Underground construction | underground dams The rise of
Underground dam construction can offer a potential way forwards in the quest to source sustainable water supplies when demands are increasing due to the pressure of population growth and climate change
GROUNDWATER COMPRISES 30% OF global freshwater reserves and in arid and semi-arid regions can account for more than 80% of the total available. It is described as often being of high quality, easily accessible, and generally less affected by short-term climatic and hydrological changes. An underground dam is a facility that enhances
Below: Is the use of underground dams on the up?
groundwater capacity through the construction of a watertight cut-off wall within an aquifer, effectively raising the groundwater level and can also prevent seawater intrusion in coastal areas. The history of underground dams can be traced back over 2000 years, but it wasn’t until the early 1980s that the first ones were built using modern civil engineering techniques. Since then they can be found in countries such as Japan, Brazil, India, South Korea, Mexico, Bolivia, the US, and across Europe. These dams have several advantages, including: High-quality water preservation. Prevention of parasite growth and malaria transmission. Greater dynamic stability compared to surface dams. Ability to recharge shallow groundwater through rainfall. Better performance than surface dams due to lower evaporation rates during dry seasons and their contribution to environmental preservation. Being an economic and efficient way of sustainably managing groundwater in semi-arid regions. Enabling the development of water resources in areas where the construction of surface dams is challenging due to geological conditions.
Unlike surface dams, land use around an underground dam remains unchanged after construction as it’s not submerged by stored water, plus underground dams are not at risk of failure due to natural or human-induced factors. Their effectiveness depends on rigorous location selection criteria that consider geology, soil depth and texture, slope, and drainage network, so as to effectively minimise location errors. With surface water resources becoming under
increasing pressure due to population growth and climate change, certain schools of thought believe groundwater offers a possible way forward for the future.
Brazil
Brazilian semi-arid regions face water challenges that can directly impact important agricultural activities. The municipality of Capoeiras, in Pernambuco, has great agricultural potential, but depends on sustainable water collection and storage strategies to overcome scarcity, ensuring local agriculture and livestock farming continues into the future. With the above in mind, recent research was carried
out to help identify potential areas for the construction of underground dams in Capoeiras. Individual maps were drawn up considering terrain, geology, soils, and hydrology, resulting in a general map of the region’s suitability, using geoprocessing, remote sensing, and open-source software. Different levels of suitability were discovered for the study area: 10.29% of the territory has high potential for the implementation of underground dams, while 31.39% has moderate potential, requiring more detailed planning. The remaining 58.32% of the territory was classified as having low potential and was considered a restricted area.
Concerns
Based on the success of an irrigation project that utilised two subsurface dams as water sources on Japan’s Miyako Island in 1993, ten additional subsurface dams have now been completed. Each of these was built under distinct geological and construction conditions, with engineers having to overcome various challenges during the construction process. Core technologies have made such subterranean dams possible – including an integrated storage model for creating water utilisation plans, and the soil mixed wall method for constructing cut-off walls. The integrated water storage model calculates the
groundwater flow and water balance by visualising daily fluctuations in the groundwater level over a 30-year period. While the soil mixed wall method
34 | November 2025 |
www.waterpowermagazine.com
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