What it means
The CAP is the Central Arizona Project, and in Scottsdale the word has two meanings that are really one. The first is a place: the wide, straight, concrete-lined canal that crosses the north end of the city, past TPC Scottsdale and WestWorld. The second is the water in it. “CAP water” is Colorado River water, and the Scottsdale Water guide puts it at about two-thirds of what comes out of the city’s taps.
You will hear it in both senses. “The house backs onto the CAP.” “The city’s CAP allocation.” When the Colorado River comes up short, the cut reaches Scottsdale through this canal, which is why the Colorado River shortage is a local story. And when someone measures that water, they do it in acre-feet.
The canal also explains a map. Most of north Scottsdale, from the Airpark to the golf communities, was built in the decades after CAP water arrived, and the state water law guide explains why new subdivisions needed a supply like it.
Where you’ll meet it
On Shea Boulevard east of Frank Lloyd Wright Boulevard, where the road crosses it; in the Phoenix Open shuttle lots at WestWorld; in water-department reports; and on your property tax bill, where the Central Arizona Project has its own secondary-tax line.
Where the word came from
The name is a federal project title, and the project took decades of politics. President Lyndon Johnson signed the Colorado River Basin Project Act authorizing the CAP in 1968; the price of California’s support was that Arizona’s CAP water would be junior to California’s in a shortage. The Central Arizona Water Conservation District was created in 1971 to run the system and repay the federal government. Construction began at Lake Havasu in 1973. Water reached the Phoenix area in 1985 and Tucson in 1992, and the system was declared complete in 1993, at a cost of more than $4 billion.
The canal’s sections carry politicians’ names. The Bureau of Reclamation’s history explains that the Phoenix leg was first called the Granite Reef Division and was renamed the Hayden-Rhodes Division by an act of Congress on June 24, 1988; the next leg south, once the Salt-Gila Division, became the Fannin-McFarland Division in 1992. The names honor Arizona congressional members who spent much of their careers lobbying for the CAP, chief among them Senator Carl Hayden and Representative John Rhodes. The Hayden-Rhodes Aqueduct runs from Lake Havasu to the Phoenix area, about 174 miles of open channel plus siphons and tunnels. Locals ignore all of it and say “the CAP.”
Scottsdale signed on early. Its CAP water treatment plant began operating in April 1987, and the city’s later growth was built largely on that supply.
What it is not
The CAP is not the Arizona Canal, the 1885 SRP canal through Old Town and the Waterfront that carries Salt and Verde river water. Different river, different century, different rules. If the canal near you has a bike path and a downtown, it is the Arizona Canal.
The fine print
The canal shaped Scottsdale’s land as well as its water. To protect the planned aqueduct from desert floods, the Bureau of Reclamation bought land in north Scottsdale in the late 1960s and early 1970s as a flood-retention basin, under the same 1968 law that authorized the project. The project’s management plan allowed public recreation on that land. In 1982 the city signed a cost-sharing agreement for 132 acres north of the canal that became the horse park now called WestWorld; in 1985 it took over the rest of the basin. On December 10, 1985, the city leased Bureau land and city parcels north of the canal to the PGA Tour for what became TPC Scottsdale.
Not everyone liked the arrangement. In July 1991 the U.S. General Accounting Office told Congress that local Bureau officials had made key decisions on personal judgment, that Scottsdale paid no compensation for the federal land, and that a reservation policy at the golf complex limited public use.
The numbers are large and slightly inconsistent by source. The CAP says it lifts water about 3,000 feet through 15 pumping plants; Wikipedia says up to 2,900 feet through 14. Its capacity is put at about 1.4 to 1.5 million acre-feet a year. Either way, it is the most junior water in Scottsdale’s mix, and the first to feel a shortage.