Evaluations of Origins and Material Transports of Submarine Groundwater Discharge

三种不同的方法，包括（1）在陆地水文研究，（2）海岸带研究，（3）海洋研究，已经完成了评估的SGD和海水-淡水相互作用在骏河湾，日本。研究区域是阿部河流域，包括海岸带和骏河湾的近海。2001年至2003年进行了测量。通过对钻孔和渗漏沃茨中地下水的稳定同位素（O-18和D）和化学成分的分析，评价了盆地地下水流系统和物质从陆地向海洋的迁移。在沿海地区，通过使用自动渗透仪和压力计以及用层析成像法进行的电阻率测量，对SGD进行了连续测量，以评估淡水和海水之间的相互作用。R/V Tansei-maru在骏河湾进行了海上测量，通过岩心钻探提取海床以下的孔隙水，在海床以上进行CTD测量，并进行了重复测量。在沿着和近海安装的自动渗透仪可以及时地获得高分辨率的SGD，从而清楚地发现了潮汐对SGD的影响; SGD速率与气压成反比关系;在海岸带每隔3小时测量一次的电阻率，显示了由于海平面的变化而引起的淡水-盐水界面的变化。通过对渗漏地下水电导率的连续测量，发现10%的SGD为淡水，90%的SGD为循环海水。

Three different approaches including (1)hydrological studies in the land,(2)coastal zone studies, and (3)oceanic studies, have been done to evaluate the SGD and seawater-fresh water interaction in the Suruga Bay, Japan. The study area is the Abe river basin including the coastal zone and the offshore of the Suruga Bay. Measurements have been done from 2001 to 2003. Analyses of stable isotopes (O-18 and D) and chemical components of groundwater in boreholes and seepaged waters have been made to evaluate the groundwater flow system in the basin and material transports from the land to the ocean. In the coastal zone, continuous measurements of SGD have been done by using automated seepage meters and piezometers, as well as resistivity measurements with tomography method to evaluate the interaction between fresh water and seawater. Offshore measurements in the Suruga Bay by R/V Tansei-maru, have been made by core boring to extract pore water below the seabed, CTD measurements above the seabed, and ROV measurements. The automated seepage meters which were installed along the coastal zone and offshore can tell us high resolutions of SGD in time, therefore, the tidal effects on SGD were clearly found. Inverse relationships between SGD rate and barometric pressure were also found. Resistivity measurements every three hours in the coastal zone showed the changes of the freshwater-saltwater interface due to the sea level change with the time delay. According to the continuous measurements of conductivity of the seepaged groundwater, 10 percent of the SGD was the fresh water, and the 90 percent of the water was the recirculated seawater.