SHATT al-ARAB (ŠAṬṬ al-ʿARAB), name given to the ca. 200 km long, 400-1500 m wide (Rzóska, p. 47), combined effluent of the Euphrates and Tigris below Qurna, to which the Karun (Kārūn) contributes from Khorramshahr (Ḵorramšahr; formerly, until 1937, Moḥammara) southward. The name derives from Arabic šaṭṭ “bank, side” , with reference to a river (Eilers, pp. 301, 316; cf. New Persian rud-bār; hence not the “Arab stream” as stated by Le Strange, p. 26). The Shatt al-Arab is influenced by tides in the Persian Gulf, from ca. 5 m around Basra to ca. 3 m at its mouth, which contribute to the high level of dissolved salts in it (Rzóska, pp. 47, 68-72). While only 10 percent of the sediment deposited in the Shatt al-Arab is brought by the Tigris and Euphrates, 90 percent is carried south by the Karun (Cressey, p. 449), and “depressions, inundation basins and marshes act as silt tanks” (Rzóska, p. 52). At different times in the past, massive dredging operations have been undertaken in order to keep the Shatt al-Arab navigable (e.g. Ferrier, p. 449 ff).

The configuration of the Shatt al-Arab has changed over time (Rawlinson, pp. 189-90). As Lees and Falcon observed in 1952, a comparison of British Admiralty naval charts from 1825 and 1942 documented “a shift of the channel of the Shatt al Arab to the northeast .”The old channel which was directed more or less straight to the southeast from Fao (al-Fāʾū) ("Manamah" [Manama] on the old chart) has now completely silted up, several miles of it having been replaced by cultivated land, and the present channel follows a northern branch” (Lees and Falcon, p. 30). In the medieval period the Tigris is thought to have flowed down the more westerly Shatt al-Hayy (Šaṭṭ al-Ḥayy) and, after joining the Euphrates, the two rivers run through the Abuʾl-Asad (Arabic) or Bahmanshir (Bahmanšir) (Persian) canal to Basra ,where another short canal known as the ‘Blind’ or ‘One-Eyed’ Tigris (Dejla al-ʿAwrāʾ) flowed to the Persian Gulf through an estuary (Le Strange, pp. 26, 43). Old Basra itself, however, was located about 19 km from the canal, and required the construction of a canal to link it to the main waterway heading south (Reitemeyer, p. 26; Pellat, p. 7). According to the 10th-century Arab geographer and historian Masʿudi (Tanbih, p. 52), the lower Tigris from al-Maftaḥ to al-Obolla and ʿAbbādān (which is the Arabic form; the Persianzed form is Ābādān; see ĀBĀDĀN, i and ii) was called Bahmanshir by the Persians (Morony, 1982, p. 48, n. 500; 1984, p. 159, n. 211). Bahmanshir is almost certainly a contraction of Bahman-Ardašir (Rawlinson, p. 187), the name of both a district and its capital in Mesene/Maysān, the most southerly portion of Mesopotamia (Fiey, p. 265).

Access to Basra and Shatt al-Arab for vessels coming from Ahwaz (Ahwāz; see AHVĀZ) via the Karun was enabled by an artificial canal. The Arab philologist and historian Qodāma b. Jaʿfar al-Kāteb al-Baḡdādi (d. before 932) called this the ‘new canal’ (al-nahr al-jadid) and it debouched into the Shatt al-Arab about 32 km south of Basra (Curzon, p. 515-16). This is thought to be identical to the Haffar (Ḥaffār) canal, which the Arab geographer Moqaddasi (fl. 2nd half of 10th c.) says was dredged and widened by the Buyid ruler ‘Ażod-al-Dawla (q.v.) (d. 983); Le Strange, p. 48). Much later European maps, such as Isaac Tirion’s Nieuwe Kaart van Arabia of 1732, show the Karun joining the Shatt al-Arab at Haf(f)ar, and Carsten Niebuhr (1765) and others called this the ‘Hafar river’ (‘Hafar Fl.’; Slot 1991, pls. 14, 38). In the early 19th century, Kinneir camped near “the Hafar cut, which is at least a hundred and fifty yards in breadth, and at high water sufficiently deep to admit a vessel of any size” (Kinneir, p. 294).

