Groundwater can help African communities diversify their water supply and enhance drought protection, according to a study led by scientists at the University of Texas at Austin.
Studies published in Environmental research letterTracked long-term changes in water storage across 13 major aquifers in Africa, and found opportunities to sustainably pump groundwater in most of the continent.
Data show that certain sub-Saharan aquifers sometimes faced low water levels, but during the rainy season, water levels recover consistently and quickly, helping to prevent abuse.
“Groundwater levels go up and down,” said Brigitte Skanron, a senior researcher at the Department of Economic Geology and lead author. “People need to know the dynamics of this resource and optimize it for its use.”
Researchers used data from NASA’s GRACE satellite to track total aquifer reservoirs from 2002 to 2020. The result is an 18-year timeline that provides a long-term perspective on water trends and their drivers.
Most cities in Africa rely on surface water from lakes, rivers and artificial reservoirs. However, there is abundant groundwater throughout the continent, and the annual groundwater recharge is comparable to the combined flow of the Congo, Nile, Niger and Zambezi rivers.
This study highlighted various regional trends in groundwater throughout the continent.
In sub-Saharan Africa, studies have shown that most aquifers increased water supply during the period. However, the data show that the water level was also frequently subject to large fluctuations. Studies show that these fluctuations are closely tracked with climate patterns known to affect rainfall in the region, such as El Nino, Indian Ocean Dipole (IOD), and La Niña. El Nino and IOD generally increase rainfall in East Africa and decrease rainfall in Southern Africa, but the La Nina phenomenon generally has the opposite effect.
This pattern means that water storage can decline sharply in years of low rainfall, but eventually returns when it rains, making it easier to replenish the aquifer. This helps protect groundwater from long-term depletion, Scanlon said.
“We can be more confident that these recharge events have occurred, so we can rely on them in the long run,” Scanlon said. “In that case, we can assume that it will be recharged every few years.”
Even in West Africa, water levels have risen overall in most aquifers. However, the increase here is relatively stable, probably due to changes in land use. Researchers cite other studies that have linked the rise in groundwater levels in the region to the clearing of deep-rooted shrublands for shallow-rooted crops.
Also in North Africa, where groundwater has shown a steady decline in water storage as all three aquifers are used for irrigation, the vast amount of water retained in these aquifers is also found. Water Aquifer Provides an additional buffer. However, sharp declines can occur locally and affect the groundwater supply of local wells and oasis.
“I have visited Africa several times and have first seen the challenge of restricted access to water due to basic drinking and agricultural needs. Africa’s population continues to grow from poverty to prosperity. Therefore, I think the results of this study are important for long-term planning. ” Scott Tinker, Director of Economic and Geological Affairs.
Jude Cobbing, a water, sanitation and sanitation advisor for the humanitarian organization Save the Children, has experience working on water development projects in Africa. He said the study provides a data-driven perspective that helps alleviate concerns about abuse, especially in sub-Saharan Africa.
“We need a better use of groundwater, a better understanding of groundwater, and we need to start taking groundwater. Groundwater “More seriously,” he said. “I think a paper like this will help drive that discussion,” he said.
The study was co-authored by the Department’s Research Scientist Associate Ashraf Rateb and scientists at NASA Goddard Space Flight Center, Kwazul Natal University, British Geological Survey, University of London, and International Food Policy. Laboratory.
Bridget R Scanlon et al, GRACE water reserves in major aquifers in Africa, hydrological extrema, and linkages between climate teleconnections, Environmental research letter (2021). DOI: 10.1088 / 1748-9326 / ac3bfc
University of Texas at Austin
Quote: Sustainable groundwater use is available from https://phys.org/news/2022-03-sustainable-groundwater-africa-issues.html on March 1, 2022. May be the answer to (1st of March)
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Sustainable groundwater use may be the answer to Africa’s water problems
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