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Flow near a pumped well in an unconfined aquifer under nonsteady conditions
Author(s) -
Streltsova T. D.
Publication year - 1973
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr009i001p00227
Subject(s) - aquifer , geology , discontinuity (linguistics) , water table , drainage , geotechnical engineering , aquifer test , water level , flow (mathematics) , hydraulic head , mechanics , groundwater , mathematics , groundwater recharge , ecology , physics , cartography , geography , biology , mathematical analysis
The problem of unsteady radial flow in an unconfined aquifer is considered as a boundary value problem with discontinuous initial conditions at the surface of the well. The discontinuity of heads occurs at the surface of the well as pumping commences; it dies down in time exponentially and thus represents the delay of the transitional process of reestablishing equilibrium in time. The downward variable movement of water in the vicinity of the well resulting from this discontinuity is proportional to the difference between the gradually falling water table and the average head and is a cause of the slow draining of the unconfined aquifer. The contribution of the unsaturated zone of the aquifer in the process of slow drainage is usually of minor importance and subordinate as far as most drainage problems are concerned. Experimental verification and model design are presented.