Water Scarcity

The Basic food-water Link

The Water Stress Index (WSI) was originally developed by Falkenmark and Lindh (1974) as a warning system ahead of potential food shortages in relation to disruptions to water availability (Damkjaer and Taylor, 2017). The WSI defines water scarcity by the number of people that compete for sustenance from one single flow unit of water (106m3/year), or in simpler terms the “hydraulic density of population” (Damkjaer and Taylor, 2017). The WSI’s existence also informs us of the regional disparity in water availability, and thus introduces one of the foundational challenges facing water and food development in Africa historically.

Most of the inhabitants of Africa live in semi-arid areas that are prone to extreme seasonal variation in freshwater availability and pose the risk of large-scale water shortages, subsequent famine and the potential for the emigration of environmental refugees (Falkenmark, 1989). Drought proved rampant in 2019 particularly in Southern Africa and he Sahel regions, where rainfall in the 2018-19 rainy season was 50% lower than average in Namibia, Western South Africa and Botswana (WMO, 2019).  The World Health Organisation now predicts that by 2025 half the World’s population will inhabit water-stressed areas (WHO, 2015).

Africa is projected to be the continent worst impacted by the effects of climate change (Niang et al, 2014, cited in Nicholson, Funk and Fink, 2018) meaning the stresses on water provision and consequentially food availability cannot rely on sources of water that are subject to intense seasonal variation. It is therefore critical, that efforts to preserve Africa’s most reliable water source now become integrated into future management approaches.

Hope from Below

Groundwater is the most abundant source of fresh water on Earth and sustains both human activity and ecosystems (Velis et al., 2017).  For arid and semi-arid areas, groundwater acts as the only perennial supply of freshwater (Taylor et al., 2013). The use of groundwater for irrigation purposes also means an intrinsic link to human development and poverty eradication through food production (Velis et al., 2017). Not only this but actually have greater economic benefits than surface water per unit volume (Burke and Moench, 2000; cited in Velis et al., 2017).

Groundwater supplies 36% of the world’s freshwater supply, and 42% of which is used for irrigation purposes (Taylor et al., 2013). The links between water and food production are evident here, but unfortunately Groundwater resources are unequally distributed across Africa (Gaye and Tindimugaya, 2019). Nevertheless, groundwater stands as a valuable resource in the face of the impending climate crisis, and it must thus be managed accordingly to ensure sustainable exploitation, the welfare of future generations and the wetland and stream habitats that it contributes to (Gaye and Tindimugaya, 2019).

The Challenge of Managing Groundwater Resources

Groundwater availability is dependent on r

(Taylor et al., 2013) 

eplenishment via recharge from effective precipitation that infiltrates the subsurface, as well as through focused groundwater recharge (Taylor et al., 2013). A study by Taylor et al. (2013) studied the fragile relationship between groundwater levels and evapotranspiration and precipitation in the context of semi-arid tropical East Africa and reveals a “highly episodic” nature of recharge events, that follow anomalously intense rainfall during the monsoon period, against a tide of annual data revealing continual regressions in groundwater level until these events (Figure One) (Taylor et al,. 2013). Due to these idyllic climate conditions being necessary for recharge, the impetus for management is great.

The Future of Water Supply 

(Macdonald et al., 2021)

Climate change is now polarising the extremes of precipitation, with drier regions becoming drier, and wetter regions wetter and this marks a problem for accessibility across the continent (Hegerl et al,. 2019). As well as being protected from pollutants (Velis et al., 2017).   

However, in-light of a new study by University College London, it appears as though the long-term recharge of groundwater resources in Africa is around 15,000 km3/decade (Figure 2), which is enough to sustain groundwater abstraction of irrigation and farming, as well as drinking water (MacDonald et al., 2021).

Thus, groundwater resources seem to be the greatest hope for a long-term plan for African water supplies, and the attainment of UN Sustainable Development Goals 2 (zero hunger) and 6 (Water and Sanitation for all) (United Nations, 2015). Whilst this is a step in the right direction, care must be given to future management of groundwater to avoid damaging or overexploiting this resource. That has been witnessed in some part of the world. Furthermore, this also requires some from of distributive mechanism to overcome the issues associated with uneven distribution of Groundwater resources.