Review of Muslim Contribution to Civil Engineering: Dam Construction

Dams are required in most hydraulic systems, for irrigation, regulating flow of rivers and in modern times for the production of energy. In the classical Islamic world, dam construction received a special attention as an integral part of large civil engineering works. Since the Umayyad Caliphate, dams were built in different Islamic regions. This article is a survey presenting the tradition of dam construction by Muslims, characterized by a rich variety of structures and forms.

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Note of the editor: This article has been published on Muslim Heritage in December 2001 in PDF format. We present it to our readers in a new editing in HTML, with illustrations.

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Introduction

In his ‘History of Dams’, Norman Smith, began his chapter devoted to Muslim dams,[1] by stating that:

Historians of civil engineering have almost totally ignored the Moslem period, and in particular historians of dam building, such as there have been, either make no reference to Moslem work at all or, even worse, claim that during Umayyad and Abbasid times dam building, irrigation and other engineering activities suffered sharp decline and eventual extinction. Such view is both unjust and untrue."[2]

A similar point is raised by Pacey, who notes that it is often said that hydraulic engineering ‘made little progress under the Muslims’, and that the latter’s achievements hardly evolved beyond the Greek or Roman’s. Pacey corrects this view, pointing out that the Islamic civilisation adapted ancient techniques ‘to serve the needs of a new age’, and that the Muslims extended the application of mechanical and hydraulic technology enormously.[3] Explaining the reasons behind the belittling of Muslim achievements, which has been noted by Smith, Pacey and others,[4] is a mammoth a task much beyond the scope of this article.


Figure 1: Satellite view of Aswan High Dam in Egypt. Completed in 1970, this gigantic dam was one of the largest earthen embankment dams in the world. It is 111 m tall, 3830 m long and nearly 1000 m wide. Its construction has had immeasurable impacts on the Egyptian economy by regulating the Nile river flooding, providing storage of water for agriculture and for generating electricity. (Source).

Muslims, as the following essay will explain, built such dams for a great variety of reasons, including economic, social, and also as Welch remarks in relation to the Tughluq princes of Muslim India (beginning1320...) their patronage not only made sound economic and military sense but also served to demonstrate piety and their concern for those they ruled.[5]

Firuz Shah (ruled 1351-1388) was a builder on a grand scale. In his own Memoirs (The Futuhat-i Firuz Shah) the sultan described his abiding architectural passion:

Among the gifts which God bestowed upon me, His humble servant, was a desire to erect public buildings. So I built many mosques and colleges and monasteries that the learned and the elders, the devout and the holy, might worship God in these edifices, and aid the kind builder with their prayers. The digging of canals, the planting of trees, and the endowing with lands are in accordance with the directions of the Law.[6]  

Dam construction became part of a grand plan or strategy as is best obvious in Muslim India, indeed. Ghiat al-Din Tughluq's short reign (1320-1325) was dominated by successful efforts to resist Mongol and Chaghatai invaders from the north and to establish firm control over the Delhi Sultanate. Central to these policies was the massive military complex to the south of modern Delhi that is dominated by the great fortress of Tughluqabad, reportedly completed during the sultan's reign.[7] Tughluqabad's huge walls extend for six kilometres, but the bastion is part of a larger complex including the adjacent smaller fort of 'Adilabad (perhaps built by his son Muhammad) 350 metres to the southeast, a third fortified structure now referred to as the Nai-ka-kot a short distance to its east, and an elaborate network of dams and sluice gates that was integral to the whole defensive scheme.[8] Tughluqabad sits in a large plain that during the monsoon was transformed into a shallow lake. Otherwise, there is no natural water source of any significance. (Today the land around Tughluqabad has become a major focus of urban development and suffers from a chronic water shortage.)[9] Ghiat al-Din realized the natural advantages of the site: if the water could be contained, it could irrigate a large area immediately adjacent to the fortress; the water itself could serve as a vast moat to protect the fort.[10]

Whilst the purposes were multiple, and were part of grand strategies, techniques and designs were also diverse.

Dams and Their Construction Techniques

The majority of the earliest Muslim dams were completed in Arabia itself; and full information on their height, length, and ratios between height and length is given by Schnitter. He notes that with the exception of the Qusaybah dam near Medina, a 30 m high-205 m long structure, which was slightly curved in plan, the alignment of all others were straight.[11] About half such dams were provided with a flood overflow at one end, and often with a downstream training wall to guide the spilled water to a safe distance from the foot of the dam. Schnitter also observes that about a third of these very early dams (7th-8th century) are still intact.[12]

Figure 2a-b: Khaybar Dam called Sadd Qasr al-Bint in the Arabian peninsula. It is one of the largest ancient dams, probably built by the Queen of Sheeba in pre-Islamic times. It is a big stone construction on a dried out river bed. Although it had been breached for about one third of its length, it is nevertheless an impressive 20 metres high and about 135 metres long. The upstream face is plastered with yellow mortar, the downstream face with bare stone. (Source).

