Land subsidence due to groundwater exploitation in Colombia

Problems

• In Colombia, subsidence occurs in major cities and causes structural damage to buildings and infrastructure. The land subsidence in Colombia was classified as the Risk4: land subsidence -0.0805 n/a in building the Formal Housing Index (FHI; Arbeláez et al., 2011). Bogotá is the largest and most populous city with a high concentration of natural hazards. Located in a moderate seismic zone, its complex topography makes it prone to landslides and floods; in addition to these geographical factors, mass migration and unbridled growing urbanization processes in recent years make it susceptible to increased vulnerability to geodynamic phenomena. 
  
  During the last 60 years, numerous tube–wells have been constructed in the Sabana de Bogotá to supply groundwater for irrigation, several town aqueducts, and numerous factories. All groundwater users in the basin face a problem: They must pump deeper every year and replace wells for others at a higher cost. This takes place precisely when surface water resources are insufficient to satisfy demand. 
  
  Groundwater level descent is the main cause of uneven compaction and land subsidence observed in surface layers of the Sabana Formation, severe damage to construction and pavement, and overpressure in deep water wells. Therefore, it is possible to say that negative experiences in the México Valley, also composed of nonconsolidated lacustrine sediments, are being repeated in the Sabana de Bogotá. 
  
  Subsidence due to uncontrolled groundwater extraction is now well understood by hydrogeologists and may be remedied. Groundwater is indispensable for agricultural irrigation and industrial applications in several towns in the Sabana de Bogotá. The regional lowering of the potentiometric level has caused the disappearance of mountain front springs, streams, and wetlands, as well as land subsidence, cracks on the ground, in buildings and roads, well collapses, the fall down of submersible pumps, and replacements with deeper wells.
  
  Addressing land subsidence requires a multifaceted approach. Sustainable groundwater management practices, such as regulated extraction, artificial recharge, and alternative water sources, are essential. Monitoring and early warning systems can also help identify at-risk areas and inform policy decisions.
  
  Colombia faces a critical juncture in managing its groundwater resources and mitigating land subsidence. Through a combination of scientific research, community engagement, and policy reform, the country can work towards a sustainable future, safeguarding its land and people from the silent crisis of subsidence.
  

• Water crisis in Colombia

  Colombia is one of the most biodiverse countries in the world, from Andean peaks and Caribbean coastlines to hidden ruins in the Amazonian jungle. But sourcing water for everyone is a problem.
  
  Colombia is one of the richest countries in freshwater, yet it is grappling with a water crisis. 
  
  Climate change and decades of industrial oil extraction, mining, and farming threaten water security for many of its population.
  
  Decades of armed conflict, drug trafficking, weak government, and corruption have made Colombia a difficult place to live for many people. The country’s economy has grown in recent years and its tourism industry has boomed, but certain regions still lack essential services.
  
  Water scarcity in Colombia can be explained by several factors:
  
  ● Climate change. Changes in rainfall patterns, rising temperatures, and extreme weather events associated with climate change disrupt the water cycle, leading to water shortages.
  
  ● Deforestation, especially in the Amazon rainforest and other critical ecosystems, reduces the land's ability to hold water, disrupts rainfall patterns, and promotes soil erosion, affecting water availability.
  
  ● Rapid urbanization and population growth are increasing the demand for water for domestic, industrial, and agricultural purposes, putting pressure on water resources.
  
  ● Pollution from industrial and agricultural runoff and inadequate waste management contaminate water sources, making them unsuitable for consumption and other uses.
  
  ● Excessive groundwater and surface water extraction for irrigation, industrial use, and domestic consumption can deplete aquifers and rivers, exacerbating water scarcity.
  
  Colombia has the sixth highest volume of renewable freshwater in the world, yet, according to the charity WaterAid, 1.4 million people lack access to clean water.

• Bogotá rationing water for 9 million people

  Nestled in the Andes mountains 2,600m (8,500ft) above sea level, Bogotá has been spared the most apocalyptic scenes. The usually rainy capital receives an average of 1,020mm (40in) yearly rainfall – nearly twice as much as London.
  
  Still, the abnormally long hot and dry spells have caused wildfires to rage in the forests surrounding the capital – choking some neighborhoods with smoke – and now the reservoirs, some 10 million people rely on, are at “critical” levels.
  
  El Niño is a natural climate pattern originating in the Pacific Ocean along the equator, influencing global weather. In Colombia, it has fueled higher temperatures and lower rainfall.
  
  El Niño, which usually causes lower rainfall in South America, has caused record-breaking droughts and temperatures in 2024, forcing administrations across the region to enact emergency measures.
  
  “Most cities around the world depend on aquifers for their water supplies. Bogota is different in that almost all our supply comes from surface waters like reservoirs, which are more susceptible to rain patterns,” said Armando Sarmiento, an ecology professor at Bogotá’s Javeriana University.
  
  This dependence on rain makes Bogotá particularly vulnerable to drought, Sarmiento told CNN.
  
  As global warming makes extreme weather such as heatwaves and drought more common and severe, experts warn that the stress on cities’ water systems will only increase.