Of the total length of the waterway, between 80% and 85% of the total was pre-existing waterway. Nonetheless, of that 80% to 85% of the waterway, much of it required the dredging of safe, uniform channels as we see them today in the Intracoastal Waterway.
Moreover, both artificial and natural inlets dot Florida’s east coast making difficult maintenance of the waterway at these points. Natural littoral drift along the entire Atlantic coast would routinely fill up these inlets and the Intracoastal Waterway. Some inlets like the Hillsboro Inlet have special navigation districts formed for the purpose of addressing littoral drift. In his report of 1889, Corthell opined that inlets would bring sea water into the inland waterway and naturally kill off fresh water plants such as the hyacinth that often clogged the waterways, representing navigational hazards.