Multi-scale coupling nested flood model construction method

Abstract

The invention relates to a multi-scale coupling nested flood model construction method. The method comprises the following steps: S1, carrying out multi-scale partition modeling; s2, multi-scale model coupling and nesting; and S3, flood model partition activation is started. Based on a flood and huge disaster physical mechanism under the coupling action of multiple disaster-inducing factors such as multiple spatial scales, rainfall, hydrological conditions, terrains, climates and land utilization changes, a hydrological hydrodynamic model and coupling nesting are adopted; the multi-scale coupling nested flood model construction method can provide technical support for rapid simulation of flood and huge disaster events in extreme weather and accurate quantitative evaluation of flood risks in a submerged area, and simulation results can provide scientific basis for formulation of regional flood control strategies and emergency plans.

Description

Technical Field

[0001] The present invention belongs to the technical field of emergency disaster prevention, and in particular relates to a method for constructing a multi-scale coupled and nested flood model. Background Art

[0002] Flood disasters are one of the most frequent, wide-ranging, and socially and economically damaging natural disasters in my country, posing a serious threat to people's lives and property. Therefore, scientifically and rationally simulating flood disasters in submerged areas under rainfall and flood events is extremely important for accurately and quantitatively assessing flood disaster risks, strengthening flood risk prevention and control, and enhancing regional flood prevention and disaster reduction capabilities.

[0003] Flood disasters have the characteristics of large temporal and spatial spans, complex multiple disaster factors, and localized flood disasters. The existing flood models have a small modeling range and cannot reveal the spatial correlation between different flood disasters. Existing large-scale flood models are difficult to capture the flood characteristics of small and medium-scale regions and local rivers, and the impact of complex terrain on flood propagation is rarely considered. There are still large errors in their local models. Therefore, there is still a lack of flood event simulation technology that meets the large-scale simulation and localized characteristics. It is still difficult to accurately quantify the risk of flood disasters. It is urgent to propose a method for constructing a multi-scale coupled and nested flood event simulation model. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a multi-scale coupled and nested flood model construction method, which is based on the physical mechanism of flood disasters under the coupling of multiple spatial scales and multiple disaster-causing factors such as precipitation, hydrological conditions, topography, climate and land use changes, and adopts hydrological and hydrodynamic models and coupled nesting. It can provide technical support for the rapid simulation of flood disaster events under extreme weather and the accurate quantitative assessment of flood risks in inundated areas. The simulation results can provide a scientific basis for the formulation of regional flood control strategies and emergency plans.

[0005] The present invention solves the technical problem by the following technical solutions:

[0006] A method for constructing a multi-scale coupled nested flood model, the method comprising the following steps:

[0007] S1, multi-scale partition modeling;

[0008] S2, multi-scale model coupling and nesting;

[0009] S3. Flood model partition activation starts.

[0010] Moreover, the S1 is specifically:

[0011] (1) Based on the geographical and topographical characteristics, water system division and division of responsibilities for flood control management in the river basin, combined with the river basin water system, flow generation and confluence relationship, mountain-plain-sea relationship and upstream-middle reaches-downstream-estuary relationship, important reservoirs and large lakes are used as important nodes to construct reservoir and lake flood control dispatch models, and areas with dense rivers and similar rainfall and flood characteristics are merged to divide the modeling scope of the large-scale hydrological model;

[0012] (2) Based on the locations of river confluence points, lakes and reservoirs in the basin, and taking into account the topography and the locations of key flood protection areas, the modeling objects of the one-dimensional hydrodynamic model of the mesoscale river and the flood inundation calculation range are divided;

[0013] (3) According to the source of urban floods, the characteristics of flood disasters, and the topography, river system, urban flood control area, flood control engineering system, population, and construction land data, determine the modeling scope of small-scale urban refined flood model;

[0014] (4) Based on the divided large-scale, medium-scale, and small-scale modeling scopes, large-scale hydrological models, medium-scale flood models for key protected areas, and small-scale refined flood models for key cities are constructed by region, water system, and river section to establish a multi-scale model library.

