Urban river network hydrodynamic element virtual monitoring method and system

Abstract

The application discloses a kind of urban river network hydrodynamic element virtual monitoring method and system, belong to the technical field of hydrology monitoring. Including: establishing river network mathematical model, according to multi-scale classification, the river network mathematical model is divided into large-scale river network model and small-scale river network model;With closed basin as unit, build basin-level hydrodynamic model, based on the basin-level hydrodynamic model, the basin boundary water level and the basin boundary flow are calculated, and the small-scale river network hydrodynamic model is obtained;The basin boundary water level and the basin boundary flow small-scale river network hydrodynamic model are input to small-scale river network model, and the water level and the river section flow of river section are calculated using the hydrodynamic model.The standardization management of hydrology hydrodynamic model data, the two-way nested coupling of multi-space scale model and so on, so as to realize the virtual perception of water level, flow hardware monitoring station layout insufficient area river network area water level, flow and other elements.

Description

Technical Field

[0001] This invention belongs to the technical field of hydrological monitoring, specifically, it relates to a virtual monitoring method and system for hydrodynamic elements of urban river networks. Background Technology

[0002] In terms of monitoring methods, traditional monitoring mainly relies on the deployment of hardware equipment. Water level monitoring equipment generally includes pressure-type and reflective types, and the principle is mostly to measure the liquid level height and calculate the water level process using a reference elevation. Flow measurement currently mostly uses unmanned surface vessels carrying current meters. Traditional hydrological monitoring stations are costly to build, requiring specialized instruments for measuring different elements such as flow and water level. Furthermore, due to their fixed locations, installation and dismantling are difficult when changing monitoring points. Therefore, there is an urgent need to fully develop and apply advanced monitoring technologies and methods, and strengthen the application of automatic monitoring technologies and equipment for hydrological elements under different application conditions.

[0003] Specialized measuring equipment has been developed for different hydrological monitoring targets. This equipment is installed at fixed points according to specific requirements to obtain monitoring data on water level, flow rate, and other parameters at those points. Commonly used water level monitoring instruments include bubble level, pressure level, float level, and non-contact radar level gauges, while commonly used flow rate monitoring instruments include acoustic Doppler current profilers and horizontal acoustic Doppler current profilers. However, the hardware is relatively expensive, and due to the cost of constructing monitoring points, they are mainly deployed at locations where water level and flow changes are significant or where tributaries converge, making it impossible to achieve full coverage of the river. Especially in river network areas, the monitoring results of a single monitoring point are often used to represent the overall situation of the adjacent river section, failing to achieve refined monitoring of the river channel. Furthermore, the monitoring results of hydrological monitoring equipment only represent data at the current moment and cannot predict or warn of future trends in water level, flow rate, and other hydrological parameters.

[0004] There are also existing methods that simulate water level and flow rate, but these are mainly based on the Saint-Venant equations. These equations cannot currently be solved analytically, so they are usually solved discretely using the difference method. The solution results include water level, flow rate, and velocity at each cross-section inside the river channel boundary. Summary of the Invention

[0005] To address the problems in related technologies, this invention proposes a virtual monitoring method and system for urban river network hydrodynamic elements, in order to overcome the aforementioned technical problems existing in the existing related technologies.

[0006] Therefore, the specific technical solution adopted by the present invention is as follows: a virtual monitoring method for hydrodynamic elements of urban river networks, comprising the following steps:

[0007] Acquire basic and monitoring data of the river network and establish a model database; use the model database to standardize and manage the basic and monitoring data according to a predetermined database table structure;

[0008] The river network is described as a topological network structure, and a mathematical model of the river network is established based on the topological network structure. The mathematical model of the river network is divided into a large-scale river network model and a small-scale river network model according to the multi-scale hierarchical classification. The large-scale river network model and the small-scale river network model constitute a two-way nested coupled watershed-region scale model.

[0009] A basin-level hydrodynamic model is constructed using a closed watershed as a unit, and the watershed boundary water level and watershed boundary discharge are calculated based on the watershed-level hydrodynamic model.

