Cokriging of geoelectric and well data to define aquifer protective layers
- Univ. of Nebraska, Lincoln, NE (United States)
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 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 in 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.
- OSTI ID:
- 5777342
- Journal Information:
- Ground Water; (United States), Journal Name: Ground Water; (United States) Vol. 31:6; ISSN GRWAAP; ISSN 0017-467X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
AQUIFERS
CLAYS
CONTAMINATION
CONTROL
DEVELOPED COUNTRIES
ENVIRONMENTAL QUALITY
GEOLOGY
GROUND WATER
HYDRAULIC CONDUCTIVITY
HYDROGEN COMPOUNDS
MAPPING
NEBRASKA
NORTH AMERICA
OXYGEN COMPOUNDS
POLLUTION CONTROL
USA
WATER
WATER POLLUTION CONTROL
WATER QUALITY