Degrove Surveyors, as part of our continuing services contract with the U.S. Army Corps of Engineers, Jacksonville District, is near completion of a hydrographic and topographic survey for beach monitoring in Duval County, Florida. The survey area includes nearly 11 miles of coastline, from the St. Johns River Inlet at Mayport, southerly to the northern part of St. Johns County. Survey data was achieved from the Coastal Construction Line on the landward side, out to 3,000 feet offshore.
Topographic field crews utilized RTK GPS to attain data onshore and out to a safe wading depth at low tide. Hydrographic data was collected in Degrove’s 26-foot SeaArk. Nearshore hydrographic data was achieved at high tide, helping to ensure overlap in the topographic and hydrographic data. The vessel is equipped with RTK GPS for positioning and heading, an electronic transducer and fathometer for soundings, and a motion reference unit (MRU) for determining heave corrections which are applied in the post-processing of the hydrographic data.
The Corps of Engineers completes these monitoring surveys on an annual basis. This is the fifth time Degrove has surveyed Duval’s beach in recent years. We have completed surveys similar to this in many Florida counties on both the Atlantic and Gulf coasts. Information is used to aid in planning beach renourishment.
Pictured above: Degrove’s Hydrographic Manager, Ray Niles, PSM, CH, operates the survey vessel to achieve hydrographic data near the Jacksonville Beach Pier (seen in background).