Estuaries are bodies of water along our coasts that are formed when fresh water from
rivers flows into and mixes with salt water from the ocean. In estuaries, the fresh river water is blocked from streaming into the open ocean by either surrounding mainland, peninsulas, barrier islands, or fringing salt marshes. This mixing of fresh and salt water creates a unique environment that brims with all kinds of life. The estuary gathers and holds an abundance of life-giving nutrients from the land and from the ocean.
They provide a unique habitat for over 75 percent of our nation's commercial fish. This along with commercial and recreational fishing, boating and tourism provides many jobs and lots of enjoyment for those who use the area.
Estuaries are important to our quality of life and our health for reasons other than jobs, healthy economies, and recreational opportunities. The local bay or sound often serves as the focal point for community life and traditions, hosting everything from harvest festivals to busy ports. They also protect water quality, are a center for research and education, and help stem the erosion of our shoreline communities.
Estuaries come in all shapes and sizes and go by many different names, often known as bays, lagoons, harbors, inlets, or sounds. Estuarine environments are among the most productive on earth, creating more organic matter each year than comparably-sized areas of forest, grassland, or agricultural land.
Among the cultural benefits of estuaries are recreation, scientific knowledge, education, and aesthetic values. Boating, fishing, swimming, surfing, and bird watching are just a few of the numerous recreational activities people enjoy in estuaries. These commercial activities thrive on the wealth of natural resources estuaries supply. The protected coastal waters of estuaries also support important public infrastructure, serving as harbors and ports vital for shipping, transportation, and industry.
Estuaries provide us with a whole suite of resources, benefits, and services. Some of these can be measured in dollars and cents, others can not. Estuaries are an irreplaceable natural resource that must be managed carefully for the mutual benefit of all who enjoy and depend on them.
Oceanographyically an estuary is "a semi enclosed coastal body of water having a free connection to the open sea and within which the sea water is measurably diluted with fresh water derviving from land drainage."1 The rive water which enters the estuary mixes to some extent with the salt water thereing and eventually flows out to the open sea in the upper layer. A corresponding in flow of sea water takes place below the upper layer. The inflow and the outflow are dynamically associated so...