FLOOD04873

• Designation Number: 359
• County: Archuleta
• Community: Pagosa Springs
• Stream Name: San Juan River and McCabe Creek
• Basin: San Juan/Dolores
• Title: Flood Hazard Analysis - San Juan River and McCabe Creek in the vicinity of Pagosa Springs, Archuleta County, Colorado
• Date: 9/1/1977
• Designation Date: 5/1/1994
• Floodplain - Doc Type: Floodplain Report/Masterplan

DESCRIPTION OF THE STUDY AREA

study area for the San Juan River, McCabe Creek, and a small amount of

local area is about 319 square miles. the San Juan River is a major

tributary to the Colorado River in the Upper Colorado, Water Resources

Council Region.

The study anea includes the flood plains of the San Juan Rivef.ftnd
McCabe Creek in the vicinity of pagosa Springs. McCabe Creek is a
tributary to the San Juan River.

From the Continental Divide, the San Juan River flows through steep and

narrow canyons in a south westerly direction. The river enters a valley

approximately a quarter of a mile wide which extends about 17 miles to

tne town of,Pagosa Springs. The river flows through the northeast

corner of Pagosa Springs and makes several bends before it exits on the

southern edge of town. Above Pagosa Springs, the drainage area of the

San Juan River Is about 298 square miles.

The San Juans are a well-defined area of rugged mountains rising abruptly

from the mesa and foothill surfaces of the adjoining Colorado Plateaus

province. They consist largely of volcanic rocks in more or less

horizontal layers overlying older sedimentary rocks. Soils are moderately

deep to shallow with rock crops; and the permeability and runoff charac-

teristics are highly variable. Ground cover consists of native grass,

brush, and forestland. Pinon-juniper and pine trees grow at the lower

elevations. Aspen and spruce-fir species are common to the higher

elevations. Topography has significant effect on the semi-arid climate.

Average annual precipitation varies from about 19 Inches at Pagosa

Springs to over 50 inches in the higher mountain elevations where most

of the precipitation occurs as snow. Melting of the snowpack causes

high runoff during the spring and sustained flow in the San Juan River.

In Pagosa Springs, the extremes in temperatures have ranged from a

maximum 98 degrees Fahrenheit in July to minimum - 460 Fahrenheit in

February. The mean annual temperature is 42.2 degrees Fahrenheit.

The drainage areas are located primarily in the northeastern part of

Archuleta County with portions of the Upper San Juan River watershed in

Mineral and Rio Grande Counties. The upstream drainage area originates

in the San Juan Mountains at the top of the Continental Divide between

'the San Juan and Rio Grande River Basins. Elevations in the San Juan

River drainage vary from more than 13,000 feet along the western slopes

of the divide to about 7,000 feet near the southern city limits of

Pagosa Springs. Upper and lower elevations of McCabe Creek are 9,360

feet and 7,050 feet (mean sea level elevations).

Draining approximately 20 square miles, the McCabe Creek watershed lies

north and west of pagosa Springs. McCabe Creek joins the San Juan River

near the center of town. Total drainage above the lower limits of the

Archuleta County was organized from part of Conejos County In 1885.

Nearly half, 47.9 percent, of the county area is devoted to the San Juan

and Rio Grande National Forests. Several guest ranches in the county

emphasize hunting and fishing as major activities. Basic factors in the

economy are agriculture, lumbering, and recreation. Because of the

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