The US Army Corps of Engineers has turned dredged sand into seven new wildlife islands. The project used 500,000 cubic yards of sand from the Mississippi River.

The sand was already being dredged to keep shipping channels open. Instead of dumping it, engineers shaped it into islands, restoring 270 acres of habitat at little extra cost.

The islands provide nesting and feeding grounds for birds, fish and other wildlife. River habitats have shrunk as engineering changed the Mississippi's natural flow.

The project shows how routine maintenance can double as conservation. What was once waste material is now living shoreline.

Wildlife managers will monitor how species colonise the new islands. Similar projects could follow on other working rivers.

The Mississippi's engineered channels erased many natural islands over decades. The new islands mimic those lost habitats. Migratory birds are already scouting the sites. Engineers say the method costs little beyond normal dredging budgets.