[0015] Moreover, the S2 is specifically:

[0016] (1) Coupling and nesting of large-scale, medium-scale and small-scale models: Using large-scale hydrological models to calculate regional surface rainfall runoff, providing hourly flood flow processes Q at inflow boundaries for flood models in key protected areas and refined flood models in key cities a ;

[0017] (2) Coupling and nesting of one- and two-dimensional hydrodynamic models in mesoscale key protected areas: In the flood model of key protected areas, the one-dimensional hydrodynamic model of the river channel provides the overflow flow process for the regional two-dimensional hydrodynamic model in the form of lateral inflow. The overflow flow Q b Calculated using the broad crested weir formula:

[0018]

[0019] h 1 =max(Z 1 ,Z 2 )-Z b

[0020] h 2 =max(min(Z 1 ,Z 2 )-Z b ,0)

[0021] In the formula, Z1 , Z 2 are the water levels of the river channel and flood area at the coupling point respectively; Z b is the overflow elevation; l b is the breach width;

[0022] Based on the Euclidean distance formula and piecewise linear interpolation, the corresponding relationship between the overflow section mileage of the one-dimensional hydrodynamic model of the river and the position of the overflow inflow channel of the regional two-dimensional hydrodynamic model is matched:

[0023] x=x 1 +(x 2 -x 1 )·p

[0024] y=y 1 +(y 2 -y 1 )·p

[0025]

[0026] Where (x, y) is the coordinate of the overflow section point of the river channel, (x 1 ,y 1 ) and (x 2 ,y 2 ) are the starting point and end point coordinates of the river channel, p is the ratio of the overflow section point to the length of the river channel, d is the distance between the center point of the overflow inflow channel and all river sections, and the river section point with the smallest distance is selected as the matching point, and the mileage value of this point is used as the mileage of the overflow section matched to the overflow inflow channel;

[0027] (3) Coupling and nesting of mesoscale and small-scale models: The regional two-dimensional hydrodynamic model in the flood model of key protected areas and the refined flood model of key cities form a unified inflow boundary. Through the real-time dynamic interaction of flood conditions in the main rivers, the spatiotemporal dynamic coupling and nesting of the flood model of key protected areas and the refined flood model of key cities is formed.

[0028] Moreover, the activation start conditions of the S3 include spatial activation: areas involved in rainfall and flood events, and process activation: areas related to the regulation of major flood risks;

[0029] The spatial activation method is as follows: considering the spatial scale and time scale of precipitation, dividing rainfall events, and setting the surface rainfall threshold P of rainfall flood events 阈 , when rainfall occurs in the region and the surface rainfall P>P 阈 When , the flood model of the area involved in the rainfall flood event is activated;

[0030] The activation method of the process is as follows: determine the relevant river overflow judgment points, hydrological control section points, flood storage and detention area inflow points, and large sluice points in the major flood risk control area, and use them as process activation points; determine the flow corresponding to the control water level according to the water level-flow relationship curve of the process activation point, and use this flow as the flow threshold of the process activation point, and obtain the flow threshold Q of the process activation point according to the water level-flow relationship curve 阈 :

[0031]

[0032] In the formula, SW is the controlled water level, (SW 1 , Q 1 ) and (SW 2 , Q 2 ) Control the water level-flow data points adjacent to the water level to meet SW 1 ≤SW≤SW 2 ;

[0033] Calculation of flow Q at process activation points using a large-scale hydrological model c , and determine the relationship between the calculated flow and the flow threshold. When Q c >Q 阈 When the flooding model is activated, the corresponding regional flood model is activated.

[0034] The positive effects that the present invention can produce are:

[0035] The present invention establishes a multi-scale model library through multi-scale zoning modeling, and adopts multi-scale model coupling and nesting technology to perform spatiotemporal dynamic coupling and nesting of large-scale hydrological models, medium-scale flood models of key protection areas (one-dimensional hydrodynamic models of river channels, two-dimensional hydrodynamic models of regions) and small-scale refined flood models of key cities, thereby realizing the full-process dynamic simulation of flood events; through the activation and start-up of flood model zoning, rapid simulation of flood events that meet the characteristics of large-scale simulation and localized floods is realized, which can provide technical support for the dynamic simulation of flood disasters under extreme weather conditions and the accurate quantitative assessment of flood risks in submerged areas under rainfall and flood events, and the simulation results can provide a scientific basis for regional flood control strategies and emergency plan formulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the present invention;

[0037] Figure 2 A schematic diagram of the coupling and nesting of the multi-scale model of the present invention;

