Whitlow Ranch Dam

Whitlow Ranch Dam is an ungated flood control structure located on Queen Creek in Pinal County, Arizona. The dam is located (see: Map 1 & Map 2) about 50 miles southeast of the City of Phoenix and about 7 miles northeast of the town of Florence Junction.  The drainage area tributary to Whitlow Ranch Dam comprises about143 square miles. This upstream area is bordered on the east by the Pinal Mountains and includes the town of Superior.  The dam was built in 1960 to provide flood protection to farmland and developed areas including the communities of Chandler, Gilbert, Queen Creek, and Florence Junction and portions of Williams Air Force Base.  The outlet works does not include any mechanical equipment that will permit significant adjustment to large outflows.   Essentially the project operates for flood control automatically.  Included in the project is a slide gate and a outlet-and-diversion structure designed to divert water and satisfy local water rights.  Local interests, who have acquired these water rights, operate the slide gate to divert outflow from the reservoir into a irrigation ditch.  Diverted flows have an negligible impact on outflows from the dam during a flood event. 

Continuous low flows (less than 10 cfs) pass through Whitlow Ranch Dam's outlet works.   Large discharges occur following heavy rains in the area above the dam.   Outflow usually percolates into the alluvial plain below the dam and rarely travels more than a few miles downstream.  Only flows from very large and infrequent storms will drain into the Gila River at a location about 40 miles downstream from the dam.