Colombian crews have closed two-thirds of a large levee canal breach that opened Nov. 30 and spilled millions of gallons of Magdalena River water across vast sections of the country's coastal plain. The disastrous flooding, worsened by persistent rainfall, has killed several hundred people, left millions homeless and resulted in billions of dollars in property damage to the South American nation. Relief crews on Dec. 27 reported success in closing 178 meters of the the 258-m-wide breach in the Dique Canal, although they warn that the remaining 80 m is the most technically difficult part of the closure operation. Water
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.