The water crisis we are experiencing, with the first rationing and ordinances limiting use for non-priority needs, is a stark reminder of how water is an increasingly fragile and precious resource.

The convenience of taps always at our disposal has led us to take such a fundamental resource for granted and inexhaustible, without considering the implications of waste and careless daily behaviour.

Today, when an overall rethinking of our relationship with the environment and water is necessary, involving both strategic infrastructures and the lifestyles of every individual, it may be useful to take a close look at what is happening in contexts where water has always been the most important resource to protect and every drop wasted can make a difference.

A glaring example are the oasis cities that dot the northern shore of the Sahara and are the stops on some of the main caravan routes; places where man, vegetation and water have coexisted for centuries in a fragile but wise balance.

Collect, distribute, preserve

The question of the supply and capillary distribution of water resources is obviously at the basis of survival in extreme contexts such as the Saharan region. No drop can be lost and so, over the centuries, extraordinary and ingenious systems have been developed to ensure a constant supply of water for cultivation and survival without deteriorating underground reserves.

The most widespread system is undoubtedly that of the underground draining tunnels, called Khettara, Foggara or Qanat, depending on the region: these are a series of wells dug a few dozen metres apart from each other and connected by an underground tunnel whose task is to intercept the groundwater, usually at the foot of a hill, and with a very slight slope to transport it to the oasis; a route that in some cases can exceed fifteen kilometres.

The water then remains underground, protected from evaporation, sand and possible contamination, before reaching the surface at the cultivated gardens. Here, the irrigation conduit passes through a special comb-shaped stone that has the task of separating it evenly (equal distribution between households is also fundamental to the social balance of the Oasis) into small open channels called Seguia, which feed small basins spread among the crops or even more capillary networks.

Technologies as ingenious as simple that tell of an ancient wisdom based on maintaining a perfect balance between the availability of resources and their use.

Climate- and resource-conscious architecture

Even the structure of cities in areas with extreme climates and low rainfall is entirely designed to increase indoor comfort and safeguard resources. Every element, from the urban form to the seemingly insignificant construction detail, contributes to the mission of creating cool and airy environments.

Cities in these contexts are therefore extremely compact, with multi-storey houses leaning against each other and narrow alleys, barely enough for people or beasts of burden to pass through. This arrangement allows the buildings to shade each other while preventing the walls from being directly hit by the sun's rays, at the same time the orientation of the main streets is often designed with the wind in mind.

Ventilation is also a fundamental element in interior spaces that are often characterised by narrow windows due to massive walls and the need to limit the passage of heat. Consequently, traditional architecture in various desert areas has developed the so-called "wind towers": simple openings in the roof or, sometimes, tall decorated chimneys that through vertical channels bring air to the ground floor; here, thanks to the presence of a small cistern or a basin filled with water, the air cools, creating a convective motion that guarantees the natural ventilation of the rooms.

The labyrinthine and cramped street level is contrasted by the upper part of the city, where the hundreds of terraces covering each building seem to form an enormous multi-level square that comes alive when the sun goes down. These spaces are used for drying grain, cooking and in the hot months also for sleeping, while the slight slope of the floor during the rare rains allows rainwater to be channelled into underground cisterns.

The role of greenery

The cities are built adjacent to cultivated plots, taking care not to subtract precious soil for agriculture and benefiting from the presence of greenery: the shade of the palm trees and the small streams of running water create a microclimate completely different from the relentless aridity of the desert.

The ecosystem of many oases is based on the coexistence of various crops, one supporting the other. Date palms in particular are the building blocks of biodiversity: thanks to their height and thick foliage, they provide shade to the ground below during the hottest hours. This makes it possible to cultivate some fruit trees and lower down vegetables, cereals or fodder that would otherwise be quickly burnt by the sun.

Even once dead, the palms do not lose their protective role: the branches are in fact used to make afregs: protective dunes that surround crops and buildings to protect them from silting up.

Rediscovering the value of balance

Water, agriculture, the built environment, all pieces of a delicate mosaic that mutually contribute to the survival of a unique ecosystem. It is no coincidence that oases abandoned due to migration tend to desertify and gradually disappear altogether.

In addition to the rediscovery of technical aspects and traditions that are always useful, the main lessons that these fragile contexts can teach us concern the urgent need to pursue the maintenance of an environmental balance that does not further deteriorate the available resources.

Today, when every place suddenly seems to become fragile, it is more necessary than ever to rediscover the value of balance through approaches that may be far removed from our contexts but which demonstrate the importance of preserving and caring.

See Siccità, lezioni dalle oasi del Sahara

Photo. The interior of a typical house in Mozab, Algeria, built with poor but heat-insulating materials