A canal is an artificial navigable watercourse. There are three main types: channeled riverbed, construction of a side channel filled with water from the river or canal built where there is no watercourse at all. The construction of a new canal must start on a [URL=/help/gnd?type=swater]sea[/URL], [URL=/help/gnd?type=fwater]river[/URL] or [URL=/help/gnd?type=pond]pond[/URL] area, and then be be extended towards the land. You can not start a canal on a coastline or riverbank.