Gauging sea-level rise in marshes
Global sea-level rise and sinking land are combining to cause water levels near Bowers Beach, Del., to climb at a rate faster than anywhere else on the Atlantic coast. Surrounding wetlands may change into mudflats if wetland elevation cannot keep pace with rising sea level. Sea Grant researchers Jack Puleo and Thomas McKenna are conducting field research in Kent County to increase our understanding of how marshes respond to sea-level rise. The work could help natural resource managers monitor marsh stability and predict future changes.
The Delaware Geologic Information Resource (DGIR) is an online data display tool and map viewer for a variety of geologic and hydrologic information released by the Delaware Geological Survey. It was designed to deliver the most commonly available and requested geologic and hydrologic information that is appropriate for use in hydrologic studies, required by regulation and ordinance, and to support state resource management decisions.
To conduct an elevation survey, a surveyor needs a starting point for which the exact elevation above mean sea level is known. These starting points are called benchmarks. State and federal agencies install benchmarks throughout every State, creating a network of elevation points which covers the entire continental United States. These benchmarks are considered to be permanent, and usually consist of a brass, bronze, or aluminum disc about 4 inches in diameter mounted in a cement post or in a drill hole in a permanent foundation.