VARIATION CHARACTERISTICS OF GROUNDWATER QUALITY IN TIDAL FLAT DURING FLOOD PERIOD

Abstract

Water environment at tidal flat is maintained by the provision of groundwater in Ota River Floodway during a flood. In this paper, variation characteristics of groundwater quality in the tidal flat, located in 5.4 km upstream from Ota River mouth were investigated by river discharge and groundwater level in Ota Rive Delta. It is considered that salinity of the groundwater in the tidal flat was decreased by outflow of the groundwater in Ota River Delta. The high gradient of water level was formed by high ground water level in the rainy season and small amplitude of the tide under the ground of the delta. As a result, ground water in the delta is easy to flow into the tidal flat.