FLOODS (sayl, sayl-āb) in Persia.
A common saying holds that probably more people died in deserts by being drowned than by thirst. Such a statement indicates that even in extremely dry environments flooding is a major factor not only in shaping the earth surface, but also causing severe damage to settlements, agriculture, and people.
Floods are usually considered to be climatically controlled events that, in connection with topography and vegetation cover, can be of considerable geomorphic significance. They may be caused either by intensive precipitation over small hilly watersheds, or by heavy rains and thunderstorms in longer periods of time over large watersheds, or as a result of rapid melting of large snow masses, e.g., in mountains. Extremely severe flooding occurs by the combination of excessive heavy rainfall and snow melt, leading to extensive fluvial runoff. Floods cause sedimentation of flood plains and, at the same time, erosion and other geomorphically relevant processes. Due to the fact that flood plains are preferred locations of human settlements and agricultural activities, floods often cause loss of human lives as well as economic disasters.
In Persia, heavy temporary rainfalls and/or, sometimes even in combination with, snow melt are the prime causes of floods and flooding. Surplus or deficit of water, mainly caused by Persia’s topography, undergoes seasonal variations with decisively stronger precipitation during the winter months (see EIr.V, fig. 45 and Table 52), which explains why floods occur predominantly during these periods. Due to an unfavorable, but by no means unusual, meteorological situation southwestern Persia was exposed to extremely heavy precipitation over parts of the Zagros between 16 March and 22 March 1972. Rainfall of up to 300 mm in a few days in combination with snow melt caused extreme runoffs in the catchment areas of Karḵa and Kārūn rivers, causing heavy erosion in the narrow mountain valleys and disastrous floods in the low lying flood plains around Sūsangerd and south of Ahvāz.
From a geomorphological and ecological perspective, floods in Persia and their distribution and effects are characterized by two basic forms: (1) river floods, especially in low-lying environments such as the coastal area of the Persian Gulf or the Caspian Sea; and (2) sheetfloods, in most parts of central Persia, especially in and around the many endorheic basins that are so characteristic of Persia’s highlands and plateaus. River floods in Persia are mainly caused by the combined factors of heavy rainfall and snow melt. As such they are especially typical of the lower parts of all those drainage systems that discharge into the drainage area of the Persian Gulf. While flooding is mostly not a problem for the upper reaches and headwaters of the fluvial systems, the lower parts of the Kārūn-Karḵa drainage area are, for instance, very sensitive to periodical and episodical extreme runoff events. The reason for this is the combination of temporarily extreme discharge, slow runoff in the lower reaches of the river system, and low, sometimes levee-type, embankments of the rivers.
Sheetfloods are a common feature in arid and semiarid environments, for which Persia is typical. While precipitation is scanty (see BĀRĀN; CLIMATE), short and concentrated rainfalls can be extremely heavy, for instance as a result of local thunderstorms. In such cases, existing drainage systems, especially those ending in endorheic basins, tend to create heavy surface runoffs discharging into desert (q.v.; kavīr). Figure 1 shows in an idealized form the typical structure of a kavīr with its periodically flooded central parts. Putting this general typology into a geographical perspective, one may conclude that in Persia there are basically three areas that are specifically prone to floods and inundations: (1) interior endorheic basins in general; (2) the Hāmūn-e-Helmand/Hīrmand in particular; and (3) the lowlands of Ḵūzestān. To a smaller extent, the southern rim of the Caspian Sea is also affected by floods.
Endorheic basins. Central Persia is part of a huge interior drainage basin, covering an area of more than 1 million km2 and extending into Afghanistan. It is subdivided into eleven watersheds, most of which are drained primarily by intermittent streams that discharge their periodic or episodic runoffs into intermittent lakes, salt marshes, and deserts (see DRAINAGE). The central desert (Dašt-e Kavīr; Figure 2) and the Hāmūn-e Jāz Mūrīān (Figure 3) are good examples of such endorheic basins, which even can be subdivided into smaller units of basins independent of each other (e.g., Dašt-e Kavīr). From a hydrological perspective, noteworthy is the fact that all of them are flooded either periodically or episodically. Winter rains in surrounding high mountains areas, combined with snow melt, may cause periodic runoff which, however, does not always reach the interior parts of the kavīrs. Only in extremely moist years are the bottoms of endorheic basins reached by fluvial runoff, creating either episodic shallow lakes or dangerous salt swamps, very often hiding under a thin surface of salt crusts. Even after long dry periods, many kavīrs are saturated with water in their lower strata, creating treacherous environments for all kinds of life and natural barriers to all forms of human use and traffic and transport. In former days, even caravan routes had to escape these dangerous flood plains of central Persia.
