Improvement and application of numerical model for the simulation of flooding in urban area

The current numerical model for simulating the flooding in urban area is established on the basis of one and two-dimensional unsteady flow theory and the technique of unstructured and irregular grids. The water level is calculated in the centroid of grids and discharge per unit width is calculated on the passages around grids. An improved method that change the parameters of cross-section to varibles is proposed to calculate the water level of river type grids and discharges on special river type passages in order to simulate the flood process in the river with different type cross-section. The method is also convenient for the model to update and extend in time according to the actual harnessing projects of river channels. The application of the improved model to the Jinan city shows that it can simulate the flooding in low-lying area and under railway interchange, flood spreading along streets and flood process in rivers more reliably and provide the imformation for the flood prevention warning and flood control decision-making.