Floods of October 1977 in southern Arizona and March 1978 in central Arizona

Abstract

As much as 14 inches of rain fell in southern Arizona and northern Mexico during October 6-9, 1977, and caused the highest discharge since 1892 in the Santa Cruz River at Tucson. The flood caused $15.2 million in damage along the Santa Cruz, San Pedro, and Gila Rivers. Widespread rainfall of 3 to 6 inches and 9 to 14 inches in places, during February 28 to March 3, 1978, caused the highest discharge since 1920 on the Salt River in Phoenix and resulted in three deaths. Statewide damage was $65.9 million, of which $37 million occurred in Maricopa County. Nine counties were declared disaster areas. Unusually high volumes of runoff and moderate peaks occurred on tributaries to the Salt and Verde Rivers upstream from reservoirs. Overflow from the Verde River reservoir system was the main cause of the flooding. Storage in the reservoirs reduced the peak discharge of the Salt River from a potential of about 260,000 ft super 3/s to 125,000 ft super 3/s and greatly reduced the duration of the flood. (USGS)