Submarine groundwater (SGW) flux, not only discharge but also recharge, near the intertidal zone is relatively rich. In this study, submarine groundwater and total phosphorus balance corresponded to the tidal period near the intertidal zone of Omae-beach was estimated by the budget analysis using the marine observation data. Water and salt budgets of the analyzed area is dominated by the through flow. But TP budget did not balanced when submarine groundwater was neglected. The ratio of TP volume supplied by submarine groundwater discharge to it by submarine groundwater recharge is 97 %. Moreover the ratio of TP volume supplied by Submarine groundwater for the variation of TP volumes of the area is 49 % in the maximums. As TP concentrations of the outer and inner part of the area are close, diffusion is small. When the benthic flux of phosphorus of the previous study is applied to our study area, release volume from pore water is just 2 %. Therefore the recirculated saline water plays the important role in material transport from pore water to water column. Submarine groundwater discharge even during high tide. It is not agrees with the previous opinion. On the other hand, the estimated discharge rate shows good agreement with direct measurement result of a year ago.
Fresh water is discharged from the seabed due to the difference of hydraulic head between the water table and the sea surface. It is called submarine fresh groundwater discharge (SFGD). Sea water is recharged to the seabed due to the tidal pumping and the wave setup, and is discharged from the seabed. The former is submarine groundwater recharge (SGR), the later is recirculated saline groundwater (RSGD). Thus sea water and pore water are exchanged at the seabed, and materials are also exchanged at the same time (Taniguchi et. al., 2002).
