Unsaturated zone travel time to groundwater on a vulnerable site

Authors

  • Karl Richards Teagasc
  • Catherine E. Coxon Trinity College Dublin
  • Michael Ryan Teagasc

DOI:

https://doi.org/10.55650/igj.2005.331

Abstract

A bromide (Br) tracing experiment was conducted to ascertain unsaturated zone travel time to groundwater on a site with a karstified limestone aquifer overlain by a thin free-draining overburden. Br tracer was applied to areas surrounding two boreholes; soil solution and groundwater Br concentrations were monitored. Bromide was first detected after eight and 34 days in the soil solution and groundwater. The quick break-through of the applied Br in the soil solution and groundwater indicates the presence of preferential flow in the soil at this site. The time to maximum groundwater Br concentration supports a dominant matrix flow path through the overburden and then preferential flow through the unsaturated limestone bedrock. The results indicated that the transport of conservative contaminants, such as nitrate, can be expected to occur in a single recharge season. The occurrence of preferential flow raises concerns over rapid transport of non-conservative contaminants such as faecal coliforms and this merits further investigation.

Author Biographies

Karl Richards, Teagasc

Johnstown Castle, Wexford

Catherine E. Coxon, Trinity College Dublin

Department of Geology

Michael Ryan, Teagasc

Johnstown Castle, Wexford

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Published

2015-01-05

How to Cite

Richards, K., Coxon, C. E., & Ryan, M. (2015). Unsaturated zone travel time to groundwater on a vulnerable site. Irish Geography, 38(1), 57–71. https://doi.org/10.55650/igj.2005.331

Issue

Vol. 38 No. 1 (2005): Issue 1

Section

Original Articles

URN

http://nbn-resolving.de/urn:irg:ie:0000-igj.v38i1.3315

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