A Basin Flood Forecasting System for Smart Water Conservancy Based on the Expansion of Flood Storage and Detention Areas by Sub-region

Abstract

The present invention discloses a basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas, which relates to the technical field of flood prevention forecasting and early warning of intelligent water conservancy, aiming to solve the problem of flood simulation and forecasting errors caused by the distortion of the water level-volume curve under low storage conditions when some sections in the flood detention area are enabled or partially breached. The system includes a main river channel hydrodynamic simulation and forecasting module, a flood detention area activation discrimination module, a flood detention area topological analysis module, and a sectional expansion simulation module for flood detention areas. The main river channel hydrodynamic simulation and forecasting module uses a hydrodynamic model to conduct flood simulation and forecasting. The flood detention area activation discrimination module determines whether the flood detention area is activated based on the user input data and the main river channel simulation results. The flood detention area topological analysis module determines the connection and expansion sequence of each independent section. The sectional expansion simulation module for flood detention areas realizes sectional expansion simulation by dynamically calculating the outer boundary and internal flood discharge, with scientific and efficient calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent water conservancy flood forecasting and early warning, and particularly relates to a basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention areas by distribution. Background Art

[0002] Flood simulation and forecasting is the core technology in the modern flood control and disaster reduction system. Under the background of vigorously developing intelligent water conservancy currently, higher requirements are put forward for flood simulation and forecasting models. Intelligent water conservancy emphasizes the use of new generation information technologies such as the Internet of Things, big data, and artificial intelligence to build an intelligent, refined, and dynamic water conservancy management system. This requires that flood simulation and forecasting models have higher spatio-temporal resolutions and can capture subtle changes in the flood evolution process more accurately; the models should also have fast computing capabilities to meet the needs of real-time forecasting, be able to complete the processing of a large amount of data and model calculations in a short time, and provide timely and effective support for flood control decision-making.

[0003] With the deepening of global climate change, the significant increase in the frequency and intensity of extreme rainfall events has made flood disasters show higher suddenness and destructiveness. Under this background, the accuracy, real-time performance, and adaptability to complex hydrological scenarios of flood simulation and forecasting face unprecedented challenges. As an important part of the flood control system, flood detention areas can effectively relieve the flood control pressure of downstream river channels by storing excess water volume and reducing the flow velocity during flood peaks. However, the operation of flood detention areas involves complex hydrodynamic processes with multiple scales and variables. Existing simulation technologies face significant bottlenecks in theoretical modeling and computational efficiency, and urgent upgrades are needed to meet the strict requirements of intelligent water conservancy for flood simulation and forecasting models in terms of accuracy, timeliness, adaptability, etc.

[0004] In the field of basin flood simulation and forecasting related to flood detention areas, the overall basin hydrodynamic model is based on the Saint-Venant Equations and can comprehensively depict the nonlinear dynamic characteristics of basin water flow. However, when solving large-scale basin problems, due to the numerical discretization requirements of its partial differential equations, the calculation is complex and it is difficult to meet the requirements of real-time forecasting for response speed.

[0005] In the simulation of flood detention areas, the existing simple treatment method is to adopt the coupling method of the main river channel hydrodynamic model and the flood detention area water balance model. Although this method simplifies the calculation to a certain extent, it exposes significant limitations when dealing with the complex operating conditions inside the flood detention area. For example, when only part of the flood detention area is enabled, gradually enabled, the internal dikes collapse, or it is dynamically intervened by artificial scheduling, the traditional model is difficult to reflect the spatio-temporal evolution characteristics of the water flow. This leads to systematic deviations in the water level-volume relationship curve of the flood detention area, especially the curve distortion phenomenon is particularly significant under low storage conditions. This deviation not only directly affects the calculation accuracy of the flood diversion flow, but also weakens the reliability of the overall flood forecast of the main river channel and the flood detention area through error transmission. Summary of the Invention

[0006] The purpose of the present invention is to provide a basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas, so as to solve the problem of flood simulation and forecasting errors caused by the distortion of the water level-volume curve under low storage conditions when only part of the flood detention area is enabled or partially breached.

