8.1. The Ottoman Period (ca 16th Century–1923)
As indicated before, during the early Islamic period irrigation was further developed and up-scaled to large schemes fed by long water conveyance canals. This was done by the Abbasid dynasty, which was headquartered in Baghdad (762–1258 AD) [12
]. A major expansion of the qanat technology to North Africa, Cyprus, and Sicily also took place during this period.
Afterwards, Turks founded the Ottoman Empire in 1299 near present-day Bursa. The Empire expanded its territory, eventually covering a large part of Europe, the Middle East and North Africa at the end of the 16th century. The Ottomans constructed important engineering works in that part of the world, and numerous bridges and irrigation systems, including dams and canals, can be found even today in Algeria, Syria, Anatolia, and the former Yugoslavia. The particular techniques Ottomans used to build those engineering structures are not known, unfortunately, as they did not report or publish their knowledge so that one could be aware of solutions used for solving different kinds of problems. The early Ottoman dams were used to store water for domestic purposes, and special devices were used for delivering water to users [132
The Sultan Mehmed II (1451–1481) commanded that urgent repairs be made to the existing water systems. During his reign, a water department was established, underscoring the relevance of water supply to the Ottomans, as it was for earlier civilizations. During the reign of Mehmet II’s son Sultan Bayezid II (1481–1512) the Bayezid waterway was built and during that of Bayezid II’s son Selim I (1512–1520), various and diverse waterworks were constructed. Aqueducts in the form of arched bridges had been used since Roman times to convey water across valleys and streams, dividing two areas of high grounds so that water did not lose head. During the reign of Süleyman the Magnificent (1520–1566), the former Roman water system, which conveyed water from the Belgrade Forest to İstanbul, was rebuilt with additions and extensions by Mimar Sinan and became known as the Kırkçeşme water system. Preliminary solutions for the water demand problems of İstanbul were handled with the construction of 40 fountains in Fatih Sultan Mehmed (also known as Mehmed the Conqueror) era. This duty was given to Mimar Sinan in the era of Sultan Süleyman. In this period, new water aqueducts were constructed, while repairing works were performed for the existing ones [133
]. In the period of Sultan Süleyman, not only numerous fountains for each district of Istanbul were constructed, but also many waterways were either constructed or repaired in the Medina and Kudus provinces. This indicates how the Ottomans effectively associated the importance of urbanization with water management [133
]. Most of the water conveyance structures built in Ottoman times are still in use today [135
Irrigation was actively performed in the Fertile Crescent (Mesopotamia, Egypt, Jordan, etc.) and other adjacent regions during the Ottoman period. Ottomans developed irrigated agriculture in river basins’ areas such as Danube, Nile, Euphrates, Tigris, Sakarya, Red, Yeşilırmak, Çoruh, Seyhan and Ceyhan, which are next to the sea in three continents.
One of the important irrigation projects in Anatolia was constructed during the Ottoman period. There were no large water structures except for the Konia Plain Irrigation (Figure 18
) in the Ottoman period [136
], and the last Sultan, Abdul Hamid (1876–1909), instigated this important irrigation project. The land to be irrigated begins at Konya and extends southeasterly, east, and west of the railway for a distance of 50–60 km, covering an area of some 500 km2
. This plain lies from 1000 to 1200 m above sea level. The rivers Beysehir and Carsamba convey water from Lake Beysehir to the Konia plain (in the present-day Turkey), where it is delivered into a system of secondary canals through three main supply canals, and then into tertiary canals. By cutting the banks of the last canals, farmers delivered water to these parts of their land for irrigation, and afterwards water could flow off into drains. A considerable amount of water was lost by evaporation, and the rest reached the main drains, which discharged onto low-lying grounds to the northeast and east of the plain [137
During the Ottoman domination, irrigation projects developed in some areas of the present day Turkey and Egypt, such as Konya and El-Fayyum. The Fayyum lies in a large natural depression in Egypt’s western desert, known as the Libyan Desert [138
] (Figure 19
), and irrigation provides a particularly good lens through which the history of Ottoman Fayyum becomes visible. Irrigation structures also allow understanding the region’s relationship to the rest of the Ottoman Empire, because it was a local process, and differed according to each particular village environment, canal, sluice gate, and embankment. Water had to be managed and controlled by individuals on the ground with in-depth knowledge and experience of the local environments. At the same time, irrigation was a process of wide concern [139
