Dam break flood emergency monitoring method and system

Abstract

The invention discloses a dam break flood emergency monitoring method and system, and particularly relates to the technical field of flood monitoring. The method comprises the following steps: acquiring real-time topographic change data and hydrological data of a breach and a downstream area at the initial stage of dam break flood, and constructing initial dynamic evolution data of a dam break flood flow channel; the nonlinear bifurcation position of the flood flow channel is identified through a topology analysis method, and nonlinear bifurcation topology feature data is formed; spatial distribution of a sediment accumulation area and an erosion area in the flood flow channel is analyzed based on coupling of sediment migration, and an abnormal bifurcation path of the flood flow channel is determined; acquiring water flow velocity, water level height and sediment concentration data on the abnormal path in real time, and generating abnormal path real-time monitoring data; analyzing a flood diffusion trend according to the abnormal path real-time monitoring data, and generating an emergency response early warning instruction; according to the invention, the monitoring accuracy and the emergency disposal capability of dam break flood disasters are improved.

Description

Technical Field

[0001] This invention relates to the field of flood monitoring technology, and more specifically, to a method and system for emergency monitoring of dam-break floods. Background Technology

[0002] Dam-break floods are characterized by their high destructiveness, suddenness, and drastic changes in path, seriously threatening the lives of people and the safety of infrastructure in downstream areas.

[0003] Existing dam-break flood monitoring methods typically focus on monitoring hydrological elements and the overall flood impact range in the initial stage of the dam break, without considering the nonlinear bifurcation effect of the channel after flood damage. This makes it difficult to accurately predict abnormal changes in the flood diffusion path. Dam-break floods are usually accompanied by severe erosion, sediment deposition, and damage to the channel structure downstream of the breach, causing sudden shifts, intersections, and nonlinear bifurcations in the flow path, making it difficult to capture the true flood diffusion path. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a method and system for emergency monitoring of dam-break floods to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for emergency monitoring of dam-break floods includes the following steps:

[0007] S1: Collect real-time topographic and hydrological data on the breach and downstream areas to generate initial dynamic evolution data of the dam-break flood channel;

[0008] S2: Based on the initial dynamic evolution data of the dam-break flood channel, perform topological analysis on the spatial structure changes of the dam-break flood channel, identify the nonlinear bifurcation locations of the dam-break flood channel, and generate nonlinear bifurcation topological feature data of the dam-break flood channel.

[0009] S3: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, a coupled analysis of sediment deposition and erosion in the dam-break flood channel is conducted to identify the distribution of sediment accumulation and erosion zones and generate sediment migration characteristic data.

[0010] S4: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths;

[0011] S5: Based on the spatial distribution data of abnormal paths, collect flow velocity, water level and sediment concentration data of abnormal paths in real time, and generate real-time monitoring data of abnormal paths;

[0012] S6: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

[0013] In a preferred embodiment, S1 specifically refers to:

[0014] Real-time topographic changes in the breach area and downstream river channel were measured using a topographic scanner to obtain real-time topographic change data for the breach area and downstream river channel.

[0015] Multi-point water level gauges were used to monitor the water flow in the breach area and the downstream river channel in real time, and hydrological data of the breach area and the downstream river channel were obtained.

[0016] Based on real-time topographic and hydrological data of the breach area and downstream river channel, initial dynamic evolution data of the dam-break flood channel are generated.

[0017] In a preferred embodiment, S2 specifically refers to:

[0018] A three-dimensional topological skeleton of the dam-break flood channel was constructed based on the initial dynamic evolution data of the dam-break flood channel.

[0019] A hydrodynamic topology model was used to calculate the node connection relationships of the three-dimensional topological skeleton of the dam-break flood channel, thereby obtaining spatial structural change data of the dam-break flood channel.

[0020] Based on spatial structure change data, nonlinear bifurcation nodes of the dam-break flood channel are identified according to the criteria that the angle between the flow direction vectors is greater than a preset angle threshold and the cross-sectional velocity gradient exceeds a preset gradient threshold.

[0021] Based on the connectivity between nonlinear bifurcation nodes and adjacent nodes, nonlinear bifurcation topological feature data of dam-break flood channels are formed.

[0022] In a preferred embodiment, S3 specifically refers to:

[0023] Based on the nonlinear bifurcation topological feature data of dam-break flood channels, a gridded spatial structure of dam-break flood channels is established.

[0024] Based on the gridded spatial structure of the dam-break flood channel, the sediment deposition rate and erosion rate of each grid cell are calculated.

[0025] Based on the sediment deposition rate and erosion rate of each grid cell, determine the location coordinates and spatial distribution range of the sediment deposition area and erosion area in the dam break flood channel;

[0026] Based on the location coordinates and spatial distribution range of sediment deposition and erosion areas, sediment migration characteristic data are generated.

[0027] In a preferred embodiment, S4 specifically refers to:

[0028] Based on the nonlinear bifurcation topology and sediment migration characteristics of the dam-break flood channel, a flow connectivity graph is constructed.

[0029] In the flow connectivity graph, calculate the sediment deposition gradient, erosion gradient, and flow direction vector for each topological edge segment;

[0030] Among all topological segments, topological segments with sediment deposition gradients or erosion gradients higher than the corresponding preset thresholds and whose flow vectors have an angle greater than a preset angle threshold with the flow vectors of adjacent upstream segments are selected as candidate segments for abnormal bifurcation.

[0031] Based on the connectivity between candidate edges of abnormal bifurcation, consecutive candidate edges of abnormal bifurcation are combined to form abnormal bifurcation paths of dam-break floods.

[0032] Geometric location and spatial interpolation are performed on the abnormal bifurcation paths of dam-break floods to generate spatial distribution data of abnormal paths.

[0033] In a preferred embodiment, S5 specifically refers to:

[0034] Based on the spatial distribution data of abnormal paths, the flow velocity, water level and sediment concentration in the abnormal bifurcation path of the dam-break flood were collected to obtain the flow velocity data, water level data and sediment concentration data at each measurement point of the abnormal bifurcation path.

