OPTIMIZATION OF MIKE21 RIVER NETWORK DRAINAGE SCHEME BASED ON DYNAMIC PLANNING THEORY

To address the problem of flooding caused by the poor drainage capacity of the river network in the southern plain during the flood season, this study selected the river network of Shenzhuangyang polder in Nanxun district of Taihu Lake basin as the research object, and the storm intensity of the corresponding flood control standard for urban drainage, applied the multi-objective dynamic planning theory, took the water level and drainage time of the river network as the limiting target, combined the existing water conservancy engineering parameters and scheduling rules in the polder area, and set up three sluice gates based on the topographic and hydrological data of the river network. A MIKE21 river network hydrodynamic model was constructed to quantitatively simulate and analyze the drainage effect of the river network under the joint regulation and control of the gates and pumps. The results showed that:when facing a rainstorm with a returning period of 10 years or less, the river network could adopt the sluice gate drainage scheme, and all three schemes could reduce the water level to the lower limit of drainage within 24 h; when facing a rainstorm with a returning period of more than 20 years to one hundred years, the river network needed to adopt the pump drainage scheme of internal and external network linkage. Except in the case of 1 pump at the western gate, which does not meet the 100-year drainage requirement, at least 2 pumps at the western gate must be opened to ensure that the water level is lowered to the lower limit within 24h, The drainage effect is positively related to the number of pumps on The results of the study can provide a theoretical basis for the scheduling of flooding and the renovation of river networks in the southern plain. The results of the study can provide a theoretical basis for flood drainage scheduling and river network renovation in the southern plain river network.