A numerical investigation on the tide-induced residence time and its association with the suspended sediment concentration in Gulf of Khambhat, northern Arabian Sea

Abstract

A 2D-numerical model is used to estimate suspended sediment (SS) transport and residence time (RT) of the Gulf of Khambhat (Gulf). Tidal current, as well as bottom topography, play a key role in sediment entrapment inside the Gulf and hinders the SS exchange between Gulf and Arabian Sea. The northern and central regions of the Gulf experiences high RT throughout the year. RT of more than a month were recorded in the northern region of the Gulf where SS concentration was also high (>500 mg/l). A barrier formed during non-monsoonal months cause distinct RT and SS in the Gulf compared to Arabian Sea. During monsoon, a partial withdrawal of the barrier could be seen leading to lower RT inside the Gulf, especially in the southern region. Whereas, the SS plume resided in the northern region even during the monsoon. Present study infers that particle entrapment occurs inside Gulf for a prolonged period.