Study on the Tidal Bore Energy along the Qiantang River Estuary, China

Abstract

Tidal bores inject large amounts of energy to the estuaries, and the variation of tidal bore is related to its energy distribution. In this study, the temporal and spatial changes of the tidal bore energy are investigated to demonstrate the propagation characteristics of tidal bores in the Qiantang River Estuary. Based on high frequency field data, the characteristics of the potential energy and the kinetic energy per unit area during the passage of tidal bores at Yanguan station is demonstrated. Numerical model employing shallow water equations is established to investigate the tidal bore energy along the estuary. Tidal level, tidal current and tidal bore during spring tides in September, 2019 are verified, and the tidal bore energy and its distribution characteristics along the sections from Ganpu to Wenjiayan are illustrated. The tidal bore energy is significantly decreased in the Daquekou reach but decreased relatively small in the reach from Qige to Wenjiayan. There is the maximum energy loss in the Jianshan reach. The tidal bore energy declines to 15% at Wenjiayan during the passage of the energetic breaking tidal bores, indicating tidal bore disappearance in the upstream reach.