El-Fayyum is separated from the Nile Valley to the east by a high ridge of loose stones and soil. The area of El-Fayyum is roughly 1733 km2
, with nearly all of it being suitable for farming and crop production (Figure 20
). This ridge is pierced at only one point by a natural opening, and through this inlet a canal conveys all of its water (except scant amounts from rain) to El-Fayyum for irrigation and other purposes. This extremely important waterway is known as Bahr Yusuf and branches off from the Nile at Beni Suef. The canal leaves the Nile Valley at an area known as al-Lahun and enters El-Fayyum later, at a point known as al-Hawara. The two most important irrigation features on Bahr Yusuf were the regulating dike of al-Lahun and the seawall-like dam of al-Gharaq [139
]. The dike of al-Lahun was built at the narrow gap that allowed Bahr Yusuf enter into El-Fayyum, and thus was crucial for regulating the canal flow and the amount of water entering the region. The dam of al-Gharaq was located farther along the canal and was much larger in surface area than the dike of al-Lahun. Ottoman information sources from the period describe it as a huge dam of impressive stature that had been in existence since ancient times [139
Thanks to the new/expanded/improved irrigation systems and use of modern agricultural tools, the variety of crops increased during the 19th century [141
]. These systems also improved the socio-economic situation of the country.
8.2. Irrigation Evolution in Present Times (1800 onward)
Although farmland irrigation has been practiced for millennia to increase and secure food supply for an exponentially growing humanity, a vast expansion in irrigated land mainly took place during the 19th and 20th centuries, with irrigated agriculture becoming the principal water consumer in many countries. Some historians referred to the large development of irrigation in these two centuries as the true catalyst for the interaction of engineering, organizational, political and entrepreneurial skills and activities that contributed to food security and produced increasingly wealthier living conditions [142
In terms of worldwide figures, it was estimated that around 1800 the extent of irrigated land was about 8 million hm2
, and it reached 47 million hm2
around 1900. The four countries with the largest irrigated areas in 1900 were India, China, the USA and Pakistan, respectively [145
During the 20th century the extent of areas equipped for irrigation doubled by 1945 and doubled again by 1980 [146
]. The area equipped for irrigation between 1900 and 2000 at global level, in stacked order for the four major irrigation countries is shown in Figure 21
and Figure 22
; whereas the information about growth in irrigated areas by decades from 1950 to 1990 is presented in Table 1
as reported by [147
However, in some regions such as sub-Saharan Africa, irrigation expansion and advances were limited with respect to the available land and water resources. In this region, many irrigation developments were attempted in the past, and several irrigation projects failed because of a combination of high investment costs, poor planning and lack of maintenance. As a result, until very recently, sub-Saharan Africa continues to have untapped water resources and a large potential for irrigation development [148
], although there are various constraints to consider [149
The UN Food and Agriculture Organization (FAO) [150
] reported that the global area equipped for irrigation worldwide increased from 184 million hm2
in 1970 to 258 million hm2
in 1990 and finally reached 324 million hm2
in 2012. In the 1980s, the rate of increase in irrigated areas slowed considerably [152
]. Siebert and Doll [154
] attributed this slower expansion of irrigated areas after 1980 to the fact that many large-scale irrigation schemes in Eastern Europe and the former Soviet Union (regions characterized at that time by the transition from central planning economies to market economies) went out of operation because water infrastructures were not sufficiently flexible to meet the requirements of new market-oriented private commercial farming models. In other irrigated areas, the lack of adequate drainage infrastructures caused water-logging and salinity problems that impaired the productivity of irrigation schemes and created urgent needs for costly rehabilitation. At the same time, limited water resources, increasing competition for water by other sectors, and environmental regulations strongly restrained irrigation expansion in many arid areas. For the period after 2000, the World Water Resources Report [146
] indicates that in a number of developing and developed countries the extent of irrigated land has stabilized or even diminished due to the very high cost of irrigation networks, salinity-induced problems, depletion of water-supply sources, and rising public concerns on environmental protection.
