A method and system for point rainstorm waterlogging risk assessment based on multi-source data

Abstract

The application discloses a kind of based on multi-source data's fixed point rainstorm waterlogging risk assessment method and system, it is related to waterlogging risk assessment technical field, including obtaining fixed point area information, according to fixed point area information, based on regional topography analysis, obtain fixed point influence area information, according to fixed point influence area information, based on D8 algorithm, obtain surface runoff path information.The application realizes fixed point influence area division and the depth adaptation of topographic feature by fixed point influence area information, lays topographic foundation for subsequent accurate identification of confluence path, dynamically determines boundary confluence distance by boundary confluence distance threshold, realizes the quantitative dynamic adjustment of influence area range, provides basis for subsequent targeted analysis of the influence of runoff in different directions on fixed point area, reduces the required monitoring point by key runoff path information, and improves risk assessment efficiency.

Description

Technical Field

[0001] This invention relates to the field of urban flooding risk assessment technology, specifically to a method and system for assessing urban flooding risk at specific locations during heavy rainstorms based on multi-source data. Background Technology

[0002] Currently, the risk assessment of urban flooding caused by rainstorms still faces challenges, including the inability to accurately analyze the designated area, accurately assess the impact of neighboring areas on the designated area, and accurately evaluate the risk of urban flooding caused by rainstorms. Existing technologies often use administrative boundaries, fixed radii, or grid units as the basis for dividing the affected area. The analysis of the runoff conditions in neighboring areas is based solely on parameters such as average elevation values, which leads to distorted judgments of runoff relationships and an inability to accurately analyze runoff conditions, thus affecting the accuracy and reliability of the risk assessment of urban flooding caused by rainstorms. Summary of the Invention

[0003] To address the aforementioned technical problems, this paper provides a method and system for assessing the risk of urban flooding caused by rainstorms based on multi-source data. This technical solution solves the problems mentioned in the background technology, such as the inability to accurately analyze fixed-point areas, the inability to accurately assess the impact of neighboring areas on fixed-point areas, and the inability to accurately assess the risk of urban flooding caused by rainstorms. Existing technologies mostly use administrative boundaries, fixed radii, or grid units as the basis for dividing the affected areas. The analysis of the runoff conditions of neighboring areas is based solely on parameters such as average elevation values, which leads to distorted judgments of runoff relationships and an inability to accurately analyze runoff conditions, thus affecting the accuracy and reliability of the risk assessment of urban flooding caused by rainstorms.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for assessing the risk of urban flooding caused by rainstorms based on multi-source data includes:

[0006] Obtain fixed-point area information, which includes fixed-point area location information and area terrain information;

[0007] Based on the fixed-point area information and the regional topography analysis, the fixed-point influence area information is obtained, wherein the fixed-point influence area includes a first fixed-point influence area and a second fixed-point influence area.

[0008] Based on the fixed-point impact area information, surface runoff path information is obtained using the D8 algorithm. The surface runoff path information includes the regional grid information corresponding to the surface runoff path. The surface runoff path represents the runoff route from the fixed-point impact area to the fixed-point area or from the fixed-point area to the fixed-point impact area.

[0009] Based on the surface runoff path information, obtain the runoff direction information corresponding to each surface runoff path, wherein the runoff direction points from the starting point to the ending point of the surface runoff path;

[0010] Based on the analysis of hydrological runoff characteristics, the runoff direction angle threshold and runoff path distance threshold are obtained;

[0011] Based on surface runoff path information, key runoff path information is obtained using runoff direction angle threshold and runoff path distance threshold. The key runoff path represents the runoff path after merging surface runoff paths, and the key runoff path information includes confluence monitoring point information.

[0012] Acquire historical runoff data, which includes rainfall and runoff volume corresponding to each surface runoff path;

[0013] Based on key runoff path information and historical runoff data, obtain the surface runoff model corresponding to each key runoff path;

[0014] Monitor the confluence monitoring points and fixed areas to obtain monitoring data;

[0015] Based on monitoring data and surface runoff models, determine whether there is a risk of rainstorm-induced flooding in designated areas. If so, issue a risk warning for rainstorm-induced flooding.

[0016] Preferably, the step of obtaining the information of the fixed-point influence area based on the fixed-point area information and regional terrain analysis specifically includes:

[0017] Based on the fixed-point area information, obtain the neighboring area information, where the neighboring area refers to the area adjacent to the fixed-point area;

[0018] Based on the fixed-point area information and the neighboring area information, and using the digital elevation model, the elevation data of the fixed-point area and the neighboring area are obtained. The elevation data includes the regional grid information and the elevation value corresponding to each grid.

[0019] Based on the elevation data of the fixed area, the area grid corresponding to the minimum elevation value in the fixed area is taken as the area confluence point;

[0020] Based on surface runoff flow analysis, runoff direction information is obtained;

[0021] Using the regional confluence point as the origin, a baseline is drawn along the runoff direction to obtain the regional confluence baseline information;

[0022] Based on the neighboring area information and the regional convergence baseline information, the neighboring areas between adjacent regional convergence baselines are taken as sub-areas, and the neighboring sub-area information is obtained;

[0023] Based on the information of neighboring sub-regions, obtain the information of the fixed-point affected area.

[0024] Preferably, obtaining the fixed-point influence area information based on the neighboring sub-region information specifically includes:

[0025] Based on a fixed area and neighboring areas, regional boundary information is obtained, where the regional boundary represents the boundary line between the fixed area and the neighboring areas.

[0026] Based on the elevation data of the fixed area and the elevation data of the adjacent area, the area grid corresponding to the area boundary is used as the area boundary grid to obtain the area boundary grid information;

[0027] Based on the elevation data of the neighboring area and the information of the neighboring sub-areas, obtain the elevation data corresponding to each neighboring sub-area;

[0028] The average elevation value of the corresponding grid in each neighboring sub-region is used as the reference elevation value for that region.

[0029] Based on the elevation data of the fixed point area, the average elevation value of the corresponding grid of the fixed point area is taken as the elevation value of the fixed point area.

[0030] The ratio of the benchmark elevation value corresponding to each neighboring sub-region to the elevation value of the fixed-point region is used as the regional elevation deviation coefficient.

[0031] Based on topographic flow analysis, a boundary flow distance threshold is obtained, which includes the maximum and minimum boundary flow distances.

[0032] The product of the minimum boundary confluence distance of each neighboring sub-region and the regional elevation deviation coefficient is taken as the boundary base confluence distance of that neighboring sub-region.

