US city plans moat to keep out migrants

Yuma goes back to basics as hostility to fences grows
Environmentalists back plan for Mexican border

Photograph: George Steinmetz/Corbis

There have been virtual fences, real fences, increased patrols and night-vision cameras. Now the latest initiative by the US to seal its increasingly porous border with Mexico harks back to one of the oldest approaches: dig a moat. City officials in Yuma, in south-western Arizona, have come up with a scheme to create a "security channel" along the nearby border by reviving a derelict two-mile stretch of the Colorado river.

"The moats that I've seen circled the castle and allowed you to protect yourself, and that's kind of what we're looking at here," Yuma county sheriff Ralph Ogden told the Associated Press. The scheme would see engineers dig out a two-mile stretch of a 180-hectare (440-acre) wetland known as Hunters Hole.

Once a haven to anglers, ducks and the Cocopah Indians, the area is now a thicket of tamarisk, forgotten shoes and old cars providing cover for smugglers and border crossers. But under the plan, all that would change. The banks of the river would be replanted with native cattail, bulrush and mesquite, and wells would supply water to the wetlands as well as to a 20-metre-wide, three-metre-deep channel that would run the length of Hunters Hole.

With the replenished river marking the frontier, would-be border crossers would have to scale a 4.5-metre levee - built with the earth excavated from the riverbed - cross a 120-metre-wide marsh and then ascend another levee on the northern side of the wetlands.