Groundwater Level Variation and Salt Infiltration in a Tidal Flat with Tidal Cycle

Abstract

In this paper, field observations were performed in order to clarify the mechanism of groundwater level rising, and variation of groundwater quality under the influence of tidal cycle. Moreover, laboratory experiments using one dimensional infiltration apparatus were conducted to investigate the behavior of salinity in a tidal flat. Observation results suggested that groundwater level rising is occurred by rising of deeper layer of groundwater when river water level is lower than ground level. From laboratory experiments, it was cleared that separation of pore water in free water and bound water is important to consider the behavior of salinity. Ratio of free water increased with increasing of void ratio and decreasing of infiltration velocity. Salinity of bound water varied with infiltration of salt or fresh water.