[0033] The boundary merge distance is obtained based on the boundary merge distance threshold and the boundary base merge distance;

[0034] Wherein, if the boundary base flow distance is lower than the minimum boundary flow distance, the minimum boundary flow distance is taken as the boundary flow distance; if the boundary base flow distance is higher than the maximum boundary flow distance, the maximum boundary flow distance is taken as the boundary flow distance.

[0035] Based on the boundary convergence distance, obtain information on the fixed-point impact area.

[0036] Preferably, obtaining the fixed-point influence area information based on the boundary confluence distance specifically includes:

[0037] Based on the regional boundary grid information and the neighboring sub-region information, the regional boundary grid corresponding to each neighboring sub-region is taken as the sub-region boundary grid of that neighboring sub-region;

[0038] Based on the boundary confluence distance, using the sub-region boundary grid as a basis, the region grid in each neighboring sub-region whose distance from the sub-region boundary grid is less than the boundary confluence distance is taken as the confluence characteristic grid of that neighboring sub-region;

[0039] Based on the elevation data of the fixed point area, the grid in the grid corresponding to the fixed point area whose distance to the boundary grid of each neighboring sub-region is less than the boundary convergence distance of the neighboring sub-region is taken as the target convergence grid of the neighboring sub-region.

[0040] The average elevation value of the confluence feature grid of each neighboring sub-region is used as the confluence elevation value, and the average elevation value of the target confluence grid is used as the target confluence elevation value.

[0041] Based on the confluence elevation and the target confluence elevation, information on the specific impact area is obtained;

[0042] Specifically, if the confluence elevation of a neighboring sub-region is higher than the target confluence elevation, then the neighboring sub-region is designated as the first fixed-point influence area; if the confluence elevation of a neighboring sub-region is lower than the target confluence elevation, then the neighboring sub-region is designated as the second fixed-point influence area.

[0043] Preferably, the step of obtaining key runoff path information based on surface runoff path information, using runoff direction angle thresholds and runoff path distance thresholds as a basis, specifically includes:

[0044] Based on surface runoff path information, surface runoff paths are classified according to the information of fixed-point impact areas. Surface runoff paths in the same type of fixed-point impact area are classified into the same type of surface runoff paths to obtain surface runoff path classification information.

[0045] Based on the surface runoff path classification information, any two surface runoff paths of the same type are grouped together as a path merging group.

[0046] The angle between the runoff directions of two surface runoff paths in the path merging group is taken as the runoff direction angle, and the minimum straight-line distance between any two regional grids in the two surface runoff paths is taken as the shortest spatial distance.

[0047] Based on the path merging group, and using the runoff direction angle threshold and runoff path distance threshold as a basis, information on mergeable paths is obtained;

[0048] If the runoff direction angle of the path merging group is lower than the runoff direction angle threshold and the shortest spatial distance is lower than the runoff path distance threshold, then the two surface runoff paths in the path merging group are mergeable paths.

[0049] Based on the mergeable path information, the path midpoint coordinates are used as the cluster center, and path merging is performed based on hierarchical clustering to obtain key runoff path information;

[0050] Based on the information of the designated impact areas, the endpoint of each critical runoff path in the first designated impact area is taken as the confluence monitoring point of that critical runoff path, and the starting point of each critical runoff path in the second designated impact area is taken as the confluence monitoring point of that critical runoff path.

[0051] Preferably, the step of determining whether there is a risk of rainstorm-induced flooding in a designated area based on monitoring data and surface runoff models specifically includes:

[0052] Based on historical runoff data and information from runoff monitoring points, the rainfall corresponding to each runoff monitoring point is obtained;

[0053] Using the rainfall at each confluence monitoring point, obtain the surface runoff model for each key runoff path;

[0054] If the critical runoff path is located in the first fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output to train the Nash instantaneous unit hydrograph model and obtain the surface runoff model.

[0055] If the critical runoff path is located in the second fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output. The SCS model is trained with historical runoff data to obtain the surface runoff model.

[0056] Based on monitoring data and a surface runoff model, the surface runoff volume is obtained.

[0057] Obtain drainage design parameter information for a specific area, including surface runoff reception rate and maximum output rate of the regional pipe network;

[0058] Based on the analysis of rainstorm-induced urban flooding, the maximum surface runoff is obtained;

[0059] Based on surface runoff, surface runoff receiving rate, and maximum surface runoff, determine whether there is a risk of rainstorm-induced flooding in a designated area. If the difference between surface runoff and surface runoff receiving rate exceeds the maximum surface runoff, then there is a risk of rainstorm-induced flooding in the designated area.

[0060] If the difference between surface runoff and surface runoff receiving rate does not exceed the maximum surface runoff, the surface input rate of the pipeline network is obtained based on the surface runoff and surface runoff receiving rate.

[0061] Based on monitoring data, the pipeline connection input rate is obtained, which represents the flow rate received by the pipeline network in a fixed area;

[0062] Based on the surface input rate of the pipeline network, the interconnection input rate of the pipeline network, and the maximum output rate of the regional pipeline network, it is determined whether there is a risk of rainstorm flooding in a designated area. If the sum of the surface input rate of the pipeline network and the interconnection input rate of the pipeline network exceeds the maximum output rate of the regional pipeline network, then there is a risk of rainstorm flooding in the designated area.

[0063] Furthermore, a point-based rainstorm flood risk assessment system based on multi-source data is proposed to implement the assessment method described above, including:

[0064] The main control module is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis; obtain the surface runoff model corresponding to each key runoff path based on the key runoff path information and historical runoff data; monitor the confluence monitoring points and fixed areas; obtain monitoring data; and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model.

[0065] The information acquisition module is used to acquire fixed-point area information, which includes fixed-point area location information and area topography information. Based on the fixed-point area information, it acquires neighboring area information. Based on the fixed-point area information and neighboring area information, it acquires fixed-point area elevation data and neighboring area elevation data based on a digital elevation model.

[0066] The runoff analysis module is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, take the adjacent areas between adjacent regional confluence baselines as sub-regions, obtain the adjacent sub-region information, obtain the fixed-point impact area information based on the adjacent sub-region information, and obtain the surface runoff path information based on the fixed-point impact area information and the D8 algorithm.

[0067] The display module interacts with the main control module to output and display monitoring data, and to provide risk warnings for rainstorms and urban flooding.

[0068] Optionally, the control unit is used to obtain the surface runoff model corresponding to each key runoff path based on key runoff path information and historical runoff data, monitor the confluence monitoring points and fixed areas, obtain monitoring data, and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model.

