaged 5,108
persons per square mile, while within the 88 square mile area of the
city of Denver, the po:pulation density was 5,950 persons per square
mile. The principal community development areas of the Denver
metropolitlUlregion which are situated adjacent to the South Platte
River are: COlumbine, Littleton, Englewood, Sheridan-Centennial,
Denver, Commerce City and Brighton. The communities in the Sand and
Toll Gate Creek basins. (metropolitan Denver) are Aurora and Commerce
City.

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