The term riverine system as used here refers to a river or stream valley measured from the stream channel to the valley edge, including floodplain or terraces that can be inundated or flooded frequently. An active riverine system is one that lacks upstream dams, has not been channelized or has constructed levees, or has been entrenched to a degree that flooding no longer occurs. They occur throughout the world in virtually every climate. In the following section, we concentrate our comments on riverine systems that are related to meandering rivers. Meandering rivers create floodplains that are associated with extensive wetlands. Although rivers themselves do not account for a large percentage of the Earth’s surface, their influence is nonetheless of paramount importance. Riverine systems contain some of the world’s most fertile agricultural and silvicultural lands, and are adjacent to numerous large cities. As a result, land within these systems is under increasing pressure from development and is exposed to a diversity of environmental hazards.