Over hundres of years the growth and development of Vienna was determined by the River Danube. The course of the river was originally influenced exclusively by natural occurences. Increasing technology and industrialisation have changed the course of the river dramatically during the last 125 years. Flood control, navigation and power supply were the main reasons for the operations undertaken. Enforced settlement and industrial development along the river followed. Subsequently, most of the habitats of the formerly large inundation area were destroyed.