What it means
The Salt River is three things in Scottsdale conversation, and you sort them by context. First, it is the river: roughly 200 miles of water that begins where the White and Black rivers meet in the White Mountains, drops through a chain of dams, and reaches the Valley at Granite Reef, where nearly all of it is diverted into canals. Second, it is the Lower Salt, the few miles of cold green water below Saguaro Lake that the whole metro area floats on in summer; our tubing and wild horses guide covers that stretch. Third, it is a proper noun borrowed by everything along the north bank: the Salt River Pima-Maricopa Indian Community, Salt River Fields, and the Salt River Project, the utility whose dams hold the river back.
You will hear “the river” from someone describing a Saturday (“we were out at the river”) and “Salt River” from someone describing a government (“Salt River police handled it”). Neither means the dry bed under the Tempe freeways, which Phoenix and Tempe now market as the Rio Salado.
Where you’ll meet it
On the Bush Highway northeast of Mesa, where the river runs. On the freeway bridges, where it usually does not. In every story about the Valley’s water, from the Hohokam canals to the Arizona Canal. And across Pima Road, where “Salt River” is the Community’s name for itself.
Where the word came from
The oldest name is the one the people who farmed it used. The Akimel O’odham call the river Onk Akimel: onk means salty and akimel means river, which is also the first word in Akimel O’odham, “river people.” Bob Mason, writing in A Peek at the Peak in 2022, traces that reading to University of Arizona research published in 1969. The salt is real. Upstream of the Valley the river crosses a large salt formation, and the writer Hiram Hodge reported in 1877 that the whole flow was “impregnated with” it; Mormon settlers built evaporation vats near the deposits, and the Salt River Herald in 1878 claimed output of 2,000 to 3,000 pounds a day.
Europeans kept renaming it. Coronado’s men crossed its headwaters in 1540 and called it the Rio de las Balsas, the river of rafts. Spanish maps over the next two centuries tried Asuncion, Azul, Prieto, Compuesto, Salinas and Salado. The fur-trapping Pattie brothers called it the Black River in 1826. Kit Carson, three years later, called it the Salt, and that one held. “Rio Salado” survived as the Spanish form and was revived in the late twentieth century as a brand for the dry bed through Tempe and Phoenix.
The river’s modern shape dates to the Reclamation Act era. Roosevelt Dam, finished in 1911, and the three dams below it (Horse Mesa, Mormon Flat, Stewart Mountain) store the river; Granite Reef Diversion Dam, built by the Bureau of Reclamation between 1906 and 1908 after the Arizona Dam washed out in 1905, splits what is released into the Arizona Canal on the north side and the South Canal on the other. The structure is 1,128 feet long and only 29 feet high, and the Salt River Project operates it today. The Granite Reef Dam entry has the detail.
What it is not
The Salt River is not the Verde River, which joins it from the north a short way above Granite Reef, though both feed the same canals. And the Salt River Community is not a place “on the Salt River” in the way a visitor might imagine; most of its 52,000 acres are miles from the water, and the river along its southern edge is usually dry.
The fine print
A dry river is still a river, and the record of the Salt’s floods is the record of the Valley learning that. The flood of 1891 is the one the pioneer histories remember. The floods of 1980, 1993 and 2005 are the ones the bridges remember: when the dams upstream fill and SRP releases water, Granite Reef cannot divert it all, and the bed from Mesa to the Gila confluence runs bank to bank. The dam is designed for that; its engineers expected major overflows every ten to forty years and built it to be overtopped. Scottsdale sits well north of the bed, but in the same wet years the Greenbelt does its work for the same reason: desert rain does not negotiate.
The accounting of the water is where the arguments live. The river’s flow belongs, under the 1903 Salt River Valley Water Users’ Association agreement and a century of law since, to the lands SRP serves; Scottsdale’s own supply is a blend of SRP water, Colorado River water from the CAP canal and groundwater, which the Arizona water law guide untangles. The cancelled Orme Dam at the Salt-Verde confluence, killed in November 1981, is the biggest thing that never happened to this river.
One hole in the record: who first wrote “Salt River” in English is a matter of tradition, not documentation. The Kit Carson attribution appears in Mason’s account and others, but no 1829 document has been produced, and the earlier Spanish “Salado” makes the English name look like a translation, not a coinage.