The environment of the Colca Valley region is nearly ideal for full-coverage survey methods, given the fact that alluviation is very localized and surficial visibility is excellent during the dry season (May-November). Sites destroyed by the construction of agricultural terraces on the slopes of the valley, and by modern settlements (reducciones) represent the principal exceptions to this rule. While the deep fill and slope modification effected by the construction of valley side terraces necessarily buries the cultural features originally present on the original surface, it is expected that the quantity and size of sites lost by terrace construction is minimal, given the fact that such valley side terraces were built to facilitate irrigation, deepen soils, and control erosion along slopes that are so steep as to be otherwise incultivible (Treacy and Denevan 1994).
Within the project, it has been important to consistently delineate criteria for what constitutes a "site," given the fact that the entire valley could be considered a low density concentration of archaeological material. Thus, "site" is defined as a marked increase in concentration of ceramic, lithic or other cultural material in a discrete area. In this way, the survey focuses on discrete habitational, mortuary, and other special function sites. Also, in order to further ensure consistent criteria of site identification in the field, discrete concentrations of cultural material located more than 100 meters apart are considered separate sites.
II. Methodological objectives
The following constitute the principal project field objectives:
1) Locate, describe, and preliminarily date all settlements, mortuary sites, special function sites, and other cultural features visible on the surface within the survey area.
2) Locate and describe infrastructural features such as hydraulic features and transportation routes.
3) Locate and describe special resources, such as obsidian sources for stone tool manufacture or clay for ceramic production.
4) Create large-scale maps at selected sites with well-preserved architectonic remains.
III. Field Methods
Following the methods delineated by Feinman et a. (1985), Wilson (1988), Blanton et al. (1982:6-10), and Stanish (1982:6-10), we are carrying in the field sections of printed, digitized copies of airphotos of the zone at 1:5000 scale, along with copies of Ministry of Agriculture and National Geographic Institute topographic maps of the area enlarged to the same scale. The survey crew is spaced 25 to 100 meters (according to context and local terrain) and walks in transects, searching the soil surface for artifactual concentrations or other cultural features. Transects are walked until the survey limit or sector limit are reached, thus systematically covering all of the survey area. We are also registering the location of sites with a GPS receiver, in conjuction with AUTOCAD and other software (specifically, Fugawi moving map software and Golden Software's Surfer) installed on a portable PC. The use of the GPS receiver and associated software will also facilitate various forms of spatial analysis after fieldwork is completed. Site elevations are determined using the GPS point location on the topographic map.
Once a site is identified, the crew rejoins for completing detailed site report forms, and for collecting a representative sample of diagnostic cultural material from the surface. Site and/or component limits (as surficially evident) are also noted. At selected sites, we have created detailed architectural and contextual maps. If discrete temporal components are no distinguishible, artifact collections are made using arbitrary sectors or by architectural units (denoted on the site map). Pertinent contextual information (e.g. building wall fill vs. soil surface) are always noted in order to provide a measure of provenience resolution.