Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Time-lapse electrical resistivity imaging of solute transport in a karst conduit
AU - Sawyer, Audrey
AU - Zhu, Junfeng
AU - Currens, James
AU - Atcher, Clay
AU - Binley, Andrew
PY - 2015/11/15
Y1 - 2015/11/15
N2 - The use of electrical resistivity surveys to locate karst conduits has shown mixed success. However, time-lapse electrical resistivity imaging combined with salt injection improves conduit detection and can yield valuable insight into solute transport behaviour. We present a proof of concept above a known karst conduit in the Kentucky Horse Park (Lexington, Kentucky). A salt tracer solution was injected into a karst window over a 45-min interval, and repeat resistivity surveys were collected every 20 min along a 125-m transect near a monitoring well approximately 750m downgradient from the injection site. In situ fluid conductivity measurements in the well peaked at approximately 25% of the initial value about 3 h after salt injection. Time-lapse electrical resistivity inversions show two broad zones at the approximate conduit depth where resistivity decreased and then recovered in general agreement with in situ measurements. Combined salt injection and electrical resistivity imaging are a promising tool for locating karst conduits. The method is also useful for gaining insight into conduit geometry and could be expanded to include multiple electrical resistivity transects.
AB - The use of electrical resistivity surveys to locate karst conduits has shown mixed success. However, time-lapse electrical resistivity imaging combined with salt injection improves conduit detection and can yield valuable insight into solute transport behaviour. We present a proof of concept above a known karst conduit in the Kentucky Horse Park (Lexington, Kentucky). A salt tracer solution was injected into a karst window over a 45-min interval, and repeat resistivity surveys were collected every 20 min along a 125-m transect near a monitoring well approximately 750m downgradient from the injection site. In situ fluid conductivity measurements in the well peaked at approximately 25% of the initial value about 3 h after salt injection. Time-lapse electrical resistivity inversions show two broad zones at the approximate conduit depth where resistivity decreased and then recovered in general agreement with in situ measurements. Combined salt injection and electrical resistivity imaging are a promising tool for locating karst conduits. The method is also useful for gaining insight into conduit geometry and could be expanded to include multiple electrical resistivity transects.
KW - karst
KW - groundwater
KW - electrical resistivity
KW - hydrogeophysics
KW - tracer
U2 - 10.1002/hyp.10622
DO - 10.1002/hyp.10622
M3 - Journal article
VL - 29
SP - 4968
EP - 4976
JO - Hydrological Processes
JF - Hydrological Processes
SN - 0885-6087
IS - 23
ER -