Regulation functions in the Beilun estuary by tidal numerical simulation

Abstract

It is a relatively short distance from mountains to the sea for the Beilun river. Its runoff seasonally varies with strong flooding and less sand. The mangroves are unique and spread wildly in the estuary to maintain a stable riverbed by scouring the waves and currents. However, the regulation structures built along the estuary by both China and Vietnam were not well-designed according to the laws of flow and sediment movement. A numerical model has been developed to simulate the functions of the regulations in this paper. Today, the shape of the estuary is mostly formed by the regulation structures. The discharge ratio and velocity changes are displayed to reveal the effects of the regulations. Coriolis force is intended to drive the flooding and ebbing flow in different ways, so the south passage usually becomes deeper and larger while the river island usually connects to the north shore in the northern portion of the earth. However, this phenomenon has not properly worked in this region, likely due to other manmade activities and the mangroves defending the shallows from scouring while the regulations are directing the flow currents.