BOONE – Geologists from Appalachian State University have identified a link between the quantity of water resources in eastern North Carolina and climate oscillations originating in the Pacific Ocean.

Bill Anderson and Ryan Emanuel, assistant professors in Appalachian’s Department of Geology, analyzed 56 years of precipitation and baseflow data throughout central and Eastern North Carolina to look for correlations between climate oscillations and groundwater flow.
The climate signals, which include the El Niño–Southern Oscillation (ENSO), are factors that are known to cause changes in temperature and moisture on time scales from years to decades. Several of these climate signals have been related to temperature and water resources variations in the western United States, but this is the first demonstrated link between these climate signals and groundwater resources in the eastern United States.

Bill Anderson, left, and Ryan Emanuel studied 56 years worth of data related to climate oscillations in the Pacific Ocean and Eastern North Carolina’s groundwater resources. The Appalachian State University geologists found that changes in groundwater resources in the eastern part of the state are linked to changes in El Niño/La Niña. (Appalachian photo by University Photographer Marie Freeman)

“I’ve been working on Hatteras Island since the early 1990s,” said Anderson. “During field work, I’d noticed the high variability in groundwater conditions on the island, and these variations seemed to track changes in El Niño/La Niña. I mentioned these anecdotal variations to Ryan, and we decided to see if the link was real.”

Anderson’s hypothesis was correct. The geologists’ findings have been published in the journal Geophysical Research Letters, a publication of the American Geophysical Union.

In their study, Anderson and Emanuel looked at seasonal variations in precipitation and baseflow, the groundwater contribution to streamflow. Statistical analyses demonstrated that winter variations of these parameters were significantly linked to El Niño/La Niña. In addition, differences in the amount of groundwater flow between wet (winter El Niño) and dry (winter La Niña) conditions varied by more than 100 percent.

These conditions are not uniform across North Carolina, however. The most prominent correlations occur along the southeast coast and decrease rapidly inland. The high correlations diminish across the Coastal Plain and do not occur in the Piedmont.

“This research is important because it helps us to understand the relationship between the global climate system and water resources at the local scale. The link we have identified between water supplies in eastern North Carolina and climate fluctuations in the Pacific Ocean demonstrates the amazing complexity and interconnectedness of Earth’s climate,” said Emanuel.

Anderson and Emanuel have begun a follow-up study of links between freshwater availability on the Outer Banks and El Niño/La Niña.

The information presented in the current study will aid water resource managers in the Coastal Plain by enabling them to use climate signals to forecast groundwater resource availability, thereby helping to alleviate water demands through conservation and planning.

“This gives water managers in eastern North Carolina a means of predicting next summer’s water availability this winter,” said Anderson. “By knowing the El Niño/La Niña forecast at the beginning of the winter season, when aquifers get most of their water, water managers will be able to plan accordingly.”

###

CONTACTS:
Dr. William “Bill” P. Anderson Jr., assistant professor, Department of Geology, 828-262-7540
Dr. Ryan Emanuel, assistant professor, Department of Geology, 828-262-3049