[f. WATER sb. + SHED sb.1
The equivalent G. wasserscheide has been in use from the 14th c. As a scientific term, it became common about 1800. The Eng. word, which first appears about the same date, was perh. formed in imitation of the Ger. synonym.]
1. The line separating the waters flowing into different rivers or river basins; a narrow elevated tract of ground between two drainage arcas: = WATER-PARTING.
1803. Prize Ess. Highl. Soc. Scot., II. 20. Strathcluony … is a very high inland tract, being the water-shed of the country between the two seas.
1830. Lyell, Princ. Geol., I. 175. The College, a small stream which flows at a moderate declivity from the eastern water-shed of the Cheviot-Hills.
1845. Darwin, Voy. Nat., xix. (1852), 442. The line of Water-shed which divides the inland streams from those on the coast, has a height of 3000 feet.
1850. Times, 16 Nov., 5/2. In order to satisfy themselves as to the amount of supply furnished by the sources in question, the Board of Health deputed Mr. Rammell to survey the various lines of watershed.
1859. H. Kingsley, G. Hamlyn, vi. He was crossing the highest watershed in the county by an open, low-sided valley.
1863. Lyell, Antiq. Man, xv. 297. We should also remember that the crests or watersheds of the Alps and Jura are about eighty miles apart.
1880. Geikie, Phys. Geog., iv. 257. The watershed of a country or continent is thus a line which divides the flow of the brooks and rivers on two opposite slopes.
fig. 1884. R. F. Burton, Bk. Sword, viii. 150, note. Hence, too, the superficial observation that the Afghans … are Jews because they have the typical Jewish look. The reason is that they are derived from the same ethnic centre, a great watershed of race.
1886. Symonds, Renaiss. It., Cath. React. (1898), VII. 208. A watershed of time between the Renaissance and the Counter-Reformation.
1893. Nation (N. Y.), 3 Aug., 87/1. That resolution marks the water-shed of our Revolutionary politics.
2. loosely. a. The slope down which the water flows from a water-parting.
1839. Murchison, Silur. Syst., I. xxxvii. 512. To the southwest of Kington the lower beds of the Old Red Sandstone … have been the sub-aqueous water-shed, down which the coarse detritus has been swept.
1877. Huxley, Physiogr., 18. To avoid all ambiguity it is perhaps best to set aside the original meaning of ‘watershed,’ and employ the term to denote the slope along which the water flows, while the expression ‘water-parting’ is employed for the summit of this slope.
b. The whole gathering ground of a river system.
1874. E. Coues, Birds N. W., Introd. p. vii. The Missouri Region, in its broadest sense, as embracing the whole watershed of that great river and its tributaries.
1880. Webster, Suppl., Water-shed. 2. The country or basin drained by any stream of water and its tributaries.
1913. White, Catskill Water Supply of N. Y., 17. The Croton watershed would in a few years be drawn on to its full capacity.
3. [? Associated with SHED v.1 4 d.] A structure for throwing off water.
1881. R. G. White, Eng. Without & Within, xiv. 319. The great wheel caught my umbrella, which was twisted out of my hand in a twinkling…. I picked up my wounded watershed, and returned with it to Burlington Arcade.
1886. Trans. R. Inst. Brit. Archit., II. 79. Nothing indicates the nature of the water-shed. It may have been some description of thatch; but more probably I think of wood shingle.
1898. J. R. Spears, in Scribner’s Mag., Oct., 503/1. A water-shed to throw the water away from the forecastle hatch was built.
