Special Series
This is Part 2 of a three-part series “Salt of the Earth” that examines the creeping threat of saltwater on the health of Delaware. Read Part 1 here.
Why Should Delaware Care?
Water conservation may seem like a problem relegated to the western United States, but as climate change and land-use changes continue to alter the places where we live and farm, understanding how to manage these natural resources is key. In Delaware, proximity to waterways along the coast means that misuse of those natural resources could limit access to clean, fresh water that people rely on for drinking, irrigation and business operations.
Some of Delaware’s most fertile farmland is found along the state’s eastern coastline, where rising tides and increasingly strong storms threaten to bring saltwater farther and farther inland.
That’s why, in recent years, the City of Dover has engineered a solution to its drinking water needs by coordinating with area farmers and pulling freshwater from different underground aquifers on a seasonal basis.
The balancing act is needed because the city’s natural supply is shared with other users, like farmer Paul Cartanza, who tends to hundreds of acres of farmland on the outskirts of Little Creek.
If the city pumps too much water from the underground aquifer, it could leave less freshwater for the farmers’ irrigation systems. Or worse, if multiple wells are drawing from the same source, it can increase the risk that saltwater from the nearby Delaware Bay gets pulled in, too.
“We had made a change to our operations so that we wouldn’t take water out of that aquifer during farmers’ growing season, even though that’s kind of the same point in time that the city needs a lot of water because people irrigate their lawns and have their own personal gardens,” explained Jason Lyon, the city’s director of public works who manages drinking water resources.
During peak growing season, typically May to October, Dover leaves the shallower Columbia aquifer to the farmers and instead pulls water from different wells that reach different, deeper aquifers.
After years of monitoring the risk of saltwater impacting those freshwater resources, researchers are still trying to figure out how far inland saltwater will actually migrate due to sea-level rise, extreme weather events and the growing pressure from competing users.
But as the grey stalks of leafless, dead trees along the edges of waterways in Kent and Sussex counties can attest, the destruction left by saltwater reaching areas that depend on freshwater is an ever-present risk. Other coastal towns, even as far north as Bowers Beach, have already seen salt creep into wells.
“I think the irrigation and farming right there is kind of on the ‘frontlines,’” Delaware Geological Survey hydrogeologist Rachel McQuiggan said of areas of eastern Kent County. “If it’s going to happen, it’s going to hit those irrigation wells first.”
Farmers on the frontlines
The Cartanza family was once one of the biggest potato farming families on the Eastern Shore.
Paul Cartanza Sr. isn’t in the business of growing spuds anymore — his fields east of Dover are tied up in corn, soybeans and other veggies like peas — but his son is hanging on as just one of a handful of the county’s remaining potato farmers.
He said his family settled on these fields decades ago, after learning that the rich soils of the area hold moisture much better than sandy fields farther south. Perfect for potatoes, he explained.
The land that the Cartanzas tend is on the frontlines of saltwater intrusion in Kent County simply due to geography: Farmland in this area abuts thousands of acres of winding marshes along the county’s eastern boundary with the Delaware Bay.
“It’s not too bad one or two times, but when it does it periodically, it becomes dead land,” he said. “We’re all affected.”
His farmland is more susceptible to what McQuiggan would describe as “salinization,” or the overwashing of salty water, like when coastal storms and high tides bring brackish floodwaters from the Delaware Bay across low-lying areas of Route 9.
As an avid hunter, Cartanza has spent many days watching those salty tides go in and out. He recalled a time about 15 years ago, when he sat in his four-wheeler in the marsh along Marshtown Road where he was hunting deer, watching the water creep closer and closer. Before he knew it, the salty water had washed over the land and up his boots.
Once that saltwater moves in, it’s really hard to get it back out of the aquifer.
Delaware Geological Survey hydrogeologist Rachel McQuiggan
Over the last 50-plus years of living on and farming land here, he’s found solutions in self-engineered berms and ditches that reroute floodwaters. But he’s remembered at least once when saltwater reached an irrigation pond and led to some burnt crops.
“It’s an issue. But it’s an issue that we’ve dealt with for many a year,” said Cartanza as he pored over maps in a barn off Little Creek Road last year, pointing to the edges of some of the roughly 600 acres of farmland and accompanying irrigation systems and ponds he now owns.
He estimated in 2024 that it cost about $1,200 per acre to plant corn, so if there’s a risk it won’t grow, he doesn’t bother planting there in the first place. Cartanza said he also leases land to hunt clubs, offering an alternative profitable purpose for that lost land.