This, and other major breakthroughs, such as the invention of payment by cheques and similar means, the erection of windmills, the building of new cities on the desert sands (such as Kufa, Basrah, Al Qayrawan…), the devising of maps, the unique military prowess in taming the two great empires of the time (Byzantium and Persia) and so on, wholly contradict the view held by many that Muslims only waited until they translated Greek works to begin their march towards civilization, and are, instead, testimonies to the central place taken by the faith in Islam greatness.[13] Back to dams, subsequently, in Iraq, in the vicinity of Baghdad, a considerable number of dams were built during the Abbasid Caliphate.[14] Most of the dams were on the Tigris, but a few are on water diversions, a further illustration of a high level of engineering skills. The Kebar dam, in Iran, dating from the 13th century, is the oldest arched dam known to have survived.[15] The dam has a core of rubble masonry set in mortar, the mortar made from lime crushed with the ash of a local desert plant, the addition of the ash making the lime hydraulic. This results in a strong, hard and impervious mortar, ideal for dams and the reason for such dam’s long life, and the absence of cracks in it.  Earlier, three dams were completed by King Mahmud of Ghaznah (998-1030) near his capital city. One named after him, was located 100 km SW of Kabul, and was 32m high, and 220m long.[16]

Further south, in Muslim India, roughly oval in form, the dam of 'Adilabad measured about 100 metres on its north-south axis and 250 metres on its east-west axis. Linking it with Tughluqabad to the north was a fortified dam, measuring about 100 metres in width and 300 metres in length that protected the entire plain as well as the two castles.[17] In its northern side, immediately adjacent to the Tughluqabad wall, is a large sluice gate and water tunnel that controlled the flow of water into the fields to the east of Tughluqabad.[18] The sluice-gate opened onto the east side of the dam and consisted of three rectangular tunnels running from west to east and ending on both sides in three arched entrances.[19] Water flow was controlled by means of large boards held in place by stone grooves on the sides. Staircases and passageways on the south and north sides of the sluice provided access.[20] All this means that water measurement and distribution was done with great care. Thus the dam and 'Adilabad created a huge catch-basin in the middle of which stood the imposing island-necropolis of Ghiat al-Din.[21] When the Monsoon season ended this artificial lake extended about one kilometre to the south were low hills formed a natural barrier.[22] Two ravines pierce these hills, and, in order to close them, two stone masonry dams were constructed: the first, about one hundred metres to the south of 'Adilabad, measured about three metres in height, two metres in width and 130 metres in length; the second, 500 metres to the south of Ghiat al-Din's tomb, was 180 metres long and about five metres high. Both dams presumably had sluice gates. [23]

Dam construction in Muslim Spain was prolific. In the city of Cordoba, on the river Guadalquivir, can be found what is probably the oldest surviving Islamic dam in the country.[24] According to the twelfth- century geographer al-Idrisi, it was built of Qibtiyya stone and incorporated marble pillars.[25] The dam follows a zig­zag course across the river, a shape which indicates that the builders were aiming at a long crest in order to increase its overflow capacity. Remains of the dam can still be seen today, a few feet above the river bed, although in its prime, it was probably about seven or eight feet above high- water level and eight feet thick.[26]

Techniques used by Muslim masons and engineers reached great heights of ingenuity. On the river Turia, in the same country, modern measurements have shown that the eight canals have between them a total capacity slightly less than that of the river, thus raising the possibility that the Muslims were able to gauge a river and then design their dams and canals to match.[27] Smith elaborates on Muslim construction skills.[28]

Muslim engineers used sophisticated land surveying methods to locate their dams in the most suitable sites, and also to lay out very complex canal systems. For such, they used astrolabes and also trigonometric calculations.[29] The search for the lasting and solid remained central throughout. Around Baghdad water was diverted into the Nahwran Canal which supplied water for irrigation, whilst improvements were made to existing systems.[30] Dams were built of carefully cut stone blocks, joined together by iron dowels, whilst the holes in which the dowels fitted were filled by pouring in molten lead.[31] An impressive structure of masonry is Hill‘s description of the dam at Marib in Yemen, with its carefully cut and fitted blocks using lead dowels in their joints.[32] It was 14 metres high and 600 metres long, with elaborate waterworks including sluices, spillways, a settling tank and distribution tank. So strong a structure it was, it survived for about ten centuries until lack of financial and technical resources made it impossible to maintain.[33]


Figure 3: View of the moder Marib dam in Yeman taken in 1986. The Marib dam blocks the Wadi Adhanah in the valley of Dhana in the Balaq Hills, Yemen. The current dam is close to the ruins of the Great Dam of Marib, dating from around the 7th century BCE. It was one of the engineering wonders of the ancient world and a central part of the south Arabian civilization around Marib. (Source).

