The engineers also built reservoirs, diversion dams, levees, aqueducts, and canals. Typical earthworks include road construction, railway beds, causeways, dams, levees, canals, and berms. Lastly, flood basins are often formed between the levees of adjacent rivers. High will cause flooding, and result in the building up of levees. In the plains appear instead villages with levees and ditches. The first artificial levees and canals were built in early colonial times. In modern times, considerable effort has been made to strengthen levees and control floods. These levees are referred to as dykes. These deposits elevate the riverbed which flows between natural levees in its lower reaches. Within a year of the storm, most of the levees were largely repaired. The Civil War resulted in destruction to the river levees and other property damage. New Orleans was originally settled on the river's natural levees or high ground. It took years for the state to rebuild levees damaged in battles. Many of the levees have been reconstructed since Katrina. This was above the safe capacity of downstream levees.