The Upper San Pedro Basin is a medium-size, 1,825 square mile basin in the southwestern portion of the planning area.  Geographic features and principal communities are shown on Figure 3.13-1. The basin is characterized by a large valley flanked by a series of mountain ranges.  Vegetation is primarily semi-desert grassland and Chihuahuan desertscrub with smaller areas of madrean evergreen woodland, plains and Great Basin grasslands and Rocky Mountain and madrean montane conifer forest. (see Figure 3.0-9)   Riparian vegetation includes cottonwood/willow, mesquite and tamarisk along the San Pedro River and conifer oak and mixed broadleaf along Gardner, Ramsey and Miller Canyons.

Principal geographic features shown on Figure 3.13-1 are:

• San Pedro River, which flows north through the San Pedro Valley east of Sierra Vista and Benson

• Babocomari River north of Sierra Vista

• Garden and Ramsey canyons southwest of Sierra Vista

• Tres Alamos Wash northeast of Benson

• Greenbrush Draw north of the Mexico border in the vicinity of Naco

• Huachuca Mountains southwest of Sierra Vista

• Whetstone Mountains southwest of Whetstone

• Canelo Hills west of Canelo

• Mule Mountains east of Bisbee

• Dragoon Mountains along the eastern boundary of the basin east of St. David

• Allen Flat in the northern part of the basin

• The highest point in the basin, 9,466 feet, at T23S, R20E in the Huachuca Mountains

• The lowest point at approximately 3,000 feet where the San Pedro River exits the basin

Click to view Figure 3.13-1 Upper San Pedro BasinGeographic Features

Arizona Water Atlas Home

Southeastern Arizona Planning Area Home