SAVANNAH RIVER, GEORGIA: SCIENCE TO SUPPORT ADAPTIVE IMPLEMENTATION OF ENVIRONMENTAL FLOWS TO A LARGE COASTAL RIVER, FLOODPLAIN, AND ESTUARY

摘要

Rivers of the Southeastern United States traverse a wide coastal plain where they are characterized by broad floodplains and expansive estuaries. Because of ample rainfall and the flat terrain, these rivers were historically subject to large, frequent floods, particularly in the spring or associated with tropical storms or other major rain events. Because floods can be hazardous to human settlements, extensive networks of dams have been built on many, if not most, major Southeastern rivers, and river flows have been closely regulated to minimize flooding. This has made it difficult for managers to meet competing interests for water such as property protection, hydropower, or recreational needs, along with the needs of downstream habitats and species. The services provided by healthy functioning floodplains are rarely considered in management plans. Floodplains provide flood protection, water reclamation, pollution abatement, aquifer recharge, wildlife habitat, and recreation opportunities. Estuaries and their associated tidal marshes are vital natural areas, providing habitat for fish, shellfish, and wildlife; maintenance of water quality via waste assimilation and nutrient processing; climate control via carbon sequestration; prevention of sediment erosion; and protection from storms. Riverine, floodplain, and es-tuarine habitats may become degraded by regulation, because many biological functions in these crucially important ecosystems rely on natural variation in flows including flooding.