| Title: |
Self potential monitoring of saline intrusion dynamics in a coastal sand aquifer |
| Authors: |
Butler, Adrian P.; Rowan, Thomas; Jackson, Matthew; McDonnell, Mark; Fernandez Aguila, Jesus; Benner, Eric; Flynn, Raymond; Donohue, Shane; Hamill, Gerard |
| Source: |
Butler, A P, Rowan, T, Jackson, M, McDonnell, M, Fernandez Aguila, J, Benner, E, Flynn, R, Donohue, S & Hamill, G 2022, 'Self potential monitoring of saline intrusion dynamics in a coastal sand aquifer', European Geophysical Union Spring Assembly 2022, Vienna, Austria, 23/05/2022 - 27/05/2022. https://doi.org/10.5194/egusphere-egu22-12643 |
| Publication Year: |
2022 |
| Collection: |
Queen's University Belfast: Research Portal |
| Subject Terms: |
/dk/atira/pure/sustainabledevelopmentgoals/clean_water_and_sanitation; name=SDG 6 - Clean Water and Sanitation |
| Description: |
Greater groundwater abstraction combined with possible reductions in recharge rates are likely to be detrimental to the long-term viability of groundwater resources (Mehdizadeh, 2019). An additional issue specifically affecting coastal aquifers is saltwater intrusion (SI). The key processes governing SI have been long understood but monitoring the ingress of saline water into coastal aquifers and especially its risk to abstraction sources is still a complex and costly exercise (Graham, 2018). Here we build on evidence that self potential (SP) could be a useful tool for remotely tracking the movement of saline-freshwater interfaces associated with SI. The work reported describes SP response, along with water level, temperature and electrical conductivity measurements from an array of piezometers under ambient and pumped conditions on a beach aquifer located on Benone Strand, on the northern tip of Northern Ireland, UK. These data are supplemented by time-dependent electrical resistance tomography (ERT) obtained from the BGS PRIME system. Self potential voltages arise from subsurface pressure and concentration gradients (Jackson et al., 2012). These gradients can cause ion separation, which gives rise to an electrical potential and a flow of electrons in order to maintain electrical neutrality. The potentials (typically in the millivolt range) can be detected and logged in the field using installed electrodes. There are two main types of SP; electro-kinetic potentials (VEK), due to differential flow velocities, and exclusion-diffusion potentials (VED), due to ion concentration gradients with different mobilities. SP has been shown to have a response to pumping tests in (Jackson et al., 2012), though this was limited in scope. In a longer-term study, tidal signatures in SP were recorded in a Chalk borehole less than 2 km inland from the English Channel (MacAllister, 2016). Separating out these two sources of SP can be challenging. Comparing SP and ERT responses coupled with groundwater level changes show tidal ... |
| Document Type: |
conference object |
| Language: |
English |
| DOI: |
10.5194/egusphere-egu22-12643 |
| Availability: |
https://pure.qub.ac.uk/en/publications/ed1557d1-3b70-4c0a-9587-217fd70e971b; https://doi.org/10.5194/egusphere-egu22-12643 |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.CF08C29E |
| Database: |
BASE |