The rapid irrigation expansion during the 19th and 20th centuries can be related to several factors. Sojka et al. [155
] pointed out that, while the main physical relationships related to water flows, i.e., among mass, energy and turbulence, were well investigated and mastered at remarkably high levels of proficiency in the ancient cultures, the understanding of physical and chemical soil–water interactions was somehow inadequate until the beginning of 19th century. In ancient irrigation development, the combination of soils, climate, water quantity and quality knowledge were more established at some locations than others. At some schemes, in fact, irrigation has continued to the present day without skilled or sophisticated management, either because seasonal rains provided sufficient leaching, or because soils were sufficiently permeable and well drained to prevent water-logging and salinity accumulation. In other cases, irrigation water had favorable chemical composition that avoided the occurrence of land-impairing situations. In other areas, increased soil salinity and/or sodicity, as well as raised water tables, have either limited the functionality of irrigation schemes or adversely affected land productivity. The success or failure of irrigation schemes, as well as their productivity and sustainability, became tightly dependent on skilled design and management, as populations grew and the need for increased food supplies encouraged irrigation development on more marginal areas with less productive soils, poorer drainage, and greater natural or induced salinity and sodicity problems. In turn, these aspects required the knowledgeable application and adaptation of scientific principles that started being developed and consolidated from the mid-19th century onwards.
Then, a conjunction of progress and learning in several scientific disciplines, including soil science, hydrogeology, chemistry, physical-chemistry, physics, and plant physiology occurred and contributed to foster irrigation development. These disciplines were adapted, blended and applied in the sub-disciplines of soil chemistry, soil physics, soil biology, crop physiology and agronomy, whose fundamentals proved being essential knowledge for irrigation design, construction and operation, as well as for their economic, social, and environmentally sustainable management.
Similar patterns occurred both in the old and new continents. For instance, from the turn of 19th century onwards, Southern Europe experienced a vigorous upturn and expansion of irrigation, which was mainly fostered by an upcoming industrial economy, high demographic pressure and adapting agriculture, as well as by the availability of affordable energy. Leibundgut and Kohn [156
] report that specific new laws for field irrigation and grassland (meadow) cultivation frequently encouraged the modernization of existing and the implementation of new irrigation systems, as well as the foundation of large irrigation cooperatives/associations. In comparison to more traditional irrigation schemes developed in historical periods (e.g., middle ages), the newly developed irrigated areas of 19th and 20th centuries were usually large-scale upstream-controlled systems laid out by engineers. Such systems were characterized by gravity-fed designs, whose implementations required labor- and capital-intensive works to reshape and modify valley-floor plains, as opposed to earlier projects largely adapted to natural landscapes and land contours. Official regional statistics and land register records begun to be available from the 19th century onwards, which provide quantitative information about the overall irrigated area [157
Leibundgut and Kohn [156
] indicate that, in terms of spatial extension and geographical distribution, irrigation in Europe probably reached its peak around the turn of the 20th century. Modern irrigation developments were launched in Spain soon after the end of the Civil War in 1939, based on a national water development plan designed by the government prior to the war. Such developments, originally established to settle small farmers, constituted the foundation of a vibrant irrigated agriculture today, which expanded to 3.7 million hm2
and is the largest irrigated area in the European Union.
In the USA, modern irrigation developments are reported to have probably begun with the Mormon settlement of the Utah Great Salt Lake Basin in 1847, followed by the cultivation of nearly 2.5 million irrigated hm2
across the inter-mountain western USA by 1900. America’s Mormon pioneers chose to settle in a remote salt-impaired desert habitat, and thus were forced to use trial and error and application of all available new knowledge to reclaim lands from the desert and practice sustainable irrigated crop husbandry, as described by [155
]. According to Reisner [158
], the Mormon pioneers were very successful in their efforts to the point that the practices they followed in reclaiming, managing, and irrigating arid and salt-affected lands provided the main guiding principles for irrigation developments that occurred throughout the western USA before and under the Reclamation Act since 1902. The passage of the Desert Land Act of 1877 and the Carey Act of 1894 spurred irrigation developments further in the western USA, providing the legal framework to land acquisition for settlement and support of governmental infrastructure for development.
