EUPHRATES, yu-frê'tîz : The greatest river of western Asia, mentioned in Gen. i. 14 as one of the four rivers of Eden. Thereafter it finds frequent mention, either by name or by epithet, in the Old Testament. It is sometimes called simply "the river" (Gen. xxxi. 21), and even "river," without the article (Isa. vii. 20, Heb. text).

Its Course. The Euphrates is formed by the union of two small streams at about lat. 39° n. and long. 39° e. in the Armenian Mountains. The larger of these two streams, the Kara Su or western Euphrates, rises on the Domli Dagh, northeast of Erzerum. The other, the Murad Su or Eastern Euphrates, a charming mountain stream, rises on the Ala Dagh, not far from Lake Van. At their junction above Keben Maden they form a noble river 120 yards wide. At no point in its long course is the river finer than here. From this point the river flows south for a short distance, and then bends in a great westerly course around the Musher Dagh, and pierces the Taurus range with many sharp bends. At this part of its course the Euphrates seems destined to discharge its waters into the Mediterranean at the Gulf of Alexandretta, but the way is blocked by the Amanus and the Lebanon, and the river assumes a southeasterly course which is maintained to the Persian Gulf. It is this lower course which is the historic river, known to all the great peoples of Western Asia.

Tributaries and Size. The tributaries of the Euphrates, after the union of the Kara Su and the Murad Su are few. The most important are the Sajur (Assyrian Sangura or Sagura) which enters from the west about lat. 36° 40'; the Belik (Assyrian Balikhu), from the east and north in long. 39° 9'; and, most important of all, the Khabur (Assyrian Haburu) entering from the northeast in lat. 35° 7', long. 40° 30'. From the Khabur to its mouth, a distance of 800 miles, the Euphrates receives no tributary, and in the lower part of its course shows a marked tendency to split up into different channels. When it receives the Khabur it is 400 yards wide and eighteen feet deep. From that point it begins to diminish in volume. At Irzah or Werdi, seventy-five miles lower down, it is 350 yards wide and of the same depth; at Hadiseh, 140 miles below Werdi, it is 300 yards wide and of the same depth; at Hit, fifty miles below Hadiseh, its width has increased to 350 yards, but its depth has been diminished to sixteen feet; at Felujiah, seventy-five miles from Hit, the depth is twenty feet, but the width has diminished to 250 yards. From this point the contraction is rapid and striking. The Saklowijeh Canal is given out upon the left, and some way farther down the Hindiyeh branches off upon the right, each carrying, when the Euphrates is full, a large body of water. The consequence is that at Hiliah, ninety miles below Felujiah, the stream is no more than 200 yards wide and fifteen feet deep; and at Lamlun, eighty-five miles lower down, it is reduced to 120 yards wide with a depth of no more than twelve feet. Some of the channels which take water out of the river afterward return to it again, but it never again attains its earlier greatness. The channel from Kurnah to El Khitr was found by Colonel Chesney to have "an average width of only 200 yards, and a depth of about eighteen or nineteen feet, which implies a body of water far inferior to that carried between the junction of the Khabur and Hit."

Inundation. The Euphrates, and also the Tigris, has a flood season exactly as the Nile has. This fact is perfectly clear and indisputable, though Herodotus directly asserts the contrary. The inundation is indeed not so great as that of the Nile, but it is regular and extensive. The river begins to swell very slowly about the beginning of March, and gradually increases until the highest point is reached about the end of May, when the waters stand about thirteen feet above low water. At this point the river remains for about a month, sinks slightly toward the middle of July, and then more rapidly till September. At the junction of the Khabur the river is described as "spreading over the surrounding country like a sea." The slow and regular rise of the river made it exceedingly valuable for irrigation, of which the Babylonian people fully availed themselves. Along the banks were constructed brick walls provided with breakwaters to divert and control the swift current at its rise. Sluice gates controlled the rise so that the eastern bank received an inundation equal to the west, while canals almost innumerable diverted the retreating waters, and prevented the overflow from damaging the cultivable area. Furthermore, the water was retained in sufficient quantity to supply an irrigation system, far back from the river, after the fall of the river. This entire system is now a vast ruin. The river rises and falls as it wills, and sweeping far over the western bank, turns the country into a desolate morass. The harm of this is both positive and negative. It makes impossible any such great ingathering of grain as was usual when this great valley was the world's granary, and it fills the land with a dangerous miasma. The Euphrates and the Tigris originally reached the Persian Gulf by separate estuaries, but they now unite and form the Shatt-al-Arab. It is believed that the Persian Gulf once extended 150 or perhaps even 200 miles farther north than at present, and the formation of alluvial land continues at the rate of about a mile in seventy years.

The whole course of the river is about 1,780 miles, and it is navigable for small vessels for about 1,200 miles. It has been well said that the "upper region of the Euphrates resembles that of the Rhine, while its middle course may be compared with that of the Danube, and its lower with the Nile." See ASSYRIA, II., § 2; BABYLONIA, II., §§ 1-2.