EUPHRATES (Shatt al Fara, Frat su) the largest river of western Asia, and the western of the two streams which flow through Mesopotamia into the Persian gulf. It may be divided into three divisions, an upper, middle and lower, the first extend ing as far as Samsat, the second to Hit, and the third to its junc tion with the Tigris at Kurna, the united stream thus formed being known as the Shatt al Arab (q.v.). Pliny writing in the first century A.D. says that the Euphrates originally had its own mouth (see MESOPOTAMIA : Geology) and within historical times the lower course of the river has changed considerably. The shore line at the end of glacial times appears to have been near Hit. Below this point the river has tended to move westwards, the old channel in Sumerian times corresponding more or less to modern Shatt al Nil, while to-day the river shows a tendency, so far more or less overcome, to desert its bed which passes the ruins of Babylon, the Hilla branch, and to follow a yet more westerly channel, the Hin diya branch. The importance of these changes to human history have been very considerable (see MESOPOTAMIA : Ancient Geogra phy). Owing to the fact that the Euphrates floods in spring, just before the burning heat of the summer, it has been necessary to use it for perennial irrigation. The tendency has been to dig canals at low water; during flood the river has tended therefore to carry silt into the irrigation canals and often to desert its bed with disastrous results. Most of the changes in the stream appear to have been the result of man's action, followed by the natural flooding of the river. The history of the river has gradually re sulted in its becoming less useful to man as it moved westwards from the Tigris, and made the emptying of the canals supplied by the Euphrates (but running into the Tigris) more and more dif ficult. Measures of conservation have been undertaken since Sumerian times, but these measures have been continually frus trated by the action of riparian owners, who disregarding the efforts alike of Rim-sin and Alexander, have persisted in raising the water level by dikes and have neglected to keep the minor channels deep.
In addition to this westward movement the river since glacial times has been continually pushing its delta southward, combining with other streams, to form first lakes, then marshes and finally dry land (for further details, see MESOPOTAMIA: Geography).
The Murad su, although longer and of greater size, has never formed a highway of communication, owing partly to the smallness of its valley below Mush, and has acquired less historical fame. It rises at a height of 11,500 ft. on the northern side of Ala Dagh, south west of Diadin. From this point it flows west to the Arish kerd plain, where it is joined by the Sharian su. Through the trough formed by the two valleys passes the trade route from Er zerum to northern Persia. The river then runs through the moun tains to the south and has two tributaries, the Patnotz on the left bank and the Khinis su on the right. It flows in a double bend in a general southwesterly direction through the plain of Bulanik to the plain of Mush, where it is joined by another river usually known as Kara su (the name means black water and is applied to several rivers) which rises near Lake Van. Below Mush its valley is much contracted ; it runs west-south-west through a rocky gorge into which flows the Guroig su (on its right bank) as far as Palu. From this point the valley is more open. About ten miles east-north-east of Kharput the Peri su, which drains the Dersim, a mountainous region between the two main branches of the Euphrates, and is the most important tributary of the Murad su, falls into it.
The length of the Murad su to its junction with the Kara su is 415 miles, the length of the latter being 275 miles. From this point the Euphrates flows in a southwesterly direction past the lead mines at Keban Maden, where it is crossed by a ferry, 120 yd. across, on the road from Kharput to Sivas. It then runs in a great bend round the Musher Dagh, and is joined by the Kuru Chai, down whose valley the road from Malatia to Sivas runs, and the Tokhma su. Shortly below the ferry it enters a deep gorge and runs through the Taurus range in a rapid fall, the course of the river being much interrupted by rapids. It runs south east, close to the source of the western Tigris, and then turns at right angles and flows south-west leaving the mountains a few miles above Samsat (Samosata), the distance from the junction of the main two rivers to the latter town being 115 miles.
