Method and system for simulating flood in transition area of'drainage basin-city 'system
The flood simulation method and system enhance precision in modeling the transition zone between river basins and urban areas by dynamically identifying boundaries and applying specific runoff calculations, addressing the imprecision in existing methods.
Patent Information
- Application Number
- CN202411168145.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2024-12-20
AI Technical Summary
Existing flood simulation methods fail to effectively address the transition between the river basin and urban areas, neglecting the direct flow of natural watershed into urban regions, leading to imprecise flood coupling calculations.
A flood simulation method and system that dynamically identifies hydraulic connection boundaries, divides the transition zone into natural watershed and urban parts, calculates runoff separately, and uses nonlinear reservoir and two-dimensional hydrodynamic equations to refine the coupling calculation, considering slope confluence and flow types.
Enhances the precision of flood simulation by accurately modeling the hydrological processes in the transition zone, providing precise boundary conditions for urban flood calculations and improving the flood coupling simulation of the 'watershed-city' system.
Smart Images
Figure CN119167814A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of flood simulation, and in particular to a method and system for simulating flood in a transition zone of a "watershed-city" system. Background Art
[0002] With the deepening of urbanization and the development of industrial scale and agglomeration, the river basin has evolved into a system with deep coupling between the river basin and the city. In the existing flood coupling calculation method of the "watershed-city" system, the river basin flow is usually used as the boundary condition of urban flood calculation in the form of upstream river inflow, which lacks consideration of the flow of natural river basin flow directly entering the urban area. Summary of the invention
[0003] The purpose of the present invention is to provide a flood simulation method and system for the transition zone of a "watershed-city" system. This method mainly focuses on the internal hydrological process of the catchment area where slope runoff in a natural watershed directly enters the urban area, making the coupling calculation of the "watershed-city" system more refined.
[0004] In order to achieve the above technical features, the purpose of the present invention is achieved as follows: a flood simulation method for a transition zone of a "watershed-city" system comprises the following steps: Step 1: Dynamically identify the hydraulic connection boundaries of the basin cities: Boundary recognition based on water flow morphology; Step 2, transition zone division: The transition zone is divided into a natural watershed part and an urban part according to the identified boundaries; Step 3, flow calculation in transition zone: The runoff generation process of the natural watershed and the urban part is calculated separately. The natural watershed is taken as a whole as a calculation unit to calculate the surface runoff, subsoil flow and return flow process. The surface runoff generation of the urban part is calculated grid by grid. Step 4, calculation of flow in transition zone: The nonlinear reservoir method is used to calculate the runoff in the natural watershed, which is then combined with the surface runoff and return flow and evenly distributed to the boundary grid as the external boundary for the runoff calculation in the urban part. The two-dimensional hydrodynamic equation is used to calculate the runoff in the urban part.
[0005] Preferably, the specific process of step 1 is: Based on terrain data, the area with large slope changes is selected as the initial boundary between the natural watershed and the urban area in the transition zone. Then, the Froude number is calculated according to the flow velocity and water depth in the overland confluence process. Based on the Froude number, the overland flow is identified as a torrent or a slow flow, and the transition point from the torrent to the slow flow is determined. The boundary between the natural watershed and the urban area in the transition zone is dynamically adjusted. ; In the formula, is the Froude number of the slope confluence process, is the water flow velocity, is the acceleration due to gravity, For water depth.
[0006] Preferably, the specific process of step 2 is: According to the transition point from the rapids to the slow flows, the area where the rapids appear in the transition zone is divided into the natural basin part, and the area where the slow flows appear in the transition zone is divided into the urban part.
[0007] Preferably, the specific process of step 3 is: Step 3.1, natural watershed partial runoff: Taking the natural watershed as a whole, calculate the surface flow, subsoil flow and return flow; Step 3.2, urban part runoff: The urban part is divided into grids and surface runoff is calculated.
[0008] Preferably, the specific process of step 4 is: The natural watershed as a whole is taken as a calculation unit, and the nonlinear reservoir method is used to calculate the confluence process on the boundary. The confluence of the natural watershed is combined with the surface runoff and return flow and then evenly distributed to the boundary grid of the urban part as the external boundary of the confluence calculation of the urban part. The two-dimensional hydrodynamic equation is used to calculate the confluence of the urban part grid by grid.
