FLOOD10395 ‎(2)‎

• County: Montezuma
• Community: Dolores
• Stream Name: Dolores River
• Title: Dolores River near Dolores, Colorado, Flood Insurance Study
• Date: 5/1/2004
• Prepared For: Dolores
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Groundhog Reservoir, the only major reservoir upstream of McPhee Reservoir, is located

about 25 miles north of Dolores, on Groundhog Creek, a tributary to West Dolores River. It was

originally constructed with a storage capacity of 11,000 acre-feet (ac-ft) about 100 years ago, to

provide water for irrigation. Later, the reservoir was enlarged to hold 21,700 ac-ft. Groundhog

Reservoir is stocked with rainbow trout, as well as native and Snake River cutthroat trout. The

dam is owned and operated for irrigation by the Montezuma Valley Irrigation Company. Fishing

is regulated by the Colorado Department ofFish and Game.

Vegetation in the Dolores Basin include Gambel oak, Pinon-juniper, Ponderosa pine,

Douglas fir, Cottonwood, sagebrush, and grassland. The immediate shoreline of the reservoir is

predominately Pinon-juniper, oakbrush, grassland and sagebrush. Ponderosa pine and Douglas fir

are found along the northern end of McPhee Reservoir, spreading up to the timberline to the east.

Cottonwood is predominant at the upper end of the reservoir (at Dolores) with scattered patches

along tributary drainages to the reservoir. Below the McPhee Dam are areas of dryland cultivated

fields, irrigated cropland and sagebrush.

5.2 Topography. The topography ofthe Dolores River Basin varies from deeply

incised river and stream canyons with isolated buttes and mesas in the lowland areas, to large

dissected pediments and rugged topography in the border areas. (See Plate 2.) The basin between

Dolores and McPhee Reservoir is chiefly low tabletop mesa terminated near the reservoir shore

by short, steep bluffs. The valley floor is relatively flat above Dolores for 20 to 25 miles

upstream; the watershed is 15 to 20 miles wide. The terrain steepens abruptly above the valley

floor into mountainous slopes topped around the basin rim by individual peaks rising to between

12,000 and 14,000 feet. Among them are Mount Wilson 14,246 feet; EI Diente Peak, 14,159 feet;

and San Miguel Peak, 13,752 feet (all located around the northeast basin rim); and Hesperus

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