A real-time analysis method for the flooding impact range of small and medium-sized reservoirs

Abstract

The present invention discloses a real-time analysis method for the flooding impact range of small and medium-sized reservoirs, comprising: obtaining the planned design water level of the target reservoir; collecting elevation information of the target reservoir to generate high-precision terrain data; extracting contour lines according to the high-precision terrain data to determine the water level line boundary of the target reservoir; performing spatial intersection analysis on the water level line boundary of the target reservoir and geographical elements to obtain spatial intersection analysis results; establishing a static influencing factor database; constructing a one-dimensional river channel-reservoir hydrological and hydrodynamic model; predicting the water level change of the target reservoir under future rainfall conditions; and determining a set of geographical elements that may be affected by the predicted water level line range in the future. Compared with the original technology that only determines the water level flooding range, the present application establishes a static influencing factor database through a spatial intersection analysis method, clarifies the geographical elements affected under each water level line of the target reservoir, and provides technical support for the refined formulation of emergency rescue plans.

Description

Technical Field

[0001] The invention relates to the technical field of flooding impact of small and medium-sized reservoirs, and in particular to a real-time flooding impact range analysis method of small and medium-sized reservoirs. Background Art

[0002] At present, there are 98,002 reservoirs in China, of which small and medium-sized reservoirs account for 96%. As important water conservancy facilities, small and medium-sized reservoirs play an irreplaceable role in regulating water resources, flood control and drainage, farmland irrigation and domestic water supply. Under the influence of increasingly frequent extreme weather events and climate change, the management and operation of small and medium-sized reservoirs face new challenges. Fluctuations in reservoir water levels may cause floods and have a significant impact on surrounding infrastructure, ecological environment and economy. Therefore, it is very important for reservoir safety to ensure that all reservoirs have forecasting capabilities, operation and dispatching plans, and emergency plans.

[0003] At present, the following methods are mainly used to analyze the flooding impact range of small and medium-sized reservoirs:

[0004] 1. Traditional geographic information technology, using digital elevation models and water level analysis to analyze potential flooding areas;

[0005] 2. Remote sensing image analysis: using visible light, infrared bands, or radar reflectivity in remote sensing images to identify water bodies and determine the scope of flooding;

[0006] 3. Hydrological and hydrodynamic models, based on physical mechanisms, simulate the flooding process;

[0007] 4. Conduct field investigations, track flood routes, and make on-site observations and record the scope of water level impact.

[0008] The current methods have the following disadvantages:

[0009] 1. Traditional geographic information technology data are mostly static data, and their real-time performance and accuracy may be limited for dynamically changing flood impacts;

[0010] 2. The collection of remote sensing data for remote sensing image analysis is greatly affected by the weather. If the satellite is blocked by clouds during its transit, it will be impossible to obtain accurate ground information;

[0011] 3. The mechanism of hydrological and hydrodynamic models is complex and requires long-term observation data for model calibration. At the same time, the two-dimensional simulation process requires high computing power and poor timeliness;

[0012] 4. Field investigations require a lot of manpower, material resources and time, and after flooding occurs, many places may be inaccessible or pose safety risks. Summary of the invention

[0013] The object of the present invention is to provide a real-time analysis method of the flooding impact range of small and medium-sized reservoirs to solve the defects in the above-mentioned background technology.

[0014] To achieve the above object, the present invention provides the following technical solution: a real-time analysis method of the flooding impact range of small and medium-sized reservoirs, comprising:

[0015] S1: Obtain the planned design water level of the target reservoir;

[0016] S2: Collect elevation information of the target reservoir within a certain range based on the planned design water level to generate high-precision terrain data;

[0017] S3: Extract contour lines based on high-precision terrain data, take the target reservoir dam as the reference line segment, extend it to both ends along the direction of the corresponding height contour line until it is closed to form a polygon, and determine the water level line boundary of the target reservoir;

[0018] S4: Perform spatial intersection analysis on the water level boundary of the target reservoir and the geographical elements to obtain spatial intersection analysis results;

[0019] S5: According to the results of spatial intersection analysis, determine the affected geographical element set within the boundary range of each water level line, and establish a static influencing element database;

[0020] S6: Construct a one-dimensional river-reservoir hydrological and hydrodynamic model based on the static influencing factor database;

[0021] S7: Obtain weather forecast data regularly, and simulate and predict the water level changes of the target reservoir under future rainfall conditions based on the one-dimensional river-reservoir hydrological and hydrodynamic model;

[0022] S8: Based on the simulated prediction of the water level changes of the target reservoir under future rainfall conditions, match the static influencing factor database and determine the set of geographical elements that may be affected by the predicted water level range in the future.

