This 24×36″ oil on canvas, “The Westward Crossing”, is fresh off the easel. This classic desert sunset is just West of our home in Marana, Northwest of Tucson. One of the few areas where water flows year round in the desert in the “Santa Cruz” river.
The 210-mile Santa Cruz originates in the San Rafael Valley of southeastern Arizona, where it flows south through one of
the last remaining expanses of a unique grassland ecosystem interspersed with oak woodlands. By the time it crosses into Mexico,
15 miles south of its headwaters, the river supports abundant streamside vegetation surrounded by mesquite bosques (forests).
In Mexico, the Santa Cruz makes a 25 mile U-turn through Sonora and returns to the U.S. just east of the cities of Nogales, Sonora, and
Nogales, Arizona. As the river approaches the border it is transformed into an ever-diminishing creek until it disappears altogether, the
result of groundwater pumping that has dropped the water table and thus dried the river’s surface flow. Just north of the border, the river’s
year-round flow and cottonwood-willow forest return due to an inflow of treated wastewater (effluent) from the Nogales International Wastewater Treatment Plant. Downstream, near the community of Rio Rico, the Santa Cruz is joined by Sonoita Creek, one of its largest tributaries. The Santa Cruz remains lush and green as it flows 15 miles north to Tubac, approximately parallel to Interstate 19.
North of Tubac, geologic formations cause the river to flow entirely underground as it proceeds toward Tucson. Before extensive groundwater pumping began in this region, the hidden river emerged in many places in the form of springs, cienegas, and surface flows. One such area of year-round flow was at the base of Sentinel Peak(“A Mountain”) near downtown Tucson. Today, due to groundwater pumping, the springs and cienegas are dry and the river flows through downtown Tucson only during storms.
The Santa Cruz flows through three distinct biomes and is surrounded by mountains known as “Sky Islands,” where wide ranges in elevation result in enormous biodiversity. The river’s north-south orientation forms an important flyway for migratory birds and bats, and its lush vegetation, in contrast to the surrounding desert, allows some subtropical species to extend their ranges north from Mexico into Arizona. Examples of the many important species in the watershed include:
15 endangered species, including the Pima pineapple cactus, Gila topminnow, and lesser long-nosed bat.
Jaguars and ocelots, which have been spotted by people and remote cameras. Efforts are underway to monitor and protect habitat for these endangered cats on both sides of the border.