1887

Abstract

Summary

Drinking water supply for the indigenous community on Milingimbi Island in the Northern Territory of Australia, is sourced from a freshwater lens beneath the island. Recent studies have suggested that this resource, vulnerable to saltwater intrusion, may not be capable of supplying the future water needs of the community because of the combined effects of climate change and projected demand. This study examined the value of complimentary hydrogeophysical data sets, specifically surface nuclear magnetic resonance (sNMR) and air and ground EM, to extend an understanding of the Islands’ groundwater system, and assist in the management of the aquifer systems present, including development of new production bores for supplementary water supply to the community. The geophysical data indicated that the freshwater resource on Milingimbi extends to ∼50m below the surface, largely confined to the weathered Cretaceous sedimentary package, but extending into underlying Cambrian metasediments. Geological logs indicate that the Islands’ aquifer system is spatially complex in composition. The sNMR data suggests that it is characterised by significant variations in lateral and vertical hydraulic properties. Modelled sNMR data and EM data imply that the sedimentary sequence should be considered as a fully connected, unconfined aquifer, with interconnected, higher yielding, facies.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.202472011
2024-05-13
2025-12-12
Loading full text...

Full text loading...

References

  1. Banks, E.W., Post, V.E.A., Meredith, K., Ellis, J., Cahill, K., Noorduijn, S., and Batelaan, O. [2021] Fresh groundwater lens dynamics of a small bedrock island in the tropics, Northern Australia.Journal of Hydrology, pp. 1–15, doi: https://doi.org/10.1016/j.jhydrol.2020.125942
    [Google Scholar]
  2. Davis, A.C., Cahill, K., Hatch, M. and Munday, T.J. [2012] Aquifer characterisation in the Uley South Basin, South Australia, using NMR: Final Report.CSIRO: Water for a Healthy Country National Research Flagship Technical Report (EP-31-01-12-14)
    [Google Scholar]
  3. Falkland, A. [1991] Hydrology and water resources of small islands: a practical guide. A contribution to the international hydrological programme (Tech. Rep.). United Nations Educational, Scientific and Cultural Organization.
    [Google Scholar]
  4. Falkland, A. [1993] Hydrology and water management on small tropical islands.Proceedings of an international symposium held at Yokohama, Japan, 13–15 July, 1993.
    [Google Scholar]
  5. Martin, K. [1991] Milingimbi geophysical salinity assessment (Tech. Rep. No. Report No.81/1991). Water Resources Power and Water Authority
    [Google Scholar]
  6. Maurer, J., and Knight, R. [2016] Models and methods for predicting hydraulic conductivity in near-surface unconsolidated sediments using nuclear magnetic resonance.Geophysics, 81(5), D503–D518. https://doi.org/10.1190/geo2015-0515.1
    [Google Scholar]
  7. Soerensen, C.C., Munday, T.J., Cahill, K., Jolley, P., Houthuysen, L., Banks, E., Ellis, J. and Ibrahimi, T. [2020] Hydrogeophysical Investigation of Milingimbi Island, Northern Territory; Final Report. CSIRO Technical Report EP19130; CSIRO, Australia.
    [Google Scholar]
  8. Terry, J.P., and Falkland, A.C. [2010] Responses of atoll freshwater lenses to storm-surge overwash in the Northern Cook Islands.Hydrogeology Journal. 1;18(3):749.
    [Google Scholar]
  9. Walsh, D.O. [2008] Multi-channel surface NMR instrumentation and software for 1D/2D groundwater investigations.Journal of Applied Geophysics, 66(3–4), 140–150. https://doi.org/10.1016/j.jappgeo.2008.03.006
    [Google Scholar]
  10. Walsh, D.O., Grunewald, E.D., Turner, P., Hinnell, A., and Ferre, T.P.A. [2014]. Surface NMR instrumentation and methods for detecting and characterizing water in the vadose zone.Near Surface Geophysics, 12(2), 271–284. https://doi.org/10.3997/1873-0604.2013066
    [Google Scholar]
  11. Werner, A.D., Sharp, H.K., Galvis, S.C., Post, V.E.A., and Sinclair, P. [2017] Hydrogeology and management of freshwater lenses on atoll islands: review of current knowledge and research needs.J. Hydrol. 551, 819–844. https://doi.org/10.1016/j.jhydrol.2017.02.047
    [Google Scholar]
  12. White, I., and Falkland, A. [2010] Management of freshwater lenses on small Pacific islands.Hydrogeol. J. 18 (1), 227–246. https://doi.org/10.1007/s10040-009-0525-0
    [Google Scholar]
  13. Woodgate, M. [2014] Milingimbi hydrogeological investigation 2013. Prepared for Power and Water Corporation, Northern Territory.Territory Groundwater Services (Tech.Rep.). Power and Water Corporation, Winnellie, 0821. Northern Territory
    [Google Scholar]
/content/papers/10.3997/2214-4609.202472011
Loading
/content/papers/10.3997/2214-4609.202472011
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error