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Kinematic wave approximation to the transport of Escherichia coli in the vadose zone
Author(s) -
Germann P. F.,
Smith M. S.,
Thomas G. W.
Publication year - 1987
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/wr023i007p01281
Subject(s) - vadose zone , macropore , soil water , water content , soil science , hydraulic conductivity , precipitation , porous medium , flow (mathematics) , subsurface flow , moisture , environmental science , hydrology (agriculture) , geology , geotechnical engineering , porosity , groundwater , chemistry , mechanics , physics , meteorology , mesoporous material , biochemistry , organic chemistry , catalysis
Threshold values for macropore flow parameters that are thought to be critical in the transport of microbial suspensions through macroporous soils were established through the application of a kinematic wave approach to bacterial breakthrough curves. According to the presented examples, moisture content w and conductance b in the macropore systems of four different soils had simultaneously to exceed 0.015 (m 3 /m 3 ) and 0.1 (m/s), respectively, before substantial microbial breakthrough was observed at the bottom of undisturbed columns of macroporous soils with lengths ranging from 0.21 to 0.32 m. The application of these thresholds in a modeling approach to large‐scale flow revealed that hardly any microbes can be transported deeper than 2–3 m in soils when durations and intensities of naturally occurring precipitation events were entered into the model. It was also shown, however, that prolonged or intensified water input to the soil surface may efficiently carry microbes deeper than 100 m into the vadose zone.