[0009] A flood simulation system for a transition zone of a "watershed-city" system, the simulation system being used to implement the simulation method, comprising: Dynamic identification of watershed-urban hydraulic connection boundary module: Based on terrain data, select the area with large slope changes as the initial boundary between the natural watershed and the urban area in the transition zone, then calculate the Froude number based on the flow velocity and water depth during the slope confluence process, identify the slope flow form as a torrent or slow flow based on the Froude number, determine the transition point from the torrent to the slow flow, and dynamically adjust the boundary between the transition zone and the urban area; Calculation module for coupled flow generation and runoff zones: divides the transition zone into natural watershed and urban areas according to the identified boundaries; Runoff generation module: Calculate the runoff generation process of the natural watershed and the urban part respectively. The natural watershed is taken as a whole as a calculation unit to calculate the surface runoff, subsoil flow and return flow process. The urban part calculates the surface runoff grid by grid. Confluence module: The nonlinear reservoir method is used to calculate the confluence in the natural watershed part, which is combined with the surface runoff and return flow and then allocated to the boundary grid as the external boundary of the urban part. The confluence is calculated using the two-dimensional hydrodynamic equation in the urban part.
[0010] The present invention has the following beneficial effects: 1. The present invention provides a flood simulation method for the transition zone of a "watershed-city" system. Compared with the existing methods, this method mainly focuses on the internal hydrological process of the catchment area where the slope confluence in the natural watershed directly enters the urban area, making the coupling calculation of the "watershed-city" system more precise.
[0011] 2. This method can calculate the hydrological process of slope runoff directly entering the urban catchment area, provide boundary conditions for urban area surface flood calculations, and improve the calculation mechanism of flood coupling simulation of the "watershed-city" system. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0013] Figure 1 This is a schematic diagram of the spatial location of the transition zone of the "watershed-city" system of the present invention.
[0014] Figure 2 This is a flow chart of flood calculation in the transition zone of the "watershed-city" system of the present invention. DETAILED DESCRIPTION
[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0016] Embodiment 1: See also Figure 1-2In the existing flood calculation methods of the "watershed-city" system, the watershed flow is usually used as the boundary condition for urban flood calculation in the form of upstream river inflow, and the flow of natural watershed flow directly entering the urban area is not considered. The transition zone mainly focuses on the internal hydrological process of the catchment area where the slope flow in the natural watershed directly enters the urban area, focusing on the flow process at the junction of the watershed and the city. Its slope flow process is the input boundary of the surface flood in the urban area, which is of great significance to the coupled flood simulation of the "watershed-city" system.
[0017] The present invention proposes a method for calculating the hydrological process in the transition zone of the "watershed-city" system. The main steps are as follows Figure 1 As shown: Step 1, dynamically identify the hydraulic connection boundary between the river basin and the city: Based on the terrain data, select the place with large slope changes as the initial boundary between the transition zone and the urban area, and then calculate the Froude number according to the water flow velocity and water depth during the slope confluence process. Based on the Froude number, identify the slope flow form as a torrent or slow flow, determine the transition point from the torrent to the slow flow, and dynamically adjust the boundary between the natural basin part and the urban area in the transition zone.
[0018] Step 2, transition zone division: divide the transition zone into a natural watershed part and an urban part according to the identified boundaries; Step 3, calculation of runoff in transition zone: calculate the runoff process of natural watershed and urban area respectively. The natural watershed is taken as a whole as a calculation unit to calculate the surface runoff, subsoil flow and return flow process. The surface runoff of urban area is calculated grid by grid. Step 4, flow calculation in transition zone: the natural watershed is taken as a whole as a calculation unit, and the nonlinear reservoir method is used to calculate the flow process on the boundary. The flow of the natural watershed is combined with the surface runoff and the return flow, and then evenly distributed to the boundary grid of the urban part as the external boundary of the flow calculation of the urban part. The two-dimensional hydrodynamic equation is used to calculate the flow of the urban part grid by grid.