[0069] An information receiving unit, which interacts with the information acquisition module and the runoff analysis module, is used to receive data and transmit it to the path identification unit.

[0070] The path identification unit is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis.

[0071] Optionally, the information acquisition module specifically includes:

[0072] A region acquisition unit is used to acquire fixed-point region information, which includes fixed-point region location information and region terrain information, and to acquire neighboring region information based on the fixed-point region information.

[0073] An elevation acquisition unit is used to acquire elevation data of a fixed area and elevation data of adjacent areas based on a digital elevation model, according to fixed area information and adjacent area information.

[0074] Optionally, the runoff analysis module specifically includes:

[0075] The regional analysis unit is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, and take the adjacent areas between adjacent regional confluence baselines as sub-regions to obtain the adjacent sub-region information.

[0076] The runoff analysis unit is used to obtain fixed-point impact area information based on neighboring sub-region information, and to obtain surface runoff path information based on the D8 algorithm based on the fixed-point impact area information.

[0077] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0078] This invention proposes a method and system for targeted rainstorm-induced urban flooding risk assessment based on multi-source data. By using targeted impact area information, it achieves in-depth adaptation between the targeted impact area division and terrain features, laying a topographical foundation for subsequent accurate identification of runoff paths. By dynamically determining the boundary runoff distance threshold, it realizes quantitative and dynamic adjustment of the impact area range, providing a basis for subsequent targeted analysis of the impact of runoff from different directions on the targeted area. By using key runoff path information, it reduces the number of monitoring points required and improves the efficiency of risk assessment. Attached Figure Description

[0079] Figure 1 This is a flowchart of a method for assessing the risk of urban flooding in a fixed location based on multi-source data, as proposed in this invention.

[0080] Figure 2 This is a flowchart of the process for obtaining information on the fixed-point influence area in this invention;

[0081] Figure 3 This is a flowchart of the process for obtaining the boundary confluence distance in this invention;

[0082] Figure 4 This is a flowchart of the process for obtaining key runoff path information in this invention;

[0083] Figure 5 This is a structural block diagram of a point-based rainstorm flood risk assessment system based on multi-source data proposed in this invention. Detailed Implementation

[0084] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0085] Reference Figure 1 - Figure 4 As shown in the figure, a method for assessing the risk of urban flooding based on multi-source data during a targeted rainstorm, as described in this embodiment of the invention, includes:

[0086] Obtain fixed-point area information, which includes fixed-point area location information and area terrain information;

[0087] Based on the fixed-point area information and the regional topography analysis, the fixed-point influence area information is obtained, wherein the fixed-point influence area includes a first fixed-point influence area and a second fixed-point influence area.

[0088] Specifically, based on the information of the designated area and the analysis of the regional topography, information on the designated impact area is obtained, including:

[0089] Based on the fixed-point area information, obtain the neighboring area information, where the neighboring area refers to the area adjacent to the fixed-point area;

[0090] Based on the fixed-point area information and the neighboring area information, and using the digital elevation model, the elevation data of the fixed-point area and the neighboring area are obtained. The elevation data includes the regional grid information and the elevation value corresponding to each grid.

[0091] Based on the elevation data of the fixed area, the area grid corresponding to the minimum elevation value in the fixed area is taken as the area confluence point;

[0092] Based on surface runoff flow analysis, runoff direction information is obtained;

[0093] Using the regional confluence point as the origin, a baseline is drawn along the runoff direction to obtain the regional confluence baseline information;

[0094] Based on the neighboring area information and the regional convergence baseline information, the neighboring areas between adjacent regional convergence baselines are taken as sub-areas, and the neighboring sub-area information is obtained;

[0095] Based on the information of neighboring sub-regions, obtain the information of the fixed-point affected area.

[0096] In this scheme, grid-level elevation data (including the specific elevation value of each grid) of the designated area and adjacent areas are obtained by combining the digital elevation model (DEM). This allows the definition of the affected area to be directly anchored to the core topographic elements of waterlogging confluence, such as "topographic relief and elevation difference". This provides an accurate and objective topographic data benchmark for subsequent screening of affected areas, anchoring the real core of confluence and ensuring the targeting of runoff analysis. By designating the grid with the smallest elevation value in the designated area as the regional confluence point, the "core aggregation point" of natural confluence in the designated area is accurately captured. This point is the key location where runoff is most prone to siltation and has the highest risk of waterlogging during rainstorms, and it is also the main target point for runoff from adjacent areas to flow into. Compared to traditional methods that randomly select reference points (such as the regional center point), leading to deviations in runoff direction judgment, this step ensures that subsequent runoff direction analysis and baseline setting revolve around the actual confluence core, guaranteeing the targeted nature of runoff path and confluence relationship analysis. This improves the accuracy of urban flooding risk assessment from the source, refines zoning according to confluence characteristics, and resolves the problem of confusion regarding confluence relationships in adjacent areas. By using the confluence point as the origin and drawing baselines along the runoff direction, the adjacent areas between adjacent baselines are divided into independent sub-regions (adjacent sub-regions), providing a regional basis for subsequent surface runoff analysis.

[0097] In this embodiment, the runoff direction information refers to the runoff direction along due north, with each runoff direction being 45° apart, for a total of 8 runoff directions.

[0098] Specifically, based on information from neighboring sub-regions, information about the targeted affected area is obtained, including:

[0099] Based on a fixed area and neighboring areas, regional boundary information is obtained, where the regional boundary represents the boundary line between the fixed area and the neighboring areas.

[0100] Based on the elevation data of the fixed area and the elevation data of the adjacent area, the area grid corresponding to the area boundary is used as the area boundary grid to obtain the area boundary grid information;

[0101] Based on the elevation data of the neighboring area and the information of the neighboring sub-areas, obtain the elevation data corresponding to each neighboring sub-area;

[0102] The average elevation value of the corresponding grid in each neighboring sub-region is used as the reference elevation value for that region.

[0103] Based on the elevation data of the fixed point area, the average elevation value of the corresponding grid of the fixed point area is taken as the elevation value of the fixed point area.

[0104] The ratio of the benchmark elevation value corresponding to each neighboring sub-region to the elevation value of the fixed-point region is used as the regional elevation deviation coefficient.

[0105] Based on topographic flow analysis, a boundary flow distance threshold is obtained, which includes the maximum and minimum boundary flow distances.

[0106] The product of the minimum boundary confluence distance of each neighboring sub-region and the regional elevation deviation coefficient is taken as the boundary base confluence distance of that neighboring sub-region.

