The potential impacts of climate change on groundwater management in west Africa

Climate change is probably going to affect groundwater resources, in Sub-Saharan ccountries (SSA) in Africa either directly, by means of changing precipitation patterns, or indirectly through the combination of changing precipitation patterns with evolving land-use practices and water request. West Africa has, over the past few decades, experienced a sharp decline in rainfall and average annual flow of watercourses. A break in the rainfall pattern was observed around ۱۹۶۸-۱۹۷۲. ۱۹۷۰ is considered as the turning point after which the decline in average rainfall worsened from minus ۱۵% to minus ۳۰% depending on the zone. This situation led to the drifting of isohyets by about ۲۰۰ km to the south. A ۱°C increment in temperature could change overflow by ۱۰%, expecting that precipitation levels stay consistent. Any reduction in groundwater recharge will intensify the impact of sea-level rise in coastal aquifers. For various reasons and at various levels, West African countries are dependent on one another. Over the past few decades, this interdependence has not only generated tension, but has also led to a dialogue and cooperation process. Only one country (Burkina Faso) are below the international standard for water scarcity (۱,۷۰۰ m۳ of renewable fresh water per year per person); On the other hand, there are major problems in terms of availability at the desired time and place. According to the Global Water Partnership, the withdrawal level of renewable water resources in West Africa (excluding Cameroon and Chad) is currently at ۱۱ billion m۳ per year for an available ۱,۳۰۰ billion m۳, which is less than ۱%. Agriculture uses ۷۵% of these withdrawals, domestic consumption ۱۷%, and industry ۷%. Although it is by far the highest in proportion, agricultural use of water resources is low. Out of the ۷۵.۵ million hectares of arable land in West Africa, only ۱.۲% (۹۱۷,۰۰۰ ha) is developed for irrigation, and ۰.۸% (۶۳۵,۰۰۰ ha) is used effectively.

Keywords:

Groundwater management , Rainfall pattern , Sustainability , Water resources