[A-CG33] 陸海相互作用－沿岸生態系に果たす水・物質循環の役割－

[ACG33-P05] 水の安定同位体から見た福井県小浜市若狭地域における陸域と海域の地下水のつながり

*山田 誠¹、杉本 亮²、小路 淳³、本田 尚美¹、小林 志保⁴、富永 修²、谷口 真人¹ (1.総合地球環境学研究所、2.福井県立大学、3.広島大学、4.京都大学)

キーワード：海底湧水, 水の安定同位体, 流出域

The Wakasa area within Obama city, Fukui Prefecture is a very small area where the mountain and the sea connect. Though groundwater is abundant, there is no conspicuous surface outflow in this area. Groundwater may flow into the sea directly. In order to clarify the connection of groundwater between the seabed of the coastal zone and the land, we sampled groundwater under the seabed and at inland wells, and analyzed the water's stable isotopes in this area. The piezometers for collecting groundwater samples in the seabed (depth: 1m) were installed in eight places along the shoreline. The groundwater from inland well was collected at six wells. The results of isotope analysis of these samples show that the groundwater from the seabed was different from groundwater from the inland well. The origin of groundwater collecting near the shore line recharged from a low elevation area. This result shows the possibility that the groundwater from inland well at the village flows at a deeper place, and discharges at a more offshore seabed.