Cochise College           Student Papers in Geology

Geology Home Page                   physical geology  historical geology  planetary  gems           

Roger Weller, geology instructor

by Richard Miller
Physical Geology
Spring 2013

Babacomari River
Southeastern Arizona


Almost everyone living in the Sierra Vista area has one time or another driven over the “San Ignacio Babacomari River,” without ever realizing it.  That’s because where highway 90 goes over the bridge in lower Huachuca City, the river seems like the ordinary ephemeral stream (dry wash).  That is only because this river that flows year around, disappears under the ground for a short distance only to reappear above ground 6 miles downriver. 

The Babacomari River is a tributary that feeds into the San Pedro River.  The river begins almost exactly on the border of Pima and Cochise County, on private property known as the “San Ignacio Del Babacomari Land Grant.”  The river is approximately 16.23 miles as a crow flies in length.  The headwaters are at an elevation of approximately 4,683 ft.  The river makes its way 16 miles plus to the San Pedro River, where the mouth of the river is at an elevation of approximately 3,898 feet.

Description: C:\Users\Richard Miller\Desktop\Babacomari Image.jpg

The springs are supplied year around by an aquifer that is filled by a basin  that stretches from the higher elevations of Elgin to the west, the north side of the Huachuca Mountains to the south and the south side of the Mustang Mountains to the North.  This basin gathers the water which feeds the Babacomari springs, these springs are where the Babacomari River begins.

Description: C:\Users\Richard Miller\Desktop\babacomari basin.jpg


The Babacomari Dam when flowing can produce as much as 790 gph, most often during the monsoons and winter rains.  This dam closely balances the use of water to irrigate the fields for livestock and also to supply the river.  Most commonly during the winter and monsoon months water is plentiful, but during the summer the river can whittle down to just a trickle in some areas.  In the worst case scenario during a bad drought, the river can even become stagnant.

Description: thumbnail3Description: F:\DCIM\100MEDIA\DSC00076.JPG   Description: F:\DCIM\100MEDIA\DSC00080.JPG

Photo from Babacomari Ranch     Photo by Richard Miller                     Photo by Richard Miller


Approximately 4.4 miles east from the Babacomari spring, both the river and the riparian zone disappear.  This forms an ephemeral stream (dry wash); this is what most people see when they drive thru lower Huachuca City.  Just a mere 126 years ago the river was flowing thru what would currently be lower Huachuca City.  On May 3, 1887 a 7.6 earthquake, which its epicenter was in Bavispe Mexico, shook southern Arizona.  This earthquake caused the Babacomari River to go underground for the next 6 miles, where it then reappears to flow like nothing ever happened.  Changes such as this in the area from this earthquake were not uncommon, 20 miles away in the town of St. David, artesian wells sprang up as well as many other geologic changes along the San Pedro River.

            The final 6.3 miles of the river developed into a beautiful riparian zone full of vegetation as if there was never any diversion of the river as a result of the earthquake.  At the mouth of the river the amount of water that reaches the San Pedro River, is only a trickle of its original amount.  Of course that should be expected, I think most people don’t understand the life that even such as small river such as the Babacomari contributes.

Description: F:\DCIM\100MEDIA\DSC00052.JPG 

Photo by Richard Miller


I was once talking to “Frank” the Ranch Manager of the Babacomari Ranch.  He said that “the cottonwoods alone drink more than a foot of water out of the pond a day in the growing season”.  I was blown away when I started multiplying the 12 miles of cottonwoods alone that this river fed.  Not including the deer, birds, plants, cats, insects, reptiles etc that this little unknown river gives life too.  One question did come to mind, “when the river stopped flowing from the earthquake for that 6 miles, did the river just go back down into the aqueduct and where river reappears is just another spring or did the river actually create another route underground?”

Description: F:\DCIM\100MEDIA\DSC00069.JPG


            There was a lot of history that goes along with the Babacomari River, too much to really sum up, but there was one specific passage I read on Babacomari Ranch website that drew me in when I first began my research. 

The following year, Coronado and his army came this way on their famed but unsuccessful search for the Seven Cities of Cibola and the ever-elusive El Dorado. Then this ancient land fell back into the prehistoric silence which had been so unexpectedly shattered by the coming of the white man and his restless search for souls and treasure. A hundred and fifty years elapsed before the black robes of the Jesuit priests were seen in the Babacomari Valley, with the redoubtable Father Francisco Eusebio Kino leading the way. This was the year 1692, when Father Kino first made the acquaintance of Chief Coro at his extensive village of Quiburi where the Rio Babacomari empties into the San Pedro, and caused Kino to remark: "it is true that I found them somewhat less docile than the foregoing people of the West." The next day he proceeded up the Babacomari to the Cienaga and village at Basosucan (modernized Huachuca) where he met Chief El Taravilla, which means "the Prattler." La Cienaga — now the site (headquarters) of Babacomari Ranch. The name of the village is still preserved in Huachuca Mountains and Fort Huachuca nearby. Huachuca was the last village of the people whom the Spaniards called Pimas Proper, those beyond were Sobaipuris."


I chose this passage from the Babacomari Ranch website in my closing because I think it really demonstrates how this small, forgotten river played not only such an important role in the development of a huge valley geologically.  But how important this river on a daily basis was for the development of mankind, for who knows how long.  So the next time you are going through lower Huachuca City and you see the sign for the “Hideout,” you know you are crossing paths with Francisco Coronado and right down that road is where the indian village “Basosucan” once was.


Links to information