Groundwater in Rwanda

Can groundwater reserves in Africa be used sustainably?

This is the question that many are concerned about because even though Africa is sitting on a sea of untapped aquifers, excessive demand may limit groundwater recharge (Guardian 2016).

Figure 1: Groundwater availability in Africa (CGIAR 2016)

Figure 1 shows the distribution of groundwater which is available for irrigation, but the diagram on the right specifically shows Ground Water Irrigation Potential (GWIP). Availability of groundwater is one thing, but access to this is limited by factors which include: the drilling and pumping cost, which is determined by the depth of groundwater; the distance to market; access to electricity; and soil fertility which will determine its suitability for agriculture (CGIAR 2016). The distribution of groundwater does favour some countries more than others which means that unlocking the potential of groundwater is not applicable to the entire continent; countries in the equatorial band receive the greatest rainfall and therefore experience the greatest groundwater recharge, due to the effects of the moving ITCZ (Altchenko and Villholth 2015). Unfortunately, this means that countries in northern and southern Africa do not have access to renewable groundwater which means that alternative methods to improve food security must be sourced.

So having discussed the potential of groundwater, I wanted to investigate whether there have been any recent movements towards exploiting this resource. In recent news, solar powered irrigation systems have been used in Rwanda, which has doubled yields for farmers (New Times 2017). Smallholders have not been able to access groundwater reserves as they do not have the finances to afford pumping systems. The deeper the groundwater, the harder it is to access and the more the smallholders are priced out. In order to resolve this equity issue, solar powered systems are replacing diesel-fuelled pumping technology, reducing the environmental impact and cutting the cost (ibid). 

Figure 2: Gerard Munyeshuri Gatete in his 8-hectare farm in Nyagatare District, Rwanda (New Times 2017)

Gatete owns an 8 hectare farm in the Nyagatare District in Rwanda and is currently enjoying a doubling of his yields after the Food and Agriculture Organisation (FAO) supported 75% of the financial cost towards the new Rwf22 million solar powered irrigation scheme (ibid). It has allowed him to farm all year round and has made him more adaptable to droughts (ibid). Just to put the finances into perspective, for one acre, farmers pay approximately $200 every month to run a diesel system to irrigate 1 acre of land. In contrast, farmers only need to pay $418 for the solar powered system which has a lifetime of 25 years, considering it is well maintained. This monetary gain is huge!

Is groundwater depletion inevitable?

Figure 3: Global groundwater depletion (IAH 2015)

As better and cheaper technologies become more accessible to farmers such as Gatete throughout Africa, the demand for groundwater will inevitably increase. Figure 3 shows the depletion of groundwater reserves worldwide and the exponential trend is very worrying. These resources need to be managed carefully and this leads to the question of who will take this responsibility? Groundwater salinisation is also an imminent threat which means that withdrawals need to be constantly monitored by specialists in order to review the impacts and vary withdrawals as necessary (IAH 2015).

However, this management takes on a unique transboundary dimension because aquifers cross international borders (World Bank 2017). This means that increased cooperation between countries is vital in order to share information on a central database to improve and contextualise management techniques (ibid). I am hopeful that with further research, groundwater can act as a safeguard during dry periods and work alongside small and large scale irrigation schemes. Groundwater depletion is not inevitable, so long as the correct management is in place.

List of References

Altchenko, Y. and K. G. Villholth (2015) ‘Mapping irrigation potential from renewable groundwater in Africa–a quantitative hydrological approach’, Hydrology and Earth System Sciences Discussions, 19, 2, 1055-1067.

CGIAR (2016) ‘Is groundwater the key to increasing food security in Sub Saharan Africa?’ (WWW) (https://wle.cgiar.org/thrive/2016/04/23/groundwater-key-increasing-food-security-sub-saharan-africa; accessed 21/12/17).

Guardian (2016) ‘Africa droughts prompt calls to start pumping untapped groundwater’ (WWW) (https://www.theguardian.com/sustainable-business/2016/aug/18/africa-drought-untapped-groundwater-aquifers-water-stress-ngo-partnership-ethiopia; accessed 21/12/17).

IAH (2015) Strategic Overview Series: Food Security & Groundwater, International Association of Hydrogeologists, Series 6.

New Times (2017) ‘Solar-powered irrigation sees farmers double their yield’ (WWW) (http://www.newtimes.co.rw/section/read/223551/; accessed 21/12/17).

World Bank (2017) ‘Hidden and Forgotten: Managing Groundwater in Southern Africa’ (WWW) (http://www.worldbank.org/en/news/feature/2017/06/07/hidden-and-forgotten-managing-groundwater-in-southern-africa; accessed 21/12/17).