A historical overview of the main methods of safeguarding water resources

Maurizio Angeloni - November 25, 2024

Introduction

The climate changes we have witnessed during the last few decades have led to dramatic water crises with disastrous consequences especially in countries of the global South and are increasingly affecting more developed countries as well. While, however, countries with more prosperous economies are managing, albeit with difficulty and with massive increases in public spending, to cope with these crises in order to somehow preserve the environment, agriculture, industry, energy production and anything else closely related to water, in the poor regions of the world stemming the consequences of water scarcity is a titanic undertaking. In such areas, in fact, the lack of water puts at risk not only the already fragile economies, but the very lives of entire populations, giving rise to dramatic humanitarian crises, threatening the peace and stability of nations and entire geographical areas, and paving the way for mass migrations with serious social and economic problems for the countries of destination. The relevance, economic on the one hand and geopolitical/humanitarian on the other, of this issue confronts the international community with the need to identify effective measures to prevent and combat water shortages in the poorest countries, also with a view to the sustainability of the measures adopted. Indeed, while for Western nations with economic resources, the answer to the water crisis may be sophisticated technology, its transfer to poor regions of the world is not always possible. On the other hand, this modern technological equipment is generally expensive and thus, unless it is provided in the form of donations, the fragile economies of many states are not always able to bear the burden of the debts incurred to acquire it. In addition to this, the maintenance of these high-tech systems also requires high costs in terms of specialized human resources and components, limiting not only their sustainability but their very applicability in some settings. In these contexts, it is therefore necessary to look at other solutions for water asset management, and traditional methods may be one of the possible alternatives.

The most historically effective water conservation techniques

Traditional methods of water management actually originated with mankind and the need to secure the constant need for water essential to his survival. By observing the plant world and imitating animals, mankind, since the time of his appearance on earth, has devised increasingly ingenious methods to be able to have a reserve of water essential not only for physiological needs but also for other activities. It is therefore not surprising that already the earliest hominids, perhaps taking an example from some animal species that dug water stores in the ground, made stores for rainwater or atmospheric water that was produced by condensation in caves. Artifacts that the generations of Homo Sapiens that followed made increasingly complex and appropriate for the development of social life and activities such as agriculture and building. Scattered around the world there is still evidence of man's actions today, proving that as early as the Paleolithic period “Hunter-Gatherers” collected drinking water in caves by exploiting the phenomenon of dripping and natural percolation.

Natural percolation water collection cisterns (Paleolithic)

Since then, humans have increasingly experimented with methods to collect, channel, store and use/reuse water or even to control its flow. Thus, techniques such as cultivated terraces that increased the soil's capacity to retain water and reduced its erosion; cisterns in which water was stored and then used for agricultural purposes but also for domestic purposes; Qanats, underground tunnels that conveyed water from mountainous areas to the plains; and aqueducts, works, the latter of which already belong to the great creations of hydraulic societies that developed in Egypt, India, Mesopotamia, Iran, China, and in 'Ancient Rome.

Qanat in the Sahara Desert

Roman Aqueduct

But among the water management systems adopted by our ancestors were also agricultural practices such as crop rotation, which maintained soil fertility with less water consumption, and flood and drip irrigation systems. The great civilizations of the past also owe studies on water production methods, such as the conception of urban architecture that exploited the phenomena of water condensation atmospheric already experienced by early humans in caves, such as aerial wells and underground cisterns.

Basilica Cistern in Istanbul

Beyond that, our ancestors had learned about and used natural ecosystems, such as desert oases. These form naturally when water flowing underground comes out at or near the surface. Stormwater that arrives on the ground during rare rainfalls seeps into it until it reaches an impermeable layer where it accumulates to form an aquifer. They then continue their path underground even for hundreds of kilometers following depressions in the ground until they encounter a shallower layer of impermeable soil that causes a spring to form. The same result occurs if the underground water table crosses another layer of impermeable soil perpendicular to it that prevents the water from flowing horizontally and forces it to rise to the surface. A similar phenomenon occurs if water that has penetrated underground is found to flow between two impermeable soil layers until it finds an outlet to the surface, basically a kind of natural artesian well. In each of these cases, once it escapes to the surface, the water forms basins around which vegetation develops and eventually a real ecosystem that is maintained by date palms, which grow precisely in arid areas with high temperatures. In fact, these plants play a key role by providing shade and microclimate with their large foliage and, by preventing excessive water evaporation, they allow other plant species to grow. In addition, their fruits are a source of nourishment for humans and animals; the large stems protect against desert wind and prevent soil erosion; and last but not least, the decomposition of fallen leaves leads to the formation of humus that serves as fertilizer for the plants themselves.

A balanced ecosystem, in short, which humans have preserved for centuries and which demonstrates, along with other traditional methods, that our ancestors knew the water cycle but, above all, were aware of and respectful of the environment.

Knowing these and other traditional methods of water management can help us develop more sustainable solutions to water crises, operate where the use of advanced technologies is not yet within the reach of local economies, and address situations of severe emergency. Traditional techniques also can be supplemented with modern tools to make them more effective and more functional for the changing realities and conditions of human life. Today, oases can be artificially created by digging artesian wells in desert areas, and an ecosystem can be created by planting date palms and other plant species.

Ancient systems that took advantage of atmospheric water condensation phenomena can also be repurposed through the creation of relatively simple and inexpensive structures. As reported in some previous AB AQUA studies, one of these is the Warka Water tower, named after a large and robust plant widespread in Ethiopia where it has been experimented, and consists of bamboo and polyethylene fabric architecture that captures moisture from the air. Or, with more complex and relatively more expensive structures such as atmospheric water generators powered by renewable energy sources, which use refrigerants to condense moisture from the 'air and produce potable water.

Warka Water tower

Certainly, among the best known traditional methods adopted in our time, is drip irrigation, now widespread and used for decades worldwide in agriculture. The experience of our ancestors gives us pointers on how to make the best use of and enrich the water heritage also through sustainable urban architecture that allows the recovery and collection of rainwater. Following the example of cisterns used in the past, in fact, local governments could incentivize or even impose by law, or rather both, the construction in civilian dwellings or productive settlements of storage tanks in which water can be stored for a certain amount of time. After being filtered, the water could be fed back into the domestic system or industrial cycle for different uses.

There are many other traditional methods of water management that are not included in this discussion and that, together with those described, represent a heritage of cultures and traditions and, at the same time, a valuable legacy of knowledge. These still prove to be relevant today, and we should make use of them, perhaps enriching them with our increased expertise, not only in particular contexts of the world characterized by poverty and underdevelopment, but also in the more developed West, threatened by increasingly frequent economic crises and dramatic climatic emergencies.