With such convincing proofs that Sahara had had water in the past, the researchers’ desire to know the reasons of climatic changes in this region is only natural. The attempt to find similarities between the Saharan climate and that of India is however fully unconvincing. In India there is a cyclic process determined by winds (monsoon) that carry the clouds from the northern Indian Ocean to the slopes of Himalaya Mt. where they discharge their precipitation, and then the waters flow down into India’s great rivers and after that- back into the ocean. The particular landforms in Africa and the distance between Sahara and the ocean exclude any resemblance between the climates of these two regions. The cause of climatic changes in Sahara must be searched elsewhere!
Getting water by pumping for agriculture from aquifer layers is not a proper solution, because their level goes deeper and deeper or even worse, as it has recently happened in Algeria. Extracting water from the first aquifer level, then from the second one and after that from the third, such water used at ground level has turned into waste water to a great extent (mixed with chemical fertilisers or with industrial pollutants, domestic waters etc.) but it was not treated and was disposed of into the desert at about 14,000 m3/day. Such water seeped into the first aquifer layer, but could not pass through to the deeper ones because of some intermediate impervious clay beds, so it raised the level of the first water-bearing layer and resulted into large-scale damage to the palm tree cultures practiced into unfriendly very wet soils.
The situation of the countries bordering the Mediterranean Sea, namely Algeria, Tunis and Libya is not better, as they also depend on water obtained from deep aquifer layers. In this respect the underground water reserves that are common to these countries acquire a strategic significance for their economic development, a little like the situation of oil deposits, since to extract and use such water they had to conclude strict trilateral agreements. There were 8,800 wells in the 1980s in the fore-mentioned countries, extracting huge water amounts for agriculture, while precipitation water represented only 0.0017% of the consumed quantity. Consequently, the current level of water-bearing beds is about 30 m deep, but it continues to drop. When such level reaches to approx. 400 m deep, the pumping system will no longer be economical and agricultural crops will have to be watered from other sources. At present various international organisations are striving to impose a balanced utilisation of underground water reserves, but in case of an acute water shortage if successive droughty years occur conflicts might arise that are difficult to control. From the above it clearly follows that in circum-Saharan states of northern Africa water drawn from underground aquifer layers is not a long term solution and another water source has to be found, but which one?
Studying the physical map of northern Africa, one can notice that Niger River, gathering its waters from the northern slopes of Mt. Fouta Djallon directs its course towards central Sahara; however a little downstream of Timbuktu it turns 90o southwards and the good running water of Niger River provided free of charge by nature is lost without a rational utilisation, flowing into the Atlantic Ocean. One can also see that the inner ring of mountains in Central Sahara enclosing Lake Chad within has got a single breaking point towards the west. The coincidence of such physical details at present cannot be overlooked, as it allows explaining the change of Niger River’s course by major geological events in the area in past millennia.
When it has detached itself from the great pre-Cambrian land, with the future African block at its centre and many territories as well whose movement in time has led to the current layout of continents, Africa underwent multiple changes, namely outflows of volcanic rocks and many deep cracks in its earth crust (Fig. 17). One of these faults oriented N-S is perpendicular to the initial course of Niger River and its waters, captured along such fault, change their flowing direction southwards; similar situations are found along other water courses as well, such as Zambezi River, at Niagara Falls, Nile River etc. (Fig. 18). The map of Africa (see Fig. 3) also shows a river bed that is currently dry (oued), outlining the initial course of Niger River that connects to central Sahara. Joining such indications to the dating of rupestral drawings, one can reconstitute that Niger River has had a continuous W-E course about 10,000-8,000 years ago, taking its waters to Lake Chad- a relict of this river which maintains a high level of aquifer layers in the region and thus allows pastures, fauna and local human communities to be found there.
Researchers arrived at the conclusion that around 8,000 years ago Sahara’s vegetation was satisfactory for regional fauna, providing rich game to the locals (period of ‘boubal’, around 7,000 BC) and harvesting of savage grains (period of ‘round heads’, around 6,000 BC). Strong movements of the African crust occurred at that time, generating the fault that deviated the course of Niger River. Saharan vegetation began missing water, and the initial savannah, once household herbivores (cattle, sheep, goat) were domesticated, changed into vast grassy lands good for grazing (‘bovid or grazing’ period, about 5,000 BC).
During this era around 3,500 BC a great migration of local population took place because of the difficult survival conditions in Sahara. Moving south and being blocked by exuberant equatorial forests, the only migrating options remained to settle north on the shores of the Mediterranean Sea and along the course of Nile River. This is the only possible explanation for the great mix of people in Egypt of various nationalities, habits and religions who finally learned to live together peacefully only because of their interest to jointly manage Nile’s waters for agriculture and navigation. It is still in this era that the first dynasties of Egyptian pharaohs came into being that, in view of unifying religious creeds, also introduced the god with ram head (symbol of Amon), which was finally accepted by the people however keeping their local deities as well. The horse introduced by Hyksos in Egypt and later on in Sahara (period of the ‘horse’, after 1250 BC) could be used for some time towards the beginning of our era when, water running scarce and pastures shrinking, it was replaced with the dromedary (period of the ‘camel’, towards 100 BC), much more adapted to the new circumstances within the region.
This is actually the cause of Saharan desertification - the transversal fault across the course of Niger River, and the measures proposed in this study lead just to ‘correcting’ nature and restoring the initial configuration.
