South Africa’s landscape is experiencing a remarkable transformation. Recent studies reveal that parts of the country are gradually rising above sea level—a phenomenon scientists have confirmed is not related to tectonic activity. Instead, this elevation change stems from an unexpected source : the country’s prolonged drought conditions depleting crucial underground water reserves.
Unusual elevation changes across South African regions
Scientists at the University of Bonn have documented a surprising geological event occurring throughout South Africa. Their research, published in the Journal of Geophysical Research : Solid Earth, shows the land rising at rates reaching two millimeters annually in certain areas. While this might seem minimal, geologically speaking, this represents significant vertical movement over relatively short timeframes.
The country’s extensive network of permanent GPS stations has been instrumental in tracking these changes. These highly sensitive instruments measure ground height with millimeter precision, revealing an average elevation increase of 6mm between 2012 and 2020 across multiple regions. The Western Cape experienced the most dramatic rise, with measurements showing 5-6mm increases during this period.
This elevation phenomenon creates conditions similar to those seen in regions where dolinas or torcas form due to changing subsurface conditions, though through different mechanisms. The rising land presents challenges for infrastructure planning and water management systems throughout the affected areas.
Regional variations have been clearly documented across the country :
RegionElevation Change (2012-2020)Hydrological StatusWestern Cape+5 to +6mmExtreme drought (2015-2019)Northern KwaZulu-Natal+2mmModerate water deficitPretoria Region+3mmModerate drought
Drought’s unexpected impact on land elevation
The correlation between drought-stricken areas and regions experiencing the most significant elevation gains reveals the underlying mechanism. Water, particularly in large quantities stored underground, exerts substantial pressure on the earth’s crust. When drought conditions persist, this pressure diminishes as water reserves deplete, allowing the ground to rebound upward.
This mechanical effect resembles how a compressed foam ball returns to its original shape when pressure is released. Similarly, the earth’s crust “rebounds” when relieved of water’s weight, though this process unfolds over years rather than seconds. The alluvial plain characteristics of many affected regions make them particularly susceptible to these elevation changes.
The relationship between water quantity and land elevation follows a clear pattern :
Water-saturated soil : Minimal elevation increase (0-0.5mm annually)
Average water levels : Moderate rise (approximately 1mm annually)
Severe drought conditions : Maximum elevation gain (up to 2mm annually)
The researchers confirmed their hypothesis by comparing GPS measurements with data from the GRACE satellite mission, which tracks Earth’s gravitational field variations. Despite relatively low spatial resolution (hundreds of kilometers), the satellite data revealed a striking inverse relationship : areas with greater water mass loss showed more significant elevation increases.
Monitoring groundwater through land movement
This newly understood relationship between land elevation and groundwater levels offers an innovative approach to water resource management. By monitoring ground height changes, authorities can indirectly assess underground water reserves—a critical capability in drought-prone regions like South Africa.
Such monitoring systems could serve as early warning mechanisms for impending water crises, potentially averting situations like Cape Town’s 2018 near-catastrophic water shortage. The approach is particularly valuable because it leverages existing GPS infrastructure, making it cost-effective and readily implementable.
The implications extend beyond South Africa to other arid regions facing similar challenges, including the Sahel countries with their distinct climate and ecological characteristics, California, and the Mediterranean basin. These areas could benefit from similar monitoring systems as climate change intensifies drought patterns globally.
Water resource specialists note that this elevation-based monitoring approach complements traditional methods by providing continuous, real-time data across extensive geographic areas. Understanding how river valleys form and evolve in response to changing water conditions becomes increasingly relevant in this context.
Future implications of rising land and depleting water
Climate projections indicate South Africa will face more frequent and severe drought episodes in coming decades. As these conditions persist, the land elevation phenomenon may become more pronounced, potentially affecting infrastructure, agriculture, and natural ecosystems throughout the region.
The depletion of groundwater reserves presents serious challenges for water security, particularly as marine pollution impacts limit alternative water sourcing options in coastal areas. Underground aquifers represent the majority of Earth’s accessible freshwater, making their preservation and management crucial for human populations.
This emerging understanding of land elevation’s relationship to water reserves could transform how we monitor and manage water resources globally. Regions accustomed to perpetual ice or consistent precipitation patterns may need to adopt monitoring approaches pioneered in drought-prone areas as climate patterns shift worldwide.
The South African case study demonstrates how geological monitoring can serve as an indirect but effective measurement of invisible resources. Similar approaches could be applied to track changes in atoll formation processes and other geological features affected by water dynamics.
As South Africa continues to rise millimeter by millimeter, scientists are gaining invaluable insights into the complex relationship between drought, groundwater depletion, and geological change—knowledge that will prove essential for managing water resources in an increasingly water-stressed world.