Bucks et al. [145
] refer that the lessons learned in the settling of the American West from 1847 onward provided many practical modern principles and methodological approaches of irrigation systems design and operation, and irrigated soil management until the end of World War II, when the total U.S. irrigated area had grown to 7.5 million hm2
. Concurrently, the innovations and designs, developed in this context, had worldwide importance. Irrigated agriculture remained an engine of the western U.S. development until the 1970s [159
After World War II, another wave of rapid irrigation expansion occurred worldwide, owing to a fast population growth and to the increasing demand for safe food supplies. For the largest part, this population expansion resulted from the progresses obtained in public health and the successful control of malaria and other insect-borne diseases in many regions, which in turn significantly increased life expectancies. In addition, the first and the second World Wars spurred advances in technology that were applied to many production areas, including agriculture. Among those, electrical, steam and internal combustion power sources became available to lift and pressurize water. New pump designs and the patenting of sprinkler delivery systems came together in a few decades between and immediately following the wars and revolutionized the ability to withdraw, convey and deliver water. Before it, with the invention of internal combustion engines and shallow well pumps, irrigation largely expanded beyond riparian and gravity flow service areas.
Available records show that irrigation gained even more prominence under the Green Revolution of the second half of the 20th century. The Green Revolution was initiated to address the issue of malnutrition in the developing world, and combined plant genetic improvements with agronomy (greater use of fertilizers, pesticides, and irrigation) to increase crop yields. In several parts of the world, the availability and use of irrigation water represented a key factor for the positive results accomplished by the Green Revolution, such as in the Indian sub-continent. The UN-FAO [160
] estimated that in 2003 the total world-wide irrigated area was 277 million hm2
, corresponding to about 18% of the total cultivated lands (Table 2
), with the largest proportion of this area (70%) being in Asia, as shown in Figure 23
The introduction of advanced western hydraulic engineering technologies in China and other Asian countries between the end of the 19th century and the beginning of the 21st century gradually encouraged the reconstruction and expansion of traditional irrigation districts and the construction of modern irrigation projects. A group of intellectuals appeared that had been exposed to both western education and oriental cultural influence, who became the promoters of hydraulic reforms during this period. Among all these practices, eight irrigation canals in the Central Shaanxi Plain, including Jinghui and Luohui canal and others, were built by Li Yizhi, who was the major representative of these promoters. Since the founding of the People’s Republic of China in 1949, irrigation in China has been developing in full scale, improving significantly the ability to resist drought and flood disasters in agriculture.
From the 1970s onwards, increasing development costs, reducing governmental support and financing, rising demand for municipal and industrial water supplies, diminishing sources of fresh water supply, and a growing concern for the environment have forced water managers and planners to begin rethinking traditional approaches to agricultural water management [161
]. Most of projects developed around the world during the 1980s were fueled by financial resources from national or international agencies and were largely expected to result in national self-sufficiency in producing staple foods. As a result, these irrigation schemes tended to be centrally organized and operated by state authorities (government-based irrigation systems), which often also directed input supply and cropping patterns. Several of these projects failed to meet expectations, as farmers had very little opportunities to get involved in management and decision-making, and felt no incentive and commitment to proper water use, system maintenance, forced crop selection, and high-productivity. A second generation of agency-funded projects encouraged farmers assuming a sense or responsible ownership of irrigation schemes as major key for success. This objective was pursued through the self-organization of water users, who could understand the economic potential of farmer-managed irrigation systems and thus assume full responsibility. Funding agencies therefore fueled irrigation expansion through development of farmers-managed irrigation schemes and through irrigation management transfer (IMT) programs, i.e., transferring responsibility, decision-making and financing of irrigation systems from public sector to water users’ organizations. In this context, one of the main funding agencies’ goal was to ensure that irrigation systems would provide adequate, flexible and more dynamic water delivery services to meet the needs of market-oriented agriculture.