SOURCE, TRANSPORT AND FATE OF SALT IN A CHANNELIZED AND PEATLAND-DOMINATED WETLAND SYSTEM, SOUTHERN ALBEMARLE ESTUARINE SYSTEM (NORTH CAROLINA, USA)

A study was conducted in the southern Albemarle Estuarine System (Eastern North Carolina, USA) in order to investigate the origin, transport and fate of salt in a channelized and peatland-dominated wetland system. Specific conductivity measurements in groundwater, canals and the Alligator River were used to characterize the source of saltwater into the wetland system, to evaluate the spatial and temporal distribution of salts, and to assess the potential effects of saltwater on Atlantic White Cedar. Results indicate that specific conductivities unexpectedly decrease from south to north, with higher specific conductivities closer to the source of the Alligator River and lower specific conductivities towards the Albemarle Sound. Meteorological data show that water levels in the canals and Alligator River are influenced by wind tides which facilitate the movement of saline waters into the interior of the wetland system, whereas reversals in the hydraulic gradient between surface water bodies and the groundwater system may facilitate the movement of brackish waters into the subsurface. Remote sensing and field studies of peatland Atlantic White Cedar stands show progressive stress and poor regeneration in areas proximate ditches and overland surges of saline waters. Attempts to better understand the mechanisms that control salinity in the southern Albemarle Estuarine System are important for water management strategies in the low lying areas in light of climate change and sea level rise. These strategies are crucial for sustaining ecosystem health. The results from this study can therefore be used by water managers to develop plans for ameliorating the effects of saltwater intrusion in coastal wetlands.