Location
The South Platte River Basin has a drainage area of
about 24,300 mi2 (Dennehy, 1991) and is located in parts of three
States (fig.1) - Colorado (79 percent of the
basin), Nebraska (15 percent of the basin), and Wyoming (6 percent of the
basin).  The
South Platte River originates in the mountains of central Colorado at the
Continental Divide and flows about 450 mi northeast across the Great Plains
to its confluence with the North Platte River at North Platte, Nebraska.
Altitude in the basin ranges from 14,286 ft at Mt. Lincoln on the Continental
Divide to 2,750 ft. at the confluence of the South Platte and North Platte
Rivers. The basin includes two physiographic provinces - the Front Range
Section of the Southern Rocky Mountain Province and the Colorado Piedmont
Section of the Great Plains Province.
Climate
The basin has a continental-type climate modified by topography, in which
there are large temperature ranges and irregular seasonal and annual precipitation.
Mean temperatures increase from west to east and on the plains from north
to south (Gaggiani and others, 1987). Areas along the Continental Divide
average 30 in. or more of precipitation annually, which includes snowfall
in excess of 300 in. In contrast, the annual precipitation on the plains
east of Denver, Colorado, and in the South Park area in the southwest part
of the basin, ranges from 7 to 15 in. (fig. 2).
Most of the precipitation on the plains occurs as rain, which typically
falls between April and September, whereas most of the precipitation in
the mountains occurs as snow, which typically falls between October and
March.
Land Use
The three-State area of the South Platte River Basin
has about 2.8 million people, over 95 percent of who live in Colorado.
The basin contains the most concentrated population density in the Rocky
Mountain region (fig. 3), located along the
Front Range urban corridor in Colorado where the mountains meet the plains.
Population densities outside the urban corridor are small and centered
in small towns located along the principal streams. The principal economy
in the mountainous headwaters is based on tourism and recreation; the
economy in the urbanized south-central region mostly is related to manufacturing,
service and trade industries, and government services; and the economy
of the basin downstream from Denver is based on agriculture and livestock
production.
Land use and land cover in the South Platte River Basin
(fig. 4) during 1975-80 (Feagas, and others, 1983) is divided into:
41 percent rangeland, 37 percent agricultural land, 16 percent forest land,
3 percent urban or built-up land, and 3 percent other land. Rangeland is
present across all areas of the basin except over the high mountain forests.
Agricultural land is somewhat more restricted to the plains and the South
Park area near Fairplay, Colo. Forest land occurs in a north-south band
in the mountains. Urban or built-up land is present primarily in the Front
Range urban corridor. The 'other land' category includes: water (110 mi2),
barren lands (160 mi2), tundra (400 mi2), and perennial
snow and ice (1 mi2). Barren lands primarily are areas under
construction or are areas of strip mining, quarries, or gravel pits.
Back to Basin Information
|