This now desolate stretch of the river was of great importance historically. It separated for long the Assyrian and Hittite em pires, and was the dividing line between the western and eastern satrapies of the Persian Empire, while at various times it formed the boundary of the Roman Empire. During the Mongol tenure of Mesopotamia it formed a fortified frontier against the Mongols. The ancient ruins along this frontier are numerous and important. Samsat is built on the site of Samosata, the capital of the Seleucid kings of Commagene; it is situated at an old crossing point of the river, and the old road from Susa to Sardis probably passed through it. A little lower down the river, at the point where the Sanjeh (Iiyyas) joins the main stream, stands the Rum-Kaleh, an ancient castle on a high rock defending another ancient cross ing; 25 m. south of this point is Birijik (ancient Birtha, the Apa mea Zeugma), the point at which the main road from east to west crosses the river, as it has done for many centuries. The point is only just over a hundred miles from the Mediterranean at an alti tude of 628 feet. From this important caravan centre the river runs sluggishly southwards past Jerablus (Carchemish), which lies close to the junction of the Sajur (Sagara), to Meskene, close to which are the ruins of Barbalissus, now a short distance from the river, but formerly a river port for the overland trade with Aleppo. At this point the river road turns westwards and crosses the desert to Aleppo. Six miles below this again is another impor tant crossing point Thapsacus (modern Kalaat Dibse). This was probably the most important of all the passages of the river in this region. It formed the point for the starting of caravans in ancient times. Cyrus here crossed the river and it was this passage which was used by Alexander. At this point the river takes a sharp bend to the east. From here onwards there are a succession of ancient towns. A few miles below Thapsacus there lies on the west bank the Kalaat Jaber (Dausera), while on the opposite bank is the more ancient Siffin (Roman Sephe). Below this again is another Roman frontier post, Sura, on the west bank, and 20 m. south of this, but away from the river, the ruins of Reseph. Below Sura (but on the other side of the river) are the ruins of Heraklea (Haragla). At the point where the Belikh, an important tributary joins the Euphrates, is the site of Nicephorum (modern Rakka) called Callinicus in Seleucid and Roman times and at one time the capital of Harun al Raschid. The Belikh (Bilechas) is a river of some importance in antiquity, on whose banks are Urfa (Edessa q.v.) and Harran (Carrhae). Below Rakka, at the point already mentioned where the river cuts through a basaltic dike, are two great ruins : on the left bank Zelebiya, on the right Halebiya (Ze nobia), which are situated about 26 m. above Deir-ez Zor. Below Deir the river opens out into a large plain and runs through two channels. This point has also been a ford of considerable impor tance and today is the meeting point of the western road, which goes by Palmyra, and the eastern road to Mosul, in addition to the up and down river road. The site is one of great antiquity and there are numerous ancient mounds. Below Deir the Khabur joins the left bank of the Euphrates, flowing from the foothills to the north. This stream, which has one important tributary the Jaghi jagh (Mygdonius) was the frontier of the Roman empire from the time of Diocletian. At this point are the ruins of the Roman Circesium (Assyrian Sirki), modern Al-Buseira. The fortress on the opposite bank, Salahiya (Ad-Daliye of Arab times) lies a little below. Between this point and Deir, on an old canal are the ruins of the Arab fort of Rahba.
Although some doubts have been raised there seems every prob ability that the Khabur is identical with the Araxes of Xenophon (called Saccoras by Ptolemy) and the distance given by Xenophon, of fifty parasangs between Thapsacus and Araxes, is a fair mate of the actual distance. All this northerly region must have been until the time of the Mongols, or even later fairly highly populated and prosperous, both on the evidence of archaeology and the statements of ancient authors. It seems probable that the change is due entirely to the devastating effect of the Mongol invasion.
Below this point the region has always been desolate, although along the river in ancient and modern times there were a series of small towns and villages. Below Salahiya on the eastern side of the river are the ruins of Al Irsi and below this again, at a point where two great wadis mark the course of a former tributary from the Syrian plateau, is an unidentified town built of unbaked brick. At this point there is a sharp bend to the east as far as Ana, above which town are a series of rapids. Ana is an ancient town, probably originally Sumerian; it lay on islands of the stream, where there are today a series of ruins, mostly of Persian and Arab date. The whole nature of the river changes at this point, the valley is very constricted, leaving very little alluvial ground for cultivation, while there are numerous islands in the stream. The vegetation also changes. Although the date palm grows as far north as Deir, here it becomes common and in favoured spots palm groves are found, while the olive, characteris tic of the Mediterranean regions, entirely disappears. Side by side with the change in flora the presence of one ruin at least of crude brick, shows that we are definitely approaching the true Meso potamian zone.
Between Ana and Hit there are four ancient sites, possibly old river guard posts. Haditha, in ancient times Baia Malcha, was an important town under the Abbasids; Al Uzz may probably be identified with the ancient Auzura (Uzzanesopolis) and Jibb Jibba, a site whose ancient name has not been identified. Olabu lies on the now uninhabited island of Telbeis. The neighbourhood of Hit is remarkable for the bitumen lakes, which supplied material for cementing bricks in ancient times and was and is still used for caulking boats. The region has been known from time immemorial as a place where there was an ooze of petroleum and it is possible that it may prove a fertile oil field.
The whole of the region of the middle Euphrates is marked by a long series of ancient sites. In classical times it was compara tively thickly populated and the descriptions of Xenophon suggest that the country was fertile and contained much game. Until the Mongol invasion this prosperity continued, and indeed there is reason to believe that it attained its greatest prosperity under the Abbasid caliphs.
All this region is extensively irrigated and the canals supplied by the river form an important part of its topography. Of these canals the largest is the Cherra Saaheh (Khandak Sabur). This great canal ran all along the edge of the alluvial plain from below Hit to the Persian gulf. It was protected by a series of guard posts and is of great antiquity; it was reconstructed in the time of Nebuchadrezzar, but its original date is unknown. The ma jority of the canals however are on the left bank, and originally tailed into the Tigris. Above Ramadi, a small town which forms the crossing place of the modern mail service across the desert, the Dojail flows across the plain and into the Tigris between Ukbara and Baghdad. Below this the Sakhlawiya, which follows closely the course of an ancient canal, leaves the Euphrates near Anbar and joins the Tigris at Baghdad. This canal had within the last sixty years been navigable for steamers. Below this again the Abu-Ghuruayb (Sarsar) crosses the plain and tails into the Tigris between Baghdad and Ctesiphon. The Nahr al Mali, sometimes called to-day the Radhwaniya canal, a little lower down joins the Tigris below Ctesiphon. Below this the Cutha canal Harl Ibrahim crosses the narrow strip between the rivers. It will be seen from an enumeration of this series how important to Mesopotamia the close position of the two rivers is and what profound changes have been effected by the altera tion of the bed of the Euphrates lower down the stream.
