 Prior to the 1950s, the only crossing of the Niger at Bamako was at the Sotuba Causeway, 8 kilometers downstream from the city, which is a low water crossing of cut stone at the location of a natural rapids.The Aigrettes Dam, 200 kilometers upstream, is a hydroelectric station and the next all season crossing to the west.The next all season crossing downstream is at the Markala Dam, over 200 kilometers east northeast past Segou, which until recently relied on ferry transport to cross one arm of the Niger.