[0019] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A flood simulation method for the transition zone of the "watershed-city" system, It is characterized in that The following steps are involved: Step 1: Dynamically identify the hydraulic connection boundaries of the basin cities: Boundary recognition based on water flow morphology; Step 2, transition zone division: The transition zone is divided into a natural watershed part and an urban part according to the identified boundaries; Step 3, flow calculation in transition zone: The runoff generation process of the natural watershed and the urban part is calculated separately. The natural watershed is taken as a whole as a calculation unit to calculate the surface runoff, subsoil flow and return flow process. The surface runoff generation of the urban part is calculated grid by grid. Step 4, calculation of flow in transition zone: The nonlinear reservoir method is used to calculate the runoff in the natural watershed, which is then combined with the surface runoff and return flow and evenly distributed to the boundary grid as the external boundary for the runoff calculation in the urban part. The two-dimensional hydrodynamic equation is used to calculate the runoff in the urban part.
2. A flood simulation method for a transition zone of a "watershed-city" system according to claim 1, It is characterized in that The specific process of step 1 is as follows: Based on terrain data, the area with large slope changes is selected as the initial boundary between the natural watershed and the urban area in the transition zone. Then, the Froude number is calculated according to the flow velocity and water depth in the overland confluence process. Based on the Froude number, the overland flow is identified as a torrent or a slow flow, and the transition point from the torrent to the slow flow is determined. The boundary between the natural watershed and the urban area in the transition zone is dynamically adjusted. ； In the formula, is the Froude number of the slope confluence process, is the water flow velocity, is the acceleration due to gravity, For water depth.
3. According to the flood simulation method of the transition zone of the "watershed-city" system of claim 1, It is characterized in that The specific process of step 2 is as follows: According to the transition point from the rapids to the slow flows, the area where the rapids appear in the transition zone is divided into the natural basin part, and the area where the slow flows appear in the transition zone is divided into the urban part.
4. According to the flood simulation method of the transition zone of the "watershed-city" system of claim 1, It is characterized in that The specific process of step 3 is as follows: Step 3.1, natural watershed partial runoff: Taking the natural watershed as a whole, calculate the surface flow, subsoil flow and return flow; Step 3.2, urban part runoff: The urban part is divided into grids and surface runoff is calculated.
5. According to the flood simulation method of the transition zone of the "watershed-city" system of claim 1, It is characterized in that The specific process of step 4 is as follows: The natural watershed as a whole is taken as a calculation unit, and the nonlinear reservoir method is used to calculate the confluence process on the boundary. The confluence of the natural watershed is combined with the surface runoff and return flow and then evenly distributed to the boundary grid of the urban part as the external boundary of the confluence calculation of the urban part. The two-dimensional hydrodynamic equation is used to calculate the confluence of the urban part grid by grid.
6. A flood simulation system for the transition zone of the "watershed-city" system, It is characterized in that The simulation system is used to implement the simulation method according to any one of claims 1 to 5, comprising: Dynamic identification of watershed-urban hydraulic connection boundary module: Based on terrain data, select the area with large slope changes as the initial boundary between the natural watershed and the urban area in the transition zone, then calculate the Froude number based on the flow velocity and water depth during the slope confluence process, identify the slope flow form as a torrent or slow flow based on the Froude number, determine the transition point from the torrent to the slow flow, and dynamically adjust the boundary between the transition zone and the urban area; Calculation module for coupled flow generation and runoff zones: divides the transition zone into natural watershed and urban areas according to the identified boundaries; Runoff generation module: Calculate the runoff generation process of the natural watershed and the urban part respectively. The natural watershed is taken as a whole as a calculation unit to calculate the surface runoff, subsoil flow and return flow process. The urban part calculates the surface runoff grid by grid. Confluence module: The nonlinear reservoir method is used to calculate the confluence in the natural watershed part, which is combined with the surface runoff and return flow and then allocated to the boundary grid as the external boundary of the urban part. The confluence is calculated using the two-dimensional hydrodynamic equation in the urban part.