Huge steel objects in the Santa Cruz River near San Xavier Road aren't remnants of a giant's game of jacks, though they do resemble and share the name of the beloved children's game.
The dozens of jacks are several feet tall and can be seen while traveling south on Interstate 19, just north of San Xavier Road. They are placed in two long rows that run parallel to the river, with shorter rows that run perpendicular to the river.
"We believe these rows of 'jacks' were installed in ADOT's right of way along the Santa Cruz River near Interstate 19 and the San Xavier Road sometime in the 1970s, and they are designed to prevent erosion downstream," said Dustin Krugel, a spokesman for the Arizona Department of Transportation.
The Federal Highway Administration says jacks "made of steel struts strung with wire" are called Kellner jacks.
They help control the flow of the river and protect the banks from erosion, according to the federal agency.
Jack fields are rows of the steel objects "tied together with cables, some rows generally parallel with the banks and some perpendicular thereto or at an angle," according to the agency.
Krugel said the jacks are common in the Midwest.
Suzanne Shields, director of the Pima County Regional Flood District, said she recalls jacks being placed in the river in Marana near Sanders Road, but she believes they were destroyed in the massive flood of 1983.
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