Estuaries

Estuaries are among the most biologically productive and geomorphologically complex environments in the coastal zone. Estuaries vary considerably in terms of geomorphology, tides, drainage basin and fluvial processes, water chemistry, wave characteristics, sediment provenance, upland land use and land cover, biodiversity, and degree of human modification. This chapter presents background information on the definition, classification, and characteristics of estuaries as well as the physical processes that shape morphology. A review of research is presented, focusing on broad-scale estuarine morphology and evolution and an examination of contemporary processes and forms in the intertidal zone. The chapter includes a discussion of current issues in estuarine research, including geomorphic-biotic interactions, human-modified estuaries, and restoration practices. The chapter concludes with a brief discussion of future areas of concern given current attention to climate variability and sea-level rise. Although the focus is on geomorphic research, there are references to key work within biology, chemistry, and hydrology.