FLOOD02969

• County: Dolores
• Basin: San Juan/Dolores
• Title: Floodplain Information Report
• Date: 9/1/2000
• Prepared For: Dolores County
• Prepared By: CWCB
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

.
.
.
I:
.
j.
.
.
.
.
.
,e
e
.
j.
:.
,

STUDY AREA DESCRIPTION

Community DescriDtion
Dolores County is located in southwestern Colorado. The county is bordered by San Miguel
County on the north, San Juan County on the east, Montezuma County on the south and the state
of Utah on the west. Dove Creek is the County Seat of Dolores County. The population of
Dolores County was estimated at 1,876 in July 1999 by the Colorado Division of Local
Government Demography Section, The area mapped in the FHBM includes the entire county
except the incolllorated communities of Dove Creek and Rico,

.
.
.
.
.
.
'.
.
.
.
e
.
:e
.
.
:.
I.
.
i.
.
e
.
.
.
e
.
.
e
.
.
e
.
.
.
.
.
i.

Watershed DescriDtion
Dolores County is located on the western slope of the Continental Divide in both the San Juan
and Dolores River basins, The western portion of the county is within the San Juan River basin
while the eastern portion of the county is within the Dolores River basin, The basins are
generally separated in the county by the western and southern rim of the Dolores Canyon,

The streams within the San Juan River basin generally originate in the higher plateaus and flow
from northeast to southwest. The streams are tributary to the San Juan River in southeastern
Utah. Most streams are intermittent minor streams which flow primarily during snowmelt and
precipitation events, Elevations of the watersheds range from approximately 8000 feet at its
headwaters to approximately 5200 feet at the Do]ores CountylUtah State line. There are no
USGS or Division of Water Resources gaging stations on any of the streams within the basin,
With the exception of Dove Creek, the watershed primarily consists of agricultural uses or
undeveloped high plateau grazing land, Agricultural uses include non-irrigated beans and wheat
and irrigated a]falfa, Higher undeveloped areas consist of scrub oak, pinon, cedar and ponderosa
pine. Lower undeveloped areas consist of scrub oak and sage brush with pinon, cedar and
cottonwood in drainageways,

The Dolores River originates within the county at the base of Grizzly Peak, The river initially
flows southwest into Montezuma County where it is impounded by McPhee Dam, It then flows
northwest through Dolores County in Dolores Canyon, There are several tributary streams to the
Dolores River within the County, Elevations of the watershed range from over 14,200 feet at
Mount Wilson to approximately 5900 feet on the floor of Dolores Canyon as it leaves Dolores
County, There is one current USGS gaging station located on the Dolores River below Rico
(0916500) and one discontinued station on the West Dolores River near Stoner (09166000),
There are also several gaging stations upstream and downstream of Dolores County along the
Dolores River. With the exception the Towns of Dolores and Rico, the watershed is primarily
undeveloped forested lands consisting of aspen, lodgepole pine, spruce, grass meadows and steep
rock faces. There are also remnants of mining activities in the area, which primarily occurred in
the late ]800's and early ]900's, According to officials with the Dolores Water Conservancy
District, McPhee Reservoir does not provide flood control storage for the Dolores Ri ver.

Floodine Problems and Floodine Historv
Floods in the subject watersheds nonnally occur during the months of late summer and early
autumn and are caused primarily by intense localized cloudbursts or thunderstorms, Typically,

2