Reconstruction of prehistoric Lake Cahuilla in the Salton Sea Basin using GIS and GPS

Abstract

During prehistoric times, the Colorado River occasionally meandered into and filled the Salton Sea Basin, creating several huge inland lakes, variously called Lake LeConte and Lake Cahuilla. Previous researchers have identified high stands of these ancient lakes using standard survey methods. The objective of this investigation was to further delineate the prehistoric shorelines using satellite imagery, global positioning system (GPS) and geographic information system (GIS) technologies. Using one-meter digital orthophotographs, points were selected in the laboratory and were located in the field using a GPS. Point data were integrated with a digital elevation model (DEM) and elevation contours were plotted on Landsat-TM images, generating a range of prehistoric shorelines. Contours were then correlated with archaeological site data, geomorphic features, and other factors to reconstruct Early American settlement patterns for Lake Cahuilla. The combined GIS coverages of ancient Lake Cahuilla and cultural resources may be used together as a model for cultural resource constraints, identifying areas of high cultural resource sensitivity for evaluation of potential impacts as a result of implementation of Salton Sea restoration project alternatives.