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Transient solution for radial two‐zone flow in unconfined aquifers under constant‐head tests
Author(s) -
Chang Y. C.,
Yeh H. D.,
Chen G. Y.
Publication year - 2010
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.7610
Subject(s) - aquifer , head (geology) , hydraulic head , aquifer test , slug test , geology , groundwater , wellbore , skin effect , specific storage , transient flow , petroleum engineering , constant (computer programming) , flow (mathematics) , transient (computer programming) , geotechnical engineering , cone of depression , groundwater flow , soil science , mechanics , geomorphology , engineering , groundwater recharge , physics , electrical engineering , surge , computer science , programming language , operating system
The constant‐head test (CHT) is commonly employed to determine the aquifer parameters. This test is also applied to many environmental problems such as recovering light nonaqueous phase liquids (LNAPL) and controlling off‐site migration of contaminated groundwater in low‐transmissivity aquifers. A well skin near the wellbore may be produced due to the well construction or development and its formation properties are significantly different from the original ones. A more appropriate description for the skin effect on the aquifer system should treat the well skin as a different formation instead of using a skin factor. Thus, the aquifer system becomes a two‐zone formation including the skin and formation zones. This study presents a mathematical model developed for analyzing a two‐zone unconfined aquifer system and the associated solution for CHTs at partially penetrating wells under transient state. The solution of the model may be used either to identify the in situ aquifer parameters or to investigate the effects of the wellbore storage and well skin on the head changes in unconfined aquifers under constant‐head pumping. Copyright © 2010 John Wiley & Sons, Ltd.