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July 11th, 2018
Courtesy of Future Directions International, an article on Kenya’s efforts to tap into groundwater to address their water scarcity situation:
Background
Kenya experiences a large degree of water insecurity. The Kenyan Government currently maintains a water-rationing policy in the capital, Nairobi, and is expected to do so until 2026. Nairobi’s main dam, the Ndakaini dam, supplies 500 million litres of water to the city per day; 200 million litres short of the city’s demand. All of Kenya’s tap water supply is currently sourced from boreholes sunk into aquifers. Given that many Kenyan rivers are quickly drying up, the process has developed as a result of the scarce surface water supply.
Comment
According to Professor Daniel Olago from the University of Nairobi, experts have historically known little about aquifers in Africa. Information such as aquifer capacity, recharge rates, how the aquifers replenish and how they respond in different climatic conditions, has been sparse. As the frequency of severe droughts continues to increase under the pressure of climate change, pumping groundwater has a high degree of risk, given that little has been understood about aquifer supplies.
Despite the historical lack of knowledge, experts from the University of Nairobi, the University of Barcelona, Oxford University and the Jomo Kenyatta University of Agriculture and Technology, have begun studying the groundwater system in Kwale County in southern Kenya. Scientists have been able to determine the Msambweni aquifer’s size and depth, as well as conduct analyses on the quality of its water. By using a specialised computer programme, scientists are able to use the data to assess the quality and quantity of Kwale County’s underground water and determine the level of demand for it. The programme also considers the risks associated with use of the aquifer and factors in the area’s economic and social conditions.
The technology will enable scientists to model projections for different scenarios, based on the quantity of water extracted and variations to climate. This will enable the Kenyan Government to determine how much water from the aquifer may be withdrawn, so that it can be used sustainably. The Kenyan Government has typically issued borehole licences to any companies that have requested them, but the information gathered from the specialised computer programme may now allow it to make informed decisions about the borehole licences it issues. Regulators will also be able to monitor falling water levels and respond by controlling the amounts of water that industry can use.
In the 1980s, Kenyan boreholes were only dug to an average depth of 80 metres before reaching water. Today, to find water licensees must drill down roughly 400 metres. Given that aquifers are slow to recharge, meeting the country’s demand through groundwater extraction has been a highly unsustainable method of sourcing water. Research into Kenyan aquifers comes at a time when global freshwater availability trends have (again) been pushed into the spotlight, as a result of studies involving the Gravity Recovery and Climate Experiment (GRACE) satellites. Data collected from Kenyan aquifers will not only help to ensure that water is used sustainably throughout Kenya, but will also contribute to a greater understanding of how the world’s underground water systems operate.