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Recharge‐induced groundwater flow over a plane sloping bed: Solutions for steady and transient flow using physical and numerical models
Author(s) -
Chapman T. G.
Publication year - 2005
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 - 10.1029/2004wr003606
Subject(s) - outflow , groundwater recharge , hydrograph , mechanics , geology , flow (mathematics) , free surface , groundwater flow , transient (computer programming) , groundwater , geotechnical engineering , hydrology (agriculture) , aquifer , physics , computer science , operating system , ecology , oceanography , surface runoff , biology
The free surface profile and outflow hydrograph for groundwater under conditions of steady uniform recharge followed by recession have been studied in viscous fluid model tests, using a sloping bed with a gradient of 0.2. The data have been compared with the nonlinear Boussinesq model and a modification of that model simulating the outflow seepage surface, obtained from a finite difference solution of the free boundary problem. It is shown that for a given bed slope, there is close to a linear relationship between outflow and storage raised to a power n, where n ranges from almost 2 for zero slopes to just above 1 at a gradient of 0.3. There is also a simple relationship between outflow and storage in the final stage of recession, when a drainage front occurs on the bed. These results lead to simple algorithms for prediction of the outflow under unsteady recharge conditions.