駿河湾沿岸における海底地下水湧出量の定量的評価(<特集>沿岸海底湧水の地球科学)

概要

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Submarine groundwater discharge (SGD) rates were measured continuously by automated seepage meters to evaluate the processes of groundwater discharge from land to the ocean in the coastal zone of Suruga Bay, Japan. Resistivity under the seabed and land surface were measured to evaluate the freshwater and saltwater interactions in the coastal aquifer. PSD analyses of SGD and groundwater level, show that dominant periods of SGD variations at near shore agree with those of groundwater level changes, and dominant periods of SGD variations at offshore agree with those of sea level changes. Resistivity measurements show that dynamics of fresh-salt water interface in the coastal aquifer changes corresponding to sea level changes. The ratio of terrestrial fresh-SGD to total-SGD was evaluated to be at most 9% by continuous measurements of SGD conductivity. SGD rate near the mouth of Abe River is smaller than those in the other area of the coast, which shows the effect of existence of the river on SGD or the effects of curvature of the bay on SGD. The role of SGD in the basin scale was evaluated from a waterbalance method in the Abe river basin. The SGD was estimated to be 39% of total discharge in the basin.
日本地球化学会の論文
2005-08-20