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The Effect of Undetected Barriers on Groundwater Drawdown and Recovery
Author(s) -
Marshall Sarah K.,
Cook Peter G.,
Miller Anthony D.,
Simmons Craig T.,
Dogramaci Shawan
Publication year - 2019
Publication title -
groundwater
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.84
H-Index - 94
eISSN - 1745-6584
pISSN - 0017-467X
DOI - 10.1111/gwat.12856
Subject(s) - drawdown (hydrology) , aquifer , groundwater , dewatering , environmental science , water well , geology , geotechnical engineering , soil science
In large‐scale pumping projects, such as mine dewatering, predictions are often made about the rate of groundwater level recovery after pumping has ceased. However, these predictions may be impacted by geological uncertainty—including the presence of undetected impermeable barriers. During pumping, an impermeable barrier may be undetected if it is located beyond the maximum extent of the cone of depression; yet it may still control drawdown during the recovery phase. This has implications for regional‐scale modeling and monitoring of groundwater level recovery. In this article, non‐dimensional solutions are developed to show the conditions under which a barrier may be undetected during pumping but still significantly impact groundwater level recovery. The magnitude of the impact from an undetected barrier will increase as the ratio of pumping rate to aquifer transmissivity increases. The results are exemplified for a hypothetical aquifer with an unknown barrier 3 km from a pumping well. The difference in drawdown between a model with and without a barrier may be <1 m in the 10 years while pumping is occurring, but up to 50 m after pumping has ceased.