A report from 1580 by the Venetian traveler Gasparo Balbi identified the Shatt al-Arab as the “Bahrain river” and the Bahmanshir as the “Hormuz river.” The former, because of its shallowness, was used only by small, local craft engaged in coastal trade between Basra, Bahrain and eastern Arabia, whereas the latter was the channel taken by sea-going vessels bound for India (Slot, 1991, p. 36; 1993, p. 11). The logbooks of two Dutch East India Company vessels that sailed from Bandar ʿAbbās in 1645 bound for Basra confirm Balbi’s report. Eventually the Dutch vessels reached Basra by sailing up the Bahmanshir channel (Slot, 1991, p. 18).

From the late 16th century onwards the Banu Kaʿb, an Arab tribe belonging to the Banu Ḵafāja, were settled in and around Quban by Afrāsiāb Pasha Dayri who won the area between Bandar Maʿšur and the Shatt al-Arab from the Safavid client ruler, Bektāš Āḡā Afšār (Perry, p. 133). By the mid-18th century the Banu Ka’b controlled the mouth of the Shatt al-Arab estuary. Their sphere of influence extended roughly from Hendiyan (Hendiān) in the east to Ahwaz in the north and to the territory between Basra and Hafar (later Mohammara/Khorramshahr) on the west. This “ambitious brigand state,” as it has been called, raided on land and, using a navy of some eighty vessels, controlled the canals, creeks and coast in and around the Shatt al-Arab (Perry, p. 131). Following Nāder Shah’s death in 1747, the Banu Kaʿb were emboldened to engage in “organised piracy,” blockading the Shatt al-Arab and expanding into lands formerly held by the Ottoman governor of Basra and refusing to pay taxes either to the Zand rulers of Persia or the Ottoman state (Perry, p. 136). As English East India Company records attest, trade at Basra was adversely affected by the Kaʿb, particularly in the 1760s when their most vigorous ruler, Shaikh Salmān, led the tribe. So serious were the depredations of the Banu Ka’b that the East India Company, the Ottoman army in Iraq, and Karim Khan Zand all undertook expeditions against them between 1763 and 1765. The presence of a British factory at Basra, then one of the most important commercial centers in Western Asia (Saldanha, 1986, p. 405) and of British-owned date plantations along the Shatt al-Arab, meant that financial losses here could be significant, and a squadron of East India Company naval vessels blockaded the Shatt al-Arab for over two years in 1767 and 1768 in an effort to bring Shaikh Salmān to heel (Perry, p. 149). Ultimately the blockade was abandoned as being ineffectual. Although the Kaʿb suffered in the plague of 1772-73, they were strong enough to attack Basra in advance of Karim Khan Zand’s siege of the city in 1775-76 (Slot, 1991, pp. 109-10), though this time it was the Zand navy that blocked the Shatt al-Arab for over a year (Perry, p. 151). Thereafter Kaʿb influence waned although one of their leaders, Shaikh Thamir (Ṯamir), was brought to Erzerum in 1847 by the Ottomans in order to provide testimony before Robert Curzon and the boundary commission (see below) on land claims along the Shatt al-Arab (Perry, p. 152).

Although Ottoman rule over the entire lands of Mesopotamia was established by 1546, an Ottoman-Persian boundary proved difficult to determine. The Treaty of Zohab (1639) established a line of demarcation from the “point where the Shatt enters the Gulf and ran along it northwards for about fifty miles till it reached the edge of the Persian plateau...leaving Mandali and Badra to Turkey” (Kaikobad, 1988, p. 7). This was reaffirmed in the Treaty of Kurdan (Kordān) (1746) and in the first Treaty of Erzerum (1823). The shifting allegiance of the Kaʿb vis-à-vis the Ottoman and Persian states and the positions of date plantations owned by vassals of the Ottoman pasha of Basra, both east and west of the Shatt al-Arab from the 16th through the mid-19th century, ensured that any proposed settlement of the boundary remained contentious. Potential hostilities with the Ottoman regime in Iraq made the alternative of using the Karun rather than the Tigris to bring goods into Iran a proposition of commercial interest to English steam companies in the late 19th century, and the Bahmanshir was surveyed as early as 1836 during the Euphrates expedition under Col. Chesney (Curzon, p. 516).

