The Rule of the Thalweg is well-established on large navigable rivers, but is generally inapplicable on smaller streams and rivers where there is no recognizable line of navigation. In smaller rivers and streams, the water depth across the bed is often relatively constant. Minor variations in depth that exist from moment to moment are insignificant to human activities and are subject to change on a daily or weekly basis. In these circumstances, the courts have rejected the validity of the Rule of the Thalweg, considering it an ephemeral and unsatisfactory basis for a boundary determination, as demonstrated by the following examples from both the U.S. Supreme Court and from numerous state courts.
Louisiana v. Mississippi: 202 U.S. 1 (1906): As to boundary lakes and landlocked seas, where there is no necessary track of navigation, the line of demarcation is drawn in the middle, and this is true of narrow straits separating the lands of two different States; but whenever there is a deep water sailing channel therein, it is thought by the publicists that the rule of the thalweg applies.
The Deepest Channel vs. Thalweg
Minnesota v. Wisconsin: 252 U.S. 273 (1920): As we view the whole record, the claim of Wisconsin cannot prevail unless the doctrine of Thalweg requires us to say that the main channel is the deepest one. So to apply it here would defeat its fundamental purpose.
Oklahoma v. Texas: 258 U.S. 574 (1922): One of the questions involved in the riparian claims relates to what was intended by the terms “middle of the main channel” and “mid-channel” as used in defining the southerly boundary of the treaty reservation and of the Big Pasture. When applied to navigable streams such terms usually refer to the thread of the navigable current, and, if there be several, to the thread of the one best suited and ordinarily used for navigation.
But this section of Red River obviously is not navigable. It is without a continuous or dependable flow, has a relatively level bed of loose sand over which the water is well distributed when there is a substantial volume, and has no channel of any permanence other than that of which this sand bed is the bottom.
The mere ribbons of shallow water which in relatively dry seasons find their way over the sand bed, readily and frequently shifting from one side to the other, cannot be regarded as channels in the sense intended. Evidently something less transient and better suited to mark a boundary was in mind. We think it was the channel extending from one cut-bank to the other, which carries the water in times of a substantial flow. That was the only real channel and therefore the main channel. So its medial line must be what was designated as the Indian boundary.
Non-Navigable Rivers—Midline Between the Banks
Hayes’s Executor v. Bowman: 22 Va. 417 (1823): Where the commonwealth, having title to lands lying on both sides of a watercourse not navigable, grants the lands lying on one side thereof, and bounded thereby, it is universally admitted, that such grant carries with it, the title to a moiety of the bed of the water-course. There can be no reason assigned, why this rule, so1 just in relation to grants by the commonwealth, should not equally apply to conveyances by individuals.
Benner’s Lessee v. Platter: 6 Ohio 504 (1834: The case of McCulloch’s Lessee v. Aten, 2 Ohio, 309, has been examined. In that ease, the court were called upon to establish for the defendant a boundary on the bank of a creek not navigable. The boundary described in the deed, as the court state it, was down the creek, with the several meanders thereof. The court say, we understand it to be a settled rule, whenever the stream is made the boundary, it is the water, and not the center of its channel that is referred to.
Starr v. Child: 20 Wend. 149 (1838): Prima facie, the proprietor of each bank of a stream is the proprietor of half the land covered by the stream.
Trustees of Hopkins Academy v. Dickinson: 63 Mass. 544 (1852): In ascertaining the thread of the river, it will be proper to take the middle line between the shores upon each side, without regard to the channel, or lowest and deepest part of the stream. And in ascertaining the shores, or water lines on each side, to measure, it will be proper to find what those lines are when the water is in its natural and ordinary stage at a medium height, neither swollen by freshets or shrunk by drought.
McCullough v. Wall: 4 Rich. 68 (1850): The situation of the main channel, whether east or west of the rock, is unimportant, for the ordinary low water mark on each side having been fixed, the medium filum aquae is ascertained by measurement across, without regard to the depth of the water.
State v. Muncie Pulp Co., 119 Tenn. 47 (1907): This question has not before been before this court; but in a case involving property rights upon an unnavigable stream, called for as a boundary line of private estates, it was held that “the thread of the stream is the middle line between the shores, irrespective of the depth of the channel, taking them in the natural and ordinary stage of the water, at medium height, neither swollen by freshets nor shrunk by droughts.”