Numerous studies over the past 30 years by federal and state groundwater experts, combined with over 35 years of data on the water level and water quality effects of pumping at the PCS facility have demonstrated that the Castle Hayne Aquifer underlying the PCS property can sustain at least 78 mgd of pumping indefinitely.  These studies show:

•  Demonstrated stability of the cone of depression resulting from PCS pumping for over 35 years, including periods when pumpage was greater than 80 mgd.  The fact that water levels are stable in the Castle Hayne demonstrates that groundwater discharge is in balance with groundwater recharge.  According to the North Carolina Division of Water Resources, this conclusion is one of the reasons that proposed reductions in pumpage from groundwater under the new Central Coastal Plain Capacity Use Area regulations do not include the Castle Hayne Aquifer.

•  Numerous studies by the U.S. Geological Survey, the State of North Carolina, and a special study group of internationally renowned hydrogeologists were use to develop the technical basis for PCS’ current permitted amount of 78 mgd.  These studies included groundwater flow and salt-water migration models and assessments. These conclusions are documented in: “Texasgulf, Inc. Aurora Phosphate Mine, Technical Report in Support of Renewal and Modification of Water Use Permit No. 3”, dated August, 1991.  The conclusion of these and subsequent studies conducted by the USGS and others, including Dr. Richard Spruill of Eastern Carolina University and his graduate students is that pumping from wells on the PCS property is simply capturing a portion of the groundwater that naturally discharges to the Pamlico River and Pamlico Sound. 

•  These studies further concluded that the natural recharge to the Castle Hayne aquifer is in balance with the combination of pumpage from PCS wells and continued natural discharge to the River and the Sound.  This balance can be sustained as long as pumpage from PCS does not exceed the 78 mgd of their permit.