As a result of the second Erzerum conference of 1847 a treaty was finalized (Schofield) which ceded Mohammara and all territory on the east bank of the Shatt al-Arab to Persia, as well as navigation rights for Persian vessels, but which effectively left the waterway itself under Ottoman control (Kaikobad, pp. 16-8). When it came to an interpretation of Article 2 on the ground, however, repeated attempts between 1850 and 1852 failed. The un-ratified status quo was retained in a series of subsequent protocols during the 1860s and 1870s, while extensive negotiations between the Ottoman and Persian governments, initiated in 1911, finally led to an attempt at demarcation in 1914. While certain islands in the Shatt al-Arab were ceded to Persia, the “frontier along the Shatt al-Arab was the left or Persian bank” (Kaikobad, p. 51).

The accession of Reżā Shah in 1921, however, reignited the issue, particularly now that the Persian port of Abadan had a major British oil refinery, yet ships anchored there were effectively in Iraqi waters. On the other hand, fully 80 percent of Basra’s commercial traffic was bound for Abadan and Mohammara, and should Persia’s dissatisfaction over the Shatt al-Arab situation have caused this to change, Basra’s economy would have been ruined. At the same time, silt carried into the Shatt al-Arab by the Karun was beginning to cause problems for Iraqi shipping, such that official, sanctioned Persian participation in the governance of the Shatt al-Arab was warranted. Nevertheless, the Iraqi government resisted any Persian claims to sovereignty over any portion of the Shatt al-Arab, viewing Persian customs and police patrols in the waterway as a violation of Iraqi jurisdiction. In 1934, Iraq made a request to the Council of the League of Nations to arbitrate in the boundary question but this was adjourned because of direct negotiations between Persia and Iraq that ultimately led to the Tehran treaty of 1937. This gave rights of passage on the Shatt al-Arab to vessels of all nations, ceded anchorage rights at Abadan to Persia, committed all duties collected from trading vessels by either side to the upkeep and improvement of the channel ,and established the boundary variously at the low water mark of the eastern bank of the waterway and in places (over a distance of four miles) at the line of deepest water (thalweg) without adversely affecting either party’s right to the use of the Shatt al-Arab (Kaikobad, pp. 130-31).

In spite of the 1937 treaty, the Shatt al-Arab continued to be a cause of disagreement both before and after World War II. In 1969 the Iranian Ministry of Foreign Affairs formally abrogated the treaty and in 1975 the Algiers Protocol was announced (Caponera), by which Iraq finally acceded to the Iranian demand to “delimit their river frontiers along the thalweg” (Kaikobad, p. 134). The Algiers agreement came under extreme pressure following the Islamic revolution in Iran early in 1979 and the accession of Saddam Hussain as president of Iraq in July of that year (McLachlan, p. 61). Hundreds of border violations by both sides preceded the outbreak of the war in September 1980, followed shortly by the Iraqi occupation of Khorramshahr and the attempted capture of Abadan. A major Iranian counter-attack on Qurna in 1984 was repulsed, and it was not until 1986 that Iranian forces got across the Shatt al-Arab and captured Fao. One year after the United Nations Security Council had passed resolution 598 calling for an end to the war, the Iranian president formally wrote to the United Nations (20 July 1988) accepting it (McLachlan, p. 69). In accepting this resolution, the Iranian government looked for the restoration of the status quo ante, including the 1975 Algiers Agreement on shared sovereignty over the Shatt al-Arab, while Iraq demanded a return to the terms of the 1937 Tehran Treaty that gave Iraq greater control over the waterway. Following the Iraqi invasion of Kuwait, Iraq offered to re-confirm the Algiers Agreement ,but this was never done in the wake of the Iraqi defeat by the allied forces ,which ousted Iraq from Kuwait in the first Gulf War of January-February, 1991 (McLachlan, p. 70). The Shatt al-Arab boundary remains unresolved.



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(D. T. Potts)

Originally Published: July 20, 2004

Last Updated: July 20, 2004