Hydrodynamic Modelling of Severn Bore and its Dependence on Ocean Tide and River Discharge

Abstract

Owing to the high tidal range, the Severn Estuary and Bristol Channel have the potential to generate huge amount of renewable electricity for the UK. During the flood tide, the surging water travels upstream to form the Severn Bore. This study explores the dynamics of the Severn Bore through hydrodynamic modelling, analysing how the tidal amplitude, mean water level, and river discharge affect the bore’s intensity, reach, and sustainability. The Delft3D simulations show that the downstream tidal amplitude plays a critical role. Tides with amplitude less than 6 m will lead to the disappearance of the Severn Bore. The mean water level also significantly influences the bore’s propagation, with a 1.5 meters drop resulting in a 15 km retreat of the bore. A high river discharge rate weakens the bore’s intensity and reduces its reach. These findings underscore the need for careful planning in tidal energy development within the Severn Estuary. Excessive exploitation of tidal energy can be detrimental to the Severn Bore and ecological function of the Estuary.