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Cokriging of Geoelectric and Well Data to Define Aquifer Protective Layers
Author(s) -
Pesti Geza,
Bogardi Istvan,
Kelly William E.,
Kalinski Robert J.
Publication year - 1993
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.1745-6584.1993.tb00863.x
Subject(s) - kriging , geology , aquifer , groundwater , aquifer properties , geostatistics , hydrology (agriculture) , layer (electronics) , spatial variability , soil science , water well , geotechnical engineering , statistics , groundwater recharge , mathematics , chemistry , organic chemistry
Cokriging and ordinary kriging of geoelectric and well data are used to determine the thickness, lateral extent, and spatial variability of a naturally occurring clay layer near Ashland, Nebraska. The clay layer that protects the underlying ground water from contaminant sources is defined by mapping the estimated clay thickness; variance maps provide an assessment of the uncertainty of the thickness estimates. Two types of information are combined in the cokriging procedure: clay thickness data estimated from drillers'logs of 128 irrigation and municipal supply wells, and thicknesses estimated from interpretation of 44 vertical electrical soundings (VES); for the ordinary kriging, well data are used alone. Both types of maps demonstrate the existence of a continuous near‐surface clay layer extending over much of the Ashland wellfield; however, the cokriged map shows much more detail in the central part of the study area, where the well data are undersampled. The relatively dense VES network in the central area provides an important information bridge between the northern and southern areas making the cokriged map more continuous and accurate than the map prepared using the well data alone and ordinary kriging.