Scientists and engineers have long kept an eye on these saltwater intrusion threats, but it’s only been recently that local farmers have faced more urgent warnings about salt creeping close to irrigation systems.
In 2019, the Delaware Department of Agriculture sent a letter to a handful of Kent County farmers flagging the risks of saltwater to certain crops like corn, fruits and vegetables. The letter urged caution for those using irrigation in the area, and advised farmers to monitor those water sources before spraying crops.
In September 2025, an updated report on one of the most vulnerable areas in eastern Kent County found that the direct threat of saltwater tainting the drinking water that area residents rely on still remains far in the future.
The aquifer can “recharge” quickly enough to stave off the immediate risk of saltwater intrusion, according to researchers. Freshwater aquifers recharge when rainwater is allowed to percolate from the surface into the soil.
But for farmers who rely on healthy — and salt-free — soil and water for irrigation, attention must still be closely paid to salt levels in certain ponds and along tidal waterways that may become increasingly brackish due to sea-level rise.
Spraying salty water on crops can mean not only poor harvests, but can also contaminate fields and leave them fallow for years. Pulling saltwater inland can mean irreversible damage.
“Once that saltwater moves in, it’s really hard to get it back out of the aquifer,” McQuiggan said. “Anything that changes that balance on one side of saltwater coming in or freshwater going out will change that dynamic.”
A seasonal solution
It was during COVID that officials with the City of Dover decided to adjust the way the city of roughly 40,000 residents gets its drinking water. The change wasn’t because the city’s supply faces an immediate threat of saltwater intrusion, but rather a seemingly proactive choice to protect those freshwater sources for nearby farmers.
“We want to be good neighbors,” said Lyon, the public works director.
The project also coincided with a multi-million-dollar upgrade to the city’s water treatment infrastructure. As part of a recent master plan for Dover, the city is also looking at major upgrades to its downtown wastewater and stormwater infrastructure.
For now, the city is balancing where it draws its water for residents to ensure ample supply to the entire community and to give time for each aquifer to naturally replenish.
The business of treating drinking water is complex and science-based — for example, the mineral properties of water drawn from the shallow Columbia aquifer versus water pulled from deeper aquifers like the Piney Neck differ. While the Columbia may need to be treated for excess nutrients, like nitrogen, deeper water sources might need to be treated for excess minerals, like iron.
While the city’s shifted water withdrawal schedule has eased concerns about a risk of overuse of the aquifer that Cartanza and others in the area rely on for fresh water, Cartanza said he’s keeping an eye on industrial competition. A nearby power plant, which was eyeing expansion some years ago, would need to pull more water for cooling if operations expanded.
On the city side, Lyon pointed to recreational marijuana as another commercial use that could tip the scales.
“It would definitely make an impact on our demand,” he said.
If all of the available spaces and licenses for growing in Dover were granted, it could mean an estimated additional 6 million gallons per day of water use. Currently, the city pumps on average 5 million to 7 million gallons per day.
“We try to look at the worst-case scenario and plan for it,” he said.
More water-hungry cannabis plants aren’t the only impending threat to coastal water systems though.
As greenhouse gases trapped in the atmosphere drive up average global land and sea temperatures, those changes fuel more extreme weather patterns from powerful coastal storms that can push salty floodwaters ashore to exacerbating drought conditions that shift the balance between fresh and salt water. Sea-level rise also pushes salty water sources farther inland.
“We’re a low-lying state, so you get a foot of sea-level rise and that’s a lot of Delaware,” McQuiggan said. “As far as saltwater intrusion, sea-level rise is going to slowly change that dynamic.”
Monitoring changes ahead
McQuiggan is continuing her work with other colleagues at the state Geological Survey and the University of Delaware, as well as the Department of Natural Resources and Environmental Control’s Division of Water, to develop a GIS-based study that includes physical data and water use information to model vulnerabilities across the state, including in eastern Kent County.
That work aims to strengthen the state’s saltwater intrusion monitoring network while also collecting and presenting information in a useful way.
Saltwater intrusion is also a highly localized problem, she said. The most recent study found saltwater made its way into two irrigation ponds and one monitoring well next to the marsh east of Dover, but overall found that deeper wells were largely protected. Everything from weather and location to the actual geologic makeup of the underground aquifers impacts whether salt can get into the freshwater system.
Now that the issue has been studied in northern and central parts of the coastal areas of the state, hydrogeologists next plan to expand monitoring well networks in Sussex County to better understand its saltwater risks.
“The farther south you get into the coastal communities living right up on that coast, that’s where you have the more immediate issue,” McQuiggan said.
