Tidal effects on estuarine water quality through a sandy marine beach: a case study in Vembar estuary, southeast coast of Tamil Nadu, India

Abstract

An integrated study of tidal ingress has been carried out to decipher the cause of wate r quality variation in the Vembar estuary . The present research has been planned in such a way to fix 6 sampling station in the banks and one in the mouth of Vembar estuary. In contrast, tidal level fluctuations, temperature variation, water quality, beach profile and texture analysis of the monitoring stations were studied. The results reveal that the tidal fluctuations are high in the river mouth and it is controlled by sediment texture. The beach profile plays an important role in determining the water quality, in the sense it acts as a barrier between the river mouth and the open sea. But, the sandy beach permits water movement under the beach surface. Thus, increases the chance of seawater mixing. The grain size varies with respect to upstream stations, as clay content is found to be high in those stations. Higher clay content results in poor water transmittance. The temperature in the monitoring stations is influenced by local climatic conditions. The water quality in the study area is found to be quite interesting as station 2 and 4, which have high value except HCO 3. This anomaly is due to the external disturbances due to saltpans and high evaporation rate. The effect of saline intrusion eventually degrades the quality of water in the Vembar estuary. This study is useful to understand the concept of tidal ingress in the estuarine channels and its effect on water quality. A B S T R A C T A R T I C L E I N F O