Urbanization, channelization, groundwater depletion, irrigated agriculture, and a variety of other activities have significantly affected many of Arizona's rivers, and citizens are awakening to the resulting problems. In contrast to their ecologically degraded counterparts, healthy, well-functioning rivers and wetlands are some of the most productive ecosystems in North America, providing habitat for wildlife, including many endangered species. They reduce flood peaks, are sinks for sediments and nutrients, provide water temperature control and groundwater recharge. Failure to protect the health of these systems can lead to loss of habitat and species, water quality degradation, storm water management problems, and loss of recreational amenities, among other issues.