This is the intracoastal waterway - a 12 - foot deep channel that runs from Brownsville Texas on the Mexican border all the way around the Gulf coast and up the Atlantic to Trenton, New Jersey. The federal government built this 2,500 mile long channel to ensure safe shipping. This channel was particularly important during WW II, when the route was used to avoid German submarines on the open seas. As you relax here you likely will see some barges or ships pass by. However, this "safe passage" has had serious impacts on freshwater marshes because it cuts off freshwater drainage from the north, and encourages salt water to invade freshwater areas. The high salinity kills vegetation and the wildlife that depend of freshwater.