Model and Desk Studies for Feasibility of Sea Route in a Complex Estuary

Development of a Jetty in an estuary with wide tidal flat is quite a challenging job as the approach channel to the deep water is a complicated issue where the disturbance to the natural hydrodynamic behaviour of the sea and the dynamic nature of the sediment movement is to be handled with utmost care. Flat slope causes reduction in velocity and there by formation of mudflats in water way. The design of the shipping channel needs to cater to the required draft for the vessels plying with most efficient hydrodynamic conditions and minimal sediment deposition to cut short the huge cost on maintenance dredging. Model study was taken up by CWPRS to design a shipping channel route inside Tapi Estuary for barges carrying coal of 3.0 MMTPA to a 360 MW coal based thermal power plant at Hazira in Gujarat. This study was conducted in two stages i.e., desk studies and numerical model studies. Initially the bed profile of Tapi Estuary was analyzed in detail and two alternative shipping routes were identified. Subsequently, tidal window analysis was carried out to determine the availability of sufficient draft for the barges to ply during high tide to economize the shipping route. Further studies were carried out to predict the probable zone of siltation and zone of erosion and to arrive at suitable navigational channel with reasonable navigational depth considering tidal window and siltation aspects.