[0007] The present invention provides a basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas, including:

[0008] The main river channel hydrodynamic simulation and forecasting module, the flood detention area enabling discrimination module, the flood detention area topological analysis module, and the flood detention area sectional expansion simulation module;

[0009] The main river channel hydrodynamic simulation and forecasting module is used to carry out the flood simulation and forecasting of the main river channel by using the hydrodynamic model, support the enabling discrimination of the flood detention area, and serve the dynamic calculation of the flood diversion flow for enabling the flood detention area;

[0010] The flood detention area enabling discrimination module is used to judge whether the flood detention area beside the main river channel is enabled and the enabling information according to the flood detention area enabling information input by the system user and in combination with the main river channel hydrodynamic simulation;

[0011] The flood detention area topological analysis module is used to determine the connectivity information and the expansion application order of each independent section of the flood detention area based on the spatial information and enabling information of the enabled flood detention area and in combination with the topological analysis method;

[0012] The flood detention area sectional expansion simulation module is used to carry out the dynamic calculation of the outer boundary and internal flood diversion flow for the enabled flood detention area, and realize the process simulation of the sectional expansion of the flood detention area.

[0013] Furthermore, the main river channel hydrodynamic simulation and prediction module is used to carry out numerical simulation of the water flow evolution in the main river channel based on the flood flow process at the upstream boundary of the basin, the flood flow process in the main river channel interval, and the water level - flow relationship curve at the downstream boundary, and provide the time - varying processes of hydraulic elements such as water level, flow rate, and flow velocity at the hydrological stations along the main river channel;

[0014] If there are enabled flood detention areas in the system, at each time step of the simulation calculation, subtract the flood diversion flow at the outer boundary gates and breach openings of the flood detention areas beside the main river channel from the storage in the main river channel, and provide the water level information of the main river channel to serve the dynamic calculation of the flood diversion flow at the breach of the outer boundary dike;

[0015] For the inflow of water at the upstream boundary of the basin and in the main river channel interval, if it is the measured flow process, carry out the simulation analysis of the basin flood; if it is the predicted flow process, carry out the flood prediction and early warning of the basin. Combine the time - process of hydraulic elements at the hydrological stations, the warning and guarantee water levels, and provide the flood over - warning or over - guarantee warning;

[0016] For carrying out the numerical simulation of water flow evolution, if there are sandbars and mid - channel bars developed in the main river channel, use a two - dimensional hydrodynamic model based on the shallow water equations; otherwise, use a one - dimensional hydrodynamic model based on the Saint - Venant equations.

[0017] Furthermore, the flood detention area activation discrimination module is used to discriminate whether the flood detention area is activated according to the main discrimination conditions and secondary discrimination conditions, and determine the activation information;

[0018] The main discrimination conditions include: if the system user inputs the flood detention area activation information, including the activated outer boundary dike gates, flood diversion flow rate and timing, and the distribution of the outer boundary dike breaches, then determine that the flood detention area is in the activated state; otherwise, turn to the secondary discrimination conditions;

[0019] The secondary discrimination conditions include: set the flood diversion flow at the gates and breach openings of the flood detention areas beside the main river channel to zero, apply the main river channel hydrodynamic simulation and prediction module to obtain the hydraulic elements at the hydrological stations of the main river channel, and evaluate whether the peak water level or flow rate at the flood control stations corresponding to the flood detention area exceeds the activation value in the design data of the flood detention area; if it exceeds, set the flood detention area to the activated state, and the activated gates and flood diversion flow rate are determined according to the design data of the flood detention area, and the activation time is the moment when the hydraulic elements first reach the activation value; otherwise, set the flood detention area to the non - activated state.

[0020] Furthermore, the flood detention area topology analysis module is used for the activated flood detention area, divides the flood detention area into multiple independent parts based on the spatial distribution of the internal dikes, and determines the water level - volume curve of each independent part based on the topographic data of the flood detention area;

[0021] Based on the elevation of the intermediate dikes, clarify the potential strong connectivity and connectivity direction of any adjacent sub - regions. For the intermediate dikes with elevations lower than the elevation of the outer boundary dikes of the flood detention and retention area, connectivity occurs under the over - topping condition when the water level on at least one side of the intermediate dike is higher than the elevation of the intermediate dike, and the connectivity direction is from the sub - region with higher water level to the sub - region with lower water level.

[0022] Based on the distribution of enabled intermediate dike gates and specified intermediate dike breach distributions in the user input, clarify the potential weak connectivity and connectivity direction of any adjacent sub - regions. Weak connectivity includes flood diversion connectivity through gates and breach - induced flood connectivity, and the connectivity direction is from the sub - region with higher water level to the sub - region with lower water level.

