Research And Application Of Hydrological And Hydrodynamic Coupling Model In Small Watershed

In the context of the frequent occurrence of river and lake problems such as water disasters,water ecology,and water resources,the local government first proposed an innovative river and lake management system with Chinese characteristics—the river length system,which broke the existing situation of water management in Kowloon and put the The task of river and lake management is unified and the related river and lake problems are resolved.Among the nine major tasks of the river length system,the problem of weak links in river channels is considered as one of the important factors for river flood management tasks.Numerical simulation of river floods is an important technical means for river flood management.Current simulations of river flood processes are mainly divided into hydrological methods based on water balance and trough storage equation and hydrodynamic methods based on Saint Venant’s equation as The main two categories,the former is difficult to simulate the river surface submergence process,the latter has insufficient consideration of the hydrological mechanism of the river flood submergence process.In order to study the hydrological process and hydrodynamic process mechanism of river floods,the hydrological and hydrodynamic processes and a two-dimensional hydrodynamic coupling mechanism are used to calculate the flood evolution process of the river channel by numerical simulation.The simulation results are used to understand the existing river channels.At the same time as the flow situation,the flood prevention capacity of the existing river is analyzed to predict the scope of the flood disaster,so as to achieve the purpose of prevention.Provide a technical basis for the establishment of a flood forecast information management system by the river length system.This research uses MIKE series software,taking Liwan River in Henan Province ** as an example.Based on hydrological and hydrodynamic processes and one-dimensional and two-dimensional hydrodynamic coupling,a MIKE FLOOD coupling numerical model is constructed for numerical simulation of floods,and small watershed river channels are developed.Numerical study of coupled hydrological and hydrodynamic models of floods.The main results of this research are as follows:1.Extract the terrain elevation data of the river basin from Google earth map,make the MIKE terrain elevation file,extract the local river section from the terrain data collected by the drone,and combine it with the terrain elevation data to build a hydrological model and one or two dimensions.The topographical data of the hydrodynamic model,combined with the relevant data,are used to select the channel roughness and other model parameters.2.The basic principles of the MIKE hydrological model and the hydrodynamic model are elaborated,and the structure and process coupling mechanism between modules is analyzed.Using basic data,a hydrological and hydrodynamic coupling model is constructed.In the coupling process of the model,firstly,the MIKE SHE hydrological model and the MIKE 11 one-dimensional hydrodynamic model are loosely coupled in one direction,and then the MIKE 11 one-dimensional hydrodynamic model and the MIKE 21 FM two-dimensional hydrodynamic model are tightly coupled.A hydrological and hydrodynamic coupling model is constructed that conforms to the characteristics of hills and plains.3.The new method of dividing hills and plains is used to calculate and design the flood course.The HEC-RAS software is used to simulate the flood surface line of the river.The HEC-RAS calculation results are collected with the measured data collected.Comparative analysis to determine the rationality of the results of the HEC-RAS model.The results are compared with the simulation calculation results of the hydrological and hydrodynamic coupling model.In the end,it is concluded that the accuracy of the hydrological-hydrodynamic coupling model is more in line with the actual situation than the HEC-RAS model.4.Combine the flood simulation results to analyze the river flow situation,and make a flood inundation analysis map for 10 years,providing technical support for the river-based information management.