The present study addresses concerns which have originated in the Resources Inventory Committee (RIC), an initiative undertaken by Provincial and Federal Governments to integrate program design and set standards for resource inventory. This study was done under the Earth Sciences Task Force, one of six task forces. The Earth Sciences Task Force has four Task Groups, including Landslide/slope stability; Seismic; Aquifer/Hydrogeology; and Archaeology.
A previous study has discussed the state of the existing inventory in British Columbia (Eldridge and Moon 1992). The present study examines the quality and coverage of archaeological surveys in British Columbia; the feasibility of incorporating existing data into predictive models; identifies areas requiring additional survey; discusses appropriate scales, sampling strategies, and environmental parameters for potential mapping (predictive modelling); determines a preferred methodology for inventory; and selects an area and techniques for testing the preferred methodology.
A sample of recent Overview Assessments were examined but it was found that generally they do not present data in a manner Usefu1 for direct application to predictive modelling/potential mapping. Most were development specific and make statements which are confined to small proportions of a region. The single most important use of overviews appears to be that they usually provide a summary of regional or local archaeology and ethnography. Very few studies follow through with a map incorporating identified potential areas on the landscape.
Two exceptions found were both linear overviews which combine potential mapping with sensitivity and significance indices to evaluate alternate routes for linear developments (Eldridge 1982; Stryd, Bouchard and Kennedy 1990) Both models appeared to have predictive value, although neither has been followed up by full-scale impact assessment and ground truthing. A similar method, but using GIS, was implemented to select preferred powerline routes in the U.S. Southwest (Moreno 1991:30). A more common method for linear surveys is to determine judgementally the potential from ethnography, prior experience, and with the aid of a helicopter over-flight.
Given their deficiencies, a detailed examination of overview assessments was not undertaken. Three recent large scale overviews consulted by this study all encountered serious limitations to their abilities to provide potential mapping. There follows a brief discussion of three recent overviews of very large areas to illustrate their general utility for potential mapping or model building.
Bussey and Alexander ( 1992) have recently completed a preliminary overview of the Cariboo Forest Region, an area which encompasses many of the best probabilistic surveys and freshwater shoreline surveys conducted in the province. Their report succeeds in integrating archaeological, ethnographic, and environmental data to produce a simple but apparently effective predictive model. Their report includes maps of areas with archaeological sensitivity or potential. The potential criteria are based on environmental units defined in accordance with traditional Native values. They note that this approach is applicable only within the last 4500 years of relatively unchanged environment. They avoided plotting known sites in order to "prevent biased interpretation of unsurveyed areas." (Ibid: 1 ).
They mapped only two potential classes, "with potential" and "without potential". In addition, each environmental unit has a written evaluation of relative potential. Potential maps are provided on a 1:250,000 map base in accordance with CORE requirements. The authors note that use of 1:250,000 scale maps resulted in "poorer definition of archaeological potential zones than is possible at the more commonly used 1:50,000 (or less) scale." (Ibid:12), and that "Future investigations should involve the use of 1:50,000 topographic maps and/or aerial photographs for interpretation." (Ibid: 134).
Bussey and Alexander's product, although coarse grained due to the scale, does have utility for regional planning. Approximately 75°/O of the area has been excluded from archaeological "potential". Bussey and Alexander tested the map by overlaying all 2155 known site locations. Only two small sites fell within the "without" potential class. Despite the apparent accuracy, there is some concern that the low potential rating is based on surveys which did not use subsurface testing in forested environments (see our discussion of probabilistic survey results below) because much of the "without" potential is forested. Nevertheless, if all areas which have mapped potential are submitted for review by Archaeology Branch officials then very positive benefits will accrue from the mapping exercise.
Another recent overview for CORE encompasses Vancouver Island (Wilson et al 1992). Vancouver Island has a large number of well documented systematic surveys and most of the probabilistic culturally modified tree (CMT) studies in the Province. However, the interior of the island further than a few hundred metres from the coast is virtually unknown archaeologically. "Predictive modelling" of site potential is confined solely to mapping an indicator of density of sites along the shoreline, high "potential" being greater than 1 site/km of shoreline, low "potential" less than 1 site. Some known ethnographic resource exploitation areas and trails are plotted on the map.
Because the present map is archaeological, only ethnographic information which would suggest the possible presence of physical remains was used for mapping purposes (Ibid:47)
hence excluding sites of mythological significance and other similar sensitive areas.
Areas comparable in topography were deleted from potential if no reference to their use could be found. This was done simply because no archaeological evidence to confirm potential areas is known (Ibid:47).
The authors also find that the 1:250,000 and even 1:50,000 scale maps are
far from perfect in terms of predicting the location of sites and sometimes even the general density of archaeological resources (Ibid:47).
This report contains no apparent attempt to analyze or integrate existing archaeological and ethnographic data in such a way as to generate variables useful for modelling site location. Environmental variables do not appear to have been incorporated into the map.
An overview of heritage resources for the Kalum South Resource Management area was conducted by Mackie and Eldridge (1992b). This area is poorly known archaeologically, with only a few high-quality riverbank corridor surveys. In addition, published ethnographic sources provide little hard data regarding settlement pattern or resource use. This study also fails to integrate ethnographic, historic and archaeological data to generate statements or maps of heritage potential. As with Bussey and Alexander, Mackie and Eldridge were constrained by concerns expressed regarding the use of data pertaining to Native peoples (Ibid:76-81, Appendix 1). A considerable body of information was collected concerning previously unrecorded heritage places, and these reinforce the general impression of insufficient data to allow potential mapping. Although no overall potential mapping was attempted, the potential statements of previous researchers were extracted and organised on a watershed management unit basis. The authors recommend that "Potential mapping should be supported by ground truth probabilistic sampling, and utilize an operational GIS." (Ibid: 90).