For coastal communities across the United States, saltwater intrusion poses an existential threat. As little as one percent of seawater contamination can ruin a freshwater resource, and creeping saltwater intrusion can affect soil on farms, rendering acres of cropland unsuitable for cultivation.

In addition to the threats to water and food systems, saltwater intrusion also has many unseen impacts on local economies and residential communities.

The latest science and research, as well as what can be done to combat saltwater intrusion in coastal Delaware communities, were the topics of discussion at a recent Saltwater Intrusion Knowledge and Question Exchange workshop held at the Virden Conference Center on the University of Delaware’s Hugh R. Sharp Campus in Lewes.

The workshop was led by Chris Petrone, director of Delaware Sea Grant’s Marine Advisory Service, and Andrew Wozniak, associate professor in UD’s School of Marine Science and Policy, as part of their National Science Foundation Accelerating Research Translation grant.

Attendees included academics, municipality representatives, members of utility and landscape companies, and state agencies.

Petrone said it was a nice cross-section of interests, and he was glad to have the opportunity to welcome experts who could share information to increase participants’ knowledge and understanding of saltwater intrusion.

“Andrew and I saw a need for this kind of information, especially in the landscape industry,” said Petrone. “There’s a lot of information related to saltwater intrusion and the impacts on agriculture and forestry, but not a lot when it comes to the residential scale of saltwater intrusion. We tend not to think about the lawns and the gardens that people are putting in at a pretty high cost, and the potential damage to those from saltwater.”

Petrone pointed to an example from the workshop of someone who lived on the coast and had put a lot of work into their property's landscape.

 “The property had a nice lawn and gardens, and saltwater got into their irrigation well, so when those sprinklers went off, it was spreading saltwater all over the grass and gardens,” said Petrone. “Saltwater and most plants and grass don't mix, and so these folks that had invested a lot of money in their lawn and landscaping, all that stuff was yellow and potentially dead.”

Saltwater Speakers

Holly Michael, director of the Delaware Environmental Institute and the Unidel Fraser Russell Career Development Chair for the Environment at UD, gave the keynote address titled “The Creeping Threat of Saltwater Intrusion (and some ways we can slow it),” speaking on the state of science regarding saltwater intrusion. Michael used Dover and the Outer Banks, North Carolina, as two examples of communities working to combat saltwater intrusion through monitoring efforts.

She also showed that groundwater sources face a dual threat from the sea and from land. From the landward side, rainfall raises the water table, leading to flooding when it exceeds the land surface. From the sea, wind and waves can raise water levels along the coast, allowing seawater to infiltrate beaches and dunes.

Other presenters included Leah Palm-Forster, associate professor in UD’s Department of Applied Economics and Statistics, and Kent Messer, S. Hallock du Pont Professor of Applied Economics, who spoke about the social science and economic impacts of saltwater intrusion.

A panel discussion was held with speakers including Ashley Norton, from the Delaware Department of Natural Resources and Environmental Control (DNREC) Division of Water, Preston Lee, from the Lewes Board of Public Works, and Travis Pitts, operations manager and agronomist for Arbor Care Plant and Turf.

Finally, the afternoon breakout sessions allowed participants to rotate through five stations on saltwater intrusion. These stations covered everything from saltwater intrusion challenges and solutions to workforce development skills and training.

Wozniak said he sees the value of these knowledge exchanges, as they give various stakeholders an opportunity to share their challenges and objectives before any policy changes or directives. “In theory, this will increase understanding between stakeholders having different perspectives and lead to more collaborative, cooperative land management practices,” said Wozniak.

Overall, Petrone said the workshop was incredibly beneficial, and they hope to turn the information they gathered into a publication or website so it can be useful to the general public.

“The point of this workshop was to get science into the hands of people who need it,” said Petrone. “This is what Sea Grant does all the time, and this NSF project is fostering that and getting some different kinds of people involved in the research translation side of things.”