The American Southwest is honeycombed with ruins from long-past civilizations. Mesa Verde National Park and Canyon de Chelly National Monument are well-known for their cliff dwellings. Those well-familiar with Canyonlands National Park know where to find granaries and areas rich with "rock art," while Chaco Cultural National Historical Park preserves a landscape once known as a major cultural center of ancestral Puebloans.

Cliff dwellings also were inhabited at one point at today's Bandelier National Monument in New Mexico, but before they were built the sandstone walls were pocked with "cavates" used as shelter.

In 2000, the National Park Service's Vanishing Treasures Program at Bandelier began a project to document and conserve the cavates in Frijoles Canyon. Cavates are hand-hewn rock chambers that were occupied from the 12th to the 16th century C.E. (Common Era), according to park staff. They are the ancestral dwellings of the Pueblo people who now live in the Rio Grande Valley.

There are more than 1,000 cavates in Frijoles Canyon, a key interpretive area of the park visited by more than 300,000 people per year, and there are at least 1,000 more in surrounding canyons and Pueblo lands, the park notes. "Cavates are unique in the architecture of the American Southwest because of the extensive modification and use of the natural environment for their creation, the high number and density of dwellings, and the excellent preservation of some interior architectural features," the researchers say.

The aim of the Vanishing Treasures Program at Bandelier is to develop methods to identify, document, conserve, and maintain the cavates as both constructed and natural heritage, and, through Native American consultation and planning, create a culturally adaptive management strategy that addresses the physical conservation of the cavates in their constantly changing landscape, park officials said in a recent release. Condition assessment has revealed that the cavates are slowly deteriorating from both environmental and human impacts, they added.

Today the cavates appear as a honeycomb of caves in the cliff face; however, when they were in use, masonry walls and multi-story buildings covered them. All of those exterior structures have since collapsed, and only ten of the cavates have prehistoric masonry enclosure or partition walls left in situ.

Cavate B002 is unusual in that two of its original walls were built of masonry. Both walls were intact in the 1920s, but one has fallen down, and the surviving wall, the largest, is extremely fragile due to extensive mortar loss between the masonry units and severe cracking in the cliff face just above it. A multidisciplinary project is currently underway to evaluate the structural stability of the wall and study deterioration of the Bandelier Tuff.

This initial phase of research includes a detailed condition assessment of Cavate B002, laser scanning to record wall geometry, design and analysis of a structural model, and development of recommendations for ongoing structural monitoring. The structural model generated from the laser scan data will be used to theoretically predict wall behavior based on small changes in existing conditions, and will provide us with the theoretical basis for establishing stability/failure thresholds. A monitoring program for this site will be developed and implemented in future phases of this project. We hope this project to serve as a model for monitoring other cavate enclosures in the park and surrounding Pueblo lands.

The primary collaborators in this project are the School of Architecture at the University of New Mexico, led by Associate Professor Douglas Porter, and the Vanishing Treasures Program at Bandelier National Monument under the direction of Lauren Meyer. University and professional participants include Angelyn Bass Rivera, architectural conservator and former manager of the Bandelier National Monument Vanishing Treasures Program, Dr. John A. Ochsendorf, Associate Professor of Civil and Environmental Engineering and Architecture at the Massachusetts Institute of Technology, and Jim Holmlund and Joe Nicoli of Western Mapping Company, Inc. This project is being facilitated by the Colorado Plateau Cooperative Ecosystem Study Unit (CESU).