WSP10356

• File Number: 8059
• Description: Section D General Studies-State Water Plan
• State: CO
• Date: 1/1/1969
• Title: Writing the Report 1969-Draft Part II-Physical Aspects of Colorado
• Water Supply Pro - Doc Type: Report/Study

3,500 to 4,000 feet near the Kansas border. The main valleys, as those of the

Arkansas and South Platte Rivers, are as much as 1,000 feet below this level,

but most other valleys are shallower, and many of the small ones are less than

100 feet below the plains' surface.

The mountainous part of Colorado has a sharp eastern border, where the

mountains rise abruptly above the plains along a slightly sinuous line, but the

western border is irregular and not sharply separable from the plateau lands to

the west. Within the mountainous tract are long subparallel ranges and sub-

circular mountain groups separated by valleys or broad basins. Two mountain

ranges, the Front Range on the east and the Park Range to the west, extend from

south-central Colorado northward into Wyoming. Between them is a line of basins

known as South, Middle, and North Parks. A high, structurally domed area known

as the White River Plateau lies west of the Park Range in northwestern Colorado,

and in central Colorado the generally elliptical Sawatch Range lies west of the

Park Range, West of the Sawatch Range are the Elk and West Elk Mountain groups.

In southern Colorado, a short range known as the Wet Mountains lies at the edge

of the plains. West of it is the long and narrow Sangre de Cristo Range, which

extends from the Arkansas River southward into New Mexico. Near the New Mexico

border, this range fronts on the plains. West of the Sangre de Cristo is a

broad basin, the San Luis Valley, and west of that, the San Juan Mountains, almost

a hundred miles in diameter,

The broad mesas of the plateau lands in the western part of the state range

from 6,000 to 11,000 feet in altitude, and the valleys between them are 2,000

to 5,000 feet lower. On the east, the plateaus grade irregularly into the moun-

tains, and on the north they end against the Uinta Mountains, a traverse range

that extends from the northwestern corner of Colorado westward into Utah. To

the west and south the plateau surface, dotted by small mountain groups and long

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