- The Santa Cruz has its headwater in the high intermontane grasslands of the San Rafael Valley to the southeast of Patagonia, Arizona, between the Canelo Hills to the east and the Patagonia Mountains to the west, just north of the international border with Mexico - Unfortunately, over the last century, human demand for water has taken a devastating toll on the Santa Cruz ... surface water and groundwater have been pumped for drinking water, agricultural irrigation, and to fuel industry and commerce to such an extent that much of the river has gone dry - From its headwaters in the San Rafael Valley in Arizona to its confluence with the Gila River north of Tucson, the Santa Cruz River stretches over 200 miles and is the only river to cross the U.S./Mexico border twice ... it first flows south from its headwaters into Mexico, where it completes a 25-mile U-turn and flows back north into the United States (a stretch referred to as the “Upper Santa Cruz”), then through Tucson (the “Lower ...