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A Nested Rediscretization Method to Improve Pathline Resolution by Eliminating Weak Sinks Representing Wells
Author(s) -
Spitz Frederick J.,
Nicholson Robert S.,
Pope Daryll A.
Publication year - 2001
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/j.1745-6584.2001.tb02369.x
Subject(s) - sink (geography) , discretization , computer science , wellhead , streamlines, streaklines, and pathlines , fortran , modflow , algorithm , computational science , simulation , mathematical optimization , mechanics , mathematics , petroleum engineering , groundwater , geology , geotechnical engineering , groundwater flow , aquifer , physics , mathematical analysis , cartography , geography , operating system
Abstract This paper discusses a method for overcoming the problem of weak sinks representing wells that result from spatial discretization effects when using MODPATH, the particle‐tracking postprocessor for the ground water low model MODFLQW. Weak sink cells are model cells that represent a well that does not discharge at a sufficiently large rate to capture all of the flow entering the cell; therefore, flowpaths within these cells cannot be uniquely defined because it is impossible to know whether a given water particle discharges to the well or passes through the cell. Creating a submodel of the well cell by using the nested rediscretization method can eliminate this ambiguity by converting the weak sink cell into a strong sink cell. The method is designed to be run manually for each well and for steady‐state conditions. Other advantages, disadvantages, technical considerations, and limitations of the method are presented. Software created for the method consists of five Fortran programs that are operated using a set of instructions. A practical application of the method is presented by using an example wellhead‐protection problem that demonstrates that nested rediscretization can provide more accurate particle‐tracking results than those obtained by using a coarsely discretized model alone.