Building across a riverbed
Indian Bend Wash was never a secret. It ran through the middle of town, dry nearly all the time, and every big storm reminded the new subdivisions that it was, in fact, a river. Scottsdale had grown from about 2,000 people at incorporation to 67,823 by the 1970 census, the city’s historic context says, and much of that growth sat in the floodway. Since the early 1960s the Army Corps of Engineers had planned a concrete channel down the wash, and Congress had authorized it in 1965. Scottsdale had resisted: a county bond to pay for the channel failed in 1966, and the city was pushing an alternative of grass and parks. The first piece, Eldorado Park, had opened in 1967.
The night the canal broke
The remnants of Tropical Storm Norma stalled over central Arizona on the holiday weekend. Statewide the storm killed 23 people, most of them on Tonto Creek in the high country; the National Weather Service still calls it Arizona’s deadliest storm. Scottsdale got about three and a half inches of rain in a day.
Water flowed into the Arizona Canal from the north all afternoon, and the overloaded canal gave way. At about 8 p.m. a section of its south bank, some 40 feet wide, broke between the Pima Road bridge and a nearby canal-maintenance bridge; a city street superintendent testified later that “it sounded like thunder, and there was a whole section of the canal went out.” Water poured south down Pima Road and into a subdivision built in the wash, filling sunken living rooms with up to 20 inches of water between 8:30 and 11 that night. Along Indian Bend Wash, the U.S. Geological Survey reported, “many homes, trailer parks, and business establishments … were damaged,” and the wash ran at about 3,900 cubic feet per second at Thomas Road. More than 250 Scottsdale homes were evacuated.
Two hundred nineteen homeowners in the subdivision sued the Salt River Valley Water Users’ Association, which ran the canal. A jury found the association liable in 1974, and in 1976 the Arizona Supreme Court upheld their damages, while striking the punitive award, and rejected the association’s argument that the builder was to blame for putting homes on a floodplain.
Grass wins
The flood did not decide the outcome; it showed that one was needed. The city’s historic context says Eldorado Park came through with only minor damage, and that in 1971 the Corps agreed the city’s grass-and-reservoir alternative would work. Two years later the June 22, 1972 flood was worse, and in April 1973 voters approved $10 million in bonds. The Corps approved the design in 1974 and signed a cost-sharing contract with the city in 1976, and the Indian Bend Wash Greenbelt was dedicated in 1985: eleven-plus miles of connected parks, Eldorado, Vista del Camino, Chaparral and more, that carry the wash’s floods and host everyday Scottsdale the rest of the year. The greenbelt fight page tells the whole argument; the rest of the year is on the 1970 page and the politics in the 1970s politics chapter.