According to Scott, the masonry of the reservoirs in Spain was of the finest quality, and the cement used was harder than stone itself.[34] Contingencies were provided for in such a manner that no overflow occurred, and no damage resulted even during the worst flooding. Evidence of Muslim engineering skills is the fact that these dams needed hardly any repair in a thousand years.[35] At first sight, the eight dams on the Turia River seem to have an exaggerated amount of weight placed on their foundations, the masonry of each dam going some fifteen feet into the river bed, further support being provided by the addition of rows of wooden piles. Such solid foundations were justified by the river’s erratic behaviour, which in times of flooding reaches a flow that is a hundred times greater than normal, the structure having to resist the battering of water, stones, rocks and trees.[36] These dams, now over ten century old, still continue to meet the irrigation needs of Valencia, requiring no addition to the system.[37] On the River Segura, the Muslims built a dam in order to irrigate vast lands in the Murcia region.[38] Because of the nature of the terrain, the location, design and construction had to be perfect. The height of the dam was only 25 feet, yet at its base its thickness was 150 and l25 feet, which may seem excessive. Such thickness was necessary to counteract the softness and weakness of the river bed and to prevent it from sliding along. The water flowing over the crest initially fell vertically through a height of 13-17 feet on to a level platform, running the length of the dam. This served to dissipate the energy of the water spilling over the crest. The over-flow then ran to the foot of the dam over flat or gently sloping sections of the face. In this way the whole dam acted as a spillway and the energy gained by the water in falling 25 feet was dissipated en route. Thus the risk of undermining the downstream foundations was greatly reduced. Like with other dams, rubble masonry and mortar were used for the interior, and the whole was finished with large masonry blocks.[39]

Approximately four kilometres to the west of the Quwwat al-Islam mosque in south Delhi is the village of Mahihpalpur, which flourished under Firuz Shah's patronage.[40] The area showed agricultural potential, and the sultan, as at Hisar, evidently wanted to encourage settlement.[41] He ordered construction of a 1.4 kilometre L-shaped masonry dam (bund), to the south of the village, to contain run-off from the hills to the east, and it was a remarkable enough structure that the chronicler, 'Afif, identifies it in his list of notable dams.[42] Sluice-gates, technically similar to those at Tughlu-qabad, were located at the northern and southern ends of the dam in order to control water-flow from the artificial lake on the east to the fertile farmland on the west that must have been criss-crossed by an extensive irrigation system.[43] The dam is about 3.5 metres above the present ground level, and the artificial lake must have been of substantial size and depth immediately after the rains. A number of stairways on the east side provided access to the top of the dam.[44] The lake and abundant vegetation around it attracted wildlife, and the sultan was a passionate hunter: to the north in the present-day village is a small mahal that may have served as a kushk-i shikar (hunting lodge) for the sultan.[45]

By far, the most original Muslim reservoirs are to be found in the region of Qayrawan in Tunisia. A lengthy account of these structures is offered by the French scholar Solignac.[46] Possibly on aesthetic grounds, and like many other Islamic achievements,[47] and despite all evidence to the contrary,[48] these reservoirs were attributed, to both Phoenicians[49] and Romans.[50] These views were adopted by a number of scholars until modern archaeological excavations and advanced studies proved the Islamic origin of such structures. The reservoirs have two basins, one used for decantation, one as a reserve, and at times a third one for drawing water out of it. Other than their impressive numbers, over two hundred and fifty in the region, such reservoirs also offer a great attraction in their form and structure.

Dams and related engineering works in Muslim India

The contribution of Muslim India (which at the time included modern day Pakistan and Bangladesh) to civilisation and technology is hardly known. Most of the focus has been placed on Iraq and al Andalus, and other places such as Syria and Egypt to some extent. We hardly, if at all, find any reference to the Muslim role in India except the Moghul Dynasty between the 16th and 18th centuries. It is as if the rest of Muslim history in India was a barren period, devoid of any accomplishment of worth. Once more this is primarily the result of Muslim (with some exceptions such as S.M. Ikram), lack of scholarly vigour in bringing to knowledge what constituted one of the great pages of Islamic civilization, that is the period of between the 12th and 14th century. So many accomplishments were made there during the so-called Turkish dynasties or the Delhi Sultanate. It is not the scope of this article to dwell on this subject, focusing instead on hydraulic engineering, dam construction in particular. The reason for this focus on this matter here is not only to cover a huge gap in knowledge of the subject, but also to show that dam construction in India and related technology were perhaps the most sophisticated of the whole Muslim world, and some of the most sophisticated in human civilization. In this respect, the works by the scholar, Antony Welch, are of the highest standards, Welch focusing on Tughluq works in the field, showing not only how the Tughluqs excelled at the construction of such dams, but also their far reaching thinking in completely transforming the landscape for the better, including their acute awareness of, and love for, a world of greenery that could be achieved through engineering works of, at times, quite gigantic scale.

The Tughluq Dynasty owes its origins to Ghiat Eddin Tughluq, who became Sultan of Delhi in September 1320; he was the son of a Turkish slave of Balban (a former ruler) and a Jat woman.[51] This Dynasty lasted for nearly a century until it was terminated by Timur the Lame who devastated India in 1398, and hence ended its existence. During the period of Tughluq ascendancy, many dams and reservoirs were completed as seen to some extent already. The elaborate system of dams Ghiat al Din built was integral to Tughluqabad's defenses: the dams doubled as walls, while the lake they contained made access from the level land on the south side di