Land subsidence due to groundwater exploitation in Spain

Problems

• Intensive groundwater exploitation has affected 77 aquifers in Spain, resulting in an annual extraction of around 700 million m3/year. Most of these cases are concentrated in the country's southeast region, where many aquifers have been intensively exploited for several decades. 
  
  It's worth noting that the Guadalentin aquifer (Spain) is the most well-known since this area experiences the most significant subsidence in Europe. The aquifer affecting the Parque Nacional de Doñana (Spain)  is another case well-known in Spain due to its environmental and media repercussions. 

• Cuase of land subsidence in Spain

  Land Subsidence caused by underground erosion occurs through a mechanical process of soil particle displacement by groundwater flow. As water moves horizontally through the soil, it mobilizes soil particles, forming channels that can lead to ground collapse.
  
  Sodium chloride and other materials, such as gypsum and carbonate rocks, are soluble in water under certain conditions. This can lead to the formation of large systems of interconnected voids. In extreme cases, the deformation and collapse of these voids can result in subsidence with a localized character.
  
  Construction works have contributed to ground subsidence in Spain, especially underground works in urban environments, where multiple buildings and infrastructures can be affected. Similarly, subterranean mining operations, especially when extracting minerals or other resources, create voids that, if left unsupported, lead to the overlying land collapsing and descending. This phenomenon is particularly prevalent in regions with extensive mining activities in Spain.  

• What are the effects of land subsidence in Spain

  Land subsidence has far-reaching consequences for Spain's environment, infrastructure, and daily human activities. One of its most visible impacts is on infrastructure: as the ground descends, buildings, roads, bridges, pipelines, and many more assets are affected. Structures may crack, tilt, or experience structural instability, leading to high repair costs and potential safety threats. 
  
  Another primary concern arises in the realm of water dynamics. Subsidence can interfere with natural drainage systems, creating depressions susceptible to flooding. This water accumulation can erode land, damage properties, and transform agricultural plots into unusable marshes. Moreover, the disruption to the hydrogeological balance might facilitate saltwater intrusion into freshwater aquifers, jeopardizing Spain's crucial drinking water sources. 

• Conclusion

  Ground subsidence Has far-reaching consequences in Spain. Monitoring and auscultation play a crucial role in assessing, managing, and mitigating the impacts of subsidence in Spain. They provide valuable information for well-informed and objective decision-making processes, infrastructure planning, and environmental protection.