Research On 3D Simulation Of Flash Flood Evolution Base On Web GIS And Distributed Hydrological Model

Although Our country has a vast territory,its terrain is mostly dominated by mountains and hills.So,flash floods persistently posing a threat to the lives and properties of the people in our country on a wide spatial scale.At present,most of the digital construction achievements in our country’s flash flood early warning system are still presented through two-dimensional visualization of data,which have some problems such as low information density,high understanding threshold,and poor interactivity.It is not conducive to promoting the development of flash flood prevention and control work in the direction of precision and intelligence Based on the Web GIS technology,combined with the flood modeling method of the distributed hydrological model,the paper realizes the a three-dimensional visualization simulation scheme for the evolution process of flash flood.The simulation results show good spatial expression,intuitively show the evolution process of flash flood,and have good application prospects in flash flood disaster analysis and tolerance assessment.Providing strong data support for formulating evacuation and rescue plans in disaster-prone areas.The main work of the paper is as follows:(1)Determine the evolution range of flash floods.It is proposed to apply the river network modeling method of the distributed hydrological model to the construction of the flash flood river network model in the area where the hydrological observation data is missing.Selecting a disaster-prone area as the research object.Then the DEM data used to produce the model and the river channel data used to verify the modeling effect are collected.The modeling of the flash flood river network is completed through the steps of filling,determining flow direction,and confluence analysis etc.The modeling effect was evaluated by superimposing the river network model,river channel data and satellite images,and the accuracy of the model was verified.(2)Visual simulation of flash flood evolution.A three-dimensional visualization simulation scheme of flash flood evolution process based on Web GIS is proposed.Firstly,the research area is selected based on the river network model.Using Drone tilt photogrammetry technology to collect Image data and product 3D scene model.Then build a spatial database for storing and processing the river network model,and provide the data access interface of the river network model to the visualization front end through the map server.Finally,the simulation of the evolution process of flash floods is realized by combining the scene model and the river network model.The simulation results clearly and correctly reflect the evolution process of torrents,proving the feasibility of the simulation scheme.(3)Application of simulation scheme.Based on the visual simulation scheme of flash flood evolution proposed in this paper,combined with spatial database,map server and front-end visual rendering technology,designing a flash flood submersion simulation platform based on B/S architecture.Realized the functions of flash flood evolution scene simulation and submerged area analysis.The platform has certain application value in the prevention,early warning and rescue of flash flood disasters.Starting from the actual needs of flash flood disaster early warning construction,this paper combines the relevant knowledge and technology in the fields of computer,geographic information and hydrology to realize the three-dimensional visualization simulation of the flash flood evolution process.It provides a new idea for flash flood management.