[0010] The small-scale river network model is divided into corresponding runoff generation and runoff generation areas according to land use type. Corresponding runoff generation and runoff generation calculation modes are set for each area. The runoff generation and runoff generation are effectively integrated to achieve a refined simulation of runoff generation and runoff generation in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model.

[0011] The watershed boundary water level and watershed boundary discharge are used as boundary conditions and input into a small-scale river network hydrodynamic model. The river cross-sectional water level and river cross-sectional discharge are calculated using the hydrodynamic model. The watershed boundary water level, watershed boundary discharge, river cross-sectional water level and river cross-sectional discharge are the river network hydrodynamic elements.

[0012] In a further embodiment, the model database includes at least: a model network library, a model logic library, and a model event library;

[0013] The model network library is configured to store basic river network information, river network engineering information, and river network topographic information.

[0014] The model logic library is used to store water conservancy project scheduling rules;

[0015] The model event library is configured to store historical monitoring data from established water level and flow monitoring stations, as well as forecasted rainfall data.

[0016] In a further embodiment, the process of dividing the large-scale river network model and the small-scale river network model includes:

[0017] The topological network structure includes several nodes and several edges, where the edges are used to describe the connection relationship between adjacent nodes; point objects within the river network are defined as nodes, and connection objects describing the connection relationship between adjacent point objects are defined as edges; and the point objects and connection objects are uniformly encoded according to a predetermined encoding format;

[0018] Point objects and connecting objects belonging to rivers of level four or above or to polder areas of 10,000 mu or more are classified into large-scale river network models, while point objects and connecting objects belonging to rivers of level four or below or to polder areas of less than 10,000 mu are classified into small-scale river network models.

[0019] The method for constructing the bidirectional nested coupled watershed-region scale model is as follows: the external nodes of the small-scale river network model are associated with the boundary edges of the large-scale river network model using an encoding method.

[0020] In a further embodiment, the watershed-level hydrodynamic model is expressed as follows:

[0021] ;

[0022] In the formula, Indicates the width of the river channel. For water level, For time, For traffic, The cross-sectional average velocity is... The distance along the course from a fixed cross-section of the waterway. Acceleration due to gravity, The cross-sectional area of ​​the water passage. For the riverbed gradient, This is to reduce the friction ratio.

[0023] In a further embodiment, the calculation process for the watershed boundary water level and watershed boundary flow is as follows:

[0024] ;

[0025] In the formula, Indicates the water level or flow rate at the watershed boundary. Represents boundary nodes. These are weighting coefficients. , Here, j represents the time index, and j represents the spatial index. Indicates spatial location and the next time step Water level or flow rate For spatial step size, For time step.

[0026] In a further embodiment, the generation and merging calculation mode is set as follows:

[0027] The runoff-generating area includes at least: an impermeable area, a semi-permeable area, a permeable area, and a water body area;

[0028] Correspondingly, the flow generation calculation mode for the impermeable area is as follows:

[0029] In the formula, Indicates the flow generation in impermeable areas. Indicates rainfall amount, Indicates the evaporation rate of rivers and lakes. Indicates the amount of plant interception;

[0030] The flow generation calculation method for the semi-permeable area is as follows:

[0031] In the formula, Indicates the runoff generation in a semi-permeable area. Indicates the water requirement of shallow soil;

[0032] The flow generation calculation mode for the permeable zone is as follows:

[0033] In the formula, Indicates the flow generated in the permeable area. Indicates the amount of deep soil infiltration;

[0034] The runoff calculation model for the water body area is as follows:

[0035] In the formula, This indicates the runoff generation in a water body area.

[0036] In a further embodiment, the refined simulation process for the generation and merging of currents is as follows:

[0037] The runoff is calculated using a runoff calculation model to determine the runoff of the corresponding area, and it is also determined whether the area is covered by a drainage network. If there is no drainage network in the current area, the runoff is calculated based on the topographic elevation information, from high to low until it flows into a nearby river. The calculation formula is as follows:

[0038] In the formula, This indicates the flow rate in areas without drainage pipe networks. Represents the roughness coefficient. For hydraulic radius, For pipe slope, The area of ​​the confluence unit;

[0039] When a drainage network exists in the area, the flow rate is calculated by having the storm drains enter the network system and then collect the wastewater at the drainage outlet, which connects to the river. The calculation formula is as follows:

[0040] In the formula, This indicates the flow rate of the area where a drainage network exists, and C is the flow rate coefficient.

