4. Toward Sustainable Rivers and Water Resources

The previous chapter reviewed a long list of human activities that have directly and indirectly altered process and form in river ecosystems, with an associated loss of ecosystem services. Management in many river basins now focuses on trying to restore some balance between existing, typically consumptive or homogenizing uses of river resources versus restoration of diversity, sustainability, and river ecosystem health. None of the latter three terms is easy to define. Diversity refers to variety but, as discussed in Chap. 2, there are multiple ways to define physical or biotic diversity and no particular metric is consistently better in all situations or for all purposes. Sustainability in an ecological context typically refers to the ability of ecosystems to remain diverse and productive. In a physical context, sustainability may refer to the ability of a system to continue functioning or providing natural resources. River health also has multiple potential definitions. Even using the relatively simple definition in Chap. 1, that river health is the degree to which a river ecosystem matches natural conditions, requires understanding natural conditions. On the one hand, use and understanding of words matters and people may use similar words but have different objectives or desired outcomes. On the other hand, diversity, sustainability, and river health are now widely used and there is at least broad consensus on the meaning of these words. So, what is being done to protect and restore river corridors? This chapter reviews the development of river restoration during the latter twentieth century and early twenty-first century; discusses particular concepts used in restoration; and presents specific examples of watershed-scale restoration.