Conference proceeding
Groundwater dynamics in a coastal aquifer; combined effects of tides and beach morphology
American Geophysical Union Fall Meeting, Vol.2013
American Geophysical Union 2013 fall meeting (San Francisco, California, 09/12/2013 - 13/12/2013)
12/2013
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Abstract
The interaction between fresh groundwater and seawater, driven by oceanic oscillations and the inland hydraulic head gradient, has been shown to affect the pore water characteristics, which in turn influence the fate of contaminants in coastal aquifers. We show here that beach morphology interacting with the tidal force can also modulate nearshore groundwater flow and solute transport. Detailed field investigations were combined with numerical simulations to examine the groundwater dynamics in a carbonate-sandy intertidal aquifer on the tropical island of Rarotonga, Cook Islands. Groundwater salinity values revealed different salinity distributions under conditions of different beach profiles, inland heads and tidal signals. Fresh groundwater was also found to discharge around an intertidal beach slope break (located in the middle region of intertidal zone). This suggests that the interplay of beach morphology and tidal forcing may play an important role in groundwater flow and solute transport near the shore. The numerical models enabled quantitatively analysis of the effects of beach morphology on groundwater circulations and solute pathway. We found that (1) the groundwater discharge location is largely controlled by beach morphology in connection with the tidal force; (2) under particular conditions, the groundwater flow pattern is very sensitive to the beach slope breaks. In particular, the beach slope break combined with the tidal oscillation can induce local circulation cells. These results further demonstrate the complexity of nearshore groundwater systems and have implications for future studies of nutrients transport and transformations associated with SGD.
Details
- Title
- Groundwater dynamics in a coastal aquifer; combined effects of tides and beach morphology
- Creators
- Y Zhang - University of Queensland, School of Civil Engineering Brisbane, Queensl. AUS AustraliaL LiD ErlerAnonymous
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2013
- Conference
- American Geophysical Union 2013 fall meeting (San Francisco, California, 09/12/2013 - 13/12/2013)
- Publisher
- American Geophysical Union
- Identifiers
- 991012978844302368
- Academic Unit
- Centre for Coastal Biogeochemistry; Faculty of Science and Engineering; Science
- Language
- English
- Resource Type
- Conference proceeding