[0041] In a further embodiment, the small-scale river network hydrodynamic model is as follows:

[0042] The continuity equation is expressed in the following form: ;

[0043] In the formula, express, All are continuous equations and linear equation systems with constant coefficients, specifically:

[0044] in, ;

[0045] In the formula, Indicates spatial location Time index is The water level at the location; Indicates spatial location Time index is The value at; Indicates spatial location Values ​​related to traffic; Indicates spatial location Time index is Traffic flow at the location; Indicates spatial location Time index is The water level at the location;

[0046] The momentum equation is expressed as follows: ;

[0047] In the formula, , , and The system of linear equations with constant coefficients is a continuity equation, specifically:

[0048] ;

[0049] In the formula, Indicates spatial location Spatial step size; This represents a parameter related to the momentum correction factor or turbulence factor. This represents a quantity related to the Chezy coefficient; Indicates the hydraulic radius; Indicates spatial location The time step is Traffic flow at the location.

[0050] A virtual monitoring system for urban river network hydrodynamic elements is used to implement the virtual monitoring method for urban river network hydrodynamic elements as described above, comprising:

[0051] The first module is set up to acquire basic data and monitoring data of the river network and establish a model database; the basic data and monitoring data are then managed in a standardized manner according to a predetermined database table structure using the model database.

[0052] The second module is configured to describe the river network as a topological network structure, establish a river network mathematical model based on the topological network structure, and divide the river network mathematical model into a large-scale river network model and a small-scale river network model according to multi-scale hierarchies. The large-scale river network model and the small-scale river network model constitute a bidirectional nested coupled watershed-region scale model.

[0053] The third module is configured to construct a basin-level hydrodynamic model using a closed watershed as the unit, and calculate the watershed boundary water level and watershed boundary discharge based on the watershed-level hydrodynamic model.

[0054] The fourth module is set up to divide the small-scale river network model into corresponding runoff-producing areas according to land use type, set corresponding runoff calculation modes, and effectively integrate runoff and runoff to achieve refined simulation of runoff generation and runoff in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model.

[0055] The fifth module is configured to input the water level and flow rate of the watershed boundary as boundary conditions into the small-scale river network model, and use the hydrodynamic model to calculate the water level and flow rate of the river section. The water level, flow rate of the watershed boundary, and flow rate of the river section are the hydrodynamic elements of the river network.

[0056] The beneficial effects of this invention are as follows: In order to effectively manage multiple types of data and facilitate data inspection and updating, this invention constructs three types of databases for the model. The model network database is used to store data related to river networks, river network projects, and topography in the model. The model logic database is mainly used for the scheduling rules of water conservancy projects such as gate pumps in the model. The model event database is mainly used to store historical monitoring data of existing water level and flow monitoring stations, as well as forecast rainfall data. The database table structure design is also clearly defined.

[0057] When using watershed-level hydrodynamic models to solve for river levels and flows, it is necessary to clearly define the boundary conditions between upstream and downstream sections of the river to address the problem that the current density of hydrological monitoring stations cannot fully cover all river channels in the river network area. Considering both computational efficiency and accuracy, this invention proposes a bidirectional nested coupling of watershed-regional scale models. Specifically, following a unified data exchange protocol, external nodes of the small-scale river network model are automatically matched with internal nodes of the large-scale watershed model. Before performing small-scale simulations, the boundary conditions for the river network simulation are generated using the large-scale model of the closed watershed.

[0058] Based on land use type, the basic runoff generation and runoff grid units are divided into impermeable areas, semi-permeable areas, permeable areas, and water bodies. Different runoff generation processes are set for each type of grid unit, and the runoff volume is calculated separately. During runoff, different runoff modes are set for each grid unit according to whether there is a drainage pipe network, and the runoff is accumulated and calculated into the river channel one by one, realizing the refined simulation of runoff generation and runoff of small-scale river network model. Attached Figure Description

[0059] Figure 1 This is a flowchart of a virtual monitoring method for urban river network hydrodynamic elements, as exemplified in this case. Detailed Implementation

[0060] To further illustrate the various embodiments, the present invention provides accompanying drawings, which are part of the disclosure of the present invention. These drawings are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementation methods and the advantages of the present invention.

