On April 15 through 17, 1985, the Institute for American Research conducted emergency archaeological testing and mitigation for a bank stabilization project along the Santa Cruz River in Tucson, Pima County, Arizona. It encompasses both banks of the Santa Cruz River, from Project Station 37+00 to Station 57+00. Elevation ranges from 2438 to 2462 feet. Locations to be affected by construction consist mostly of floodplain silt and sand deposits, overlying a sand and gravel river terrace stratum. Scheduled construction activities include cutting existing riverbank in some areas and filling in others, to obtain evenly tapering sides that can be protected with soil cement. Previous archaeological inspections had shown that prehistoric Hohokam and historic Papago artifacts were scattered over the ground surface on the east bank of the river from about Station 45+00 northward to Station 37+00. This segment is along the southwestern edge of the Valencia Site, a large prehistoric Indian village ruin. Designated AZ BB:13:15 in the Arizona State Museum archaeological survey records, the Valencia Site is the only Tucson Basin ruin known to contain evidence of all the prehistoric human occupation periods of southern Arizona. The site is listed in the National Register of Historic Places, and is being considered for development of an archaeological park by the City of Tucson. When it was reported that stabilization efforts might adversely affect Indian ruins in this area, Pima County halted construction so that archaeologists could determine whether significant subsurface cultural materials were present.