System alerts bay communities of coming floods

On Mother’s Day of 2008, high tides, strong northeast winds and heavy rains left a handful of tiny communities along the Delaware Bay in Kent County under several feet of water.

The storm left in its wake one fatality, dozens of people homeless and more than $1 million in property damage, but it also prompted state officials and University of Delaware researchers to put their heads together to develop an early warning system for coastal flooding to facilitate planning in the future.

The result was an alert notification system and website displaying pertinent information regarding forecasted local water levels. It initially focused on six coastal communities along the Delaware Bay—Leipsic, Little Creek, Pickering Beach, Kitts Hummock, Bowers Beach and Slaughter Beach—for testing the system, but it has since been expanded.

Launched in 2011, the Coastal Flood Monitoring System (CFMS) supports planning and emergency management for Delaware Bay communities before and during coastal storm or high tide events. It was developed by John Callahan, a research associate for the Delaware Geological Survey (DGS), and Kevin Brinson, a researcher for the Delaware Environmental Observing System (DEOS). The Delaware Department of Natural Resources and Environmental Control and the Delaware EPSCoR program funded the project.

The CFMS includes several elements:

  • An early warning system that alerts emergency managers and coastal resource managers of potential flood events via email and text messages;
  • Flood inundation maps and elevation profiles along primary evacuation routes using the latest LiDAR (Light Detection and Ranging) data;
  • Predicted water-level data from NOAA’s Delaware Bay Operational Forecast System (DBOFS) and Extratropical Surge (ET-Surge) models for up to four days in advance; and
  • A website and user guide that combines all aspects of the system with links to more real-time information.

All the information is tailored to specific locations, so an official from Bowers Beach, for example, can look at inundation maps and use them to make decisions about evacuating residents or calling in rescue crews.

“Delaware has coastal flooding issues just about every time there’s a major storm, and, with increases in sea level, we have the potential for these incidents to occur more frequently,” says Dan Leathers, professor of geography in UD’s College of Earth, Ocean, and Environment and Delaware state climatologist. “The monitoring system won’t alleviate flooding, but it can help us better prepare for the effects of coastal flooding on people and property.”

Callahan points out that in coastal Kent County, the roads are barely above water under normal conditions.

“Let’s say it’s high tide and we get just a small amount of onshore wind—that’s all it takes to cause flooding in this area,” he says. “That’s why displaying the road profiles on the website is an important feature for planners and rescue personnel as they try to answer questions like ‘Can we get a fire truck through or do we need to use boats to get people out?’ ”

The team currently is working on the next generation of the system that will go as far north as New Castle and as far south as Lewes. It will feature increased quality and resolution of forecasts, an improved alerts system and a new web interface.

Leathers explains that expansion of the system to other areas of the state involves much more than just extending its geographic boundaries. “We have to consider different hydrodynamic issues in each of these areas,” he says.

While the monitoring system provides a service to coastal communities, it is also firmly grounded in research. The team is comparing model predictions with actual behavior to improve system accuracy.

They also have started taking measurements in preparation for creating a similar system for Delaware’s Inland Bays, which are influenced by different climatic and hydrodynamic phenomena.

Leathers applauds the state for the support they give to DEOS and DGS researchers.

“There’s a lot of environmental observation going on in the state, which really helps with projects like this,” he says. “There are more monitoring stations here than there are in many states much larger than Delaware.”

For questions and information, contact DGS at, 302-831-2833