River management is a rapidly evolving science and recent major floods have prompted a re-examination of traditional approaches such as channelization, levees, flood walls and dams. These flood control measures are capital intensive, require significant maintenance costs, only protect local regions, and often require a tradeoff with ecological resources. Further, recent analyses have shown that the intended benefits and hydraulic performances are not achieved. A new paradigm in river management is evolving, which requires a broad range of design objectives to be met that include reduction in flood risks, ecological enhancement, recreation and aesthetics, as well as complying with strict environmental protection legislation. These more complex projects require extensive data and simulation tools to assist decision makers and communities in selecting management strategies which offer the maximum benefits, whilst preserving and enhancing the ecological integrity of the river system. A framework for the systematic analysis of the river ecosystem is outlined and illustrated by examples from the Western U S A.