[0035] Based on the flow velocity data, water level data, and sediment concentration data at each measurement point along the abnormal bifurcation path, real-time monitoring data for the abnormal path is generated.

[0036] In a preferred embodiment, S6 specifically refers to:

[0037] Based on real-time monitoring data of abnormal paths, we analyze the real-time changing trends of flow velocity, water level and sediment concentration data at each measurement point on the abnormal bifurcation path of the dam break flood.

[0038] Based on real-time trends, predict the spatial extent, direction of spread, and rate of spread of abnormal bifurcation paths of dam-break floods;

[0039] Based on the spatial expansion range, diffusion direction, and diffusion rate, determine the geographical coordinates and boundaries of the risk areas involved in the spread of dam-break floods;

[0040] Emergency response warning instructions are generated based on the geographical coordinates and boundaries of the risk area.

[0041] On the other hand, the present invention provides an emergency monitoring system for dam-break floods, comprising:

[0042] Data acquisition module: Collects real-time topographic and hydrological data of the breach and downstream areas, and generates initial dynamic evolution data of the dam-break flood channel.

[0043] Topology Analysis Module: Based on the initial dynamic evolution data of the dam-break flood channel, the module performs topology analysis on the spatial structure changes of the dam-break flood channel, identifies the nonlinear bifurcation locations of the dam-break flood channel, and generates nonlinear bifurcation topology feature data of the dam-break flood channel.

[0044] Sediment Analysis Module: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, this module performs coupled analysis on sediment deposition and erosion in the dam-break flood channel, identifies the distribution of sediment accumulation and erosion zones, and generates sediment migration characteristic data.

[0045] Path determination module: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths;

[0046] Real-time monitoring module: Based on the spatial distribution data of abnormal paths, it collects flow velocity, water level and sediment concentration data of abnormal paths in real time and generates real-time monitoring data of abnormal paths;

[0047] Early warning instruction module: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

[0048] The technical effects and advantages of the emergency monitoring method and system for dam-break floods of this invention are as follows:

[0049] By acquiring real-time topographic and hydrological changes in the breach and downstream areas, the system accurately depicts the initial evolution of the dam-break flood channel. Based on this evolution data, spatial topological analysis is conducted to accurately identify nonlinear bifurcation locations. Combining nonlinear bifurcation topological characteristics with sediment migration information, the system precisely locates sediment deposition and erosion areas. Anomaly bifurcation paths are identified based on topological and sediment dynamic characteristics, and a spatial distribution model of these paths is constructed to fill monitoring gaps in path bifurcation monitoring. Flow velocity, water level, and sediment concentration are collected to achieve continuous monitoring of all elements of anomaly bifurcation paths. Real-time monitoring data is used to dynamically predict flood diffusion trends and generate emergency response warnings, making warnings more timely and accurate. This research reveals the complex changes in the channel and sediment migration patterns after dam-break flood damage, improving the accuracy of flood diffusion path prediction. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of an emergency monitoring method for dam-break floods according to the present invention;

[0051] Figure 2 This is a schematic diagram of the structure of an emergency monitoring system for dam break floods according to the present invention. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] Figure 1 This invention provides an emergency monitoring method for dam-break floods, which includes the following steps:

[0055] S1: Collect real-time topographic and hydrological data on the breach and downstream areas to generate initial dynamic evolution data of the dam-break flood channel;

[0056] S2: Based on the initial dynamic evolution data of the dam-break flood channel, perform topological analysis on the spatial structure changes of the dam-break flood channel, identify the nonlinear bifurcation locations of the dam-break flood channel, and generate nonlinear bifurcation topological feature data of the dam-break flood channel.

[0057] S3: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, a coupled analysis of sediment deposition and erosion in the dam-break flood channel is conducted to identify the distribution of sediment accumulation and erosion zones and generate sediment migration characteristic data.

[0058] S4: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths;

[0059] S5: Based on the spatial distribution data of abnormal paths, collect flow velocity, water level and sediment concentration data of abnormal paths in real time, and generate real-time monitoring data of abnormal paths;

[0060] S6: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

[0061] S1: Collect real-time topographic and hydrological data on the breach and downstream areas to generate initial dynamic evolution data of the dam-break flood channel, including:

[0062] Real-time topographic changes in the breach area and downstream river channel were measured using a topographic scanner to obtain real-time topographic change data for the breach area and downstream river channel.

[0063] In the initial stages of a dam breach, topographic scanners are used to measure real-time topographic changes in the breach area. Topographic scanners can acquire real-time information on the elevation and spatial coordinates of the target area. For example, if a dam breaches, initially forming a gap several meters to tens of meters wide, this is the breach area. The breach area is the spatial region created by the impact of water flow within the original dam structure. The rapid outflow of water from the breach area causes drastic topographic changes, manifested as erosion, collapse, or damage to the original surface or building structures. After the dam breach, multiple scanning points are set up in a safe area. The topographic scanner emits high-frequency laser beams from different scanning points towards the breach area. After the laser beams illuminate the surface of the breach area, real-time three-dimensional coordinate data is obtained through the reflected signals. Continuous scanning captures the three-dimensional spatial morphology of the breach area at each instant. For example, by collecting topographic changes in the breach area at a scanning frequency of 10 times per second and continuously monitoring for at least one minute, 600 real-time topographic changes in the breach area are obtained, forming a continuous data set reflecting changes in elevation and spatial structure of the breach area.

[0064] Simultaneously, real-time measurements were taken of the topographic changes in the downstream river channel area. The downstream river channel area refers to the area below the breach after the dam collapse, including the main river channel, riverbank slopes, and surrounding land that may be affected. Following the rapid downstream flow, the downstream river channel area experienced severe erosion, deposition, and damage to the riverbed structure within a short period. Dramatic changes occurred to the original riverbed and riverbank slopes, including widening of the river channel, deepening of the riverbed, collapse of riverbank slopes due to water flow, sediment accumulation, and the formation of new river channels. Multiple scanning stations were set up along the riverbanks in the downstream river channel area, each covering a certain area of ​​the river channel. The scanner used a high-frequency laser ranging method to perform real-time scanning measurements of the riverbed, riverbanks, and surrounding areas. Data such as riverbed height, riverbank slope morphology, and river channel cross-sectional profile were collected in real-time at the same scanning frequency in the downstream river channel area. For example, in the first ten minutes after a dam break, the geomorphological changes in the river channel area are monitored in real time at a scanning frequency of 10 times per second, thereby obtaining continuous data reflecting the evolution of the riverbed and riverbank topography over time.

