Megacity pumping and preferential flow threaten groundwater quality
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ncomms12833.pdf
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1.9 MB
Format
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Checksum (MD5)
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Author(s)
Khan, Mahfuzur R.
Koneshloo, Mohammad
Knappett, Peter S. K.
Ahmed, Kazi M.
Bostick, Benjamin C.
Mailloux, Brian J.
Mozumder, Rajib H.
Zahid, Anwar
van Geen, Alexander
Michael, Holly A.
Date Issued
September 2016
Journal
Nature Communications
Publisher
Nature Publishing Group
Citation
Khan, Mahfuzur R. et al. “Megacity Pumping and Preferential Flow Threaten Groundwater Quality.” Nature Communications 7 (2016): 12833.
Version
Final published version
Abstract
Many of the world’s megacities depend on groundwater from geologically complex aquifers that are over-exploited and threatened by contamination. Here, using the example of Dhaka, Bangladesh, we illustrate how interactions between aquifer heterogeneity and groundwater exploitation jeopardize groundwater resources regionally. Groundwater pumping in Dhaka has caused large-scale drawdown that extends into outlying areas where arsenic-contaminated shallow groundwater is pervasive and has potential to migrate downward. We evaluate the vulnerability of deep, low-arsenic groundwater with groundwater models that incorporate geostatistical simulations of aquifer heterogeneity. Simulations show that preferential flow through stratigraphy typical of fluvio-deltaic aquifers could contaminate deep (>150 m) groundwater within a decade, nearly a century faster than predicted through homogeneous models calibrated to the same data. The most critical fast flowpaths cannot be predicted by simplified models or identified by standard measurements. Such complex vulnerability beyond city limits could become a limiting factor for megacity groundwater supplies in aquifers worldwide.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Terms of Use
Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1038/ncomms12833