Hāmūn-e Hīrmand (Figure 4). A very specific case of an endorheic flood plain is the Sīstān depression in the border region between Persia and Afghanistan. Without going into further details, it must suffice to say that this huge depression (see HĀMŪN) has an east-west extension of approx. 500 km and a north-south extension of more than 300 km. As such, this depression is the most eastern of the big endorheic basins of the Persian highlands. Its specific character stems from its more or less regular flooding by four perennial rivers, all of which originate in the western Hindu Kush, namely Hārūtrūd, Farāhrūd, Ḵāšrūd, and Hīrmand (see HELMAND). The last mentioned tributary, with a length of approximately 1500 km, is the largest and most important for the annual flooding of the basins, creating three periodic lakes (Hāmūn-e Kūh-e Ḵᵛāja, Hāmūn-e Ṣāberī, and Hāmūn-e Pūzak). The fourth and lowest depression at 467 m above mean sea-level is the Gowd-e Zereh, which, however, is flooded only under extremely high runoff conditions. The specific situation of the Hāmūn-e Hīrmand is distinguished by the fact that, unlike almost all other endorheic basins of Persia, the flood plain is characterized by a very specific flora and fauna that is also of great, but mainly regional and/or local, economic importance. The harvesting of reeds (Aypha angustifolia) is especially widespread and used for the production of mats and curtains (parda, ḵolak, ḥaṣīr), which are exported as far as Tehran. Fishing is also of importance.
The lowlands of Ḵūzestān (Figure 5). Unlike the endorheic basins of central Persia, southwestern Persia is part of the exorheic/oceanic drainage system. Especially the southern parts of the lowlands between the Kārūn in the east and the Tigris in the west and south of Ahvāz are characterized by an extremely low-lying and flat surface. With a height of only a few meters above sea-level, the Karḵa River, flowing between Kārūn and Tigris, ends in a swamp marsh and is especially prone to flooding. As a matter of fact, southern Ḵūzestān may be the most important single region within Persia where floods are connected with heavy damage to settlements, traffic, and the economy at large. Especially after heavy rainfall over the catchment areas of Karḵa, Kārūn, and their tributaries, even more so in combination with snow melt, rivers tend to rise above their natural embankments. Due to the fact that over centuries or even millennia the natural banks of these rivers were formed during flooding by the deposition of silt, many of these embankments (called levees) are the highest portion of the flood plain. During high floods land between the river embank ments may be inundated. As a result fields and pastures as well as settlements, highways, and railway tracks have often been severely damaged in the past.
W. B. Fisher, “Physical Geography,” in Camb. Hist. Iran I, pp. 3-110.
Gazetteer of Afghanistan II, pp. 103-5.
E. Huntington, “The Depression of Sistan in Eastern Persia,” Journal of the American Geographical and Statistical Society 37, 1905, p. 271-81.
Idem, “The Basin of Eastern Persia and Sistan,” in R. Pumpelly, W. M. Davis, and E. Huntington, eds., Explorations in Turkestan, with an Account of the Basin of Eastern Persia and Sistan, Carnegie Institution 26, Washington, 1905, p. 219-317.
T. M. Oberlander, “Hydrography,” in Camb. Hist. Iran I, pp. 264-79.
Perso-Afghan Arbitration Commission 1906: Seistan, Simla, 1906 (8 reports).
G. Stöber, Die Ṣayād: Fischer in Sistan, Sistan Projekt 3, Marburger Geographische Schriften 85, Marburg an der Lahn, 1981.
Persia, essentially an arid land with almost no major perennial rivers, has nevertheless been subject to devastating floods throughout her recorded history. In terms of lives lost and material damage, flooding does not constitute so severe a hazard as earthquakes (q.v.), but some large-scale events have been reported, in addition to the flash floods that strike isolated riverbeds following localized storms in the mountains, carrying away unwary travelers, transport, and bridges.
Flooding is usually triggered by rapid melting of winter snows (see BARF), sometimes compounded by a period of intense rainfall. Most of the recorded floods in history (see Melville, 1984, for a preliminary survey of the literature) have occurred in the spring months (March-May). Winter precipitation (see BĀRĀN) can itself be directly responsible for flooding, as in Ḵūzestān in December 1921, January 1924, and February 1934, and in Anār and Rafsanjān (Kermān) in December 1924, following downpours throughout southern Persia. It is not surprising therefore that the worst instances of flooding are often associated either directly or indirectly with severe winter weather. Exceptionally, summer storms also generate destructive floods, as for example in Sarāb in 1001/1593 (Afūštaʾī Naṭanzī, p. 528), and Rašt in August 1923 (after which Reżā Khan ordered that money intended for a statue of himself should be set aside for relief of the victims). Nevertheless, the beneficial effects of heavy rainfall sometimes more than compensate the short-term damage caused. When possible, surface runoff was channeled into cisterns and tanks for later use for irrigation (see ĀB-ANBĀR; Beazley and Harverson, ch. 3).
