Callist Tindimugaya argues that the water beneath Africans’ feet could transform the continent’s agricultural production, but only if it is managed wisely
Kuru Magersa gives the starter cable on her small irrigation pump a hefty tug and it roars into life. Within a few seconds water from her new well is flowing onto her fields. Her vegetable plot near Ziway in Ethiopia is a splash of green in a dusty dry landscape.
“I now sell cabbages every two weeks,” she says. “It covers all our expenses including the children’s school fees.”
Magersa’s prospects are being transformed by groundwater - the subsurface water store that has the potential to revolutionize African agriculture.
An Undertapped Resource
With drought afflicting much of Southern Africa and parts of Ethiopia, it’s all too easy to succumb to the stereotype that Africa is a dry continent. Far from it. Recent estimates suggest that there is one hundred times more supply of groundwater in Africa than on the surface, for instance in lakes and rivers. Huge quantities of this subterranean water could be used sustainably for irrigation. The most recent calculations suggest that up to 1,650 km³, the equivalent of 23 Lake Chads, could be withdrawn year after year.
Yet, at present only 5% of crops in Africa are irrigated. In many regions, famers simply cannot afford the technologies needed to lift water from below the surface. This means they can only grow crops when the rains come. As rainfall is highly seasonal in much of Africa, that can leave smallholders mired in poverty, unable to exploit this valuable, and potentially renewable resource for a year-round income.
If irrigation could be increased using groundwater, not only would it be a boost to continental food security, but millions of smallholder farmers like Magersa could have more resilient livelihoods.
Finding the Right Balance
Globally, about 1,000 cubic kilometers (km³) of groundwater is withdrawn each year: enough to cover the entire surface of Tanzania with a meter of water. Half or more of this is taken by smallholder farmers. In India, 600 million people directly benefit from groundwater-supported agriculture. Many researchers have demonstrated that this approach is often more productive and equitable than centrally run irrigation schemes.
With good science, groundwater can be effectively and sustainably managed. New data, maps and modern computing power can now make better predictions of how much groundwater can be safely used without imperiling supplies - helping to work out the sustainable yield and design long-term strategies that maintain water levels and quality for future generations and that cater for the multiple uses groundwater must serve, including the environment such as by contributing to rivers and wetlands.
Sustainability is therefore critical and lessons from other regions should be noted. In parts of Asia, for example, overuse of groundwater is leading to rapidly declining water tables. More water is being taken out than natural recharge is replacing. This requires deeper wells and higher energy costs for farmers. It also risks rising salinity that can degrade land for decades.
An Invisible Commons
The fundamental challenge is that groundwater is an ‘invisible commons’ - farmers cannot directly see the resource, so find it difficult to judge how much they can sustainably use. In addition, pricing incentives designed to boost agricultural production, such as indiscriminate cheap power for pumps, have actually worsened problems of depletion in some areas. Establishing sustainable use, therefore, will be dependent on the creation of effective and equitable incentives and institutions to govern and regulate the resource. This will be challenging as most groundwater sources come under the jurisdiction of multiple authorities. Also, farmers using groundwater have been fiercely resistant to curbs on their access. Local initiatives to co-manage the resource are increasingly explored as an important element in sustainable groundwater use as farmers realize their common interest in safeguarding the resource.
Just this year, a new global partnership, the Groundwater Solutions Initiative for Policy and Practice (GRIPP), was launched to advance the agenda on sustainable groundwater management, fill knowledge gaps and guide decision-makers in smart policies and investments to increase productivity while not sacrificing long-term use of groundwater. Led by the International Water Management Institute, the GRIPP partnership has more than 10 members including the Africa Groundwater Network all of whom are working with donors, national partners, the private sector and farmers in sub-Saharan Africa to identify the best options to develop groundwater irrigation in prospective areas for securing livelihoods, food security and climate resilience.
In Africa, there is a fantastic opportunity to develop groundwater as an additional and sustainable resource for increased food security. Shallow wells can be supplemented with simple pump bores. Lessons learned in Asia can help African policymakers and farmers to avoid past mistakes, and implement robust and equitable management practices.
For years, African farmers like Kuru Magersa have looked to the skies to see when the rain would come and their fields could be sown. Now they have another option: right under their feet.
Callist Tindimugaya is Ugandan Hydrogeologist, Commissioner for Water Resources Planning and Regulation in the Ministry of Water and Environment (Uganda), responsible for planning and regulating the use of the water resources of Uganda, and a partner in GRIPP, a global initiative for sustainable groundwater management. Find out more: http://gripp.iwmi.org/ http://www.agw-net.org/