Brantley Dam is on the Pecos River at mile 478.5, about 13 miles upstream from the city of Carlsbad, New Mexico. It is about 10 miles upstream from the Avalon Dam in the Carlsbad Project and 25 miles downstream from Artesia.
The Brantley Project area extends about 16.5 miles above the damsite. The Pecos River watershed is in a semi-arid region. Average annual precipitation in the Pecos River Basin varies from about 10 inches near Pecos, Texas, to greater than 33 inches in th
The project's main purpose is to replace McMillan Dam, which was declared unsafe. Additional benefits include irrigation, flood control, fish and wildlife enhancement, and recreation.