What was the evolution of water technologies like
The history of water use and technologies to bring water to human societies is long, particularly in some of the world's most arid regions where human settled societies first began. Technologies of water also evolved as other technologies developed and social organization and states changed. While we often think of Roman aqueducts as a great marvel, which they were, other complex water technologies, just as complex, existed before.
The earliest water technologies are likely to have been simple ditches or cuts made to irrigate fields. In the Near East, irrigation likely began soon after agriculture began to be developed. Most likely these types of irrigation canals would be too small or small in scale to leave any major archaeological remains. Evidence of terrace agriculture from the Neolithic, however, suggests that water captured from higher ground was beginning to be transferred to lower areas, including possibly using canals to move water. In China, similar Neolithic evidence has been found, showing that early villages had sometimes a relatively complex network of canals near village fields, where even field systems have been partially preserved.
Wells would have been also constructed for early villages. In particular, many early villages were located on hills or higher ground, which allowed them to be better drained and avoid flooding in the wet seasons. However, this created the problem of easily accessing water. This led to the development of wells, as water underneath these hilly areas could be easily accessed.
Early Historical Societies
By the 4th and 3rd millennium BC, more complex societies developed with larger settlements. In particular in southern Mesopotamia (southern Iraq), where we see the first cities form. However, the region is very dry and depended heavily on two major rivers, the Tigris and Euphrates. Irrigation began to become more complex, with longer channels and managed by groups of people at different points, including controlling sluices that would release water to different areas. This development is similar to the Indus region along the Indian and Pakistani border, where the Indus river became important in dry regions as major cities developed. Similar types of canals to those of southern Mesopotamia seem to have developed, leading to also large cities by the 3rd millennium BC.
In Arabia, already new forms of water capturing technologies may have developed. This includes surface channels and dams to capture water from the highlands and bring the water down to lowland region. Some have suggested that already underground channels, called falaj/qanats, were already developed, but this is not universally accepted.
Iron and Irrigation Technology
Probably one of the most important developments to enable more advanced water technologies was the development and use of iron. In fact, the increasing sophistication of mathematics and engineering by the 1st millennium BC, along with iron technology, enabled the next major phase of development for irrigation technologies to occur. With the use of iron, rock could be excavated more easily. This facilitated the development of more sub-surface irrigation features, including tunnels and qanat systems, which were essentially tunnels with access holes that brought water from highland regions to lowland areas. These qanats also required a large amount of engineering, as channels had to be cut across mountains or difficult hilly areas, while channels were sometimes even cut from different areas and were met some place in the middle. Surface channels cut into mountain rock were now also developed, which allowed the capture of water from elevated regions. These technologies appear to have developed perhaps in Anatolia, Iran, or Arabia, although the origins are not completely clear. During the Iron Age (early 1st millennium BC), another important development occurred. That is, the development of aqueducts began to appear. In fact, the first aqueduct we know of developed in northern Iraq, just north of the city of Mosul. This aqueduct, part of a large canal system bringing water to the city of Nineveh, enabled water to be brought over different watersheds. In other words, it now allowed societies to build irrigation features that crossed natural elevation change that would have restricted where you could irrigate.
Irrigation and water technologies have been critical to human societies for millennia. The first great use of water technologies probably began soon after the development of settled societies. However, as societies became more complex, that is larger cities developed, and technologies, such as iron, and mathematics improved, we begin to see far more sophisticated use of water technologies. In fact, qanats and aqueducts, both invented probably by the Iron Age in the early 1st millennium BC, are still in use today, showing the durability of this technology. Some qanats and aquaducts used today, in fact, date to the Roman period.