[0061] Example 1

[0062] This embodiment addresses the technical problems existing in the background art by providing a virtual monitoring method for urban river network hydrodynamic elements, comprising the following steps:

[0063] Acquire basic and monitoring data of the river network and establish a model database; use the model database to standardize and manage the basic and monitoring data according to a predetermined database table structure;

[0064] The river network is described as a topological network structure, and a mathematical model of the river network is established based on the topological network structure. The mathematical model of the river network is divided into a large-scale river network model and a small-scale river network model according to the multi-scale hierarchical classification. The large-scale river network model and the small-scale river network model constitute a two-way nested coupled watershed-region scale model.

[0065] A basin-level hydrodynamic model is constructed using a closed watershed as a unit, and the watershed boundary water level and watershed boundary discharge are calculated based on the watershed-level hydrodynamic model.

[0066] The small-scale river network model is divided into corresponding runoff generation and runoff generation areas according to land use type. Corresponding runoff generation and runoff generation calculation modes are set for each area. The runoff generation and runoff generation are effectively integrated to achieve a refined simulation of runoff generation and runoff generation in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model.

[0067] The watershed boundary water level and watershed boundary discharge are used as boundary conditions and input into a small-scale river network model. The river cross-sectional water level and river cross-sectional discharge are calculated using the hydrodynamic model. The watershed boundary water level, watershed boundary discharge, river cross-sectional water level and river cross-sectional discharge are the hydrodynamic elements of the river network.

[0068] In a further embodiment, the basic data includes river network topology connections, river cross sections, water conservancy projects and scheduling rules, and topographic data; the monitoring data mainly includes the locations of existing monitoring stations, historical water levels of monitoring stations, flow monitoring data, and water conservancy project scheduling data.

[0069] It is worth mentioning that the river network topology refers to the morphology of river channels within a region and the connections between different channels; the river cross-section reflects changes in the riverbed topography and is a key factor influencing changes in water level and flow; water conservancy projects mainly include reservoirs, sluice gates, and pumping stations, and the information that needs to be collected includes reservoir location, water level-storage capacity curve, sluice gate location, sluice gate bottom elevation, number of gates, gate width, pumping station location, number of pumping stations, and flow capacity; scheduling rules are mainly used to guide the scheduling of sluice gates and pumps, clarifying the timing of sluice gate and pump opening and closing, and the operation of water conservancy projects will have a significant impact on river water level and flow; topographic data includes digital elevation data of the land surface, land use data, etc., which will affect hydrological runoff and confluence processes.

[0070] In this embodiment, considering the numerous data types and massive amounts of data involved in the hydrological and hydrodynamic model, and the fact that most of the data changes continuously over time, standardized data management is necessary to ensure simulation accuracy and facilitate data inspection and updates. Therefore, a model database needs to be constructed according to the different types of model data. Thus, the model database includes at least: a model network library, a model logic library, and a model event library.

[0071] The model network library is set up to store basic river network information, river network engineering information, and river network topographic information. Correspondingly, the library table structure is as follows: the fields in the basic river information table include river name, river node name, river node number, river node longitude, river node latitude, left bank levee elevation of river node, and right bank levee elevation of river node.

[0072] The basic information tables for the project are divided into three categories: reservoir information tables, gate information tables, and pumping station information tables. The reservoir information table mainly includes fields such as reservoir name, reservoir number, reservoir longitude, reservoir latitude, reservoir discharge method, reservoir spillway crest elevation, reservoir spillway width, reservoir sluice gate bottom elevation, reservoir sluice gate width, and number of reservoir sluice gates. A separate table stores the reservoir water level-capacity-area relationship. The gate information table mainly includes fields such as gate name, gate number, gate longitude, gate latitude, gate bottom type, gate bottom elevation, number of gates, and single gate width. The pumping station information table mainly includes fields such as pumping station name, pumping station longitude, pumping station latitude, number of pumping stations, and single pump capacity.

[0073] The main fields of the river cross-section information table include cross-section name, longitude, latitude, and elevation.

