PROJC00189

• Contract/PO #: C150006
• Contractor Name: Palisade, Town of
• Contract Type: Loan
• Water District: 72
• County: Mesa
• Bill Number: HB 95-1155
• Loan Projects - Doc Type: Feasibility Study

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of about 9.1 miles. Both streams have their upper headwaters on the top
of Grand Mesa on the flat, open area known as Lands End, which
comprises the far westward extension of Grand Mesa. The total drainage
area for the two streams is as follows:

Cottonwood Creek - 3,627 acres (5.67 sq. mi.)
Rapid Creek - Above Confluence - 7,895 acres (12.34 sq. mi.)
- Below Confluence - 434 acres (0.68 sq. mi.)
Total 11,956 acres (18.68 sq. mi.)

Elevations in the Rapid Creek Basin range from 4800 ft. to 10,000 ft. The
streams pass through four separate life zones (Upper Sonoran through Sub-
Alpine) on their way from the top of Grand Mesa to the Colorado River.
Sagebrush and juniper are the most common vegetation in the lower part of
the basin. Oakbrush is prevalent in the mid basin, and aspen and spruce
are common at high altitudes. Some cottonwood trees grow along Rapid
and Cottonwood Creeks.

Palisade normally takes its water only from the upper part of the drainage
basin. The lowest spring is located at an elevation of 6817 feet along
Rapid Creek and the lowest intake used on a regular basis is at 6800, also
on Rapid Creek. However, the Town can also take water from intakes
located further down on Cottonwood Creek and Rapid Creek, but prefers
not to because water quality rapidly deteriorates in the lower sections (due
to the type of soils and rock formations in the lower area).

2.

Geology and J{ydmlogy

A very complete description of geology, topography and goo-hydrology is
provided in a reference prepared by the US Geological Survey (Brooks,
1986). Much of the infonnation in this section is summarized from that
reference.

The lower portion of the basin from the Colorado River to an elevation of
about 7200 feet consists of the Mesa Verde sandstones and shales (Figure
IV-2). Both Cottonwood Creek and Rapid Creek have created deep,
narrow canyons as they pass through this formation. The Wasatch
formation, which consists of clays with some sandstone and limestone, sits
on top of the Mesa Verde fonnation, and it is about 1000 feet thick at this
location. The Green River formation, which sits above the Wasatch
formation, is about 1400 feet thick, and includes sandstone, madstone and
shale. There is an unnamed fonnation above the Green River formation
which is about 400 feet thick. The top of the Grand Mesa is capped with
a 230 foot thick layer of basalt. Much of the upper basin of both streams
is covered with landslide deposits from the Green River formation. The

IV-2