As sea levels rise, so do groundwater levels. Beaufort Co. studying impact with $300K grant
When people think of sea level rise, they can reckon with what’s in front of them, like visible flooding and rising tides, but they don’t often think about what’s beneath their feet: Groundwater.
The very water below the Earth’s surface that’s used for irrigation and drinking purposes could be subjected to negative impacts from rising sea levels, which can cause problems with drainage and underground infrastructure.
It’s what Alicia Wilson, a groundwater hydrologist at the University of South Carolina’s School of the Earth, Ocean and Environment, said is overlooked in discussions of sea-level rise.
They’re issues already cropping up along South Carolina’s coastline, Wilson said. The S.C. Sea Grant Consortium, a multidisciplinary team of scientists, and Beaufort County are diving deeper into the issue.
But there’s a lot of unknowns, said Robert Merchant, Beaufort County Planning and Zoning director.
With a nearly $300,000 grant from the National Oceanic and Atmospheric Administration’s Climate Program Office, scientists will analyze how sea-level rise impacts underground infrastructure and groundwater to define the unknowns and aim to lessen potential impacts. The two-year grant is called “Beaufort County Adapts: Sea Level Impacts Beneath Our Feet.”
Merchant said launching the study is like “knowing your enemy.” If researchers can understand the impacts of sea level rise on groundwater, they can plan better mitigation strategies.
Starting soon, the team will site and monitor about 15 shallow groundwater wells in areas of Alljoy, Mossy Oaks, Shell Point and St. Helena. Locations that, due to their low elevation, already are experiencing issues, Beaufort County’s long range planner Juliana Smith said.
Scientists will collect water-height measurements every three months and then model the projected impacts of sea level rise on groundwater conditions and infrastructure. They’ll watch for tide cycles, rainfall, storm events and drought. Social scientists will work alongside the research team, talking with communities.
“It’s easy for us to all read the articles and the data about predictions for sea level rise that are coming out from your federal agencies and your national institutions, but we really want to understand what does that mean here,” Smith said.
What’s below the surface?
There’s a multitude of possible issues when sea level rise interacts with groundwater. Drainage is at the top of Smith’s list.
“It would fill in ponds that would otherwise be reserved for holding on to storm water or for runoff and rain,” she said.
Then there’s what’s below the surface. Septic tanks and electrical lines.
“If your water doesn’t run through (your property) the way it used to, because groundwater is sitting there all the time, then you can’t have a functioning septic tank,” Smith said.
Septic tank failure can be problematic if sewage leaks into rivers or creeks nearby.
What’s less known is the impact on underground electrical lines. She isn’t certain how the lines would fair, but postulated that more frequent water exposure could have an effect.
On the back-burner of concern, but not to be ruled out, is sea level rise spiking salt content of groundwater. When sea level rises, so does the salt water underneath groundwater. When it gets to a certain height, salt water can infiltrate into wells.
The grant’s mission will also interact with an ongoing project that gauges tide levels locally to find out what’s happening to local waters when flooding strikes.
“We take this issue very seriously,” Merchant said. “Our comprehensive plan really projects being proactive about the issue of flooding and sea level rise, and trying to do everything we can at the local level to understand the issue to then be in a better situation to come up with solutions.”