[0074] The main fields of the river network surface topography table include object number, object area, object longitude, object latitude, object elevation, and object land use type.

[0075] The model logic library is used to store water conservancy project scheduling rules, mainly including reservoir scheduling rule tables, sluice gate scheduling rule tables, and pumping station scheduling rule tables. Correspondingly, the library table structure is as follows: the fields in the reservoir scheduling rule table mainly include reservoir number, open reservoir water level, and closed reservoir water level, etc.

[0076] The fields in the sluice gate scheduling rules table include sluice gate number, open inner water level, open outer water level, closed inner water level, and closed outer water level.

[0077] The fields in the pump station scheduling rules table include pump station number, open inner water level, open outer water level, closed inner water level, and closed outer water level.

[0078] The model event library is configured to store historical monitoring data from established water level and flow monitoring stations, as well as forecasted rainfall data. It mainly includes rainfall meters, water level meters, and flow meters.

[0079] The main fields of the rain gauge include: rain gauge number, rain gauge longitude, rain gauge latitude, time, and rainfall. The time intervals are the same and can be 1 minute, 10 minutes, 0.5 hours, 1 hour, etc. After the data is input into the model, the model will use an algorithm to distribute it evenly over the calculation time.

[0080] The main fields of the water level table include: water level monitoring point number, water level monitoring point longitude, water level monitoring point latitude, time, and water level. The time intervals are the same and can be 1 minute, 10 minutes, 0.5 hours, 1 hour, etc. After the data is input into the model, the model will use an algorithm to interpolate the water level values ​​at each calculation time.

[0081] The main fields of the flow table include: flow monitoring point number, flow monitoring point longitude, flow monitoring point latitude, time, and flow rate. The time intervals are the same and can be 1 minute, 10 minutes, 0.5 hours, 1 hour, etc. After the data is input into the model, the model considers the flow rate to be the same within the same calculation period.

[0082] To address the applicability of the Saint-Venant equations and considering the closure of the model's boundary conditions, a basin-level hydrological and hydrodynamic model is constructed using a closed watershed as the unit. The calculation results of the whole watershed model are used to provide boundary conditions for the calculation of the internal regional river network. The construction of the multi-scale river network model is divided into the construction of the river network mathematical model and the multi-scale hierarchical classification.

[0083] Furthermore, the process of dividing large-scale and small-scale river network models includes:

[0084] The topological network structure includes several nodes and several edges, whereby the edges are used to describe the connection relationship between adjacent nodes. Point objects within the river network are defined as nodes, and connection objects describing the connection relationship between adjacent point objects are defined as edges. The point objects and connection objects are uniformly encoded according to a predetermined encoding form (refer to the data structure above for uniform encoding).

[0085] The topological network structure includes several nodes and several edges, whereby the edges describe the connection relationships between adjacent nodes. Point objects within the river network are defined as nodes, and connection objects describing the connections between adjacent point objects are defined as edges. The point objects and connection objects are uniformly encoded according to a predetermined encoding format. For example, point objects within the river network can be physical objects such as river crossings, manholes, and regulating reservoirs. Connection objects can be river sections between river bifurcation points, or objects such as sluice gates, weirs, and pumping stations between upstream and downstream sections.

[0086] Point objects and connecting objects belonging to rivers of level four or above or to polder areas of 10,000 mu or more are classified into large-scale river network models, while point objects and connecting objects belonging to rivers of level four or below or to polder areas of less than 10,000 mu are classified into small-scale river network models.

[0087] The method for constructing the bidirectional nested coupled watershed-region scale model is as follows: the external nodes of the small-scale river network model are associated with the boundary edges of the large-scale river network model using an encoding method.

[0088] In this embodiment, the definition of a river of level four or above is based on the river classification method. Level one and two rivers are mostly major rivers that cross two or more provinces; Level three and four rivers mostly affect provinces and cities, and their importance is slightly less than that of Level one and two rivers.

[0089] This embodiment uses a watershed-level hydrodynamic model to describe the hydrodynamics of a large-scale river network model, and its expression is as follows:

[0090] ;

[0091] In the formula, Indicates the width of the river channel. For water level, For time, For traffic, The cross-sectional average velocity is... The distance along the course from a fixed cross-section of the waterway. Acceleration due to gravity, The cross-sectional area of ​​the water passage. For the riverbed gradient, This is to reduce the friction ratio.

