Megacity pumping and preferential flow threaten groundwater quality

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 gro...

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Main Authors:	Khan, Mahfuzur R., Koneshloo, Mohammad, Knappett, Peter S. K., Ahmed, Kazi M., Bostick, Benjamin C., Mailloux, Brian J., Mozumder, Rajib H., Zahid, Anwar, Harvey, Charles F., van Geen, Alexander, Michael, Holly A.
Format:	Online
Language:	English
Published:	Nature Publishing Group 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052627/

id	pubmed-5052627
recordtype	oai_dc
spelling	pubmed-50526272016-10-21 Megacity pumping and preferential flow threaten groundwater quality Khan, Mahfuzur R. Koneshloo, Mohammad Knappett, Peter S. K. Ahmed, Kazi M. Bostick, Benjamin C. Mailloux, Brian J. Mozumder, Rajib H. Zahid, Anwar Harvey, Charles F. van Geen, Alexander Michael, Holly A. Article 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. Nature Publishing Group 2016-09-27 /pmc/articles/PMC5052627/ /pubmed/27673729 http://dx.doi.org/10.1038/ncomms12833 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Khan, Mahfuzur R. Koneshloo, Mohammad Knappett, Peter S. K. Ahmed, Kazi M. Bostick, Benjamin C. Mailloux, Brian J. Mozumder, Rajib H. Zahid, Anwar Harvey, Charles F. van Geen, Alexander Michael, Holly A.
spellingShingle	Khan, Mahfuzur R. Koneshloo, Mohammad Knappett, Peter S. K. Ahmed, Kazi M. Bostick, Benjamin C. Mailloux, Brian J. Mozumder, Rajib H. Zahid, Anwar Harvey, Charles F. van Geen, Alexander Michael, Holly A. Megacity pumping and preferential flow threaten groundwater quality
author_facet	Khan, Mahfuzur R. Koneshloo, Mohammad Knappett, Peter S. K. Ahmed, Kazi M. Bostick, Benjamin C. Mailloux, Brian J. Mozumder, Rajib H. Zahid, Anwar Harvey, Charles F. van Geen, Alexander Michael, Holly A.
author_sort	Khan, Mahfuzur R.
title	Megacity pumping and preferential flow threaten groundwater quality
title_short	Megacity pumping and preferential flow threaten groundwater quality
title_full	Megacity pumping and preferential flow threaten groundwater quality
title_fullStr	Megacity pumping and preferential flow threaten groundwater quality
title_full_unstemmed	Megacity pumping and preferential flow threaten groundwater quality
title_sort	megacity pumping and preferential flow threaten groundwater quality
description	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.
publisher	Nature Publishing Group
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5052627/
_version_	1613674559394807808

Megacity pumping and preferential flow threaten groundwater quality

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