[0023] This application collects elevation points around small and medium-sized reservoirs to determine the boundaries of water levels, establishes a static influencing factor database based on the map using a spatial analysis algorithm, constructs a one-dimensional river-reservoir hydrological and hydrodynamic model, efficiently simulates reservoir water level changes, accesses regional rainfall forecast data to achieve real-time simulation of reservoir water levels, and compares the simulated water levels with the static influencing factor database. This allows for real-time and efficient analysis of the impact of small and medium-sized reservoir inundation based on future weather forecasts in the event of heavy or continuous rainfall during the flood season.

[0024] Preferably, S2: collecting elevation information of a target reservoir within a certain range based on the planned design water level to generate high-precision terrain data includes:

[0025] S2.1: Based on the vector boundary of the target reservoir, a buffer zone of 2-3 km is established as the point collection range;

[0026] S2.2: Use ground remote sensing measurement to obtain elevation point clouds within the point collection range;

[0027] S2.3: Generate continuous surface elevation data based on the three-dimensional coordinate information of the elevation point cloud data;

[0028] S2.4: Use high-precision GPS measuring instruments to conduct detailed supplementary measurements of surface elevation data to obtain high-precision terrain data.

[0029] Preferably, the geographical elements include: urban lifeline facilities, residential areas, public buildings and emergency resources, and the urban lifeline facilities include main roads, water supply systems, drainage systems, power systems and communication systems.

[0030] Preferably, the judgment criteria for determining the set of geographical elements affected within the boundary range of each water level line is: the geographical element is located within the boundary of the water level line and the elevation value of the geographical element is lower than the elevation value of the water level line.

[0031] Preferably, the calculation process of the one-dimensional river channel-reservoir hydrological and hydrodynamic model includes:

[0032] S6.1: Generalize river and reservoir elements;

[0033] S6.2: Perform multi-level catchment division based on the river level obtained by element generalization;

[0034] S6.3: Calculate surface runoff based on multi-level catchment areas;

[0035] S6.4: Calculate streamflow based on surface runoff.

[0036] Preferably, generalizing river and reservoir elements includes: generalizing the river and reservoir according to cross-section data, generalizing the center points of cross-section survey lines into nodes, generalizing the center lines of the river into connections, each connection having an irregular shape, generalizing reservoir elements into reservoirs, and setting the water storage curve according to the target reservoir characteristic curve.

[0037] Preferably, the multi-level watershed division includes: dividing the rivers into three levels: main rivers, first-level tributaries, and second-level tributaries according to the topography and water system characteristics of the basin; dividing the watersheds of different levels in descending order of river levels and according to the direction of surface water flow; and determining their internal fine boundaries to obtain multi-level watersheds.

[0038] Preferably, calculating surface runoff includes:

[0039] S6.3.1 Calculate runoff based on fill and infiltration losses using a surface runoff model. Infiltration losses are calculated using the Horton infiltration equation.

[0040] S6.3.2 Based on the surface runoff model, the nonlinear reservoir method is used to characterize the surface runoff process. The surface runoff is regarded as the regulation process of the nonlinear reservoir. The calculation process is as follows:

[0041] ,in, is the inflow, For outflow, is the water storage capacity, is the storage capacity coefficient, is a dimensionless constant ranging from 0 to 1.

