ASSESSING SALINITY DISTRIBUTIONS IN THE EMILY AND RICHARDSON PREYER BUCKRIDGE COASTAL RESERVE, EASTERN NORTH CAROLINA

The Emily and Richardson Preyer Buckridge Coastal Reserve is a low-lying, peatland-dominated area that lies at the southern end of the Gum Neck Peninsula (eastern North Carolina) and is surrounded on three sides by drowned tributaries of the Alligator River estuarine system. Over the past century, the hydrology of the reserve has been altered by the construction of a canal network that was dedicated to facilitating timber harvest and draining of adjacent agricultural lands. In recent years, the natural habitat in the reserve has been observed to be degrading. The degradation that has been observed has been linked to saltwater intrusion emanating from the Alligator River. We present preliminary results that indicate elevated levels of salinity in groundwater, canals and the Alligator River.

Using electrical conductivity as measure of salinity, preliminary data indicate that brackish water conditions are present in both the canal network and the groundwater system. Salinity levels in the Alligator River are observed to be more elevated upstream than downstream, particularly under the influence of southwesterly winds. The groundwater data reveal that salinity levels are higher in the south of the reserve than in the north and that there is generally less variability of electrical conductivity in groundwater than in surface water. These observations suggest that the intra-coastal waterway to the south of the reserve influences electrical conductivity levels in the Alligator River and the reserve by acting as a conduit for saltwater intrusion from Pamlico Sound. Canals that connect to the Alligator River appear to be influenced more by variable wind tide directions and have larger differences between deep and shallow water salinities than those that are not connected. It is hoped that continued monitoring of the salinity distributions in the canal network and groundwater system will provide means to determining causes that could have lead to degradation of the natural habitat in the reserve.