[0107] The boundary merge distance is obtained based on the boundary merge distance threshold and the boundary base merge distance;

[0108] Wherein, if the boundary base flow distance is lower than the minimum boundary flow distance, the minimum boundary flow distance is taken as the boundary flow distance; if the boundary base flow distance is higher than the maximum boundary flow distance, the maximum boundary flow distance is taken as the boundary flow distance.

[0109] Based on the boundary convergence distance, obtain information on the fixed-point impact area.

[0110] In this scheme, the spatial visualization of the boundary location is achieved by defining the grid corresponding to the boundary line between the fixed-point area and the adjacent area as the regional boundary grid. Traditional methods often use abstract administrative boundary lines or geographical coordinate lines to delineate regional boundaries without associating them with specific grid units. This results in a lack of clear spatial benchmarks for subsequent calculations of confluence distances and elevation comparisons, easily leading to the problem of "misjudging confluence relationships across grids." This step, however, transforms the boundary into quantifiable and analyzable grid units, providing a precise spatial carrier for subsequent "elevation comparisons and confluence distance calculations between sub-regions and the fixed-point area," ensuring the spatial accuracy of the area delineation, quantifying elevation deviation relationships, and establishing an objective basis for confluence potential. By calculating the ratio of the benchmark elevation value of the adjacent sub-region (the average elevation value of the sub-region grid) to the elevation value of the fixed-point area (the average elevation value of the fixed-point area grid) as the regional elevation deviation coefficient, the "topographical differences between the sub-region and the fixed-point area" are quantitatively represented. Traditional methods only qualitatively determine whether the average terrain of a sub-region is higher or lower than that of a fixed-point region. It's important to note that a sub-region's overall terrain being higher or lower than a fixed-point region does not necessarily mean that the terrain of the boundary sub-regions is higher or lower. Therefore, a specific analysis of the terrain at the boundary is necessary. By multiplying the minimum boundary runoff distance by the regional elevation deviation coefficient, the basic boundary runoff distance is obtained, achieving a dynamic binding between the runoff distance and terrain characteristics. Traditional methods use fixed runoff distances (e.g., uniformly set at 30 meters or 50 meters), ignoring the impact of elevation differences between different sub-regions on the runoff range: sub-regions with large terrain differences (large deviation coefficients) should have a wider runoff range (higher elevations allow water flow to cover farther grids), but are limited by the fixed distance; sub-regions with small terrain differences (small deviation coefficients) should have a narrower runoff range, but are included in irrelevant grids due to the fixed distance. This step dynamically adjusts the runoff distance according to the elevation deviation coefficient, ensuring that the influence range of each sub-region matches its actual runoff capacity, avoiding distortion of the influence area caused by "too wide / too narrow" ranges.

[0111] In this embodiment, the boundary confluence distance threshold is 10m-30m. Surface runoff has a "minimum confluence unit". When the distance is less than 10m, the elevation difference between the confluence feature grid and the boundary grid can be ignored, which can easily lead to excessive fragmentation of the affected area and make it impossible to form an effective confluence analysis unit. 30m is the typical grid association range of DEM data, which ensures that the accuracy of confluence analysis matches that of terrain data and avoids misjudging confluence relationships across grids.

[0112] Specifically, based on the boundary confluence distance, information on the fixed-point impact area is obtained, including:

[0113] Based on the regional boundary grid information and the neighboring sub-region information, the regional boundary grid corresponding to each neighboring sub-region is taken as the sub-region boundary grid of that neighboring sub-region;

[0114] Based on the boundary confluence distance, using the sub-region boundary grid as a basis, the region grid in each neighboring sub-region whose distance from the sub-region boundary grid is less than the boundary confluence distance is taken as the confluence characteristic grid of that neighboring sub-region;

[0115] Based on the elevation data of the fixed point area, the grid in the grid corresponding to the fixed point area whose distance to the boundary grid of each neighboring sub-region is less than the boundary convergence distance of the neighboring sub-region is taken as the target convergence grid of the neighboring sub-region.

[0116] The average elevation value of the confluence feature grid of each neighboring sub-region is used as the confluence elevation value, and the average elevation value of the target confluence grid is used as the target confluence elevation value.

[0117] Based on the confluence elevation and the target confluence elevation, information on the specific impact area is obtained;

[0118] Specifically, if the confluence elevation of a neighboring sub-region is higher than the target confluence elevation, then the neighboring sub-region is designated as the first fixed-point influence area; if the confluence elevation of a neighboring sub-region is lower than the target confluence elevation, then the neighboring sub-region is designated as the second fixed-point influence area.

[0119] In this scheme, by associating each neighboring sub-region with its corresponding regional boundary grid as a "sub-region boundary grid," a one-to-one spatial anchoring of the boundary position between neighboring sub-regions and the fixed-point region is achieved. Traditional methods do not clearly define the correspondence between sub-regions and boundaries, which can easily lead to "cross-sub-region misjudgment" when selecting confluence grids (e.g., classifying the boundary grid of sub-region A as sub-region B). This step, however, gives each sub-region its own boundary benchmark, ensuring that subsequent confluence distance calculations and grid selection are all carried out within the spatial range of the sub-region itself. This provides clear spatial coordinates for the accurate identification of the core confluence grid, avoids spatial misalignment of confluence relationships, and accurately delineates the core grid based on the confluence distance, avoiding the ineffective inclusion of traditional coarse-scale ranges. By using the sub-region boundary grid as a starting point, grids with distances less than the boundary confluence distance are selected as confluence feature grids (neighboring sub-regions) and target confluence grids (fixed-point regions), improving evaluation efficiency and accuracy.

[0120] Based on the fixed-point impact area information, surface runoff path information is obtained using the D8 algorithm. The surface runoff path information includes the regional grid information corresponding to the surface runoff path. The surface runoff path represents the runoff route from the fixed-point impact area to the fixed-point area or from the fixed-point area to the fixed-point impact area.

[0121] Based on the surface runoff path information, obtain the runoff direction information corresponding to each surface runoff path, wherein the runoff direction points from the starting point to the ending point of the surface runoff path;

[0122] Based on the analysis of hydrological runoff characteristics, the runoff direction angle threshold and runoff path distance threshold are obtained;

[0123] Based on surface runoff path information, key runoff path information is obtained using runoff direction angle threshold and runoff path distance threshold. The key runoff path represents the runoff path after merging surface runoff paths, and the key runoff path information includes confluence monitoring point information.