[0065] Multi-point water level gauges were used to monitor the water flow in the breach area and the downstream river channel in real time, and hydrological data of the breach area and the downstream river channel were obtained.

[0066] A multi-point water level gauge is a real-time monitoring device capable of measuring water level and flow velocity at multiple monitoring points. It comprises multiple independently configured sensing units, each capable of independently measuring water level, flow velocity, and other information, and outputting the measurement results in real time. For example, multiple water level gauge units can be deployed in safe, fixed locations near the breach area, with no fewer than five monitoring points spaced several meters to tens of meters apart. Each water level gauge unit continuously measures changes in water level and flow velocity in the breach area via a buoy, water level sensor probe, or ultrasonic ranging probe. For instance, a water level gauge unit in the breach area can perform more than 10 measurements per second, reflecting real-time changes in water flow within the breach area. In the downstream river area of ​​the breach, multiple water level monitoring devices are also deployed. Each device uses a probe to detect real-time changes in the height and velocity of the water surface, monitoring the hydrological dynamics of the downstream river. For example, water level gauges are deployed on both sides of the river, with monitoring points spaced tens of meters apart on each side, forming a longitudinally arranged monitoring array to monitor changes in water flow height and velocity in real time, ensuring that real-time hydrological data of the downstream river area is obtained.

[0067] Based on real-time topographic and hydrological data of the breach area and downstream river channel, initial dynamic evolution data of the dam-break flood channel are generated.

[0068] Real-time topographic change data and hydrological data refer to the data set of spatial location coordinates, elevation changes, water level height, flow velocity, and flow direction changes continuously measured during the monitoring period. To generate initial dynamic evolution data, it is necessary to perform unified spatiotemporal coordinate registration on the continuously acquired data set. The real-time topographic change data obtained by the topographic scanner and the hydrological data obtained by the multi-point water level gauge are aligned and correlated according to timestamps and spatial coordinates to form a unified data coordinate system. Based on this unified data coordinate system, the topographic change data obtained at each time point is synchronously merged and spatially interpolated with the corresponding hydrological data to obtain the spatial distribution characteristics of the dam-break flood channel evolution over time, thus obtaining the initial dynamic evolution data of the dam-break flood channel.

[0069] S2: Based on the initial dynamic evolution data of the dam-break flood channel, perform topological analysis on the spatial structure changes of the dam-break flood channel, identify the nonlinear bifurcation locations of the dam-break flood channel, and generate nonlinear bifurcation topological feature data of the dam-break flood channel, including:

[0070] A three-dimensional topological skeleton of the dam-break flood channel was constructed based on the initial dynamic evolution data of the dam-break flood channel.

[0071] The three-dimensional topological framework of a dam-break flood channel is a topological structure represented in three-dimensional spatial coordinates, including topological nodes and topological segments connecting them. Topological nodes represent key locations in the flood channel, such as confluences, branching points, locations where channel morphology changes, areas with significant changes in channel width, channel bends, and locations of abrupt changes in elevation. The location of topological nodes is determined using three-dimensional coordinates, obtained from spatial coordinates and elevation data recorded in initial dynamic evolution data. Topological segments connect adjacent topological nodes; each segment represents a spatial path between two adjacent nodes in the channel. Path information includes three-dimensional spatial information such as changes in flow direction between the two nodes, path length, channel width, and changes in spatial curvature. For example, in the initial stage of a dam-break flood, when the floodwaters rapidly flow through the breach into the downstream river channel, multiple river erosion or deposition areas may appear. Based on the collected spatial location and elevation change data, the locations where multiple river erosion or deposition occurs are set as topological nodes. Then, the topological nodes are connected according to the water flow direction information to construct a three-dimensional topological skeleton of the dam-break flood channel that represents the actual channel spatial structure.

[0072] A hydrodynamic topology model was used to calculate the node connection relationships of the three-dimensional topological skeleton of the dam-break flood channel, thereby obtaining spatial structural change data of the dam-break flood channel.

[0073] Hydrodynamic topology models are mathematical methods used to calculate the connectivity relationships between nodes in a flow channel, determining the flow connectivity and direction changes between nodes. Employing a hydrodynamic topology model first requires topological nodes and edges from the three-dimensional topological framework of a dam-break flood channel as input. Each topological node has a defined spatial coordinate position, and each topological edge has a spatial path and a flow direction vector. Using the spatial coordinates of the topological nodes as a basis, and based on the actual flow direction vector data, the hydrodynamic topology model determines the connectivity relationships between each node and its surrounding nodes, calculating the connectivity weights and directions between each node. The node connectivity data represents the spatial structural changes in the dam-break flood channel, recording the connection forms between nodes in the topological framework, the flow direction relationships between nodes, and the spatial topological order of the topological edges. For example, when river branching, erosion, bank collapse, or sediment deposition occur in the early stages of a dam-break flood, leading to multiple newly formed flow paths, the hydrodynamic topology model can calculate the connectivity paths between nodes based on the node coordinates and the flow direction of the paths, thereby obtaining spatial structural change data that represents the spatial connectivity relationships and flow direction characteristics between nodes.

[0074] Based on spatial structure change data, nonlinear bifurcation nodes of the dam-break flood channel are identified according to the criteria that the angle between the flow direction vectors is greater than a preset angle threshold and the cross-sectional velocity gradient exceeds a preset gradient threshold.

