By ecoRI News staff
Drinking water wells at homes along the Rhode Island coastline are being contaminated by an intrusion of salt water, and as sea levels rise and storm surge increases as a result of the changing climate, many more wells are likely to be at risk.
To address this situation, a team of University of Rhode Island researchers is conducting a series of geophysical tests to determine the extent of the problem.
“Salt water cannot be used for crop irrigation, it can’t be consumed by people, so this is a serious problem for people in communities that depend on freshwater groundwater,” said Soni Pradhanang, associate professor in the URI Department of Geosciences and the leader of the project. “We know there are many wells in close proximity to the coast that have saline water, and many others are vulnerable. Our goal is to document how far inland the salt water may travel and how long it stays saline.”
Salt water can find its way into well water in several ways, according to Pradhanang. It can flow into the well from above after running along the surface of the land, for instance, or it could be pushed into the aquifer from below. Sometimes it recedes on its own at the conclusion of a storm, while other times it remains a permanent problem.
Pradhanang and graduate student Jeeban Panthi are focusing their efforts along the edge of the salt ponds in Charlestown and South Kingstown, where the problem appears to be the most severe.
Since salt water is denser than fresh water, it typically settles below. So the scientists are using ground-penetrating radar and electrical resistivity tests — equipment loaned from the U.S. Geological Survey and U.S. Department of Agriculture — to map the depth of the saltwater/freshwater interface.