Potential effects of regional pumpage on groundwater age distribution
Article first published online: 21 JUN 2007
Copyright 2007 by the American Geophysical Union.
Water Resources Research
Volume 43, Issue 6, June 2007
How to Cite
2007), Potential effects of regional pumpage on groundwater age distribution, Water Resour. Res., 43, W06418, doi:10.1029/2006WR004865., and (
- Issue published online: 21 JUN 2007
- Article first published online: 21 JUN 2007
- Manuscript Accepted: 13 MAR 2007
- Manuscript Revised: 22 JAN 2007
- Manuscript Received: 5 JAN 2006
 Groundwater ages estimated from environmental tracers can help calibrate groundwater flow models. Groundwater age represents a mixture of traveltimes, with the distribution of ages determined by the detailed structure of the flow field, which can be prone to significant transient variability. Effects of pumping on age distribution were assessed using direct age simulation in a hypothetical layered aquifer system. A steady state predevelopment age distribution was computed first. A well field was then introduced, and pumpage caused leakage into the confined aquifer of older water from an overlying confining unit. Large changes in simulated groundwater ages occurred in both the aquifer and the confining unit at high pumping rates, and the effects propagated a substantial distance downgradient from the wells. The range and variance of ages contributing to the well increased substantially during pumping. The results suggest that the groundwater age distribution in developed aquifers may be affected by transient leakage from low-permeability material, such as confining units, under certain hydrogeologic conditions.