[0092] Based on the above watershed-level hydrodynamic model, the calculation process for watershed boundary water level and watershed boundary discharge is as follows:

[0093] ;

[0094] In the formula, Indicates the water level or flow rate at the watershed boundary. Represents boundary nodes. These are weighting coefficients. , Here, j represents the time index, and j represents the spatial index. Indicates spatial location and the next time step Water level or flow rate For spatial step size, For time step.

[0095] To refine the small-scale river network model, this embodiment divides the hydrodynamics of the model into runoff generation and runoff collection. The runoff generation area includes at least: impermeable areas, semi-permeable areas, permeable areas, and water bodies. For example, impermeable areas can be industrial land, logistics and warehousing land, urban residential land, building land, etc.; semi-permeable areas can be rural roads, railway land, square land, etc.; permeable areas are dry land, paddy fields, green spaces, etc.; and water bodies are lakes, rivers, etc.

[0096] Correspondingly, the flow generation calculation mode for the impermeable area is as follows:

[0097] In the formula, Indicates the flow generation in impermeable areas. Indicates rainfall amount, Indicates the evaporation rate of rivers and lakes. Indicates the amount of plant interception;

[0098] The flow generation calculation method for the semi-permeable area is as follows:

[0099] In the formula, Indicates the runoff generation in a semi-permeable area. Indicates the water requirement of shallow soil;

[0100] The flow generation calculation mode for the permeable zone is as follows:

[0101] In the formula, Indicates the flow generated in the permeable area. Indicates the amount of deep soil infiltration;

[0102] The runoff calculation model for the water body area is as follows:

[0103] In the formula, This indicates the runoff generation in a water body area.

[0104] The detailed simulation process for flow generation and merging is as follows:

[0105] The runoff is calculated using a runoff calculation model to determine the runoff of the corresponding area, and it is also determined whether the area is covered by a drainage network. If there is no drainage network in the current area, the runoff is calculated based on the topographic elevation information, from high to low until it flows into a nearby river. The calculation formula is as follows:

[0106] In the formula, This indicates the flow rate in areas without drainage pipe networks. Represents the roughness coefficient. For hydraulic radius, For pipe slope, The area of ​​the confluence unit;

[0107] When a drainage network exists in the area, the flow rate is calculated by having the storm drains enter the network system and then collect the wastewater at the drainage outlet, which connects to the river. The calculation formula is as follows:

[0108] In the formula, This indicates the flow rate of the area where a drainage network exists, and C is the flow rate coefficient.

[0109] Based on the above calculation model for runoff, the small-scale river network hydrodynamic model is as follows:

[0110] The continuity equation is expressed in the following form: ;

[0111] In the formula, express, All are continuous equations and linear equation systems with constant coefficients, specifically:

[0112] in, ;

[0113] In the formula, Indicates spatial location Time index is The water level at the location; Indicates spatial location Time index is The value at; Indicates spatial location Values ​​related to traffic; Indicates spatial location Time index is Traffic flow at the location; Indicates spatial location Time index is The water level at the location;

[0114] The momentum equation is expressed as follows: ;

[0115] In the formula, , , and The system of linear equations with constant coefficients is a continuity equation, specifically:

[0116] ;

[0117] In the formula, Indicates spatial location Spatial step size; This represents a parameter related to the momentum correction factor or turbulence factor. This represents a quantity related to the Chezy coefficient; Indicates the hydraulic radius; Indicates spatial location The time step is Traffic flow at the location.

[0118] The technical solution of this embodiment includes standardized management of hydrological and hydrodynamic model data, bidirectional nested coupling of multi-spatial scale models, etc., thereby realizing virtual perception of water level, flow and other elements in river networks in areas with insufficient deployment of hardware monitoring stations. While effectively controlling costs, it provides support for the improvement of the hydrological monitoring system and water conservancy management work such as water conservancy project scheduling.