[0042] Preferably, calculating the river confluence includes: completely solving the Saint-Venant equations using a dynamic wave method based on a river confluence model, including:

[0043] ,

[0044] ,

[0045] is the cross-sectional area of ​​water flow, For excess flow, For time, is a spatial variable, is the water level; is the hydraulic radius, is the roughness, is the acceleration due to gravity.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. This application collects elevation points around small and medium-sized reservoirs to determine the boundaries of water levels, establishes a static influencing factor database based on maps using spatial analysis algorithms, constructs a one-dimensional river-reservoir hydrological and hydrodynamic model, efficiently simulates reservoir water level changes, accesses regional rainfall forecast data to achieve real-time simulation of reservoir water levels, and compares simulated water levels with the static influencing factor database to achieve real-time and efficient analysis of the flooding impact range of small and medium-sized reservoirs based on future weather forecasts in the event of heavy or continuous rainfall during the flood season;

[0048] 2. Based on the previous work, this application presets the water level inundation range and the corresponding impact, that is, establishes a static database, abandons the two-dimensional model with high computing power requirements, and adopts a one-dimensional model to abstract the basin into a river channel + multiple catchment areas, simulates the flow into the reservoir, and calculates the water level based on this inflow flow to match the preset water level inundation situation. The one-dimensional model is adopted, and the efficiency has been significantly improved, which can provide early warning and forecast of the impact of reservoir water level inundation under short-term heavy rainfall weather;

[0049] 3. Compared with the original technology that only determines the scope of water level inundation, this application establishes a static influencing factor database through spatial intersection analysis method, clarifies the geographical elements affected by each water level line of the target reservoir, and provides technical support for the detailed formulation of emergency rescue plans;

[0050] 4. Compared with the traditional geographic information system and the complex one- and two-dimensional coupled hydrological and hydrodynamic model, this application establishes a relatively efficient one-dimensional river channel-reservoir hydrological and hydrodynamic model, and matches it with a static database, thus realizing dynamic and efficient analysis of the impact range of reservoir water level;

[0051] 5. This application supports efficient analysis of the impact range of reservoir water levels under future weather conditions, greatly improving the forecasting and prediction capabilities of reservoir water and rainfall conditions and their impacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A flowchart of the steps in a real-time analysis method of the flooding impact range of small and medium-sized reservoirs proposed by the present invention;

[0053] Figure 2 A schematic diagram of spatial intersection analysis in a real-time analysis method of the flooding impact range of small and medium-sized reservoirs proposed by the present invention;

[0054] Figure 3 This is a schematic diagram of river grade classification in a real-time analysis method of the flooding impact range of small and medium-sized reservoirs proposed in the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The present invention provides a real-time analysis method of the flooding impact range of small and medium-sized reservoirs. Figure 1 As shown, including:

[0057] S1: Obtain the planned design water level of the target reservoir. The planned design water level comes from the overall project planning scheme, reservoir structure design scheme and water storage and discharge scheme of small and medium-sized reservoirs, including: flood limit water level, normal water level, 20-year return level, 50-year return level, 100-year return level and various intermediate water levels.

[0058] S2: Collect elevation information of the target reservoir within a certain range based on the planned design water level to generate high-precision terrain data, including:

[0059] S2.1: Based on the vector boundary surveyed by the planning and resource department of the target reservoir, a buffer zone of 2-3 kilometers is established as the point collection range;

[0060] S2.2: Use LiDAR and UAV to conduct ground remote sensing measurement and obtain elevation point cloud within the point collection range;

[0061] S2.3: Generate continuous surface elevation data, i.e., digital elevation model, based on the x, y and z axis coordinate information of the elevation point cloud data;

[0062] S2.4: Use high-precision GPS measuring instruments to conduct detailed supplementary measurements of surface elevation data to obtain high-precision terrain data.

[0063] S3: Extract contour lines based on high-precision terrain data, take the target reservoir dam as the reference line segment, extend it to both ends along the direction of the corresponding height contour line until it is closed to form a polygon, determine the water level line boundary of the target reservoir, and determine the water level line boundary specified in S1 (W1, W2, W3...).

[0064] S4: Figure 2 As shown in the figure, the spatial intersection analysis result is obtained by performing spatial intersection analysis on the water level boundary of the target reservoir and the geographical elements, wherein the geographical elements include: urban lifeline facilities, residential areas, public buildings and emergency resources; urban lifeline facilities include trunk roads, water supply systems, drainage systems, power systems and communication systems. Figure 2 The blue rectangle in the middle is the water level boundary, and the yellow circle is the residential area. The intersection analysis is performed through the spatial position coordinates to obtain the common part of the two areas.

[0065] S5: According to the results of spatial intersection analysis, determine the affected geographic element sets (F1, F2, F3...) within the boundary range of each water level line, establish a static influencing element database, and determine the judgment criteria for the affected geographic element sets within the boundary range of each water level line: the geographic element is located within the water level line boundary and the elevation value of the geographic element is lower than the elevation value of the water level line.

