These properties are located on canals, basins or lakes but do not have access to the river and the Gulf of Mexico. The freshwater canals are separated form the saltwater canals by a “Weir”. A weir resembles a low concrete dam or spillway. An example of a weir is shown here. As water flows into the freshwater canals from rain, the overflow will spill over into the saltwater canals. You can not take a boat over the weirs.