Centennial Museum gecko logo

Desert Diary


Not all pirates roamed the waters of earth in ships—in fact, waters themselves have committed piracy in the northern Chihuahuan Desert.

As the Pecos River eroded its way northward from what now is the Rio Grande, it intercepted streams flowing to the east. Decapitating these rivers, the Pecos diverted their waters to the south.

Our own Rio Grande has engaged in a bit of piracy, too. Originally, the Rio Grande Rift was a series of closed basins arranged from southern Colorado to El Paso. As the basins filled, they overflowed into lower-elevation basins to the south, eventually forming the ancestral Rio Grande. But this river flowed not to the Gulf of Mexico, but into a closed drainage basin in the Casas Grandes region of Chihuahua. As the Mesilla Bolson filled with sediments, however, the river overflowed north of the Franklin Mountains into the Hueco Bolson and on to the southeast. Later, headward erosion from below El Paso cut through at the river's current location, and the mature Rio Grande retired to respectability.
pen and ink

Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.


Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio, University of Texas at El Paso.



Part of the evidence for stream piracy on the part of the Pecos River is the presence of empty stream valleys between Lubbock and Amarillo, TX. At one time, waters flowed from the west through these valleys, but were diverted to the south when the Pecos intercepted them. ahh


Web Resources

Blue Ridge Stream Piracy. Though not of our region, the description fits well. rule