[0066] S6: A one-dimensional river-reservoir hydrological and hydrodynamic model is constructed based on the static influencing factor database. The calculation process of the one-dimensional river-reservoir hydrological and hydrodynamic model includes:

[0067] S6.1: Generalize the river and reservoir elements, specifically including: generalize the river and reservoir according to the cross-section data, generalize the center points of the cross-section survey lines into nodes, generalize the center lines of the river into connections, and the shape of each connection is irregular. The reservoir elements are generalized into storage tanks, and the water storage curve is set according to the characteristic curve of the target reservoir.

[0068] S6.2: Multi-level watershed division is performed based on the river level obtained by element generalization, specifically including: dividing the rivers into three levels: main river, first-level tributary, and second-level tributary according to the topography and water system characteristics of the basin; dividing the watersheds of different levels according to the order of river levels from high to low and the direction of surface water flow; determining the internal fine boundaries to obtain multi-level watersheds; the basic algorithms for division include: judging the water flow path according to the DEM data flow direction analysis (D8 algorithm); the D8 algorithm is a single flow direction algorithm, assuming that the water in each pixel can only flow along the steepest downhill direction; calculating the maximum slope drop of the central pixel through a 3×3 grid window traversal; the calculation formula is:

[0069] , is the maximum slope drop between two grids, is the elevation difference between the two grids, is the distance between the centers of two grid cells, and this direction is taken as the direction of water flow.

[0070] S6.3: Calculate surface runoff based on multi-level catchment areas. Specifically,

[0071] Calculation of surface runoff includes:

[0072] S6.3.1 Calculate runoff based on fill and infiltration losses in conjunction with the surface runoff model. Infiltration losses are calculated using the Horton infiltration equation. The Horton infiltration equation is an empirical formula for calculating infiltration curves. Its parameters have wide flexibility. The calculation formula includes:

[0073] , is the infiltration rate, unit: mm / s; is the stable infiltration rate, unit: mm / s; is the initial infiltration rate, unit: mm / s; For time, For Empirical constants related to soil properties;

[0074] S6.3.2 Based on the surface runoff model, the nonlinear reservoir method is used to characterize the surface runoff process. The surface runoff is regarded as the regulation process of the nonlinear reservoir. The flow process line of the subcatchment area is calculated as follows:

[0075] ,in, is the inflow, For outflow, is the water storage capacity, is the storage capacity coefficient, is a dimensionless constant ranging from 0 to 1.

[0076] S6.4: Calculation of river flow based on surface runoff includes: using the dynamic wave method based on the river flow model to completely solve the Saint-Venant equations. The calculation process is as follows:

[0077] ,

[0078] ,

[0079] is the cross-sectional area of ​​water flow, For excess flow, For time, is a spatial variable, is the water level; is the hydraulic radius, is the roughness, is the acceleration due to gravity.

[0080] S7: Regularly obtain weather forecast data, extract rainfall, drive the model, and simulate and predict the water level changes of the target reservoir under future rainfall conditions based on the one-dimensional river-reservoir hydrological and hydrodynamic model.

[0081] S8: Based on the simulated prediction of the water level changes of the target reservoir under future rainfall conditions, match the static influencing factor database and determine the set of geographical elements that may be affected by the predicted water level range in the future.

[0082] In summary, the method for establishing a static water level line influencing factor database of the present invention uses elevation point data collection to determine the boundaries of each water level line from the flood limit water level to the designed 100-year flood level. Then, according to the location of the geographical elements, a static influencing factor database is established using a spatial analysis algorithm. This technology is an important part of the present invention, which can accurately describe the impact of the water level changes of the reservoir on the surrounding geographical elements, and adopts a one-dimensional river channel-reservoir hydrological and hydrodynamic model combined with a static influencing factor database to replace the one- and two-dimensional coupling model with high computing power requirements. At the same time, using weather forecast data, it can realize a rapid reservoir flooding impact range analysis under future meteorological conditions. It is a new technology based on a static influencing factor database that combines a one-dimensional river channel-reservoir hydrological and hydrodynamic model with this. Compared with the traditional reservoir water level flooding analysis method, its advantage is that it can analyze the flooding impact range of the reservoir in real time and efficiently, greatly saving computing time and resources. It is an efficient and accurate model design method.

