[307] See, for instance, the treaty of Washington of January 11, 1909—Martens, N.R.G. 3rd Ser. (1911), p. 208—between Great Britain and the United States concerning the utilisation of the boundary waters between the United States and Canada.
[308] See Annuaire, XXIV. (1911). See also Bar in R.G. XVII. (1910), pp. 281-288.
I. When a stream of water forms the frontier of two States, neither State may, without the consent of the other, and in the absence of a special and valid legal title, make any changes prejudicial to the bank of the other State, nor allow such changes to be made by individuals, societies, &c. Moreover, neither State may on its own territory utilise the water, or allow it to be utilised, in such a manner as to cause great damage to its utilisation by the other State or by the individuals, societies, &c., of the other.
The foregoing conditions are also applicable when a lake is situated between territories of more than two States.
II. When a stream of water traverses successively the territories of two or of several States:—
(1) The point at which this stream of water traverses the frontiers of the two States, whether natural or from time immemorial, may not be changed by the establishments of one of the States without the assent of the other.
(2) It is forbidden to make any alteration injurious to the water, or to throw in injurious matter (coming from factories, &c.).
(3) Water may not be withdrawn by the establishments (especially factories for the working of hydraulic pressure) in such a quantity as to modify greatly the constitution, or, in other words, the utilisable character or the essential character, of the stream of water on its arrival at the territory nearer the mouth of the river.
The right of navigation by virtue of a title recognised by International Law cannot be restricted by any usage whatever.