[0119] Example 2

[0120] This embodiment discloses a virtual monitoring system for urban river network hydrodynamic elements, used to implement the virtual monitoring method for urban river network hydrodynamic elements described in Embodiment 1, including: a first module, configured to acquire basic data and monitoring data of the river network and establish a model database; and to use the model database to standardize and manage the basic data and monitoring data according to a predetermined database table structure.

[0121] The second module is configured to describe the river network as a topological network structure, establish a river network mathematical model based on the topological network structure, and divide the river network mathematical model into a large-scale river network model and a small-scale river network model according to multi-scale hierarchies. The large-scale river network model and the small-scale river network model constitute a bidirectional nested coupled watershed-region scale model.

[0122] The third module is configured to construct a basin-level hydrodynamic model using a closed watershed as the unit, and calculate the watershed boundary water level and watershed boundary discharge based on the watershed-level hydrodynamic model.

[0123] The fourth module is set up to divide the small-scale river network model into corresponding runoff-producing areas according to land use type, set corresponding runoff calculation modes, and effectively integrate runoff and runoff to achieve refined simulation of runoff generation and runoff in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model.

[0124] The fifth module is configured to input the water level and flow rate of the watershed boundary as boundary conditions into the small-scale river network model, and use the hydrodynamic model to calculate the water level and flow rate of the river section. The water level, flow rate of the watershed boundary, and flow rate of the river section are the hydrodynamic elements of the river network.

Claims

1. A virtual monitoring method of water dynamic elements of an urban river network, characterized in that, Includes the following steps: Acquire basic and monitoring data of the river network and establish a model database; use the model database to standardize and manage the basic and monitoring data according to a predetermined database table structure; The river network is described as a topological network structure, and a mathematical model of the river network is established based on the topological network structure. The mathematical model of the river network is divided into a large-scale river network model and a small-scale river network model according to the multi-scale hierarchical classification. The large-scale river network model and the small-scale river network model constitute a two-way nested coupled watershed-region scale model. Points and connected objects belonging to rivers of level four or above, or to polder areas of 10,000 mu or more, are classified into the large-scale river network model, while those belonging to rivers below level four, or to polder areas of less than 10,000 mu, are classified into the small-scale river network model. Rivers of level four or above are defined according to the river classification method: Level I and II rivers are major rivers that cross two or more provinces; Level III and IV rivers are rivers that affect provinces and cities, and their importance is less than that of Level I and II rivers; other rivers are those below level four. The method for constructing the bidirectional nested coupled watershed-region scale model is as follows: the external nodes of the small-scale river network model are associated with the boundary edges of the large-scale river network model using an encoding method. A basin-level hydrodynamic model is constructed using a closed watershed as a unit, and the watershed boundary water level and watershed boundary discharge are calculated based on the watershed-level hydrodynamic model. The small-scale river network model is divided into corresponding runoff generation and runoff generation areas according to land use type. Corresponding runoff generation and runoff generation calculation modes are set for each area. The runoff generation and runoff generation are effectively integrated to achieve a refined simulation of runoff generation and runoff generation in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model. The watershed boundary water level and watershed boundary discharge are used as boundary conditions and input into a small-scale river network hydrodynamic model. The river cross-section water level and river cross-section discharge are calculated using the hydrodynamic model. The watershed boundary water level, watershed boundary discharge, river cross-section water level and river cross-section discharge are the river network hydrodynamic elements. The runoff generation and confluence calculation mode is set as follows: the runoff generation area includes at least: impermeable area, semi-permeable area, permeable area and water body area; The detailed simulation process for the flow generation and merging is as follows: The runoff is calculated using a runoff calculation model to determine the runoff of the corresponding area, and it is also determined whether the area is covered by a drainage network. If there is no drainage network in the current area, the runoff is calculated based on the terrain elevation information, from high to low until it flows into a nearby river. The calculation formula is as follows: In the formula, This indicates the flow rate in areas without drainage pipe networks. Represents the roughness coefficient. For hydraulic radius, For pipe slope, The area of ​​the confluence unit; When a drainage network exists in the area, the flow rate is calculated by having the storm drains enter the network system and then collect the wastewater at the drainage outlet, which connects to the river. The calculation formula is as follows: ; where, represents the catchment area of the sewer network, and C is the catchment coefficient. The process of dividing the large-scale river network model and the small-scale river network model includes: The topological network structure includes several nodes and several edges, whereby the edges are used to describe the connection relationship between adjacent nodes; point objects within the river network are defined as nodes, and connection objects describing the connection relationship between adjacent point objects are defined as edges; and the point objects and connection objects are uniformly encoded according to a predetermined encoding format. The watershed-level hydrodynamic model is expressed in the following form: ； In the formula, Indicates the width of the river channel. For water level, For time, For traffic, The cross-sectional average velocity is... The distance along the course from a fixed cross-section of the waterway. Acceleration due to gravity, The cross-sectional area of ​​the water passage. For the riverbed gradient, For the friction ratio decrease; The calculation process for the watershed boundary water level and watershed boundary discharge is as follows: ； In the formula, Indicates the water level or flow rate at the watershed boundary. Represents boundary nodes. These are weighting coefficients. , Here, j represents the time index, and j represents the spatial index. Indicates spatial location and the next time step Water level or flow rate For spatial step size, For time step.

