National Park Service


Date of this Version



Midwest Archeological Center, National Park Service (2006).


Prehistoric sites with architectural remains are those most commonly disturbed by contemporary activities in the area surrounding McPhee Reservoir in southwest Colorado. This study used exploratory procedures to (1) assess whether associations exist between a set of characteristics of a prehistoric site and evidence of modern activities at that place; (2) ascertain how evidence of subsurface “looting” varies with site characteristics; and (3) assess the vulnerability of sites to contemporary human activities during exposure after periods of inundation. Four categorical variables reflecting modern activities were used with five prehistoric site descriptors to describe the relationships between the remains of human activities in the past and present at 29 sites. Over half of these sites have been subjected to subsurface digging and eleven of the 32 sites examined have been subjected to inundation at some time since 1986. This study resulted in the construction of testable predictions oriented toward gaining insight into how and where contemporary visitors to the area use places of prehistoric activity. Using a small sample of sites an analytical framework was pursued that can be used with expanded data and with refined categorical variables to enhance management protection as well as further interest in contemporary recreational behavior at those places on the landscape used by humans in prehistory.

The rate at which a place of prehistoric activity incurs change to its material and spatial integrity is enhanced by modern human activities. Change due to processes of the non-human environment can be monitored, measured, and to some extent, made predictable. Use of a place of prehistoric activity by modern humans can, in many cases, alter if not destroy remains that have been assigned public value. It is the assigned socio-economic value to some prehistoric material items that contributes to the probability of non-research oriented illicit digging at these places for the purpose of acquiring artifacts, often called “looting” or “pot-hunting”. Procuring these items for the antiquities market that fluctuates through time and geographically has been a phenomenon in the Four Corners area of the northern Colorado Plateau for over a century. Sites with architectural remains are those most commonly looted. Predicting, however, what particular sites, under what social and economic conditions have been or will be looted is acknowledged to be difficult. Efforts to construct descriptive models of the vulnerability of prehistoric sites to looting have been undertaken in southwest Colorado (Nickens et al. 1981), San Juan County, Utah (Wylie and Nagel 1989), and on Perry Mesa in central Arizona (Ahlstrom et al. 1992). Surface characteristics of sites easily recognized by potential looters were considered as variables “attractiveness” or “richness”. Surface evidence of architecture is considered to be a significant factor in a site’s vulnerability to looting.

For over ten years more than 1600 archaeological sites were recorded along an approximately 15km length of the Dolores River valley in southwest Colorado in preparation for the river’s impoundment as McPhee Reservoir and associated projects. The Dolores Archaeological Program (DAP 1978-1985) resulted in the subsurface testing or excavation of 101 of these sites. Results of intensive research in this area demonstrated that the bulk of prehistoric occupation and activity occurred between approximately A.D. 650-900, or in traditional Pecos chronology terms, late Basketmaker III through Pueblo I periods. Based on the number and sizes of households discovered approximately 4000 people are believed to have lived along this portion of the river by A.D. 860 (Kane 1986; 1989). This area, currently listed on the National Register of Historic Places as the Anasazi Archaeological District, is managed by the San Juan National Forest.