[0124] Specifically, based on surface runoff path information, and using runoff direction angle thresholds and runoff path distance thresholds as a basis, key runoff path information is obtained, including:

[0125] Based on surface runoff path information, surface runoff paths are classified according to the information of fixed-point impact areas. Surface runoff paths in the same type of fixed-point impact area are classified into the same type of surface runoff paths to obtain surface runoff path classification information.

[0126] Based on the surface runoff path classification information, any two surface runoff paths of the same type are grouped together as a path merging group.

[0127] The angle between the runoff directions of two surface runoff paths in the path merging group is taken as the runoff direction angle, and the minimum straight-line distance between any two regional grids in the two surface runoff paths is taken as the shortest spatial distance.

[0128] Based on the path merging group, and using the runoff direction angle threshold and runoff path distance threshold as a basis, information on mergeable paths is obtained;

[0129] If the runoff direction angle of the path merging group is lower than the runoff direction angle threshold and the shortest spatial distance is lower than the runoff path distance threshold, then the two surface runoff paths in the path merging group are mergeable paths.

[0130] Based on the mergeable path information, the path midpoint coordinates are used as the cluster center, and path merging is performed based on hierarchical clustering to obtain key runoff path information;

[0131] Based on the information of the designated impact areas, the endpoint of each critical runoff path in the first designated impact area is taken as the confluence monitoring point of that critical runoff path, and the starting point of each critical runoff path in the second designated impact area is taken as the confluence monitoring point of that critical runoff path.

[0132] In this scheme, surface runoff paths are divided into similar paths based on the type of fixed-point impact area (first / second fixed-point impact area), achieving "functional attribute clustering" of runoff paths. The first type of path corresponds to "nearby-to-fixed-point confluence," and the second type corresponds to "fixed-point-to-nearby diversion." The two types of paths have distinct roles in terms of urban flooding impact (risk source / mitigation channel), providing a precise basis for subsequent differentiated merging and monitoring. The scheme quantifies the path similarity standard, improving the objectivity and accuracy of path merging. By calculating the "runoff direction angle" and "shortest spatial distance" (reflecting spatial proximity) of the path merging group, and using clear thresholds to screen mergeable paths, redundant paths are clustered and merged. Based on hierarchical clustering, mergeable paths are integrated into key runoff paths, significantly reducing the number of paths that need to be monitored and analyzed. For example, 10 confluence paths in the same direction and adjacent to each other can be merged into 1 key path, requiring only the setting of monitoring points and the construction of models for the key path. Traditional methods require individual monitoring of each original path, resulting in dense monitoring points and a massive amount of data. This increases both hardware deployment costs and the subsequent computational burden. Targeted monitoring points (the endpoint of the first type of path and the starting point of the second type) allow the monitoring points to accurately anchor the "key nodes of runoff impact"—the endpoint of the first type of path is the entrance for runoff to enter the designated area, and the starting point of the second type of path is the exit for runoff to leave the designated area. The rainfall and runoff data of the two types of nodes are directly related to the risk of urban flooding in the designated area.

[0133] In this embodiment, the runoff direction angle threshold is 15° and the runoff path distance threshold is 50m. It can be understood that the difference in direction angle reflects the consistency of the confluence direction of two runoff routes. The direction of surface runoff is dominated by the topographic slope. When the difference in direction angle exceeds 15°, the "dynamic direction" of the confluence path will be significantly differentiated. The runoff path distance threshold reflects the spatial proximity of two runoff routes. Key parameters affecting confluence, such as land use type and surface roughness, have spatial continuity and usually remain stable within a range of 50m.

[0134] Acquire historical runoff data, which includes rainfall and runoff volume corresponding to each surface runoff path;

[0135] Based on key runoff path information and historical runoff data, obtain the surface runoff model corresponding to each key runoff path;

[0136] Monitor the confluence monitoring points and fixed areas to obtain monitoring data;

[0137] Based on monitoring data and surface runoff models, determine whether there is a risk of rainstorm-induced flooding in designated areas. If so, issue a risk warning for rainstorm-induced flooding.

[0138] Specifically, based on monitoring data and surface runoff models, the risk of urban flooding during heavy rain is determined in designated areas, including:

[0139] Based on historical runoff data and information from runoff monitoring points, the rainfall corresponding to each runoff monitoring point is obtained;

[0140] Using the rainfall at each confluence monitoring point, obtain the surface runoff model for each key runoff path;

[0141] If the critical runoff path is located in the first fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output to train the Nash instantaneous unit hydrograph model and obtain the surface runoff model.

[0142] If the critical runoff path is located in the second fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output. The SCS model is trained with historical runoff data to obtain the surface runoff model.

[0143] Based on monitoring data and a surface runoff model, the surface runoff volume is obtained.

[0144] Obtain drainage design parameter information for a specific area, including surface runoff reception rate and maximum output rate of the regional pipe network;

[0145] Based on the analysis of rainstorm-induced urban flooding, the maximum surface runoff is obtained;

[0146] Based on surface runoff, surface runoff receiving rate, and maximum surface runoff, determine whether there is a risk of rainstorm-induced flooding in a designated area. If the difference between surface runoff and surface runoff receiving rate exceeds the maximum surface runoff, then there is a risk of rainstorm-induced flooding in the designated area.

[0147] If the difference between surface runoff and surface runoff receiving rate does not exceed the maximum surface runoff, the surface input rate of the pipeline network is obtained based on the surface runoff and surface runoff receiving rate.

[0148] Based on monitoring data, the pipeline connection input rate is obtained, which represents the flow rate received by the pipeline network in a fixed area;

[0149] Based on the surface input rate of the pipeline network, the interconnection input rate of the pipeline network, and the maximum output rate of the regional pipeline network, it is determined whether there is a risk of rainstorm flooding in a designated area. If the sum of the surface input rate of the pipeline network and the interconnection input rate of the pipeline network exceeds the maximum output rate of the regional pipeline network, then there is a risk of rainstorm flooding in the designated area.

