National Park Service

Sonoran Desert I&M Network (SODN)

Tumacácori National Historical Park

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Interactive Data: Climate and Streamflow
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Sonoran Desert Network parks
Location of Tumacácori National Historical Park
in the Sonoran Desert Network. Click for larger image.
Tumacácori National Hisotric Park
Tumacácori National Historical Park

Size: 144 hectares
Elevation range: 994–1,097 meters

Tumacácori National Historical Park, in southern Arizona, was established in 1908 to protect, preserve, and tell the story of the old Spanish and O'odham mission church. In 2005, more than 121 hectares were added to the park, reuniting the church grounds with a small piece of historical mission property. The addition also placed more than a mile of the Santa Cruz River, mesquite bosque (forest), and a section of the Juan Bautista de Anza National Historical Trail ("Anza Trail") within the park.

The park comprises three units, all containing adobe ruins of Spanish colonial missions: Tumacácori, Guevavi, and Calabazas. There is a visitor center at the Tumacácori unit.

The Santa Cruz River supports a rare southwest cottonwood-willow riparian environment, one of the most endangered ecosystems in the U.S., as it flows through the park. In addition to the riparian and mesquite environments, the park grounds also include eight former agricultural fields.

The Sonoran Desert Network monitors air quality; climate; invasive exotic plants; groundwater; landbirds; and streams at Tumacácori National Historical Park.

Life Zones

With an elevation range of approximately 3,261–3,599 feet (994–1,097 m), the three units of Tumacácori National Historical Park occupy one life zone: thornscrub. Average annual precipitation is 16 inches (408 mm).

Lifezone elevation profile for Tumacácori National Historical Park
Life zone elevation profile for Tumacácori National Historical Park.

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Santa Cruz River

Santa Cruz River
Top: Santa Cruz River in Tumacácori NHP, 2012.
Bottom: Santa Cruz River in Tumacácori NHP, July 2013.
Santa Cruz River Map
After leaving its Arizona headwaters, the Santa Cruz River hooks south into Mexico and then turns back north into Arizona. The Santa Cruz is the only river to originate within the U.S., flow out of the country, and then re-enter it.

The Santa Cruz River flows through the park on its way north after curving south into Mexico not far from its headwaters in the U.S. Sometimes known as "the lessening stream," its flow has historically varied widely with changes in natural conditions and human use. Since 1951, the Santa Cruz at Tumacácori NHP has been bolstered by a flow of effluent from the Nogales International Wastewater Treatment Plant (NIWTP), located 10 miles upstream of the park. This steady flow has supported growth of a rare southwest cottonwood-willow riparian environment, one of the most endangered ecosystems in the U.S.

Reduced inputs from the NIWTP, however, caused the river to stop flowing in the park in mid-April 2013. If current conditions continue, it is likely that the composition of this forest will change. Read more

Last Updated: December 30, 2016 Contact Webmaster