Seawater Intrusion Could Affect Coastal Drinking Water Treatment

Drinking water sources in coastal areas are increasingly vulnerable to seawater intrusion.

New research published in the journal Science this month pinpoints hotspots for “contaminant discharge to marine waters and saltwater intrusion into coastal aquifers,” according to the study.

Saltwater intrusion into some water supplies “may mean turning to more energy-intensive water treatment processes” for utilities, according to the American Council for an Energy-Efficient Economy, a nonprofit.

“It takes only a small amount of saltwater to render drinking water non-potable, so saltwater invasion is a big concern for water resource management in coastal areas,” lead study author Audrey Sawyer of Ohio State University said in a statement.

Urban development is a major culprit behind saltwater intrusion.

“The researchers commented that increased urbanization — and the extensive pavement that goes along with it — will also decrease groundwater recharge and ultimate draining to coastal regions where the population is growing, which increases the likelihood of saltwater intrusion,” according to the statement from the university.

Sawyer called on policymakers to improve their strategies for protecting water quality amid coastal land development.

“Right now, we’ve created a map of American coastlines that highlights some previously known as well as unknown areas of vulnerability along the U.S. coastline, but we hope to be able to do it for the world shortly, as data become available.”

Los Angeles and San Francisco were among the most vulnerable to saltwater intrusion, along with Southeastern Florida and Long Island, NY.

The study “has removed the cloak from hidden groundwater transfers between land and sea,” said co-author Cédric David of NASA’s Jet Propulsion Laboratory, which partnered on this study.