[0150] This scheme significantly improves the accuracy of runoff prediction by employing the Nash instantaneous unit hydrograph model (adapting to the nonlinear response of the confluence process) and the SCS model (adapting to the runoff-confluence coupling law of the diversion process) respectively, based on the type of the fixed-point impact area to which the key runoff path belongs (first area for confluence-type and second area for diversion-type). This provides reliable data support for risk assessment and drives runoff calculation with monitoring data, replacing empirical estimation and ensuring data objectivity. Surface runoff is obtained based on "real-time monitoring data from confluence monitoring points + a trained surface runoff model," replacing the traditional method that relies on the empirical formula of "historical average rainfall - runoff." Traditional empirical estimation is easily affected by yearly differences and topographic changes (such as newly hardened ground), leading to large deviations in runoff. This step uses real-time monitoring data (such as actual rainfall at confluence monitoring points) as model input, combined with model parameters trained from historical data, allowing runoff calculation to be directly anchored to the current actual hydrological conditions, ensuring the objectivity and timeliness of runoff data, and avoiding the interference of subjective errors in empirical estimation on risk assessment. A layered, progressive risk assessment logic based on the "surface-pipeline network" framework is constructed to cover the entire process of urban flooding formation. By first assessing surface-level risks (the relationship between runoff and receiving rate, and maximum surface runoff), and then assessing pipeline-level risks (the relationship between pipeline input rate and maximum output rate), a comprehensive, layered screening of urban flooding risks is achieved. Traditional methods often focus only on a single aspect (such as checking whether surface runoff exceeds standards, ignoring pipeline drainage capacity), leading to missed assessments—for example, even if surface runoff does not exceed standards, a drainage bottleneck caused by interconnected inputs in the pipeline network can still trigger urban flooding. This layered logic covers the key "surface water accumulation-pipeline drainage" stage of urban flooding formation, avoiding both "missed risk assessment due to pipeline overload despite surface standards" and "misjudged risk assessment due to surface water accumulation despite pipeline compliance," significantly improving the comprehensiveness and accuracy of risk assessment.

[0151] In this plan, the specific surface runoff is as follows:

[0152]

[0153] In the formula, Surface runoff, Rainfall in a designated area, expressed in mm / h. For the area of ​​the fixed point, Indicates the first fixed-point influence area Surface runoff models corresponding to key runoff paths, Indicates the first fixed-point influence area Rainfall at the confluence monitoring points of key runoff paths, Indicates the second fixed-point influence area. Surface runoff models corresponding to key runoff paths, Indicates the second fixed-point influence area. Rainfall at the confluence monitoring points of key runoff paths.

[0154] In this embodiment, the maximum surface runoff is the product of the maximum allowable runoff depth and the area of ​​the fixed area. Based on the "Outdoor Drainage Design Standard" and the "Technical Standard for Urban Waterlogging Prevention and Control" (GB51222-2017), the maximum runoff depth is set to 90mm.

[0155] In this embodiment, the training process of the Nash instantaneous unit line model (applicable to the first fixed-point influence region) is described.

[0156] The first fixed-point influence area is a "confluence region" (the confluence elevation of neighboring sub-regions > the target confluence elevation of the fixed-point area, and runoff flows from neighboring regions to the fixed-point area). The specific training process of the Nash instantaneous unit hydrograph model is as follows:

[0157] Data preprocessing extracts rainfall data (input amount, denoted as ) from the confluence monitoring points of key runoff paths within the first fixed-point impact area from historical runoff data. (unit: mm / h) and the total runoff volume of the corresponding surface runoff path (output, denoted as...) ,unit Align the data by time series (time step Δt = 1h) and remove outliers (such as negative rainfall or runoff exceeding the reasonable range).

[0158] The core formula for initializing the Nash instantaneous unit line model parameters is:

[0159]

[0160] The ordinate of the unit line represents the runoff process line generated per unit of rainfall. To regulate parameters, The number of linear reservoirs. For gamma functions; initialize parameter range: , (Conforms to the standard parameter range of Nash models in the hydrological field).

[0161] Preprocessed Input the initial model and calculate the simulated runoff. ,Right now:

[0162]

[0163] With the objective function of minimizing the mean square error (MSE) between simulated and measured runoff, a particle swarm optimization (PSO) algorithm is used for iterative optimization. , The iteration termination condition is: the change in MSE after 100 consecutive iterations is < Or the number of iterations reaches 1000;

[0164] Model validation uses 70% of historical runoff data as the training set and 30% as the validation set. If the Nash efficiency coefficient (NSE) of the validation set is ≥0.75, the model training is complete; if NSE <0.75, the parameter initialization range is readjusted and the training steps are repeated.

[0165] The training process of the SCS model (applicable to the second fixed-point influence area), where the second fixed-point influence area is a "diversionary area" (the runoff elevation of the adjacent sub-regions is less than the target runoff elevation of the fixed-point area, and the runoff flows from the fixed-point area to the adjacent areas), is as follows:

[0166] Data preprocessing extracts rainfall data (input amount, denoted as ) from the confluence monitoring points of key runoff paths within the second fixed-point influence area. (unit: mm / h) and the total runoff volume of the corresponding surface runoff path (output, denoted as...) ,unit ).

[0167] The core formula and parameter initialization formula for the SCS model are as follows:

[0168]

[0169] Initialize CN value range: According to the "SCS Hydrological Model Technical Specification", urban built-up area .

[0170] Preprocessed Input the initial model and calculate the simulated runoff. With the goal of minimizing MSE, the gradient descent method is used to optimize the CN value, with an optimization range of ±10 (not exceeding [70,95]).

[0171] If the validation set NSE ≥ 0.7, the model training is complete; otherwise, adjust the initial value of CN and repeat the training steps.

[0172] The formula for calculating the mean square error between simulated and measured runoff is a well-known formula, so it will not be described in detail in this scheme.

[0173] Reference Figure 5 As shown, further, combining the above-mentioned method for targeted rainstorm-induced urban flooding risk assessment based on multi-source data, a targeted rainstorm-induced urban flooding risk assessment system based on multi-source data is proposed, including:

[0174] The main control module is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis; obtain the surface runoff model corresponding to each key runoff path based on the key runoff path information and historical runoff data; monitor the confluence monitoring points and fixed areas; obtain monitoring data; and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model.

[0175] The information acquisition module is used to acquire fixed-point area information, which includes fixed-point area location information and area topography information. Based on the fixed-point area information, it acquires neighboring area information. Based on the fixed-point area information and neighboring area information, it acquires fixed-point area elevation data and neighboring area elevation data based on a digital elevation model.

[0176] The runoff analysis module is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, take the adjacent areas between adjacent regional confluence baselines as sub-regions, obtain the adjacent sub-region information, obtain the fixed-point impact area information based on the adjacent sub-region information, and obtain the surface runoff path information based on the fixed-point impact area information and the D8 algorithm.

[0177] The display module interacts with the main control module to output and display monitoring data, and to provide risk warnings for rainstorms and urban flooding.

[0178] The main control module specifically includes:

[0179] The control unit is used to obtain the surface runoff model corresponding to each key runoff path based on key runoff path information and historical runoff data, monitor the confluence monitoring points and fixed areas, obtain monitoring data, and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model.

