ABSTRACT
Rivers and other surface water courses are indispensable for the welfare of human societies. They offer a number of ecosystem services essential for life itself as well as for meeting the needs of higher, organized civilizations. Large rivers are complex natural systems consisting of both living and non-living components. Human societies have striven for millennia to modify rivers and better exploit their resources, mainly in the form of water for drinking, sanitation or irrigation. Starting several centuries ago, the industrial revolution ushered in an era of explosive expansion
of technological power that completely reshaped these natural systems. Large rivers globally have become so heavily modifi ed (Gleick 2003) that their natural cycles and functions are mostly dominated by human infrastructure. This infrastructure also isolated society from water, shaping social perception of high water fl ows radically through centuries of living fearfully behind dykes.
