WSP11669

• File Number: 8149.100
• Description: Miscellaneous Small Projects and Project Studies - NRCS-Ft Lyon Canal Co Limestone Graveyard Creeks
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 9/1/1996
• Author: Bent Soil Conservati
• Title: Limestone-Graveyard Creeks Watershed Bent County Colorado Prowers County Colorado Watershed Plan and Environmental Assessment
• Water Supply Pro - Doc Type: EIS

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

054G

PROJECT SETTING

Location and Size

The Limestone-Graveyard Creeks Watershed is located in eastern Bent and
western Prowers Counties in Southeastern Colorado. The watershed
consists of 59,250 acres and averages about 5 miles wide and 16 miles
long. Lamar, Colorado is on the east edge and Las Animas is slightly
west of the watershed. Pueblo, Colorado is 100 miles west of the
watershed area.

The watershed is bounded on the west by the Prowers Arroyo, north by
the Fort Lyon Canal, east by the Pleasant Valley Drain, and south by
the Arkansas River. It includes Limestone and Graveyard Creeks,
prowers Arroyo, Pleasant Valley and Wiley Drains which outlet into the
Arkans.. River.

Topoe", .'y and Drainaae

The highest elevation in the watershed is the Fort Lyon Canal. It
varies from an elevation of 3950 ft. on the west edge to 3860 ft. on
the east edge. The Arkansas River, or southern boundary, is the lowest
elevation in the watershed. It varies from 3740 ft. at the west edge
to 3630 ft. at the east edge. The watershed is gently sloping with
approximately 1/2 of the drop in elevation occurring below the
irrigation area in the final mile as the drainages ente~ the Arkansas
River \",.ley.

The dra~nages of the watershed all outlet into the Arkansas River.
Prowers Arroyo, Limestone Creek, Graveyard Creek, Wiley Drain, and
Pleasant Valley Drain all have small year around flows.

GeoloGY 1/

The watershed is located within the Colorado Piedment Section of the
Great Plains Physiographic Province (Fenneman, 1931). The Colorado
Piedmont represents an old erosion surface. It is a mature to old,
broadly rolling, elevated plain with local scarps.

Bedrock consists primarily of cretaceous marine shales and limestones.
These formations dip slightly to the northwest, toward the Denver
structural basin. The oldest formation that crops out in the
watershed is the Lower Cretaceous Dakota sandstone, which is found
along the valley side above the Arkansas River flood plain. Overlying
the Dakota Formation (from oldest to youngest) is the Graneros shale, '
Greenhorn limestone, Carlile shale, and the Fort Hays limestone member
of the Niobrara Formation. Younger Quaternary deposits overlay the
bedrock over much of the watershed area.

Shales and limestones have higher concentrations of some minerals than
other rock types have. This is particularly true of mine~als such as
sulfur and trace minerals such as arsenic, boron, and selenium
(Turekian and Wedepohl, 1961).

8