[0180] An information receiving unit, which interacts with the information acquisition module and the runoff analysis module, is used to receive data and transmit it to the path identification unit.

[0181] The path identification unit is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis.

[0182] The information acquisition module specifically includes:

[0183] A region acquisition unit is used to acquire fixed-point region information, which includes fixed-point region location information and region terrain information, and to acquire neighboring region information based on the fixed-point region information.

[0184] An elevation acquisition unit is used to acquire elevation data of a fixed area and elevation data of adjacent areas based on a digital elevation model, according to fixed area information and adjacent area information.

[0185] The runoff analysis module specifically includes:

[0186] The regional analysis unit is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, and take the adjacent areas between adjacent regional confluence baselines as sub-regions to obtain the adjacent sub-region information.

[0187] The runoff analysis unit is used to obtain fixed-point impact area information based on neighboring sub-region information, and to obtain surface runoff path information based on the D8 algorithm based on the fixed-point impact area information.

[0188] In summary, the advantages of this invention are as follows: By using information on the fixed-point impact area, it achieves a deep adaptation between the division of the fixed-point impact area and the terrain features, laying a topographical foundation for subsequent accurate identification of confluence paths; by dynamically determining the boundary confluence distance through the boundary confluence distance threshold, it achieves quantitative and dynamic adjustment of the impact area range, providing a basis for subsequent targeted analysis of the impact of runoff from different directions on the fixed-point area; by constructing a logic for defining the fixed-point impact area, it achieves synergistic connection between the impact area and subsequent surface runoff path analysis and urban flooding risk calculation, providing an accurate and reliable regional scope foundation for the entire fixed-point rainstorm and urban flooding risk assessment; and by using key runoff path information, it reduces the number of monitoring points required and improves the efficiency of risk assessment.

[0189] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for assessing the risk of urban flooding caused by rainstorms based on multi-source data, characterized in that, include: Obtain fixed-point area information, which includes fixed-point area location information and area terrain information; Based on the fixed-point area information and the regional topography analysis, the fixed-point influence area information is obtained, wherein the fixed-point influence area includes a first fixed-point influence area and a second fixed-point influence area. Based on the fixed-point impact area information, surface runoff path information is obtained using the D8 algorithm. The surface runoff path information includes the regional grid information corresponding to the surface runoff path. The surface runoff path represents the runoff route from the fixed-point impact area to the fixed-point area or from the fixed-point area to the fixed-point impact area. Based on the surface runoff path information, obtain the runoff direction information corresponding to each surface runoff path, wherein the runoff direction points from the starting point to the ending point of the surface runoff path; Based on the analysis of hydrological runoff characteristics, the runoff direction angle threshold and runoff path distance threshold are obtained; Based on surface runoff path information, key runoff path information is obtained using runoff direction angle threshold and runoff path distance threshold. The key runoff path represents the runoff path after merging surface runoff paths, and the key runoff path information includes confluence monitoring point information. Acquire historical runoff data, which includes rainfall and runoff volume corresponding to each surface runoff path; Based on key runoff path information and historical runoff data, obtain the surface runoff model corresponding to each key runoff path; Monitor the confluence monitoring points and fixed areas to obtain monitoring data; Based on monitoring data and surface runoff models, determine whether there is a risk of rainstorm-induced flooding in designated areas. If so, issue a risk warning for rainstorm-induced flooding. The step of obtaining information about the designated impact area based on the designated area information and regional topography analysis specifically includes: Based on the fixed-point area information, obtain the neighboring area information, where the neighboring area refers to the area adjacent to the fixed-point area; Based on the fixed-point area information and the neighboring area information, and using the digital elevation model, the elevation data of the fixed-point area and the neighboring area are obtained. The elevation data includes the regional grid information and the elevation value corresponding to each grid. Based on the elevation data of the fixed area, the area grid corresponding to the minimum elevation value in the fixed area is taken as the area confluence point; Based on surface runoff flow analysis, runoff direction information is obtained; Using the regional confluence point as the origin, a baseline is drawn along the runoff direction to obtain the regional confluence baseline information; Based on the neighboring area information and the regional convergence baseline information, the neighboring areas between adjacent regional convergence baselines are taken as sub-areas, and the neighboring sub-area information is obtained; Based on a fixed area and neighboring areas, regional boundary information is obtained, where the regional boundary represents the boundary line between the fixed area and the neighboring areas. Based on the elevation data of the fixed area and the elevation data of the adjacent area, the area grid corresponding to the area boundary is used as the area boundary grid to obtain the area boundary grid information; Based on the elevation data of the neighboring area and the information of the neighboring sub-areas, obtain the elevation data corresponding to each neighboring sub-area; The average elevation value of the corresponding grid in each neighboring sub-region is used as the reference elevation value for that region. Based on the elevation data of the fixed point area, the average elevation value of the corresponding grid of the fixed point area is taken as the elevation value of the fixed point area. The ratio of the benchmark elevation value corresponding to each neighboring sub-region to the elevation value of the fixed-point region is used as the regional elevation deviation coefficient. Based on topographic flow analysis, a boundary flow distance threshold is obtained, which includes the maximum and minimum boundary flow distances. The product of the minimum boundary confluence distance of each neighboring sub-region and the regional elevation deviation coefficient is taken as the boundary base confluence distance of that neighboring sub-region. The boundary merge distance is obtained based on the boundary merge distance threshold and the boundary base merge distance; Wherein, if the boundary base flow distance is lower than the minimum boundary flow distance, the minimum boundary flow distance is taken as the boundary flow distance; if the boundary base flow distance is higher than the maximum boundary flow distance, the maximum boundary flow distance is taken as the boundary flow distance. Based on the regional boundary grid information and the neighboring sub-region information, the regional boundary grid corresponding to each neighboring sub-region is taken as the sub-region boundary grid of that neighboring sub-region; Based on the boundary confluence distance, using the sub-region boundary grid as a basis, the region grid in each neighboring sub-region whose distance from the sub-region boundary grid is less than the boundary confluence distance is taken as the confluence characteristic grid of that neighboring sub-region; Based on the elevation data of the fixed point area, the grid in the grid corresponding to the fixed point area whose distance to the boundary grid of each neighboring sub-region is less than the boundary convergence distance of the neighboring sub-region is taken as the target convergence grid of the neighboring sub-region. The average elevation value of the confluence feature grid of each neighboring sub-region is used as the confluence elevation value, and the average elevation value of the target confluence grid is used as the target confluence elevation value. Based on the confluence elevation and the target confluence elevation, information on the specific impact area is obtained; Specifically, if the confluence elevation of a neighboring sub-region is higher than the target confluence elevation, then the neighboring sub-region is designated as the first fixed-point influence area; if the confluence elevation of a neighboring sub-region is lower than the target confluence elevation, then the neighboring sub-region is designated as the second fixed-point influence area.