Below Museyib the river has from ancient times divided into two branches, the Hindiya and the Hilla branch. The ancient channel however seems to have flowed still more to the east, past a series of ancient sites of which the most important are Kish and Nippur, below which it again divided into two channels. (See MESOPOTAMIA : Ancient Geography.) The two modern branches join again near Samawa, i io m. lower down. Between 1865 and 1890 the main stream shifted its course into the western branch. The Hilla branch was threatened with complete desicca tion. A new Hindiya barrage was erected and a regulator was built on the Hilla branch to ensure a proper distribution of the water. Considerable progress is being made in this region in restoring the ancient irrigation system. The Shatt al Nil, a canal which probably followed more or less the ancient stream bed, is once more in use and is irrigating a large amount of land; it runs quite close to the ancient city of Kish. Near Diwaniya there is also another large canal.
On the Hindiya branch there are no important towns, on the Hilla branch is Hilla itself, lying on both sides of the river, the two banks being connected by a bridge of boats; below is Diwani ya. At Samawa the two branches reunite and flow to Na sariyeh. From this point onwards the Euphrates is lower than the Tigris. Nasariyeh probably marks the spot where at one time the two rivers joined. The Shatt al Hai, which flows along the old bed of the Tigris, even to-day carries a good deal of Tigris water into the Euphrates and was carrying the main stream cer tainly down to 2000 B.C. From this point onwards it flows through marshy land and eventually joins the Tigris at Kuala. From this point onwards the united streams are known as the Shatt al Arab (q.v.).
From Hilla onwards there are no ancient sites on the present course of the Euphrates, though Ur is close to the stream. Con siderable discussion has taken place concerning the place where the Euphrates flowed into the sea in ancient times. There is absolutely no doubt that the ancient texts definitely state that Eridu was on the edge of salt water. If it be argued that it was on the edge of a lake this lake must have been salt, unless we are to disregard the ancient statements. Campbell Thomson's discovery of fresh water mussels has been put forward as proving that the ancient texts must be disregarded. His account however does not disprove that the mussels in the earliest stratum were in situ and had not been used for food. Some sea shells were also found, which may equally well have been used for food. In later times the abundance of fresh water shells on the surface shows that the area must have been a large lake. There is further evi dence of numerous lacustrine lakes along the Euphrates; in clas sical times there was one as high up as Karbala. To-day such lakes as exist have become marshes. The river is however still young and has not yet firfnly established itself in its channel. The de position of silt will probably in time accomplish this. The point however is an important one, for naturally on the amount of silt which the river can deposit on its way to the sea will greatly depend its power of adding to its delta at the mouth.
Navigation.—Although high water may be said to extend from Dec. to June, the river does not begin to rise high till the end of March, attaining its maximum about the end of May, and its minimum at the end of November. In ancient times there seems to have been considerable traffic on the river, practically all down stream. Much of the modern traffic, both in the forms of the boats and in methods of navigation, does not differ very much from the ancient methods. From Meskene to Hit the local traffic is carried downstream in flat bottomed boats. Much of the river is interrupted by rapids and navigation is difficult except at high water. Below Hit the river can be navigated by steamers with a draught of under 5 feet. The width of the stream varies be tween 15o and Soo yd., with a current of 5 m. an hour, draining to 14 at low water. The discharge at Hit varies from 4,00o cu. metres a second to as low as 2 7o. The observations on the Hindiya branch are too few to furnish a just estimate; no continuous navigation can be Carried on in the Hilla branch. In the Hindiya branch there are locks planned to take vessels drawing 5 ft. at low water, but at the barrage and Samawa at certain times only 2 ft. is available. South of Samawa, between this town and Nasariyeh the river flows in a firm bed and a minimum of 5 ft. is always available and there are no obstacles to navigation. Below this point the river is no longer navigable except in flood time.
The main channel below Suk esh Sheyuk no longer carries any large amount of water and the Euphrates discharges through the Hammar lake to the Shatt al Arab at Kurmat Ali. During the World War certain efforts were made to dredge the old channel and to cut through the bar at Chubaish, but these were discon tinued and a large expenditure would no doubt be necessary to make navigation possible along the whole stream. Sir W. Will cocks proposed to use the river purely as a drain for the water used for irrigation from the Tigris. Considerable divergence of opinion has been expressed on this point, and some authorities have considered that the river might be used for both purposes, although considerable works might have to be undertaken. In the lower reaches of the river no doubt considerable maintenance charges would be needed. It has been considered that, if the obstacles up stream were removed and a different method of irrigation employed, the upper reaches could be used for up stream as well as down stream navigation, which in time might be com mercially profitable.