Temporal variations of groundwater tables and implications for submarine groundwater discharge: a 3-decade case study in central Japan
Fresh submarine groundwater discharge (SGD) is the key pathway of flux and nutrients for the groundwater from land to the ocean. SGD flux is a current issue of discussion and a means to clarify the coastal marine system under climate change. SGD flux accounts for about one-quarter of the river ru...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-07-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/3417/2017/hess-21-3417-2017.pdf |
| Summary: | Fresh submarine groundwater discharge (SGD) is the key pathway of flux and
nutrients for the groundwater from land to the ocean. SGD flux is a current
issue of discussion and a means to clarify the coastal marine system under
climate change. SGD flux accounts for about one-quarter of the river runoff
in the Katakai alluvial fan in Uozu, Toyama, Japan, which is an ideal area to
study SGD flux considering the need for a rapid response to climate change
and the prior research on SGD there. In this paper, the monthly groundwater
table's condition over 30 years is analyzed using monthly rainfall, snowfall,
and the climate change index. Rainfall has been on an upward trend, but the
snowfall has decreased over 40 years. Furthermore, the groundwater table at
monitoring wells in the coastal area increased, as a result of the increased
rainfall. However, the relationship between snowfall and groundwater is
negative. As expected by Darcy's law, SGD flux was controlled by the
hydraulic gradient of the coastal groundwater. The estimated historic SGD
flux by groundwater table variation shows an upward trend of SGD. Considering
the increase in precipitation and the groundwater table, SGD flux may
increase under climate change. |
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| ISSN: | 1027-5606 1607-7938 |