**2.1 Water sources in Africa and water shortages: what a contrast**

Water scarcity is when water demand exceeds water availability and refers to lack of sufficient water, or lack of access to safe water supplies [3]. There are four dimensions of water scarcity: (i) the first-order water scarcity describes limited available water resources for both current and future needs; (ii) the second-order scarcity highlights lack of financial resources needed to make improved water resources available to the people; (iii) the third-order water scarcity results from the failure of institutional setup or inadequate infrastructure; and (iv) the fourth-order water scarcity is induced by social disparity with the less privileged people experiencing difficulty to have access to safe and sufficient water [6]. These four forms of water scarcity exist in different areas of SSA.

The water crisis is a global issue worldwide. Even though 80% of the Earth's surface is covered by water, fresh water supply has increasingly become a crucial global problem [3]. This global problem received the attention of the United Nations to adopt the Sustainable Development Goal (SDG) target 6 in 2015 [7]. Despite the relative success of the Millennium Development Goals (MDGs) water target in different parts of the world, half of the people who drink water from unsafe sources live in Africa. Specifically, in SSA, 319 million people still live without improved drinking water sources and only 27% of SSA's population has access to basic sanitation [5]. Apparently, Africa seems to be endowed with abundant water resources. The relationship between the abundance of water sources in Africa in general and in sub-Sahara in particular and water scarcity is contrasting. This is why water shortages are experienced even in countries where freshwater is in abundance. Therefore, water scarcity does not mean the absence of water in the natural environment. Actual Africa's hydro potential is irrefutably huge; the continent disposes of 17 major rivers, close to a hundred lakes, coupled with sizeable groundwaters [8]. In addition, Africa has abundant rainfall and relatively low levels of withdrawals of water especially for use in community water supply and agriculture [8]. Inspite of this potential, water sources are unevenly distributed between different zones of the continent [8] with SSA having the greatest part of the water blessing. While the Central Region is endowed with 48% of the continent's water, the Gulf of Guinea claims 24% of the water potential of the continent. At the country level, the Democratic Republic of Congo alone holds 23% of African water [8]. Additionally, natural factors such as rainfall deficit and drought

cause significant reductions in the overall availability of water due to the geographical location of several African countries [9]; the present threat on the disappearance of Lake Chad is symptomatic of the growing scarcity of water in SSA. The Lake Chad basin has drastically been reduced by 90% in its surface area [9].
