Underground saltwater intrusion is expect to severely affect three out of every four coastal regions globally by the year 2100, as per the findings publish in Geophysical Research Letters.
This research, a collaboration between NASA’s Jet Propulsion Laboratory (JPL) and the U.S. Department of Defense, highlights significant risks to freshwater resources in coastal aquifers due to rising sea levels and reduce groundwater recharge.
The U.S. Eastern Seaboard and other low-lying regions have identified as some of the most vulnerable areas.
This phenomenon, known as saltwater intrusion, occurs beneath coastlines, where freshwater from aquifers and seawater naturally balance each other.
Sea level rise, driven by climate change, is increasing the pressure of seawater against land, while slower groundwater recharge due to reduce rainfall weakens the inland flow of fresh water.
This shift disrupts the delicate balance, allowing seawater to move further inland, threatening water quality and ecosystem health.
According to study, saltwater intrusion is project to occur in 77% of the coastal watersheds examine.
Rising sea levels alone are expect to influence 82% of these areas, causing the transition zone between fresh and salt water to move up to 200 metres inland.
Conversely, decrease groundwater recharge will impact 45% of regions, with the transition zone extending as far as 1,200 metres inland in some cases, particularly in arid regions such as the Arabian Peninsula and Western Australia.
Lead author Kyra Adams, a groundwater scientist at JPL, explain in a press release by NASA that the primary driver of intrusion, whether sea level rise or reduced recharge, varies by location, influencing management strategies.
For example, areas impact by low recharge may benefit from protective measures for groundwater resources, while regions facing sea level-induce risks may consider redirecting groundwater supplies.
The research use data from the HydroSHEDS database and incorporate a model accounting for groundwater dynamics and sea level rise.
Co-author Ben Hamlington of NASA’s Sea Level Change Team said that the findings align with global coastal flooding patterns, underscoring the compound risks pose by rising sea levels and changing climatic conditions.
Ben Hamlington told NASA that nations with limited resources face the highest risks, highlighting the importance of global frameworks to address these challenges.
