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information must know. To attempt to prove that the Mississippi or the Missouri is a navigable stream would seem an insult to the intelligence of the court. The presumption of general knowledge weakens as we pass to smaller and less known streams; and yet, within the limits of any State the navigability of its largest rivers ought to be generally known, and the courts may properly assume it to be a matter of general knowledge and take judicial notice thereof."

It is reasonable that the courts take judicial notice that certain rivers are navigable and others not, for these are matters of general knowledge. But it is not so clear that it can fairly be said, in respect to a river known to be navigable, that it is, or ought to be, a matter of common knowledge at what particular place between its mouth and its source navigability ceases. And so it may well be doubted whether the courts will take judicial notice of that fact. It would seem that such a matter was one requiring evidence, and to be determined by proof. That the Rio Grande, speaking generally, is a navigable river is clearly shown by the affidavits. It is also a matter of common knowledge, and therefore the courts may properly take judicial notice of that fact. But how many know how far up the stream navigability extends? Can it be said to be a matter of general knowledge, or one that ought to be generally known? If not, it should be determined by evidence. Examining the affidavits and other evidence introduced in this case, it is clear to us that the Rio Grande is not navigable within the limits of the Territory of New Mexico. The mere fact that logs, poles and rafts are floated down a stream occasionally and in times of high water does not make it a navigable river. It was said in The Montello, 20 Wall. 430, 439, "that those rivers must be regarded as public navigable rivers in law which are navigable in fact. And they are navigable in fact when they are used, or are susceptible of being used, in their ordinary condition, as highways for commerce, over which trade and travel are or may be conducted in the customary modes of trade and travel on water." And again (p. 442): "It is not, however, as Chief Justice Shaw said, 21 Pickering, 344, 'every small creek in

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which a fishing skiff or gunning canoe can be made to float at high water which is deemed navigable, but, in order to give it the character of a navigable stream, it must be generally and commonly useful to some purpose of trade or agriculture.'"

Obviously, the Rio Grande within the limits of New Mexico is not a stream over which in its ordinary condition trade and travel can be conducted in the customary modes of trade and travel on water. Its use for any purposes of transportation has been and is exceptional, and only in times of temporary high water. The ordinary flow of water is insufficient. It is not like the Fox River, which was considered in The Montello, in which was an abundant flow of water and a general capacity for navigation along its entire length, and although it was obstructed at certain places by rapids and rocks, yet these difficulties could be overcome by canals and locks, and when so overcome would leave the stream in its ordinary condition susceptible of use for general navigation purposes. We are not, therefore, disposed to question the conclusion reached by the trial court and the Supreme Court of the Territory, that the Rio Grande within the limits of New Mexico is not navigable.

Neither is it necessary to consider the treaty stipulations between this country and Mexico. It is true that the Rio Grande, for several hundred miles above its mouth, forms the boundary between this country and Mexico, and that the seventh article of the treaty between the United States and Mexico of February 2, 1848, 9 Stat. 928, stipulates that "the River Gila and the part of the Rio Bravo del Norte lying below the southern boundary of New Mexico being, agreeably to the fifth article, divided in the middle between the two Republics, the navigation of the Gila and of the Bravo below said boundary shall be free and common to the vessels and citizens of both countries, and neither shall, without the consent of the other, construct any work that may impede or interrupt, in whole or in part, the exercise of this right, not even for the purpose of favoring new methods of navigation. The stipulations contained in the present article shall