[0075] Spatial structure change data refers to the connectivity and spatial topology information between nodes obtained through a hydrodynamic topology model, including parameters such as the coordinates of each node's location and the flow direction information of the channel. To identify nonlinear bifurcation nodes in the channel during a dam-break flood, certain criteria are established. One criterion is that the angle between the flow direction vectors exceeds a preset threshold. This means that for each topological node, the angle formed by the flow direction vectors between the node and its adjacent nodes is calculated. When the angle exceeds a certain preset threshold (e.g., 30 degrees), it indicates a nonlinear deflection of the flow direction at that node. Another criterion is that the velocity gradient at the cross-section exceeds a preset threshold (e.g., a velocity change greater than 1 meter per second). When both criteria are met, the topological node is identified as a nonlinear bifurcation node. A nonlinear bifurcation node represents a special location in the channel where the flow path undergoes a sharp turn or split. For example, when a flood encounters a location with abrupt topographic changes or severe riverbed erosion during its discharge, the water flow rapidly changes direction and its velocity changes significantly. On the topological framework, the corresponding node at this location satisfies the criteria for a nonlinear bifurcation node.

[0076] Based on the connectivity between nonlinear bifurcation nodes and adjacent nodes, nonlinear bifurcation topological feature data of dam-break flood channels are formed.

[0077] After identifying the nonlinear bifurcation nodes, the topological connectivity between the nonlinear bifurcation nodes and their directly connected adjacent nodes is recorded, based on the connectivity relationships between nodes in the spatial structure change data. This data is digitized using node coordinates, edge paths, and connectivity patterns to form a set of topological data representing the location of nonlinear bifurcation nodes and their upstream and downstream connections in the channel's spatial structure; this set is called nonlinear bifurcation topological feature data. For example, when a dam-break flood channel bifurcates at a certain node, the nonlinear bifurcation topological feature data can clearly record the node's connection relationships with adjacent upstream and downstream nodes, its spatial coordinates, and path direction, among other topological features, using the node connection information in the spatial structure change data.

[0078] S3: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, a coupled analysis of sediment deposition and erosion in the dam-break flood channel is performed to identify the distribution of sediment deposition and erosion zones, and to generate sediment migration characteristic data, including:

[0079] Based on the nonlinear bifurcation topological feature data of dam-break flood channels, a gridded spatial structure of dam-break flood channels is established.

[0080] The flood channel of a dam-break flood is spatially divided into multiple adjacent three-dimensional grid cells. Each grid cell has fixed spatial boundary coordinates, determined by latitude, longitude, and elevation information. The division is based on the spatial distribution of topological nodes and the path distribution of topological segments. Each grid cell typically covers an area of ​​several to tens of square meters. By dividing the space into grids, the continuous flood channel structure is transformed into multiple independent three-dimensional spatial cells, each with its own spatial location, topological path, and node data. For example, assuming that after a dam-break flood, the initial channel forms three bifurcations in the downstream river region, the nonlinear bifurcation topological characteristics of the flood channel can be used to obtain the bifurcation path coordinates and node connections. Based on the spatial coordinate range, each bifurcation path corresponds to a set of continuous grid cells. The spatial boundaries of these grid cells are tightly connected without gaps, forming a gridded spatial structure that expresses the spatial relationships of the flood channel. The data storage format for each grid cell stores its spatial location coordinates, topological node number, boundary coordinates, and path information, providing a spatial basis for sediment deposition and erosion analysis.

[0081] Based on the gridded spatial structure of the dam-break flood channel, the sediment deposition rate and erosion rate of each grid cell are calculated.

[0082] Sediment deposition rate and erosion rate represent the amount of sediment deposited or eroded by water flow per unit time within each grid cell, respectively, expressed in kilograms per square meter per second. The method for calculating sediment deposition rate and erosion rate is as follows: within each grid cell of the dam-break flood channel, calculations are performed based on real-time collected data on water flow velocity, water level, sediment concentration, and channel topographic features. First, based on the flow velocity data and direction within the grid cell, the sediment movement trend within the grid cell is determined. Then, combined with the spatial topographic slope and riverbed material characteristics of the cell, the sediment deposition and erosion situation within the cell is determined. The sediment deposition rate is the mass of sediment entering the grid cell and settling on the riverbed or bank per unit time divided by the cell area. The sediment erosion rate is the mass of sediment washed away by the water flow within the grid cell per unit time divided by the cell area. For example, when a dam-break flood flows through a river bend, the water velocity decreases and the sediment concentration is higher within the grid cell, resulting in a higher calculated sediment deposition rate. Conversely, in cells with faster flood velocity and a looser riverbed structure, a higher sediment erosion rate is calculated. By performing these calculations on all grid cells, the sediment deposition rate and erosion rate representing each spatial grid cell of the dam-break flood channel are obtained.

[0083] Based on the sediment deposition rate and erosion rate of each grid cell, determine the location coordinates and spatial distribution range of the sediment deposition area and erosion area in the dam break flood channel;

[0084] The calculated sediment deposition and erosion rates within each spatial grid cell of the dam-break flood channel are compared with preset thresholds. When the sediment deposition rate of a grid cell exceeds the preset threshold, the cell is classified as a sediment deposition area; when the erosion rate exceeds the preset threshold, the cell is classified as an erosion area. The location coordinates of each sediment deposition and erosion area are recorded as the spatial center coordinates of the grid cell, and the spatial distribution range is clearly recorded as the spatial boundary of the set of adjacent grid cells that meet the criteria. For example, when a dam-break flood passes through a certain area, if the calculated sediment deposition rate exceeds 1 kg / m² / s due to a rapid decrease in flow velocity, the grid cell and its surrounding similar cells are collectively identified as a sediment deposition area. Conversely, in areas where the flood velocity increases rapidly and the riverbed material is loose and easily eroded, if the calculated erosion rate exceeds 1 kg / m² / s, the area is classified as an erosion area. The location coordinates and distribution boundary data of sediment deposition and erosion within the spatial range of the dam-break flood channel are obtained using this method.

[0085] Based on the location coordinates and spatial distribution range of sediment deposition and erosion areas, sediment migration characteristic data are generated.