The devastation caused by floods depends on whether they affect chiefly rural areas and damage agriculture, with the loss of livestock, interruption of communications and blocking or collapse of qanāts(q.v.), or mainly towns and cities, resulting in more concentrated damage to property and goods. Among examples of the damage to rural qanāts are the floods that affected parts of Kermān province in the winter of 1088/1677 and spring 1091/1680, both years also associated with heavy snowfalls (Māšīzī Bardasīrī, pp. 462-63, 480-81). The former type need not be associated with river overflow so much as surface runoff of storm water. Damage to rural dwellings, relatively easily replaced, though common, is perhaps not the most important aspect of such disasters, even though loss of life can be heavy. Thousands of people are said to have been downed in the Harāz valley and in Āmol in 1600 (Mahjūrī, III, p. 369), and over five hundred people in the districts round Dehkord (modern Šahr-e Kord) in 1914 (Nīkzād, p. 44). On the whole, however, reported casualties seldom exceed one hundred to two hundred people, and are usually measured in tens rather than hundreds.
Urban floods are usually due to the sudden inundation of a normally dry riverbed running through the town center. Such incidents are reported for most of the major provincial cities in Persia (though not to any great extent for Tehran itself, nor for Hamadān, probably due in the latter case to a lack of local chronicles). Notable examples of this are the 1929 and 1934 floods in Tabrīz, reflecting a persistent problem visible in the sources since the Safavid period (Eskandar Beg, p. 160; Melville, 1983). Other cities for which famous flood disasters are reported include Qazvīn (floods in 965/1558, 1002/1594, 1267/1851, c. 1898); Qom (in 294/905, 1045/1636, 1080/1670, 1881, 1893; see Calmard; Houtum-Schindler, pp. 65-66); Shiraz (1079/1688, January 1908 and March 1910); Yazd (673/1275, 860/1456 and April 1941); and Kermān (notably in July 1932). Some floods affected more than one of these cities at the same time. In the case of large-scale events, triggered by prolonged and widespread periods of heavy rainfall, flooding can affect both towns and their rural hinterland over a large area, as in the case of the floods of February 1594 all around the edges of the Kavīr from Qazvīn to Kermān (Afūštaʾī Naṭanzī, pp. 530-34) and, more recently, in March 1910, particularly severe around Anār and Rafsanjān.
Given the incompleteness of the data currently available, and the distorting effects of the documentary emphasis on the major towns, it is not useful to plot either the spatial or time distribution of floods in Persia. Predictably, however, the most persistent incidences of flooding are connected with the main river regimes, namely the Kārūn in Ḵūzestān (see. e.g. the floods mentioned above) and the Helmand (Hīrmand) in Sīstān. The Tārīḵ-e Sīstān contains information on floods round the capital, Zarang, in 429/1037 and 640-41/1243-44, and, more interestingly, on the budget set aside for the repair to damage caused by floods, constructing dams, and maintaining dykes and embankments (ed. Bahār, pp. 32-33, 364-65, 397-98). Many of these irrigation and flood management systems were destroyed in the Timurid period (see Christensen, pp. 237-42). The sources are then silent until the present century, when several instances of flooding and the measures taken to channel and contain the unruly waters of the Hāmūn basin are detailed in various reports by British diplomatic and consular officials (see also Tate, esp. Part II).
Responses to the flood hazard in the pre-modern period were on the whole ad hoc, and typically consisted of the construction of canals, drainage ditches, barriers or dams (band, q.v.). If the onset of flooding was relatively slow, the inhabitants could try to construct defenses to bar or deflect the rising waters, but more usually new defenses were built, or inadequately maintained banks and canals were restored, only in the aftermath of a destructive flood. Little attempt was made to reduce vulnerability by avoiding building in the flood plain, despite evidence that people were aware of the risks (see the examples in Melville, 1984, from the floods of 1908 in Shiraz and 1950 in Mašhad). On the contrary, in the early Pahlavi period vulnerability was often enhanced by the filling in of city moats, destruction of town walls, and the creation of wide boulevards, which facilitated the inroads of flood waters. It is only in recent times that government relief measures have provided support for flood victims.
The current flood risk in Persia, greatly modified by enormous changes in population density and urban topography, the use of new building materials and techniques, the construction of large dams and altered land-use patterns, cannot be evaluated solely on the basis of past experience. Nevertheless, a fuller historical record would be useful in identifying the areas most at risk over the long-term. See also ĀB, ĀBȲĀRĪ.
Bibliography (for cited works not given in detail, see “Short References”):
Maḥmūd b. Hedāyat-Allāh Afūštaʾī Naṭanzī, Naqāwat al-āṯār fī ḏekr al-aḵyār, ed. E. Ešrāqī, Tehran, 1350 Š./1971.
E. Beazley and M. Harverson, Living with the Desert: Working Buildings of the Iranian Plateau, Warminster, 1982.
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C. Melville, “The 1934 Floods in Tabriz, N.W. Iran,” Disasters 7/2, 1983, pp. 107-17.
Idem, “Meteorological Hazards and Disasters in Iran: A Preliminary Survey to 1950,” Iran 22, 1984, pp. 113-50.
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N. Smith, A History of Dams, London, 1971, esp. pp. 58-89.
G. P. Tate, Seistan: A Memoir on the History, Topography, Ruins and People of the Country, London, 1910.
(Eckart Ehlers, Charles Melville)
Originally Published: December 15, 1999
Last Updated: January 31, 2012
This article is available in print.
Vol. X, Fasc. 1, pp. 39-43