[0038] Figure 3 It is a schematic diagram of the matching relationship between the overflow section mileage of the one-dimensional hydrodynamic model of the river channel and the overflow inflow channel position of the two-dimensional hydrodynamic model of the region;

[0039] Figure 4 This is a schematic diagram of the activation and starting of the flood model of the present invention;

[0040] Figure 5 This is a diagram showing the rapid simulation results of flood events in the Dongjiang River Basin according to the present invention. DETAILED DESCRIPTION

[0041] The present invention is further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0042] like Figure 1 As shown, a method for constructing a multi-scale coupled nested flood model is innovative in that the steps of the method are:

[0043] 1. According to the needs of building a multi-scale coupled nested flood model, collect the basin's natural geographical data, hydrological data, socio-economic data, historical flood disasters, structures and engineering scheduling data, and analyze and process them. The Dongjiang River Basin is located in Guangdong Province, my country, and is an important part of the Pearl River system. Its flood disasters mainly occur from June to July each year, and are characterized by strong seasonality and concentrated rainfall. Short-term heavy rainfall is common in the basin, leading to severe floods in some areas. At the same time, affected by terrain conditions, rainfall runoff will quickly flow into rivers, increasing the rate and intensity of floods.

[0044] 2. According to the river system, flow generation and confluence relationship, mountain-plain-sea relationship and upstream-middle reaches-downstream-estuary relationship, considering the main stream, tributaries, important reservoirs, large lakes and other factors of the river, determine the coupling and embedding points of the large-scale hydrological model and the mesoscale flood model of key protection areas / small-scale key city refined flood model, delineate the hydrological calculation unit and the modeling object of the one-dimensional hydrodynamic model of the river, and delineate the scope of the flood inundation area in combination with the location of the flood protection area, the key flood control area and the overflow section of the one-dimensional hydrodynamic model of the river. Based on the collected and collated data, construct large-scale hydrological models, mesoscale one-dimensional hydrodynamic models of rivers, mesoscale regional two-dimensional hydrodynamic models and small-scale key city refined flood models by region, water system and river section, and establish a multi-scale model library.

[0045] (1) According to the data of soil type, land use, topography, river channel, etc., the basic parameters of the delineated hydrological calculation unit are determined, and a large-scale hydrological model library is established based on the Xin'anjiang model of the three water sources. The tank storage equation and water balance equation formulas used are:

[0046] W=K(xl+(1-x)Q)=KQ'

[0047]

[0048] Where: W is the channel storage capacity of the river section; t is time; I and Q are the inflow and outflow of the river section respectively; Q' is the indicated storage flow; x is the flow weighting factor, dimensionless; K is the channel storage coefficient.

[0049] (2) According to the modeling objects of the one-dimensional hydrodynamic model of the river channel, a one-dimensional hydrodynamic model library of the mesoscale river channel is established. Among them, the upstream calculation boundary and the lateral calculation boundary are provided by the large-scale hydrological model, and the hourly flood flow process is used as the boundary inflow; the downstream calculation boundary is the estuary or the confluence of the main and tributary rivers, and the water level-flow relationship of the most downstream section is used as the control condition. The basic equation used is:

[0050] Continuity equation

[0051]

[0052] Momentum equation

[0053]

[0054] In the formula, Q is the flow rate; A is the cross-sectional area; A d is the cross-sectional area without flow; q 1at is the lateral inflow; t is the time step; x is the space step; g is the gravitational acceleration; β is the velocity distribution coefficient; Z is the water surface elevation; S f For energy loss.

[0055] (3) According to the regional topography, distribution of key towns, population and GDP distribution, etc., different computational grid scales are divided for different flood inundation areas, and a medium-scale regional two-dimensional hydrodynamic model library is established. The model grid calculation scale is set to 100m, 200m-300m, and 500m. Among them, key towns, flood-prone areas, population and GDP distribution areas are divided into fine grids, and hilly areas, transition areas and plains with few people are divided into coarse grids. The water flow movement is described by the plane two-dimensional shallow water equation:

[0056] Continuity equation:

[0057]

[0058] Momentum equation:

[0059]

[0060] Where t is time; u and v are the components of the velocity in the x and y directions respectively; v is the elevation of the riverbed; d is the still water depth; h is the water depth, h = d + η; g is the acceleration of gravity; f is the Coriolis force; ρ is the density of water; s xx 、s xy 、s yx 、s yy is the radiation stress component; Pa is the atmospheric pressure; ρ 0 is the relative density of water; S is the source term; u s 、v s is the source water velocity; u and v are the average velocity along the water depth direction; T ii is the lateral stress.

