History July 10, 2019 at 01:09 pm

How the Berbers of North Africa used gravity to transport water under the desert

Nii Ashaley Asé Ashiley | Contributor

Nii Ashaley Asé Ashiley July 10, 2019 at 01:09 pm

July 10, 2019 at 01:09 pm | History

Image source: youtube.com

Desert oases have remained one of the wonders that grace the planet Earth’s surface, unique rest ‘islands’ in the midst of a sweltering desert atmosphere specially made for the weary traveller whose mission it is to create for himself his fair share of an oasis in a morally deserted world. The question surrounding the existence of oases, however, lingers on in the minds of those curious thinkers whose desire it is to know how they came about.

The Berbers of North Afrika are claimed by scholars of human history to be descendants of a Neolithic Capsian group whose spiritual faith and cultural conventions were channelled into the Islamic religion upon Arab contact. They were a group of people organized in accordance with tribal mode with a male head. Farming and pastoral labours were some of the diversified economic activities that fed their growth and development.

Given; their dependence on an agro-based culture, the rapid deforestation of their regions of habitat and the scarcity of rainfall characteristic of the North African desert areas, the First Berbers as they are known engineered a system of water storage and transportation under the desert sands to feed their villages, farms and the subsequent creation of some oases in the desert regions.

Khettara is what this ingenious irrigation system was named. Some scholars have submitted that this system of water storage and transportation using gravity and the land gradient was prevalent throughout communities outside of Africa that also subsisted on farming in a ‘water-locked’ climate.

A brief documentary on Khettara.
Video credit: YouTube.

The whole mechanism of Khettara usually consisted of series of vertical shafts/tunnels dug into the desert ground to a certain degree in order to meet an underlying horizontal tunnel that can stretch to about 48 kilometres in length. The horizontal tunnels are dug close to an underground water table to allow for the collection of water from the Earth and water condensed from above. The vertical shafts/tunnels are dug to meet the underlying horizontal tunnel at about 10 meters apart from each other. These tunnels are engineered to serve the purposes of ventilation, maintenance of the underlying horizontal tunnel beneath the desert and condensation of water from the atmosphere above.

This underground water tunnel was constructed by skilled manual labour who sloped its course from a higher land gradient towards a relatively lower land gradient; that is the catchment area for the water was dug in the highland regions and the connecting tunnel carefully sloped into the village or farm which usually lay in the lowland areas. This technique enabled the First Berbers to make use of gravity in the transportation of water from an area of high water density to an area of low water density.

Image result for Khettara
A vertical cross-section of the Khettara technique.
Image source: en.ird.fr

Fitzwilliam-Hall (2009) documented an estimated 1600 Khettaras in Morocco out of which about 350 were still in good working condition. He goes on to submit that without the engineering of Khettaras by the First Berbers, the date palm oases of southern and central Morocco may not have been in existence.


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