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@article{MacAllister:2018:10.1002/2017WR021034,
author = {MacAllister, DJ and Jackson, MD and Butler, AP and Vinogradov, J},
doi = {10.1002/2017WR021034},
journal = {Water Resources Research},
pages = {1669--1687},
title = {Remote detection of saline intrusion in a coastal aquifer using borehole measurements of self potential},
url = {http://dx.doi.org/10.1002/2017WR021034},
volume = {54},
year = {2018}
}
TY - JOUR
AB - Two years of selfpotential (SP) measurements were made in a monitoring borehole in the coastal UK Chalk aquifer. The borehole SP data showed a persistent gradient with depth, and temporal variations with a tidal power spectrum consistent with ocean tides. No gradient with depth was observed at a second coastal monitoring borehole ca. 1 km further inland, and no gradient or tidal power spectrum were observed at an inland site ca. 80 km from the coast. Numerical modeling suggests that the SP gradient recorded in the coastal monitoring borehole is dominated by the exclusiondiffusion potential, which arises from the concentration gradient across a saline front in close proximity to, but not intersecting, the base of the borehole. No such saline front is present at the two other monitoring sites. Modeling further suggests that the ocean tidal SP response in the borehole, measured prior to breakthrough of saline water, is dominated by the exclusiondiffusion potential across the saline front, and that the SP fluctuations are due to the tidal movement of the remote front. The electrokinetic potential, caused by changes in hydraulic head across the tide, is one order of magnitude too small to explain the observed SP data. The results suggest that in coastal aquifers, the exclusiondiffusion potential plays a dominant role in borehole SP when a saline front is nearby. The SP gradient with depth indicates the close proximity of the saline front to the borehole and changes in SP at the borehole reflect changes in the location of the saline front. Thus, SP monitoring can be used to facilitate more proactive management of abstraction and saline intrusion in coastal aquifers.
AU - MacAllister,DJ
AU - Jackson,MD
AU - Butler,AP
AU - Vinogradov,J
DO - 10.1002/2017WR021034
EP - 1687
PY - 2018///
SN - 0043-1397
SP - 1669
TI - Remote detection of saline intrusion in a coastal aquifer using borehole measurements of self potential
T2 - Water Resources Research
UR - http://dx.doi.org/10.1002/2017WR021034
UR - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017WR021034
UR - http://hdl.handle.net/10044/1/56766
VL - 54
ER -