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not impair the territorial rights of either Republic within its established limits." But by the fourth article of the Gadsden treaty of December 30, 1853, 10 Stat. 1034, it was provided that "the several provisions, stipulations and restrictions contained in the seventh article of the treaty of Guadalupe Hidalgo shall remain in force only so far as regards the Rio Bravo del Norte, below the initial of the said boundary provided in the first article of this treaty, that is to say, below the intersection of the 31st degree 47' 30" parallel of latitude, with the boundary line established by the late treaty dividing said river from its mouth upwards, according to the fifth article of the treaty of Guadalupe." And on December 26, 1890, a convention was concluded between the United States and Mexico, 26 Stat. 1512, which provided for an international boundary commission, to which was given, by article five, the power to inquire, upon complaint of the local authorities, whether works were being constructed in the Rio Grande prohibited by any prior treaty stipulations. There is no suggestion in the bill that any action by these commissioners was invoked, although it appears from one of the affidavits that the commission has been duly constituted. Now it is debated by counsel whether the construction of a dam at the place named in New Mexico, a place wholly within the territorial jurisdiction of the United States, is a violation of any of the treaty stipulations above referred to- they being, primarily at least, limited to that portion of the river which forms the boundary line between the two nations; and also whether the fact that the Rio Grande is partially within the limits of Mexico, would give that nation, under the rules of international law, any right to complain of the total appropriation of its waters for legitimate uses of the people of the United States. Such questions might under some circumstances be interesting and important; but here the Rio Grande, so far as it is a navigable stream, lies as much within the territory of the United States as in that of Mexico, it being where navigable the boundary between the two nations, and the middle of the channel being the dividing line. Now, the obligations of the United States to preserve for their own citizens, the

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navigability of its navigable waters, is certainly as great as any arising by treaty or international law to other nations or their citizens, and if the proposed dam and appropriation of the waters of the Rio Grande constitute a breach of treaty obligations or of international duty to Mexico, they also constitute an equal injury and wrong to the people of the United States.

We may, therefore, properly limit our inquiry to the effect of the proposed dam and appropriation of waters upon the navigability of the Rio Grande, and, in case such proposed action tends to destroy such navigability, the extent of the right of the Government to interfere. The intended construction of the dam and impounding of the water are charged in the bill and admitted in the answer. The bill further charges that the purpose is to obtain control of the entire flow of the river, and divert and use it for irrigation and supplying waters for municipal and manufacturing uses; that, by reason of the porous soil, the dry atmosphere and consequent rapid evaporation, but little water thus taken from the river and distributed over the surface of the earth will ever be returned to the river, and that this appropriation of the waters will so deplete and prevent the flow of water through the channel of the river below the dam as to seriously obstruct the navigable capacity of the river throughout its entire course even to its mouth. The answer, while denying an intent to appropriate all the waters of the Rio Grande, states that the entire flow, during the irrigation season, at the point where defendants propose to construct reservoirs, had long since been diverted, and was owned and beneficially used by parties other than defendants, that they did not seek to disturb such appropriation, but that their sole intention was to appropriate only such waters as had not already been legally appropriated, and that the beneficial rights to be acquired in the stream by virtue of the structures would be very largely only so acquired from the excess, storm and flood waters now unappropriated, useless and going to In other words, the bill charges that the defendants, at the places where they proposed to construct their dam,

waste.

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intend thereby to appropriate all the waters of the Rio Grande, and defendants qualify that charge only so far as they say that most of the flow of the river is already appropriated, and they only propose to take the balance. The bill charges that such appropriation of the entire flow will seriously obstruct the navigability of the river from the place of the dam to the mouth of the stream. The defendants deny this, but as the court found that there was no equity in the bill, and dismissed the suit on that ground, we must for the purposes of this inquiry assume that it is true, that defendants are intending to appropriate the entire unappropriated flow of the Rio Grande at the place where they propose to construct their dam, and that such appropriation will seriously affect the navigability of the river where it is now navigable. The right to do this is claimed by defendants and denied by the Government, and that, generally speaking, is the question presented for our consideration.

The unquestioned rule of the common law was that every riparian owner was entitled to the continued natural flow of the stream. It is enough, without other citations or quotations, to quote the language of Chancellor Kent, 3 Kent Com. § 439: "Every proprietor of lands on the banks of a river has naturally an equal right to the use of the water which flows in the stream adjacent to his lands, as it was wont to run (currere solebat) without diminution or alteration. No proprietor has a right to use the water, to the prejudice of other proprietors, above or below him, unless he has a prior right to divert it, or a title to some exclusive enjoyment. He has no property in the water itself, but a simple usufruct while it passes along. Aqua currit et debet currere ut currere solebat is the language of the law. Though he may use the water while it runs over his land as an incident to the land, he cannot unreasonably detain it, or give it another direction, and he must return it to its ordinary channel when it leaves his estate."

While this is undoubted, and the rule obtains in those States in the Union which have simply adopted the common law, it is also true that as to every stream within its dominion