[0086] Sediment migration characteristic data is a collection of data recording the dynamic migration process of sediment within the spatial range of a dam-break flood channel. Utilizing the location coordinates and spatial distribution of sediment deposition and erosion areas, combined with real-time water flow direction information, sediment source information, and temporal evolution information, a dataset representing the spatial relationship and changing trends of sediment migration from eroded areas to sediment deposition areas is formed. For example, if significant erosion occurs in a specific location during the initial stage of a dam-break flood, and sediment deposition is observed in a similar location downstream, then the sediment migration characteristic data will represent the spatial relationship between the eroded and depositional areas, the sediment migration path, migration direction, and temporal changing trends. This data expresses the spatial migration process, migration direction, migration scale, and spatial distribution characteristics of sediment within the dam-break flood channel.

[0087] S4: Based on the nonlinear bifurcation topological characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths, including:

[0088] Based on the nonlinear bifurcation topology and sediment migration characteristics of the dam-break flood channel, a flow connectivity graph is constructed.

[0089] Using topological nodes from nonlinear bifurcation topological feature data as spatial nodes, each topological node records its location coordinates and serves as a node element in the connected graph. The path connectivity between topological nodes is recorded as edge elements in the connected graph, with each edge recording the spatial coordinates and flow path information of the two connected topological nodes. Sediment migration feature data is overlaid onto the topological nodes and edges, allowing each node and edge to simultaneously record sediment deposition or erosion information, forming a data graph expressing the spatial path relationships, flow direction relationships, and dynamic sediment migration relationships of a dam-break flood channel—this is the flow direction connected graph. For example, when a dam-break flood passes through the downstream area of ​​the breach, three bifurcation paths are generated. The spatial locations of the bifurcation paths are determined using nonlinear bifurcation topological feature data, and each node and path connection method in the bifurcation path is recorded. Sediment migration feature data is then used to record the sediment deposition or erosion locations on the bifurcation paths, ultimately forming a connected graph expressing the spatial path structure, flow direction, and sediment migration.

[0090] In the flow connectivity graph, calculate the sediment deposition gradient, erosion gradient, and flow direction vector for each topological edge segment;

[0091] The sediment deposition gradient and erosion gradient represent the spatial variation rates of sediment deposition and erosion rates along the direction of a topological segment, respectively, expressed in kilograms per square meter per second per meter. They indicate the degree of variation in sediment deposition or erosion rate per meter of path length. The calculation method is as follows: taking each topological segment in the flow connectivity graph as a unit, the spatial coordinates, sediment deposition rate, and erosion rate of the nodes at both ends of the segment are obtained. The deposition gradient and erosion gradient along the direction of the topological segment are determined using a spatial difference calculation method. The difference between the sediment deposition rate or erosion rate measured at the start and end nodes of the topological segment is calculated and then divided by the spatial path length of the topological segment to obtain the sediment deposition gradient or erosion gradient. The flow direction vector of each topological segment represents the spatial direction from the start point to the end point of the segment, recorded as a three-dimensional spatial vector containing both spatial direction and length. For example, if the length of a topological segment is 10 meters, the sediment deposition rate at the starting point is 0.5 kg / m² / s, and the deposition rate at the ending point is 2.5 kg / m² / s, then the sediment deposition gradient is (2.5 - 0.5) / 10 = 0.2 kg / m² / s / meter; the erosion gradient is calculated similarly. Meanwhile, the flow direction vector of the segment is the spatial direction vector from the starting point coordinates (e.g., 120.00°E, 30.00°N, elevation 50 meters) to the ending point coordinates (e.g., 120.01°E, 30.01°N, elevation 48 meters). Calculations are performed for each topological segment to obtain the complete sediment deposition gradient, erosion gradient, and flow direction vector.

[0092] Among all topological segments, topological segments with sediment deposition gradients or erosion gradients higher than the corresponding preset thresholds and whose flow vectors have an angle greater than a preset angle threshold with the flow vectors of adjacent upstream segments are selected as candidate segments for abnormal bifurcation.

[0093] The selection of candidate segments for anomalous bifurcation requires the simultaneous fulfillment of two criteria: the first criterion is that the sediment deposition gradient or erosion gradient exceeds a preset threshold, for example, a sediment deposition gradient exceeding 0.3 kg / m² / s / m or an erosion gradient exceeding 0.3 kg / m² / s / m; the second criterion is that the angle between the flow direction vector of the topological segment and the flow direction vector of the adjacent upstream segment is greater than a preset angle threshold, for example, 30 degrees. The angle between the flow direction vectors of each topological segment and its upstream adjacent topological segment is calculated. If both criteria are met, the topological segment is recorded as a candidate segment for anomalous bifurcation. For example, if the sediment deposition gradient of a topological segment is 0.35 kg / m² / s / m and the angle between its flow direction vector and the upstream segment is 45 degrees, exceeding the preset threshold, then this topological segment is marked as a candidate segment for anomalous bifurcation. By applying the above criteria to all topological segments, a dataset of candidate segments for anomalous bifurcation, representing the characteristics of abnormal flow and sediment changes, is formed.

[0094] Based on the connectivity between candidate edges of abnormal bifurcation, consecutive candidate edges of abnormal bifurcation are combined to form abnormal bifurcation paths of dam-break floods.

[0095] Anomalous bifurcation candidate segments possess spatial connectivity, represented by the positional relationships of nodes connecting topological segments. By analyzing the dataset of anomalous bifurcation candidate segments, spatially connected and continuously arranged anomalous bifurcation candidate segments are combined to form a continuous spatial path structure, thus forming annomalous bifurcation paths for dam-break floods. For example, if five topological segments in the flow connectivity graph are marked as anomalous bifurcation candidate segments, and if these anomalous bifurcation candidate segments are continuously connected to form a continuous spatial path, then combining these five anomalous bifurcation candidate segments constitutes an anomalous bifurcation path, representing the spatial orientation, path length, and topological structure relationships of anomalous flow and sediment changes.

