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DRAFT - Upper Colorado River Basin Resource Guide: San Juan River

Sponsored by the The Water Center at Colorado Mesa University


Detailed map

  • Drainage Area: ~ 26,000 square miles of Colorado, New Mexico, and Arizona before merging with Lake Powell and the Colorado River system in Utah. Major tributaries include San Miguel River, Animas River, and La Plata River.
  • Length : The San Juan River is the second longest (or largest??) tributary to the Colorado River. Its source is on the Continental Divide in southern Colorado. It flows approximately 350 miles west to its confluence with Lake Powell.
  • Largest cities/towns in the basin:
    • Farmington, NM
    • Durango, CO
  • Elevation: Ranges from greater than 14,000 ft. in the San Juan Range and headwaters of Animas and Los Pinos Rivers to 4,500 ft. as Mancos River exits the state of Colorado, east of the Four Corners and  ~ 3,700 ft at the confluence with Lake Powell.
  • Land use: Agricultural, mining, recreation, tourism (??)
  • Storage-Major reservoirs:
    • McPhee Reservoir - 381,100 ac-ft
    • Vallecito Reservoir- 129,700
    • Lemon Reservoir - 40,100
  • Major Exports from Basin:
    • San Juan-Chama Project - 89,832 ac-ft

Source: San Juan/Dolores River Facts