BAROMETRIC EFFICIENCY: AN AQUIFER RESPONSES TO HURRICANES AND PUMPING

Coastal regions of the eastern Carolinas rely on Cretaceous aquifers as a primary source of water for municipalities, industries, and agriculture. This groundwater is deemed a safe and reliable source of water, given that the aquifers are confined. However, the aquifers do not necessarily have the same level of confinement everywhere due to a thin or missing confining layer. We have been monitoring groundwater levels and barometric pressure within Robeson County since December 2017 using a network of 13 monitoring wells across the county that are tapped into the Black Creek Aquifer. The analysis of groundwater levels and barometric pressure data from the county wells and state wells in the county was conducted to study the aquifer response to the changes in barometric pressure during three tropical storms (Florence, Michael, and Dorian) and the summer months. A graphical method was used to estimate the slope of a best-fit line for changes in water level and barometric pressure, which have no range limit, unlike barometric efficiency. The aquifer has noticeably different slopes during the three tropical storms and pumping periods. The larger the storm, the steeper the slope. The slope ranges from positive 5 to negative 4, which indicates the aquifer was under significant stress from both natural and anthropogenic activities. Should the aquifers exhibit induced infiltration, the public health and economy of the region could be at risk.