[0096] Geometrically locate and spatially interpolate the abnormal bifurcation paths of dam-break floods to generate spatial distribution data of abnormal paths;

[0097] The geometric positioning method involves geometrically calculating the three-dimensional spatial coordinates of each topological node and edge segment in the anomalous bifurcation path to determine the overall spatial location and coordinate range of the anomalous path. The spatial interpolation method uses a spatial interpolation algorithm to perform data-intensive processing based on the node coordinates and edge spatial orientation information on the path, making the spatial data on the path continuous and smooth. After geometric positioning and spatial interpolation processing, a dataset representing the spatial structure, geometric coordinates, and spatial boundaries of the anomalous bifurcation path of a dam-break flood is finally generated, i.e., the spatial distribution data of the anomalous path. For example, if the node spacing in the initial data of the anomalous bifurcation path is large, geometric positioning and spatial interpolation processing can generate data points with spatial coordinates every tens of centimeters to one meter along the path, thus expressing the continuous spatial structural characteristics of the path.

[0098] S5: Based on the spatial distribution data of abnormal paths, collect real-time data on flow velocity, water level, and sediment concentration along the abnormal paths to generate real-time monitoring data for the abnormal paths, including:

[0099] Based on the spatial distribution data of abnormal paths, the flow velocity, water level and sediment concentration in the abnormal bifurcation path of the dam-break flood were collected to obtain the flow velocity data, water level data and sediment concentration data at each measurement point of the abnormal bifurcation path.

[0100] Multiple measurement points are set up along the abnormal bifurcation path, with the coordinates of each point provided by the spatial distribution data of the abnormal path. The measurement point locations are typically selected from the starting and ending points of the abnormal bifurcation path, as well as multiple intermediate points set at fixed intervals along the path length. Each measurement point is equipped with a water flow velocity measurement device, a water level height measurement device, and a sediment concentration measurement device.

[0101] The water flow velocity measurement device employs an ultrasonic Doppler current meter. This meter emits high-frequency ultrasonic signals into the water and measures the three-dimensional velocity of the water flow in real time based on the frequency changes of the reflected ultrasonic signals. One ultrasonic Doppler current meter is installed at each measurement point, fixed on a stable support. The probe faces the water surface and extends to an appropriate depth, such as 20 to 50 centimeters below the surface. The ultrasonic Doppler current meter samples at a frequency of at least 5 times per second to ensure real-time monitoring of water flow velocity within abnormal bifurcation paths. For example, if 20 measurement points are selected within an abnormal bifurcation path, 20 ultrasonic Doppler current meters will be deployed. Each meter records the real-time water flow velocity changes at its assigned point, resulting in a large amount of water flow velocity data for each measurement point within the monitoring period.

[0102] The water level measurement device uses an ultrasonic level gauge. The ultrasonic level gauge emits ultrasonic pulses towards the water surface and calculates the real-time water level based on the propagation time of the ultrasonic pulses from the instrument to the water surface. One ultrasonic level gauge is installed at each measurement point, approximately 1 meter above the water surface, ensuring the instrument accurately detects real-time water level changes along abnormal bifurcation paths. The ultrasonic level gauge measures at a frequency of no less than 5 times per second, forming a real-time water level data set.

[0103] The sediment concentration measurement device uses an optical turbidimeter. The optical turbidimeter uses an infrared light source to clearly emit light into the water, measuring the scattering and absorption of infrared light by suspended sediment in the water. The changes in the optical signal are then converted into the real-time sediment concentration in the water, expressed in milligrams per liter. One optical turbidimeter is installed at each measurement point, with the instrument's measuring probe fixed at a suitable depth underwater, such as 30 centimeters below the surface, to ensure accurate measurement of real-time changes in sediment concentration. The optical turbidimeter measures at least five times per second, and real-time sediment concentration data is continuously recorded at each measurement point during the measurement period.

[0104] Based on the flow velocity data, water level data and sediment concentration data of each measurement point on the abnormal bifurcation path, real-time monitoring data of the abnormal path is generated.

[0105] Using the spatial coordinates of each measurement point along the abnormal bifurcation path as the basis for data indexing, the flow velocity, water level, and sediment concentration collected at each measurement point at each timestamp are spatiotemporally aligned. Data collected at the same timestamp for each measurement point are mapped to form a time-series data set.

[0106] Data fusion processing is performed on the time series dataset. Point-by-point and time-by-time integration is adopted to combine flow velocity data, water level data, and sediment concentration data obtained at the same time and the same measurement point into a data unit. Each data unit contains a measurement timestamp, spatial coordinates of the measurement point, real-time flow velocity value, real-time water level height value, and real-time sediment concentration value.

[0107] For example, 20 measurement points are set up at the abnormal bifurcation path, the measurement cycle lasts for 10 minutes, and 5 measurements are taken per second. Each measurement point generates 3,000 real-time monitoring data units within the measurement cycle (i.e., 300 measurements per minute, a total of 3,000 measurements in 10 minutes). Each data unit records the spatial coordinates of the measurement point, the real-time water flow velocity, the real-time water level and the real-time sediment concentration, as well as the recorded measurement timestamp, forming a real-time monitoring data set for the abnormal path.

[0108] S6: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output emergency response warning instructions for dam-break floods, including:

[0109] Based on real-time monitoring data of abnormal paths, we analyze the real-time changing trends of flow velocity, water level and sediment concentration data at each measurement point on the abnormal bifurcation path of the dam break flood.

[0110] First, time series analysis is employed, using the time series data collected at each measurement point as a basis to calculate the variation amplitude of flow velocity, water level, and sediment concentration data within different time intervals. Moving average analysis is then used to smooth the flow velocity, water level, and sediment concentration data, and the average trend within each time window is calculated. For example, using a 10-second time window, the data within each window is averaged sequentially to obtain consecutive time-series sequences of average flow velocity, average water level, and average sediment concentration. The difference is then calculated based on these consecutive average sequences to obtain the real-time trends of flow velocity, water level, and sediment concentration at each measurement point.

