Effect of ship-lock-induced surges on navigation safety in a branched lower approach channel system

Ships docking and traveling in a branched lower approach channel system are at risk from surges caused by multi-lane locks during emptying operations. For this reason, water-level variations in the lower approach channel in response to discharge, interval running time, and outlet location of lock operations were studied using a 2-D hydrodynamic model validated by physical model tests, and the impact of water level variation on navigation safety under extreme operation scenarios of a quadruple-lane lock group was identified. Results indicated that discharge and interval running time of lock emptying had the greatest impact on the water level variation at the lock head. Water level variation at the lower lock head of the ship lift exhibited a trend of first decreasing and then increasing with the increment of the discharge from the lock chamber into the outer river. Specifically, the surge height at the lock head of the ship lift reached the minimum when approximately 40% of the discharge generated by dual-lane locks during emptying operations was released into the outer river. Overall, the simultaneous operation of quadruple-lane lock group and unit load rejection should be avoided in engineering applications.