Finding Salty Groundwater

When flood disasters strike the coast, traditional water sources such as surface water or shallow drinking water wells may become contaminated or otherwise unavailable.

In such situations, it is imperative for emergency response crews to immediately know where they still have reliable sources of clean drinking water. Fresh groundwater sources can often be a local solution, providing reliable access to relatively clean water, yet often get overlooked. This absence of local fresh water automatically can lead to bottled water or water cisterns unnecessarily being carried over great distances. With this in mind, it is important for decisionmakers to know where their fresh water resources are located, so that they can be safeguarded for use during future shortages.

The global maps showing flooding due to tsunamis, storm surge or other causes are available, and make it possible to estimate which coastal areas will experience groundwater salinization during floods.

Global models provide information about the amount of time needed for aquifers to recover (i.e. to become fresh again) if they become saline. An example (Indonesia) of these global maps, focusing on tsunami flooding, is provided below. Note that the focus on tsunamis is why the Caribbean is not really affected.

With this information, global maps of the fresh-saline groundwater distribution after extreme flooding events can be used by decision makers to effectively safeguard their fresh groundwater resources.

This knowledge could, for example, be used by disaster reduction response teams to focus on accessing clean groundwater sources by bringing in pumps and fuel following a flood, rather than transporting bottled water via ship or helicopter to provide local residents with a more reliable source of drinking water. This is especially applicable in the case of Small Island Development States (SIDS).