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Numerical versus field studies of delayed yield in response to a moving water‐table
Author(s) -
Gutub S. A.,
Awadalla S. A.
Publication year - 1994
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.3360080505
Subject(s) - vadose zone , aquifer , water table , yield (engineering) , flux (metallurgy) , mechanics , flow (mathematics) , water content , computer simulation , geology , soil science , richards equation , geotechnical engineering , exponential function , work (physics) , moisture , groundwater , mathematics , thermodynamics , meteorology , materials science , physics , mathematical analysis , metallurgy
As pumping proceeds in an unconfined aquifer the water‐table is lowered and slowly drains out of the initially saturated material giving a delayed yield from storage. Although considerable work has been carried out on delayed yield, a definitive solution is still lacking. The unsaturated zone was treated here as a significant factor in delayed yield analysis. The one‐dimensional unsaturated flow equation was solved numerically to simulate the flow in the zone located between successive water levels in the unconfined aquifer for the case with zero flux at the upper boundary. The moisture content distribution curve was integrated numerically to determine the amount of water drained with time. The study shows that the numerical results are in close agreement with the monitored field data, which implies the important role of the unsaturated zone and the reliability of the numerical simulation in describing this physical phenomenon. The results show that the relationship between the flux and time is sensibly in exponential form, which agrees with the general applicability of Boulton's assumption.