2. The method according to claim 1, wherein, The model database includes at least: a model network library, a model logic library, and a model event library; The model network library is configured to store basic river network information, river network engineering information, and river network topographic information. The model logic library is used to store water conservancy project scheduling rules; The model event library is configured to store historical monitoring data from established water level and flow monitoring stations, as well as forecasted rainfall data.

3. The method according to claim 1, wherein, The small-scale river network hydrodynamic model is as follows: The continuity equation is expressed as follows: ; In the formula, represents, are continuous equation constant linear equations, specifically: wherein ; In the formula, Indicates spatial location Time index is The water level at the location; Indicates spatial location Time index is The value at; Indicates spatial location Values ​​related to traffic; Indicates spatial location Time index is Traffic flow at the location; Indicates spatial location Time index is The water level at the location; The momentum equation is expressed as follows: ; wherein , , and are linear equations with constant coefficients, in particular: ； In the formula, Indicates spatial location Spatial step size; This represents a parameter related to the momentum correction factor or turbulence factor. This represents a quantity related to the Chezy coefficient; Indicates the hydraulic radius; Indicates spatial location The time step is Traffic flow at the location.

4. The urban river network hydrodynamic element virtual monitoring method according to claim 1, characterized in that, The calculation method for the flow generation in the impermeable zone is as follows: ; wherein, represents the runoff of the impermeable area, represents the rainfall, represents the evaporation of the river and lake, represents the plant interception; The flow generation calculation method for the semi-permeable area is as follows: ; wherein represents the runoff of the semi-pervious area, represents the water requirement of the shallow soil; The flow generation calculation mode for the permeable zone is as follows: ; wherein, represents the runoff of the permeable area, represents the infiltration of the deep soil; The runoff calculation model for the water body area is as follows: ; wherein represents the runoff of the water body area.

5. A system for implementing the method for virtual monitoring of water dynamic elements of an urban river network according to any one of claims 1 to 4, characterized in that, include: The first module is set up to acquire basic and monitoring data of the river network and establish a model database; The basic data and monitoring data are standardized and managed according to a predetermined database structure using a model database. The second module is configured to describe the river network as a topological network structure, establish a river network mathematical model based on the topological network structure, and divide the river network mathematical model into a large-scale river network model and a small-scale river network model according to multi-scale hierarchies. The large-scale river network model and the small-scale river network model constitute a bidirectional nested coupled watershed-region scale model. The third module is configured to construct a basin-level hydrodynamic model using a closed watershed as the unit, and calculate the watershed boundary water level and watershed boundary discharge based on the watershed-level hydrodynamic model. The fourth module is set up to divide the small-scale river network model into corresponding runoff-producing areas according to land use type, set corresponding runoff calculation modes, and effectively integrate runoff and runoff to achieve refined simulation of runoff generation and runoff in the small-scale river network model, thus obtaining a small-scale river network hydrodynamic model. The fifth module is configured to input the water level and flow rate of the watershed boundary as boundary conditions into a small-scale river network model, and use the hydrodynamic model to calculate the water level and flow rate of the river section. The water level, flow rate of the watershed boundary, water level and flow rate of the river section are the hydrodynamic elements of the river network.

Images