Problem: Land Boundary Law: Water Boundaries

Which of the following terms best describes the deepest or most navigable part of a river channel?



(A)    The mean high water mark

(B)    The thread

(C)    The batture

(D)    The thalweg


Come back next week for the solution!</strong><br>This is problem 59(3-33) from the new second edition of <em>1001 Solved Surveying Problems</em> by Jan Van Sickle. Reprinted with permission from <em>1001 Solved Surveying Problems</em> by Jan Van Sickle (1997, 728 pp., Professional Publications Inc.). For details on this and other FLS exam-prep books, call 800/426-1178 or visit


Answer: D


The line connecting the lowest part of a valley and the deepest part of a river is known as the thalweg. The term is also used to denote the middle of the main navigable channel.