[0061] (4) According to the needs of quantitative assessment of flood risk in key cities, the modeling scope of refined flood models in key cities is defined, and a small-scale refined flood model library for key cities is established by combining basic geography, hydrology and flood data, engineering scheduling, socio-economic data and other data in the modeling area. Two-dimensional non-steady flow is used to describe the plane water flow, and the effective rainfall intensity and the drainage intensity of the underground drainage pipe network system in the urbanized area are considered, where the effective rainfall intensity is the runoff generated by the rainfall during the calculation period (rainfall × runoff coefficient). The study area is discretized by unstructured irregular grids by combining the finite volume method and the finite difference method, and the model grid scale is less than 100m.

[0062] 3. If Figure 2 As shown in Figure 2, the specific process of multi-scale model coupling and nesting is as follows:

[0063] (1) The large-scale hydrological model is used to calculate regional surface rainfall runoff and provide the inflow flood process for the one-dimensional hydrodynamic model of the mesoscale river. The large-scale hydrological model can be used to obtain the flood flow process Q of the upstream inflow boundary and the lateral inflow boundary of the one-dimensional hydrodynamic model of the mesoscale river. a , and use it as the upstream inflow boundary condition and lateral inflow boundary condition of the medium-scale key protected area flood model / small-scale key city refined flood model to achieve continuous coupling of the flood process.

[0064] (2) In the flood model of the mesoscale key protection area, the one-dimensional hydrodynamic model of the river channel is used to calculate the flood flow process of the section along the river channel. According to the flood flow process, the hourly flood flow process of the river overflow mileage is calculated in real time and input into the regional two-dimensional hydrodynamic model in the form of lateral inflow, realizing the coupling and nesting of the one-dimensional hydrodynamic model of the river channel and the regional two-dimensional hydrodynamic model. Since the flood flow state at the overflow is close to the wide crest weir flow, the overflow flow Q b Calculated using the broad crested weir formula:

[0065]

[0066] h 1 =max(Z 1 ,Z 2 )-Z b

[0067] h 2 =max(min(Z1 ,Z 2 )-Z b ,0)

[0068] In the formula, Z 1 , Z 2 are the water levels of the river channel and flood area at the coupling point respectively; Z b is the overflow elevation; l b is the breach width.

[0069] like Figure 3 As shown in the figure, according to the coupling nesting relationship of the one-dimensional hydrodynamic model of the key protected area, the corresponding relationship between the overflow section mileage of the one-dimensional hydrodynamic model of the river and the position of the overflow inflow channel of the regional two-dimensional hydrodynamic model is matched based on the Euclidean distance formula and piecewise linear interpolation:

[0070] x=x 1 +(x 2 -x 1 )·p

[0071] y=y 1 +(y 2 -y 1 )·p

[0072]

[0073] Where (x, y) is the coordinate of the overflow section point of the river channel, (x 1 ,y 1 ) and (x 2 ,y 2 ) are the starting and ending coordinates of the river channel, p is the ratio of the overflow section point to the length of the river channel, and d is the distance between the center point of the overflow inflow channel and all river sections. The river section point with the smallest distance is selected as the matching point, and the mileage value of this point is used as the mileage of the overflow section matched to the overflow inflow channel.

[0074] The examples of the matching information of the overflow section mileage of the one-dimensional hydrodynamic model of the river and the overflow inflow channel of the regional two-dimensional hydrodynamic model are listed in Table 1.

[0075] Table 1

[0076]

[0077] (3) The mesoscale flood model for key protected areas and the small-scale refined flood model for key cities set a unified calculation boundary. Through the real-time dynamic interaction of flood conditions in the main rivers, a coupled nesting of time and space scales is formed to meet the needs of simulation and calculation of flood events at different spatial scales.

[0078] Through the above method, the spatiotemporal dynamic coupling and nesting of multi-scale models are carried out from the two aspects of boundary coupling and water flow conditions to realize the full process dynamic simulation of flood events.

