Modeling the potential impact of seasonal and inactive multi-aquifer wells on contaminant movement to public water-supply wells

Journal of the American Water Resources Association
By: , and 

Links

Abstract

Wells screened across multiple aquifers can provide pathways for the movement of surprisingly large volumes of groundwater to confined aquifers used for public water supply (PWS). Using a simple numerical model, we examine the impact of several pumping scenarios on leakage from an unconfined aquifer to a confined aquifer and conclude that a single inactive multi-aquifer well can contribute nearly 10% of total PWS well flow over a wide range of pumping rates. This leakage can occur even when the multi-aquifer well is more than a kilometer from the PWS well. The contribution from multi-aquifer wells may be greater under conditions where seasonal pumping (e.g., irrigation) creates large, widespread downward hydraulic gradients between aquifers. Under those conditions, water can continue to leak down a multi-aquifer well from an unconfined aquifer to a confined aquifer even when those multi-aquifer wells are actively pumped. An important implication is that, if an unconfined aquifer is contaminated, multi-aquifer wells can increase the vulnerability of a confined-aquifer PWS well.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Modeling the potential impact of seasonal and inactive multi-aquifer wells on contaminant movement to public water-supply wells
Series title Journal of the American Water Resources Association
DOI 10.1111/j.1752-1688.2011.00526.x
Volume 47
Issue 3
Year Published 2011
Language English
Publisher Wiley
Contributing office(s) Ohio Water Science Center, California Water Science Center
Description 9 p.
First page 588
Last page 596