Flash Flood in Tanque Verde Creek, Tucson, Arizona

Abstract

The flood of July 26, 1981, in Tanque Verde Creek east of Tucson, Arizona, that killed eight people near Tanque Verde Falls was just a small one for this stream. Dangerous floods are not necessarily large ones; two much larger floods occurred there within a week. Floods can travel for miles at rates of rise and speeds too great for a person to escape from rough stream channels. Reports by survivors and initial observations by hydrologists indicated a large flood had occurred. However, when records of streamflow at a gaging station downstream were analyzed, it was apparent the killer flood was small and the peak discharge could be expected to be exceeded at least once every 2 yr. Storm and drainage‐basin characteristics are important in the production of dangerous floods. Survivors' reports of a wall of water were corroborated by hydrologic and hydraulic flood routing.