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.
Original language | English (US) |
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Pages (from-to) | 588-596 |
Number of pages | 9 |
Journal | Journal of the American Water Resources Association |
Volume | 47 |
Issue number | 3 |
DOIs | |
State | Published - Jun 2011 |
Keywords
- Drinking water
- Groundwater hydrology
- Nonpoint source pollution
- Point source pollution
- Simulation
- Source water protection
- Water supply
ASJC Scopus subject areas
- Ecology
- Water Science and Technology
- Earth-Surface Processes