Identifying long term empirical relationships between storm characteristics and episodic groundwater recharge

Water Resources Research
By: , and 

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Abstract

Shallow aquifers are an important source of water resources and provide base flow to streams; yet actual rates of groundwater recharge are difficult to estimate. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on groundwater recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land use types across North Carolina. We extract storm duration, magnitude, average rate, and hourly weighted intensity from long-term precipitation records over periods of 12–35 years at 10 locations. Using time series of water table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. Increased RPR correlates with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity of precipitation. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land use change for water resources in subtropical climates. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas of the American Southeast could further limit groundwater availability.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Identifying long term empirical relationships between storm characteristics and episodic groundwater recharge
Series title Water Resources Research
DOI 10.1002/2015WR017876
Volume 52
Issue 1
Year Published 2016
Language English
Publisher American Geophysical Union
Contributing office(s) Geologic Hazards Science Center
Description 15 p.
First page 21
Last page 35
Country United States
State North Carolina
Online Only (Y/N) N
Additional Online Files (Y/N) N