Question 1510Navigation General

The correct answer is B) the least available water in a channel which limits the draft of boats and tows. The controlling depth of a river refers to the minimum depth available in the navigable channel that determines the maximum draft or depth of vessels that can safely operate in that waterway. This is the key factor that limits the size and load capacity of boats and tows that can transit the river. The other options are incorrect because they do not directly address this critical navigational constraint.