<Tr> <Th> Owner </Th> <Td> Office of Coast Survey </Td> </Tr> <Tr> <Th> Operator </Th> <Td> U.S. Army Corps of Engineers </Td> </Tr> <P> The Intracoastal Waterway (ICW) is a 3,000 - mile (4,800 km) inland waterway along the Atlantic and Gulf of Mexico coasts of the United States, running from Boston, Massachusetts, southward along the Atlantic Seaboard and around the southern tip of Florida, then following the Gulf Coast to Brownsville, Texas . Some sections of the waterway consist of natural inlets, saltwater rivers, bays, and sounds, while others are artificial canals . It provides a navigable route along its length without many of the hazards of travel on the open sea . </P> <P> The shipping hazards and safe havens of the Atlantic coast have been well known and appreciated since colonial times, and considered of great commercial, communication, and military importance to both the colonial power and the newly established, independent United States . The physical features of the eastern coast were advantageous for intracoastal development, resulting from erosion and deposition of sediment over its geologic history, but also enhanced and redistributed by the action of the Atlantic Ocean currents along it . Since the coastline represented the national border and commerce of the time was chiefly by water, the fledgling US government established a degree of national control over it . Inland transportation to supply the coasting trade at the time was less known and virtually undeveloped, but when new lands and their favorable river systems were added in 1787, a radically new and free national policy was established for their development and transportation use . Over time, internal improvements of natural coastal and inland waterways would develop into the Great Loop, which allows for waterborne circumnavigation of the eastern continental United States, using minimal ocean travel, with the Intracoastal Waterway providing its eastern end . </P>

What are constructed waterways that connect natural waterways