PROJECTS

CULTURAL RESOURCES

Linear Facility APS Southwest Valley Project

The APS Southwest Valley 500kV Transmission Project was built in 2003 and is located in Maricopa County just west of Phoenix, Arizona. EPG completed an intensive pedestrian survey for cultural resources of more than 1,400 acres and approximately 37 miles in length in support of the project. The study identified one major prehistoric archaeological site along the northern margins of the Gila River, the Alkali Ruin, as being directly affected by the project. Alkali Ruin is a large Hohokam village site dating to the Pre-Classic and Classic periods. Prior to construction, EPG developed a data recovery plan for the site, which was approved by the Arizona State Historic Preservation Office (SHPO). The plan was implemented and resulted in the recovery of several thousand artifacts, multiple subsurface features, and a radio-carbon date that demonstrated that the occupation of the site began approximately 1,500 years ago. One of the most interesting results was the analysis of an obsidian projectile point that indicated the obsidian came from western New Mexico and was of a type rarely seen in central Arizona.

Additional regulatory conditions required archaeological monitoring during construction to help prevent any inadvertent damage to those portions of the Alkali Ruin that were not cleared as part of the mitigation plan. EPG archaeological monitors provided environmental training to construction crews and a monitoring report to SHPO upon the completion of the project.