TY - JOUR
T1 - SPATIAL DISTRIBUTIONS IN GROUNDWATER DISCHARGE ON VARIOUS TIDAL FLATS IN A SMALL AND STEEP ISLAND, WESTERN JAPAN
AU - Nozaki, Shingo
AU - Onodera, Shin Ichi
AU - Tomozawa, Yusuke
AU - Saito, Mitsuyo
N1 - Funding Information:
This research was supported by JSPS KAKENHI Grant 18H04151 and 18H03411. We appreciate the reviewers and editors for their suggestions, and Ms. Morita and Mr. Hanioka for their cooperation.
Publisher Copyright:
© 2021 Int. J. of GEOMATE. All Rights Reserved.
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/5
Y1 - 2021/5
N2 - To manage and conserve the seagrass bed and ecosystem in tidal flats, this study examined to confirm spatial distribution in groundwater (SGD) on tidal flats with the area of around 100 m square in a small and steep island. Various groundwater and nutrient discharges were observed at the W and E sites. 1) Based on the water budget, the groundwater flux was estimated to be 8.68 m/yr or 23.9 mm/day in E, and 17.75 m/yr or 48.6 mm/day in W, respectively. 2) Spatial distributions of groundwater contribution ratio (%) in pore water at W was around 60% in average, which was 8 times of that in E site. 3) The NO3-N concentration in pore water at W site was about 30 times of that at E because of the low attenuation rate with high groundwater velocity. 4) The temporal variation in groundwater flux with tidal fluctuation indicated 2.5 m/day in maximum and -4.0 m/day in minimum. This huge difference between the average flux and maximum indicated also large seawater recirculation and heterogeneous distribution of SGD. This heterogeneous distribution at this tidal flat would contribute to the activity of seagrass and diversity of ecosystem.
AB - To manage and conserve the seagrass bed and ecosystem in tidal flats, this study examined to confirm spatial distribution in groundwater (SGD) on tidal flats with the area of around 100 m square in a small and steep island. Various groundwater and nutrient discharges were observed at the W and E sites. 1) Based on the water budget, the groundwater flux was estimated to be 8.68 m/yr or 23.9 mm/day in E, and 17.75 m/yr or 48.6 mm/day in W, respectively. 2) Spatial distributions of groundwater contribution ratio (%) in pore water at W was around 60% in average, which was 8 times of that in E site. 3) The NO3-N concentration in pore water at W site was about 30 times of that at E because of the low attenuation rate with high groundwater velocity. 4) The temporal variation in groundwater flux with tidal fluctuation indicated 2.5 m/day in maximum and -4.0 m/day in minimum. This huge difference between the average flux and maximum indicated also large seawater recirculation and heterogeneous distribution of SGD. This heterogeneous distribution at this tidal flat would contribute to the activity of seagrass and diversity of ecosystem.
KW - Island
KW - Spatial distribution
KW - Submarine groundwater discharge
KW - Tidal flat
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U2 - 10.21660/2021.81.6131
DO - 10.21660/2021.81.6131
M3 - Article
AN - SCOPUS:85101549854
VL - 20
SP - 66
EP - 71
JO - International Journal of GEOMATE
JF - International Journal of GEOMATE
SN - 2186-2982
IS - 81
ER -