[0111] For example, 20 measurement points are set up in the abnormal bifurcation path, the monitoring time is 10 minutes, and the sampling frequency is 5 times per second. Each measurement point can obtain more than 3,000 data units. Through trend analysis, the flow velocity change trend, water level change trend and sediment concentration change trend of each measurement point in the abnormal bifurcation path every few seconds are obtained. The trend value is recorded as positive, negative or zero value, which respectively represent the upward trend, downward trend or stable trend of the data. The magnitude of the trend change is also recorded to form a set of real-time trend feature data of the measurement points.

[0112] Based on real-time trends, predict the spatial extent, direction of spread, and rate of spread of abnormal bifurcation paths of dam-break floods;

[0113] Based on real-time water level and sediment concentration trend data at each measurement point, the potential lateral and longitudinal expansion areas of the flood along the abnormal bifurcation path are determined. When both the water level and sediment concentration trends are continuously rising, it indicates a large accumulation of sediment at a specific location along the abnormal bifurcation path, leading to a rapid rise in water level and potentially widening of the path. In this case, the lateral expansion space at that specific location is clearly defined as the potential flood-affected spatial expansion range. Simultaneously, based on the connection relationship between the water level trend data at the measurement points and the path topology, the potential spatial expansion range downstream of the abnormal bifurcation path is calculated along the longitudinal topology of the path.

[0114] Based on the real-time flow velocity trend data and path spatial coordinate data of the measurement points, the direction of water flow velocity change at each measurement point is calculated, and the direction change of the flow velocity vector between adjacent measurement points is calculated to obtain the main direction of water flow diffusion within the spatial location of the abnormal bifurcation path, specifically the azimuth angle or the direction on the spatial coordinate axis.

[0115] The water flow acceleration is calculated based on real-time flow velocity trend data at the measurement point to represent the degree of velocity change per unit time, thereby calculating the water flow diffusion rate at future moments. For example, if the real-time trend shows a continuous increase in flow velocity data, indicating a significant acceleration in the water flow in the measurement point area, the diffusion rate of the anomalous bifurcation path at the next moment is predicted to be significantly faster.

[0116] Based on the above methods for predicting spatial expansion range, diffusion direction, and diffusion rate, a spatial prediction data set is obtained through real-time trend analysis.

[0117] Based on the spatial expansion range, diffusion direction, and diffusion rate, determine the geographical coordinates and boundaries of the risk areas involved in the spread of dam-break floods;

[0118] Using the predicted spatial expansion range data, and based on the coordinates of measurement points in the real-time monitoring data of abnormal paths, spatial geometric calculations are performed to determine the possible lateral and longitudinal geographic coordinate range of each measurement point; then, based on the diffusion direction data, the main direction of the risk area diffusion is determined, and the area range along the main diffusion direction is calculated; finally, based on the diffusion rate prediction data, the geographic spatial range that may be affected in a specific time period in the future is calculated, such as the location coordinate boundary that may be reached in the next 10 minutes.

[0119] For example, if the predicted direction of the abnormal path is southeast and the diffusion rate is 50 meters per minute, then the risk area that the dam breach flood may affect in the next 10 minutes is calculated from the existing abnormal path location as the starting point, along the southeast direction, to obtain the spatial expansion range with a radius of 500 meters, forming a set of geographical coordinates of the risk area and the boundary range of the area.

[0120] Based on the geographical coordinates and boundaries of the risk area, generate emergency response warning instructions;

[0121] After obtaining the set of geographical coordinates and boundary range of the risk area, the risk area data is explicitly input into the emergency response system. Based on the geographical coordinates and boundary range of the risk area, an emergency response early warning instruction is generated.

[0122] Emergency response early warning instructions include the latitude and longitude coordinates, elevation range, spatial coordinates of the area boundaries, predicted arrival time of the flood, diffusion rate, and specific areas that may be affected. The instructions record the estimated arrival time of the flood in each risk area, provide evacuation recommendations, and offer the location coordinates of safe areas.

[0123] For example, an emergency response warning directive states that within 10 minutes of a dam-break flood, areas within the range of 120.01°E to 120.02°E and 30.01°N to 30.02°N may be affected by the flood, and it is recommended that people in these areas be quickly evacuated to a safe area at 120.03°E and 30.03°N. The warning directive records the geographical coordinates of the risk area, the predicted arrival time, evacuation routes, and the coordinates of the safe area.

[0124] Example 2

[0125] The difference between Embodiment 2 and Embodiment 1 is that this embodiment introduces an emergency monitoring system for dam-break floods.

[0126] Figure 2 A schematic diagram of a dam-break flood emergency monitoring system according to the present invention is provided. The dam-break flood emergency monitoring system includes:

[0127] Data acquisition module: Collects real-time topographic and hydrological data of the breach and downstream areas, and generates initial dynamic evolution data of the dam-break flood channel.

[0128] Topology Analysis Module: Based on the initial dynamic evolution data of the dam-break flood channel, the module performs topology analysis on the spatial structure changes of the dam-break flood channel, identifies the nonlinear bifurcation locations of the dam-break flood channel, and generates nonlinear bifurcation topology feature data of the dam-break flood channel.

[0129] Sediment Analysis Module: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, this module performs coupled analysis on sediment deposition and erosion in the dam-break flood channel, identifies the distribution of sediment accumulation and erosion zones, and generates sediment migration characteristic data.

[0130] Path determination module: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths;

[0131] Real-time monitoring module: Based on the spatial distribution data of abnormal paths, it collects flow velocity, water level and sediment concentration data of abnormal paths in real time and generates real-time monitoring data of abnormal paths;

[0132] Early warning instruction module: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

[0133] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.

