Global map protecting ground water

discharge of ground water into ocean


Global map protecting ground water

  • Scientists have created high-resolution maps of points around the globe where groundwater meets the oceans — the first such analyses of its kind that may help protect both drinking water and the seas.
  • It showed that nearly one-half of fresh submarine groundwater discharge flows into the ocean near the tropics.


  • They also found that regions near active fault lines send greater volumes of groundwater into the ocean than regions that are tectonically stable.
  • They found that dry, arid regions have very little groundwater discharge, opening the limited groundwater supplies in those parts of the world to saltwater intrusion.

Managing drinking water

  • The findings may help coastal communities better protect and manage their drinking water.
  • Freshwater-groundwater discharge is a natural line of defense against saltwater intrusion.
  • It’s a problem that dry regions have as little groundwater discharge as they do because these are also the places where people are going to tend to look for groundwater to meet their freshwater needs.
  • The research work, the first near-global and spatially distributed high-resolution map of fresh groundwater flow to the coast, could give scientists better clues about where to monitor groundwater discharge.
  • Most of the water that gets to lakes and oceans comes from surface water sources.
  • However, groundwater plays an important role, too, carrying minerals and, in some cases, pollutants, to surface bodies of water.
  • The study found that in some parts of the world, groundwater could be polluting oceans and lakes with nutrients and other chemicals.
  • Groundwater, for example, can carry higher concentrations of nitrates — a key contributor of the types of harmful algal blooms — as well as high concentrations of mercury.
  • Understanding how and where groundwater gets to surface water could help policy-makers create better plans to improve those bodies of water.

Point to remember

  • Ground water meeting zone
  • Active fault line
  • Management of drinking water
  • Algae bloom