Chaco Culture National Historical Park - Geography

Geography

Chaco Canyon lies within the San Juan Basin, atop the vast Colorado Plateau, surrounded by the Chuska Mountains in the west, the San Juan Mountains to the north, and the San Pedro Mountains in the east. Ancient Chacoans drew upon dense forests of oak, piñon, ponderosa pine, and juniper to obtain timber and other resources. The canyon itself, located within lowlands circumscribed by dune fields, ridges, and mountains, is aligned along a roughly northwest-to-southeast axis and is rimmed by flat massifs known as mesas. Large gaps between the southwestern cliff faces—side canyons known as rincons—were critical in funneling rain-bearing storms into the canyon and boosting local precipitation levels. The principal Chacoan complexes, such as Pueblo Bonito, Nuevo Alto, and Kin Kletso, have elevations of 6,200 to 6,440 feet (1,890 to 1,960 m).

The alluvial canyon floor slopes downward to the northeast at a gentle grade of 30 feet (9.1 m) per mile (6 meters per kilometer); it is bisected by the Chaco Wash, an arroyo that rarely bears water. The canyon's main aquifers were too deep to be of use to ancient Chacoans: only several smaller and shallower sources supported the small springs that sustained them. Aside from occasional storm runoff coursing through arroyos, substantial surface water—springs, pools, wells—is virtually non-existent.