[0134] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more sets of available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0135] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0136] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0137] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0138] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0139] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0140] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0141] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0142] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for emergency monitoring of dam-break floods, characterized in that, Includes the following steps: S1: Collect real-time topographic and hydrological data on the breach and downstream areas to generate initial dynamic evolution data of the dam-break flood channel; S2: Based on the initial dynamic evolution data of the dam-break flood channel, perform topological analysis on the spatial structure changes of the dam-break flood channel, identify the nonlinear bifurcation locations of the dam-break flood channel, and generate nonlinear bifurcation topological feature data of the dam-break flood channel. S3: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, a coupled analysis of sediment deposition and erosion in the dam-break flood channel is conducted to identify the distribution of sediment accumulation and erosion zones and generate sediment migration characteristic data. S4: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths; S5: Based on the spatial distribution data of abnormal paths, collect flow velocity, water level and sediment concentration data of abnormal paths in real time, and generate real-time monitoring data of abnormal paths; S6: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

2. The emergency monitoring method for dam-break floods according to claim 1, characterized in that, S1, specifically: Real-time topographic changes in the breach area and downstream river channel were measured using a topographic scanner to obtain real-time topographic change data for the breach area and downstream river channel. Multi-point water level gauges were used to monitor the water flow in the breach area and the downstream river channel in real time, and hydrological data of the breach area and the downstream river channel were obtained. Based on real-time topographic and hydrological data of the breach area and downstream river channel, initial dynamic evolution data of the dam-break flood channel are generated.

3. The emergency monitoring method for dam-break floods according to claim 2, characterized in that, S2, specifically: A three-dimensional topological skeleton of the dam-break flood channel was constructed based on the initial dynamic evolution data of the dam-break flood channel. A hydrodynamic topology model was used to calculate the node connection relationships of the three-dimensional topological skeleton of the dam-break flood channel, thereby obtaining spatial structural change data of the dam-break flood channel. Based on spatial structure change data, nonlinear bifurcation nodes of the dam-break flood channel are identified according to the criteria that the angle between the flow direction vectors is greater than a preset angle threshold and the cross-sectional velocity gradient exceeds a preset gradient threshold. Based on the connectivity between nonlinear bifurcation nodes and adjacent nodes, nonlinear bifurcation topological feature data of dam-break flood channels are formed.

4. The emergency monitoring method for dam-break floods according to claim 3, characterized in that, S3, specifically: Based on the nonlinear bifurcation topological feature data of dam-break flood channels, a gridded spatial structure of dam-break flood channels is established. Based on the gridded spatial structure of the dam-break flood channel, the sediment deposition rate and erosion rate of each grid cell are calculated. Based on the sediment deposition rate and erosion rate of each grid cell, determine the location coordinates and spatial distribution range of the sediment deposition area and erosion area in the dam break flood channel; Based on the location coordinates and spatial distribution range of sediment deposition and erosion areas, sediment migration characteristic data are generated.

5. The emergency monitoring method for dam-break floods according to claim 4, characterized in that, S4, specifically: Based on the nonlinear bifurcation topology and sediment migration characteristics of the dam-break flood channel, a flow connectivity graph is constructed. In the flow connectivity graph, calculate the sediment deposition gradient, erosion gradient, and flow direction vector for each topological edge segment; Among all topological segments, topological segments with sediment deposition gradients or erosion gradients higher than the corresponding preset thresholds and whose flow vectors have an angle greater than a preset angle threshold with the flow vectors of adjacent upstream segments are selected as candidate segments for abnormal bifurcation. Based on the connectivity between candidate edges of abnormal bifurcation, consecutive candidate edges of abnormal bifurcation are combined to form abnormal bifurcation paths of dam-break floods. Geometric location and spatial interpolation are performed on the abnormal bifurcation paths of dam-break floods to generate spatial distribution data of abnormal paths.

6. The emergency monitoring method for dam-break floods according to claim 5, characterized in that, S5, specifically: Based on the spatial distribution data of abnormal paths, the flow velocity, water level and sediment concentration in the abnormal bifurcation path of the dam-break flood were collected to obtain the flow velocity data, water level data and sediment concentration data at each measurement point of the abnormal bifurcation path. Based on the flow velocity data, water level data, and sediment concentration data at each measurement point along the abnormal bifurcation path, real-time monitoring data for the abnormal path is generated.

7. The emergency monitoring method for dam-break floods according to claim 6, characterized in that, S6, specifically: Based on real-time monitoring data of abnormal paths, we analyze the real-time changing trends of flow velocity, water level and sediment concentration data at each measurement point on the abnormal bifurcation path of the dam break flood. Based on real-time trends, predict the spatial extent, direction of spread, and rate of spread of abnormal bifurcation paths of dam-break floods; Based on the spatial expansion range, diffusion direction, and diffusion rate, determine the geographical coordinates and boundaries of the risk areas involved in the spread of dam-break floods; Emergency response warning instructions are generated based on the geographical coordinates and boundaries of the risk area.

8. A dam-break flood emergency monitoring system, used to implement the dam-break flood emergency monitoring method according to any one of claims 1-7, characterized in that, include: Data acquisition module: Collects real-time topographic and hydrological data of the breach and downstream areas, and generates initial dynamic evolution data of the dam-break flood channel. Topology Analysis Module: Based on the initial dynamic evolution data of the dam-break flood channel, the module performs topology analysis on the spatial structure changes of the dam-break flood channel, identifies the nonlinear bifurcation locations of the dam-break flood channel, and generates nonlinear bifurcation topology feature data of the dam-break flood channel. Sediment Analysis Module: Based on the nonlinear bifurcation topological characteristics of the dam-break flood channel, this module performs coupled analysis on sediment deposition and erosion in the dam-break flood channel, identifies the distribution of sediment accumulation and erosion zones, and generates sediment migration characteristic data. Path determination module: Based on the nonlinear bifurcation topology characteristics and sediment migration characteristics of the dam-break flood channel, determine the abnormal bifurcation paths of the dam-break flood and generate spatial distribution data of the abnormal paths; Real-time monitoring module: Based on the spatial distribution data of abnormal paths, it collects flow velocity, water level and sediment concentration data of abnormal paths in real time and generates real-time monitoring data of abnormal paths; Early warning instruction module: Based on real-time monitoring data of abnormal paths, predict the flood spread trend and output early warning instructions for dam-break flood emergency response.

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