However, rivers, especially those with complex hydrological boundary conditions, are prone to flood disasters (J. Xia & Chen, 2021). Modeling the river hydrodynamic variation helps to quickly grasp or even forecast the hydrological regime of rivers under changing environment. It is an effective technical means to strengthen water security assessment and water resources management, and convenient for decision makers to develop response plans in time.There are many methods for numerical modeling of rivers with complex boundaries like typical lake-connected rivers (