The Horn of Africa's deep groundwater could be a game-changer for drought resilience

Extreme heat and drought have ravaged the Horn of Africa with devastating consequences. For many in Djibouti, Eritrea, Ethiopia and Somalia, it continues today. For others, the spectre of drought looms ever near.

The region recently suffered its worst drought in almost half a century and experienced six consecutive failed rainfall seasons. Adaptive capacities are low and humanitarian impacts confronting: 50 million people were directly affected; 100 million more indirectly affected; 20 million risked acute food insecurity and potential famine; more than 4.4 million required humanitarian aid; and refugees numbered in the hundreds of thousands.

Recurrent drought spikes food prices, adversely impacts GDP and intensifies insecurity and conflict risk. Climate change is a disaster risk multiplier, exacerbating extreme drought-flood cycles and exposing already vulnerable populations to potential displacement. The Horn of Africa contains the world’s largest population of nomadic herders, representing half the population in some countries, and who are increasingly chasing rains that never come. Less mobile smallholder farmers are also impacted. Over 40 million people in regional border areas have little or no water infrastructure.

In response, relief agencies and governments struggle to support water and food insecure displaced persons and affected host communities. In 2022, the United Nations Refugee Agency (UNHCR) received less than half the required financial resources to respond to regional droughts. And although drought forecasting capacities are increasing, it is the delivery of tangible and sustainable drought resiliency outcomes on-the-ground that matters most.

Contrary to popular belief, water is not limiting drought resiliency in the region. Rather, it is a lack of access to water during drought events for those who need it most. Fortunately, the solution may lay directly beneath their feet.

Globally, groundwater supplies half of all drinking water and approximately one-third of irrigation and industry water. In contrast to surface water (and shallow groundwater resources), which is often diminished during drought events, deeper groundwater resources may provide unpolluted, climate-resilient and voluminous supplies.

Take sub-Saharan Africa. Groundwater volumes (renewable and non-renewable) are estimated to be equivalent to thousands of years of average total flow of the Nile River. Yet, it is estimated that less than 5% of annual available renewable groundwater in the region is utilized.

Similar characteristics are present in the Horn. Studies confirm that plentiful and accessible groundwater — typically less than 200m deep — is often available, and periodically recharged, in recurrent drought hotspots. This has been further confirmed by recent reinterpretations of vintage oil exploration well data. For example, 400,000 olympic-size swimming pools of rechargeable fresh groundwater was discovered in Somalia, and a deep aquifer in nearby Tanzania is estimated to provide water for two million people, with flow rates up to twenty times higher than shallow bores. However, such resources remain largely unaccessed, despite the Somalia resource being considered the “most cost-effective and sustainable solution to water scarcity affecting millions”, and separate findings that groundwater, coupled with mechanized piping, can be 50 times cheaper than rainfed supplies and water trucking during drought relief operations.

Multiple factors may be contributing to delayed progress. Globally, a predominant groundwater conservation narrative warns of overexploitation, pollution, salinization and subsidence. As recently as 2020, deep groundwater was classified as an “unconventional water resource” by the United Nations. Prior to that, there was a perception that groundwater across sub-Saharan Africa was widespread but low in volume. Today, data on local resource dynamics remains outstanding and political economy, financial and knowledge and capacity challenges remain.

However, narratives are shifting. Groundwater is now considered critical to achieving the Sustainable Development Goals and there are high-level calls for concerted action to “properly develop and protect groundwater” and to make the “invisible, visible”. The UNDP’s recently launched Groundwater Access Facility aims to sustainably utilize large volumes of untapped groundwater resources in the region to support those most affected by chronic drought and severe food insecurity. Shifting to tangible actions is the next step.

One option that merits further investigation is a strategic network of deep groundwater bores to support regional drought resiliency. This concept builds upon knowledge that:

A network of deep bores could potentially be harnessed full-time for multiple-use community water supply or only during drought emergencies, depending on factors such as resource sustainability and local management preferences. Boreholes could be specially designed and constructed to reliably function under even the most severe drought conditions. Inclusive and participatory approaches could empower communities as drivers of change, engaging them in aspects of planning, design, operation, maintenance and ownership. For example, local communities could determine optimum borehole locations for periods of acute water stress. Funding may be sought from government and relief/development agencies — justified by ex-ante resilience building generating greater humanitarian, socioeconomic and cost benefits than ex-post relief efforts.

Deep borehole development could form part of broader climate-resilient, integrated water resource management. For example, where flood follows drought, excess surface water may be diverted for infiltration into groundwater reserves. Deep boreholes could be linked to small-scale agro-forestry initiatives to support emergency food and feed production. Boreholes could become assets around which to coordinate drought relief programmes.

The proposal, although potentially promising, is not without challenges and trade-offs. For example, how would deep boreholes affect movements, decision-making and adaptive capacities for nomadic herders and displaced communities? Could boreholes become potential points of conflict in already fragile settings? Should non-renewable fossil aquifers be accessed? Will water treatment be required and how will water be managed sustainably? How could potential environmental impacts and transboundary resources be managed?

Such questions, and many others, require answers. And whilst caution is merited, today’s devastating reality for millions of people in the region surely warrants exploration of innovative, pragmatic and actionable solutions. With the World Water Forum, Global Day of Action on Extreme Heat and Conferences of the Parties (COPs) on climate change, nature and desertification upcoming in 2024, the time for action is now.

Knowing that voluminous freshwater lies at accessible depths beneath the feet of those suffering acute and chronic water scarcity now becomes an issue of justice for us all.

Jude Cobbing and Bradley Hiller’s academic paper has been cited over 75 times and their co-authored World Bank report has been cited over 220 times. Bradley Hiller advanced this article during a Rockefeller Foundation Bellagio Residency.