[0083] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and range of equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs, characterized by: include: S1: Obtain the planned design water level of the target reservoir; S2: Collect elevation information of the target reservoir within a certain range based on the planned design water level to generate high-precision terrain data; S3: Extract contour lines based on high-precision terrain data, take the target reservoir dam as the reference line segment, extend it to both ends along the direction of the corresponding height contour line until it is closed to form a polygon, and determine the water level line boundary of the target reservoir; S4: Perform spatial intersection analysis on the water level boundary of the target reservoir and the geographical elements to obtain spatial intersection analysis results; S5: According to the results of spatial intersection analysis, determine the affected geographical element set within the boundary range of each water level line, and establish a static influencing element database; S6: A one-dimensional river-reservoir hydrological and hydrodynamic model is constructed based on the static influencing factor database. The calculation process of the one-dimensional river-reservoir hydrological and hydrodynamic model includes: S6.1: Generalize river and reservoir elements; S6.2: Multi-level watershed division based on river levels obtained by element generalization; S6.3: Calculate surface runoff based on multi-level catchment areas; S6.4: Calculate river runoff based on surface runoff; Calculation of river confluence includes: Based on the river confluence model, the dynamic wave method is used to completely solve the Saint-Venant equations, including: ， ， is the cross-sectional area of ​​water flow, For excess flow, For time, is a spatial variable, is the water level; is the hydraulic radius, is the roughness, is the acceleration due to gravity; S7: Obtain weather forecast data regularly, and simulate and predict the water level changes of the target reservoir under future rainfall conditions based on the one-dimensional river-reservoir hydrological and hydrodynamic model; S8: Based on the simulated prediction of the water level changes of the target reservoir under future rainfall conditions, match the static influencing factor database and determine the set of geographical elements that may be affected by the predicted water level range in the future.

2. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 1, characterized in that: S2: Based on the planned design water level, the elevation information of the target reservoir is collected within a certain range to generate high-precision terrain data including: S2.1: Based on the vector boundary of the target reservoir, a buffer zone of 2-3 km is established as the point collection range; S2.2: Use ground remote sensing measurement to obtain the elevation point cloud within the point collection range; S2.3: Generate continuous surface elevation data based on the three-dimensional coordinate information of the elevation point cloud data; S2.4: Use high-precision GPS measuring instruments to conduct detailed supplementary measurements of surface elevation data to obtain high-precision terrain data.

3. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 1 or 2, characterized in that: Geographical elements include: urban lifeline facilities, residential areas, public buildings and emergency resources. Urban lifeline facilities include main roads, water supply systems, drainage systems, power systems and communication systems.

4. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 1, characterized in that: The criteria for determining the set of geographical features affected by each water level boundary are: the geographical features are within the water level boundary and the elevation values ​​of the geographical features are lower than the elevation values ​​of the water level.

5. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 4, characterized in that: The generalization of river and reservoir elements includes: generalizing the river and reservoir according to the cross-section data, generalizing the center points of the cross-section survey lines into nodes, generalizing the center lines of the river into connections, and the shape of each connection is irregular. The reservoir elements are generalized into storage tanks, and the water storage curve is set according to the characteristic curve of the target reservoir.

6. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 1, characterized in that: The multi-level watershed division includes: dividing rivers into three levels: main rivers, first-level tributaries, and second-level tributaries according to the topography and water system characteristics of the basin; dividing watersheds of different levels in descending order of river levels and according to the direction of surface water flow; and determining their internal fine boundaries to obtain multi-level watersheds.

7. A real-time analysis method of the flooding impact range of small and medium-sized reservoirs according to claim 1, characterized in that: Calculation of surface runoff includes: S6.3.1 Calculate runoff based on fill and infiltration losses using a surface runoff model. Infiltration losses are calculated using the Horton infiltration equation. S6.3.2 Based on the surface runoff model, the nonlinear reservoir method is used to characterize the surface runoff process. The surface runoff is regarded as the regulation process of the nonlinear reservoir. The calculation process is as follows: ,in, is the inflow, For outflow, is the water storage capacity, is the storage capacity coefficient, is a dimensionless constant ranging from 0 to 1.

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