CCU groundwater and resistivity study - Summer 2013 Dr. Richard F. Viso Coastal Carolina University

Center for Marine and Wetland Studies 1270 Atlantic Avenue Coastal Carolina University Conway South Carolina 29526 USA

rviso@coastal.edu http://ww2.coastal.edu/rviso/ Georgia Coastal Ecosystems LTER Project

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

gcelter@uga.edu https://gce-lter.marsci.uga.edu/ Dr. Richard F. Viso Coastal Carolina University

Center for Marine and Wetland Studies 1270 Atlantic Avenue Coastal Carolina University Conway South Carolina 29526 USA

rviso@coastal.edu http://ww2.coastal.edu/rviso/ Principal investigator Matthew Carter Coastal Carolina University

Center for Marine and Wetland Studies 1270 Atlantic Avenue Coastal Carolina University Conway South Carolina 29526 USA

mlcarte2@g.coastal.edu Co-investigator Dr. Richard N. Peterson Coastal Carolina University

Center for Marine and Wetland Studies 1270 Atlantic Avenue, Room 111 Coastal Carolina University Conway South Carolina 29526 USA

rpeters2@coastal.edu Co-investigator 2026

Our goal during this research effort will be two-fold: 1.) use geochemical time-series measurements at 3 locations in the Duplin river to evaluate groundwater inputs to the Duplin river and 2.) electrical resistivity measurements. Piezometer and resistivity cable transects will be laid out in several locations for about 24hrs each. Geochemical time series: Three radon-222 monitoring stations will be placed along the Duplin River over the month of June from existing docks at Marsh Landing, Lumber Landing and Moses Hammock. A submersible bilge pump will be deployed about 1m below the surface. Pumps will be powered by an on-site 12v car battery stored in a plastic box on the dock and changed twice a day. Water will be pumped continuously into an air-water exchanger through a short section of garden hose. The air-water exchanger is equipped with spray nozzles to equilibrate dissolved gasses form the water. Water will overflow from the air-water exchanger and return to the river. A closed air loop will connect the air-water exchanger to a commercial radon-in-air monitor (Durridge Co., Inc) and desiccant column, both will be housed in the on-site plastic box. A Solinst CTD probe will be anchored in the river at each site secured with rope for recovery. In addition to the time-series set-ups we will collect 6-L groundwater grab samples from existing piezometers located at Moses Hammock. Groundwater samples at the remaining two sites will be through temporary piezometers ( ½” PVC pipe with a 3” slotted section at the bottom of ½” PVC) in a perpendicular transect from the upland marsh to river bank. This effort will use a self-contained peristaltic pump and tubing to collet water into our gas tight radon analysis bottles. Geophysical measurements: subsurface resistivity time-series measurements will be conducted by laying a resistivity cable (100m) along a transect form the upland through he marsh and into the river. The cable will remain on the ground surface for about 24hrs measuring the subsurface resistivity. Multiple transect measurements will be taken during the research trip form June 2-28.

Area 2: Patterns within the Domain (more information)

marsh subterranean water column/neritic depth salinity temperature LTER NSF GCE chemistry geophysics hydrography pore-water chemistry Overall geographic extent of the research project -81.297445 -81.258908 31.497026 31.416399 2013-06-03 2013-06-28

GCE-LTER sub-award for groundwater quantification, NSF, $75K

estuary marsh complex Hunt Camp - Barrier island/marsh site on western Sapelo Island. This site is located at the upper reaches of the Duplin River, and is within the Sapelo Island National Estuarine Research Reserve. Existing well fields border small marsh area to northwest, some wells have been installed to south end of hammock where marsh is more extensive and permanent plots are located. Two existing hydrographic sondes and weather stations within this site are operated by SINERR (Hunt Camp dock) and UGAMI (flume dock). -81.295506 -81.258908 31.497026 31.462320 Marsh Landing - Marsh landing, where the Georgia DNR ferry docks on its route between the mainland (Meridian) and Sapelo Island. -81.297445 -81.294606 31.418899 31.416399 LumberLanding - Lumber Landing dock on the Duplin River at Sapelo Island, Georgia -81.277455 -81.277455 31.459769 31.459769 Map (Google Earth KML/KMZ or map image) https://gce-lter.marsci.uga.edu/private/registration/files/Maps/GCE-45-2013_Maps_Duplin_River_Radon_Measurements.kmz

Dock at Marsh Landing: 31°25'4.11"N 81°17'46.51"W Dock at Lumber Landing: 31°27'35.92"N 81°16'38.46"W Dock and piezometers at Moses Hammock: 31°28'44.14"N 81°16'23.11"W

One plastic box at each site containing radon measuring gear and power supply for bilge pumps. A weight will be deployed to the bottom that houses each water level logger. All of the field equipment will be removed at the end of the 4 week field effort. Shallow PVC piezometers, 100m electrode array and control box will be deployed in short 24hr periods.

Photo of the research site or equipment https://gce-lter.marsci.uga.edu/private/registration/files/Photos/GCE-45-2013_Photos_Areal_Photo_of_Research_Sites.docx