2. The method for assessing the risk of urban flooding based on multi-source data at specific locations during rainstorms, as described in claim 1, is characterized in that... The process of obtaining key runoff path information based on surface runoff path information, using runoff direction angle thresholds and runoff path distance thresholds as a basis, specifically includes: Based on surface runoff path information, surface runoff paths are classified according to the information of fixed-point impact areas. Surface runoff paths in the same type of fixed-point impact area are classified into the same type of surface runoff paths to obtain surface runoff path classification information. Based on the surface runoff path classification information, any two surface runoff paths of the same type are grouped together as a path merging group. The angle between the runoff directions of two surface runoff paths in the path merging group is taken as the runoff direction angle, and the minimum straight-line distance between any two regional grids in the two surface runoff paths is taken as the shortest spatial distance. Based on the path merging group, and using the runoff direction angle threshold and runoff path distance threshold as a basis, information on mergeable paths is obtained; If the runoff direction angle of the path merging group is lower than the runoff direction angle threshold and the shortest spatial distance is lower than the runoff path distance threshold, then the two surface runoff paths in the path merging group are mergeable paths. Based on the mergeable path information, the path midpoint coordinates are used as the cluster center, and path merging is performed based on hierarchical clustering to obtain key runoff path information; Based on the information of the designated impact areas, the endpoint of each critical runoff path in the first designated impact area is taken as the confluence monitoring point of that critical runoff path, and the starting point of each critical runoff path in the second designated impact area is taken as the confluence monitoring point of that critical runoff path.

3. The method for assessing the risk of urban flooding based on multi-source data at specific locations during rainstorms, as described in claim 2, is characterized in that... The determination of whether a designated area is at risk of flooding due to rainstorms, based on monitoring data and surface runoff models, specifically includes: Based on historical runoff data and information from runoff monitoring points, the rainfall corresponding to each runoff monitoring point is obtained; Using the rainfall corresponding to each confluence monitoring point, obtain the surface runoff model corresponding to each key runoff path; If the critical runoff path is located in the first fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output to train the Nash instantaneous unit hydrograph model and obtain the surface runoff model. If the critical runoff path is located in the second fixed-point influence area, the rainfall at the confluence monitoring point of the critical runoff path is used as the input, and the total runoff of the surface runoff path corresponding to the critical runoff path is used as the output. The SCS model is trained with historical runoff data to obtain the surface runoff model. Based on monitoring data and a surface runoff model, the surface runoff volume is obtained. Obtain drainage design parameter information for a specific area, including surface runoff reception rate and maximum output rate of the regional pipe network; Based on the analysis of rainstorm-induced urban flooding, the maximum surface runoff is obtained; Based on surface runoff, surface runoff receiving rate, and maximum surface runoff, determine whether there is a risk of rainstorm-induced flooding in a designated area. If the difference between surface runoff and surface runoff receiving rate exceeds the maximum surface runoff, then there is a risk of rainstorm-induced flooding in the designated area. If the difference between surface runoff and surface runoff receiving rate does not exceed the maximum surface runoff, the surface input rate of the pipeline network is obtained based on the surface runoff and surface runoff receiving rate. Based on monitoring data, the pipeline connection input rate is obtained, which represents the flow rate received by the pipeline network in a fixed area; Based on the surface input rate of the pipeline network, the interconnection input rate of the pipeline network, and the maximum output rate of the regional pipeline network, it is determined whether there is a risk of rainstorm flooding in a designated area. If the sum of the surface input rate of the pipeline network and the interconnection input rate of the pipeline network exceeds the maximum output rate of the regional pipeline network, then there is a risk of rainstorm flooding in the designated area.

4. A point-based rainstorm flood risk assessment system based on multi-source data, used to implement the assessment method as described in any one of claims 1-3, characterized in that, include: The main control module is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis; obtain the surface runoff model corresponding to each key runoff path based on the key runoff path information and historical runoff data; monitor the confluence monitoring points and fixed areas; obtain monitoring data; and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model. The information acquisition module is used to acquire fixed-point area information, which includes fixed-point area location information and area topography information. Based on the fixed-point area information, it acquires neighboring area information. Based on the fixed-point area information and neighboring area information, it acquires fixed-point area elevation data and neighboring area elevation data based on a digital elevation model. The runoff analysis module is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, take the adjacent areas between adjacent regional confluence baselines as sub-regions, obtain the adjacent sub-region information, obtain the fixed-point impact area information based on the adjacent sub-region information, and obtain the surface runoff path information based on the fixed-point impact area information and the D8 algorithm. The display module interacts with the main control module to output and display monitoring data, and to provide risk warnings for rainstorms and urban flooding.

5. A point-based rainstorm flood risk assessment system based on multi-source data according to claim 4, characterized in that, The main control module specifically includes: The control unit is used to obtain the surface runoff model corresponding to each key runoff path based on key runoff path information and historical runoff data, monitor the confluence monitoring points and fixed areas, obtain monitoring data, and determine whether there is a risk of rainstorm flooding in the fixed areas based on the monitoring data and surface runoff model. An information receiving unit, which interacts with the information acquisition module and the runoff analysis module, is used to receive data and transmit it to the path identification unit. The path identification unit is used to obtain key runoff path information based on surface runoff path information, using runoff direction angle threshold and runoff path distance threshold as a basis.

6. A point-based rainstorm flood risk assessment system based on multi-source data according to claim 4, characterized in that, The information acquisition module specifically includes: A region acquisition unit is used to acquire fixed-point region information, which includes fixed-point region location information and region terrain information, and to acquire neighboring region information based on the fixed-point region information. An elevation acquisition unit is used to acquire elevation data of a fixed area and elevation data of adjacent areas based on a digital elevation model, according to fixed area information and adjacent area information.

7. A point-based rainstorm flood risk assessment system based on multi-source data according to claim 4, characterized in that, The runoff analysis module specifically includes: The regional analysis unit is used to draw a baseline along the runoff direction with the regional confluence point as the origin, obtain the regional confluence baseline information, and take the adjacent areas between adjacent regional confluence baselines as sub-regions to obtain the adjacent sub-region information. The runoff analysis unit is used to obtain fixed-point impact area information based on neighboring sub-region information, and to obtain surface runoff path information based on the D8 algorithm based on the fixed-point impact area information.

Images