During an extreme rainfall event that occurred September 29-30, 2016, more than 12 inches in one day, caused the water table to rise over 5 feet near Harbeson, Delaware. A subsequent 3.6 inch storm on October 8 - 9 caused the water table to rise above land surface and flood the area for nearly 8 hours.
Delaware Sea Grant-funded researchers John Callahan, Kevin Brinson and Tina Callahan organized a workshop on Delaware high water marks at the Delaware National Estuarine Research Reserve (DNERR) St. Jones Reserve Training Center in Dover on June 23. The workshop included an update on current progress to catalog, display, and distribute high water mark data collected in Delaware for past flooding events from 1960-present, and discussed plans for regional coordination of pre-storm deployment of water level sensors at temporary monitoring locations for future storms. Callahan, an associate scientist with the Delaware Geological Survey, subsequently shared a similar update on the project with the Delaware State Hazard Mitigation Council at the Delaware Emergency Management Agency’s main offices in Smyrna on June 30 to help assess the impacts from past storms and better prepare for future events.
Sea-level rise, dissipating dunes and susceptibility to storm surges are a few of the factors that contribute to a vulnerable coast. A coast at risk means an increased potential for damage to coastal communities and ecosystems in the event of tropical systems, nor'easters or other damaging weather.
More than 40 experts representing state and federal agencies and regional universities gathered to discuss these and other important issues during the Coastal Flood Research, Modeling and Monitoring Workshop on Sept. 16.
John Callahan presented on several ongoing CEOE projects that focus on the monitoring of the tides and storm surge, such as from water level tide gages and satellite imagery, as well as on past data analysis and future forecasts. The presentation also included a live demonstration of the Delaware Coastal Flood Monitoring System. The operational and research-based projects are being jointly conducted by the Delaware Geological Survey, Delaware Sea Grant, the Delaware Environmental Observing System, the Delaware Environmental Monitoring and Analysis Center and the state Department of Natural Resources and Environmental Control Delaware Coastal Programs.
DGS is building a database and web distribution system to collect, manage, and display high water marks (HWMs) that are observed throughout Delaware as a result of flooding events. Historical peak water levels can be extracted for past storms or for a selected geographic area. Development is being done in partnership with the Office of the Delaware State Climatologist, the Delaware Environmental Observing System (DEOS) and the Delaware Environmental Monitoring and Analysis Center (DEMAC).