[0079] 4. The specific process of flood model zoning activation is as follows:

[0080] The flood model constructed above is used to simulate massive flood random events and accurately quantify flood disaster risks. However, during the model calculation process, the operation of the flood model in areas where flood disasters have not occurred will cause a large amount of computing power resources to be consumed. Therefore, in order to improve the calculation efficiency of the flood model, spatial activation and process activation start conditions are set to dynamically activate and start the flood model in the flood disaster area. The activation start conditions are:

[0081] Spatial activation: areas involved in rainfall and flood events.

[0082] Process activation: areas related to major flood risk regulation.

[0083] In this way, the flood model is dynamically activated and started in different regions, such as Figure 4 The specific activation method is as follows:

[0084] (1) Considering the spatial scale and temporal scale of precipitation, rainfall events are divided and the surface rainfall threshold P of rainfall flood events is set. 阈 , when rainfall occurs in the region and the surface rainfall P>P 阈 When the rainfall and flood events occur, the flood model of the area involved in the rainfall and flood events is activated. Taking the Dongjiang River Basin as an example, when rainfall occurs in area 5 and reaches a rainfall and flood event, the large-scale hydrological model and the medium-scale flood models 1 and 2 of the key protected areas are activated; when rainfall occurs in area 12 and reaches a rainfall and flood event, the rainfall data is directly input to activate the small-scale key city refined flood model 5.

[0085] (2) Determine the overflow judgment points, hydrological control section points, flood storage and detention area inflow points, and large sluice points in the areas related to the risk control of major floods, and use them as process activation points. Determine the flow corresponding to the control water level based on the water level-flow relationship curve of the process activation point, and use this flow as the process point flow threshold Q 阈 .

[0086] According to the water level-flow relationship curve, the flow threshold Q of the process activation point is obtained 阈 :

[0087]

[0088] Where, SW is the controlled water level; (SW 1 , Q 1 ) and (SW 2 , Q 2) Control the water level-flow data points adjacent to the water level to meet SW 1 ≤SW≤SW 2 .

[0089] Calculation of flow Q at process activation points using a large-scale hydrological model c , and determine the calculated flow rate Q c With the flow threshold Q 阈 The size relationship between them is that when Q c >Q 阈 When the flood risk control of the region is needed, the corresponding regional flood model is activated. Taking the Dongjiang River Basin as an example, a rainfall flood event occurs in Region 5, and the large-scale hydrological model is activated to calculate the flow at the process activation point. When the calculated flow Q of the process activation point corresponding to the flood inundation area 4 located downstream is c Greater than the flow threshold Q 阈 When , the mesoscale key protected area flood model 4 is activated.

[0090] (3) Parallel calculation of all activated regional flood models to quickly simulate flood events. Taking the Dongjiang River Basin as an example, when rainfall occurs in region 5 and reaches a rainfall flood event, the regional activation activates mesoscale key protection area flood models 1 and 2, and the process activation activates mesoscale key protection area flood model 4. By parallel calculation of mesoscale key protection area flood models 1, 2, and 4, flood events in flooded areas 1, 2, and 4 are quickly simulated. Figure 5 The simulation results for 5, 10, 20, and 30 hours are shown. When a rainfall flood event occurs in area 5, floods occur in key protection areas 1 and 2 in the rainfall area. Key protection area 4 located downstream of the rainfall area also experiences floods due to river floods. The flooding range of each key protection area changes from nothing to something, from small to large, without mutations or discontinuities, showing obvious spatial heterogeneity. The simulation results can accurately quantify and assess the risk of regional flood disasters, accurately reveal the spatial correlation and localized characteristics of different flood events, and provide decision support and scientific basis for enhancing the emergency response capability of flood disasters, regional flood prevention and mitigation capabilities, and formulating regional flood prevention strategies and emergency plans.

[0091] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims, and that simple modifications or equivalent substitutions of the technical solutions of the present invention are all within the protection of the present invention. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method for constructing a multi-scale coupled and nested flood model, characterized by: The steps of the method are: S1, multi-scale partition modeling; S2, multi-scale model coupling and nesting; S3. Flood model partition activation starts.

2. The method for constructing a multi-scale coupled nested flood model according to claim 1, characterized in that: The S1 is specifically: (1) Based on the geographical and topographical characteristics, water system division and division of responsibilities for flood control management in the river basin, combined with the river basin water system, flow generation and confluence relationship, mountain-plain-sea relationship and upstream-middle reaches-downstream-estuary relationship, important reservoirs and large lakes are used as important nodes to construct reservoir and lake flood control dispatch models, and areas with dense rivers and similar rainfall and flood characteristics are merged to divide the modeling scope of the large-scale hydrological model; (2) Based on the locations of river confluence points, lakes and reservoirs in the basin, and taking into account the topography and the locations of key flood protection areas, the modeling objects of the one-dimensional hydrodynamic model of the mesoscale river and the flood inundation calculation range are divided; (3) According to the source of urban floods, the characteristics of flood disasters, and the topography, river system, urban flood control area, flood control engineering system, population, and construction land, the scope of modeling of small-scale urban refined flood model is determined; (4) Based on the divided large-scale, medium-scale, and small-scale modeling scopes, large-scale hydrological models, medium-scale flood models for key protected areas, and small-scale refined flood models for key cities are constructed by region, water system, and river section to establish a multi-scale model library.

3. The method for constructing a multi-scale coupled nested flood model according to claim 2, characterized in that: The S2 is specifically: (1) Coupling and nesting of large-scale, medium-scale and small-scale models: Using large-scale hydrological models to calculate regional surface rainfall runoff, providing hourly flood flow processes Q at inflow boundaries for flood models in key protected areas and refined flood models in key cities a ; (2) Coupling and nesting of one- and two-dimensional hydrodynamic models in mesoscale key protected areas: In the flood model of key protected areas, the one-dimensional hydrodynamic model of the river channel provides the overflow flow process for the regional two-dimensional hydrodynamic model in the form of lateral inflow. The overflow flow Q b Calculated using the broad crested weir formula: h1=max(Z1,Z2)-Z b h2=max(min(Z1,Z2)-Z b ,0) Where Z1 and Z2 are the water levels of the river channel and flood area at the coupling point respectively; Z b is the overflow elevation; l b is the breach width; Based on the Euclidean distance formula and piecewise linear interpolation, the corresponding relationship between the overflow section mileage of the one-dimensional hydrodynamic model of the river and the position of the overflow inflow channel of the regional two-dimensional hydrodynamic model is matched: x=x1+(x2-x1)·p y=y1+(y2-y1)·p In the formula, (x, y) is the coordinate of the overflow section point of the river channel, (x1, y1) and (x2, y2) are the coordinates of the starting point and the end point of the river channel respectively, p is the ratio of the overflow section point of the river channel to the length of the river channel, d is the distance between the center point of the overflow inflow channel and all river sections, and the river section point with the smallest distance is selected as the matching point, and the mileage value of this point is used as the mileage of the overflow section matched to the overflow inflow channel; (3) Coupling and nesting of mesoscale and small-scale models: The regional two-dimensional hydrodynamic model in the flood model of key protected areas and the refined flood model of key cities form a unified inflow boundary. Through the real-time dynamic interaction of flood conditions in the main rivers, the spatiotemporal dynamic coupling and nesting of the flood model of key protected areas and the refined flood model of key cities is formed.

4. The method for constructing a multi-scale coupled nested flood model according to claim 3, characterized in that: The activation start conditions of S3 include spatial activation: areas involved in rainfall and flood events and process activation: areas related to the regulation of major flood risks; The spatial activation method is: considering the spatial scale and time scale of precipitation, dividing the rainfall events, and setting the surface rainfall threshold P of the rainfall flood event 阈 , when rainfall occurs in the region and the surface rainfall P>P 阈 When , the flood model of the area involved in the rainfall flood event is activated; The activation method of the process is to determine the relevant river overflow judgment points, hydrological control section points, flood storage and detention area inflow points, and large sluice points in the major flood risk control area as the process activation points; According to the water level-flow relationship curve of the process activation point, the flow corresponding to the control water level is determined, and the flow is used as the flow threshold of the process activation point. According to the water level-flow relationship curve, the flow threshold Q of the process activation point is obtained. 阈 : Where SW is the control water level, and the water level-flow data points adjacent to the control water levels (SW1, Q1) and (SW2, Q2) satisfy SW1≤SW≤SW2; Calculation of flow Q at process activation points using a large-scale hydrological model c , and determine the relationship between the calculated flow and the flow threshold. When Q c >Q 阈 When the flooding model is activated, the corresponding regional flood model is activated.

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