[0023] Furthermore, the flood detention and retention area sub - region expansion simulation module includes: an electric drainage pump station simulation unit, a gate hydraulics simulation unit, a breach development simulation unit, an intermediate dike over - topping simulation unit, and a flood detention and retention area sub - region expansion simulation unit;

[0024] The electric drainage pump station simulation unit is used to quantitatively reflect the drainage effect of the electric drainage pump station in the flood detention and retention area sub - region regulation and calculation; according to the operation and management regulations of each electric drainage pump station in the flood detention and retention area, clarify the designed drainage flow under different water level conditions; in one time step of the flood detention and retention area sub - region regulation and calculation, subtract the sub - region storage volume from the storage volume of the sub - region where the pump station is located according to the designed drainage flow of the pump station corresponding to the sub - region water level multiplied by the time step length; then carry out a calculation rationality check: if the sub - region storage volume is less than zero, force it to be assigned as zero, and at the same time update the current time step pump station drainage flow;

[0025] The gate hydraulics simulation unit is used to quantitatively reflect the flow - through effect of the enabled outer boundary dike gates and internal intermediate dike gates in the flood detention and retention area sub - region regulation and calculation;

[0026] The breach development simulation unit is used to quantitatively reflect the development process and flow - through effect of the outer boundary dike breaches and internal intermediate dike breaches in the flood detention and retention area sub - region regulation and calculation;

[0027] The intermediate dike over - topping simulation unit is used to quantitatively reflect the flow - through effect of intermediate dike over - topping in the flood detention and retention area sub - region regulation and calculation; in one time step of the flood detention and retention area sub - region regulation and calculation, combined with the water levels of the two sub - regions on both sides of the intermediate dike, judge whether the water level of the higher - side sub - region exceeds the elevation of the intermediate dike. If it exceeds, carry out the intermediate dike over - topping simulation;

[0028] The flood detention and retention area sub - region expansion simulation unit is used to incorporate the new sub - regions involved in the continuous propagation of the water storage volume after the flood detention and retention area is enabled into the calculation domain, realize the simulation of the progressive expansion process of the flood detention and retention area by sub - region, and provide the storage volume and water level process of each sub - region;

[0029] According to the initial storage volume and water level of each sub - region of the flood detention and retention area input by the system user, carry out an outer - loop calculation within the simulation time range with the user - specified time step length; then traverse each independent sub - region of the flood detention and retention area and carry out an inner - loop calculation.

[0030] The said gate hydraulic simulation unit is used for the following calculations:

[0031] For each enabled outer boundary dike gate of the flood storage and detention area, in one time step of the distributed regulation and storage calculation of the flood storage and detention area, if the current time step has not reached the flood diversion timing input by the system user, the flow rate through the gate is zero; otherwise, the flow rate through the gate is the flood diversion flow rate input by the user. Subsequently, a calculation rationality check is carried out: if the total storage volume of the flood storage and detention area at the end of the time step exceeds the designed volume of the flood storage and detention area, the flow rate through the gate at the current time step is updated with the limit that the total storage volume rises to the designed volume.

[0032] For each enabled intermediate dike gate of the flood storage and detention area, the engineering dimensions of the gate, the number of gates opened and the opening degree under different water level conditions are determined according to the gate operation management regulations. In one time step of the distributed regulation and storage calculation of the flood storage and detention area, combined with the distributed water levels on both sides of the internal intermediate dike, it is judged whether the flow through the intermediate dike gate at the current time step is free outflow or submerged outflow, and the flow rate through the gate is calculated using the orifice flow formula. The flow rate multiplied by the time step length is deducted from the storage volume of the higher water level side, and is incorporated into the storage volume of the lower water level side. Subsequently, a calculation rationality check is carried out: if the water level of the higher water level side at the beginning of the time step is lower at the end of the time step, the water levels on both sides are limited to be equal, and the flow rate through the gate at the current time step is updated simultaneously.

[0033] Furthermore, the breach development simulation unit is used for the following calculations:

[0034] In one time step of the distributed regulation and storage calculation of the flood storage and detention area, the development process of the outer boundary dike breach and the internal intermediate dike breach specified by the system user is simulated, and the simulation control equations are:

[0035] = , = ;

[0036] Wherein, B is the breach width; H is the breach depth; is the relationship between the evolution of the breach width B and the breach width B , the breach depth H , the breach velocity v , the high water levels on both sides of the breach upstream and downstream Z us , the low water level Z ds ; is the relationship between the evolution of the breach depth H and the breach width B , the breach depth H , the breach velocity v , the high water levels on both sides of the breach upstream and downstream Zus , low side water level Z ds The quantitative relationship is specified by the system user based on experience;

[0037] For the breach of the outer boundary levee specified by the system user, in a time step of the partial storage routing of the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water level of the outer main river channel and the water level of the inner flood storage and detention area, it is judged whether the breach flow at the current time step is free outflow or submerged outflow, and the breach flow rate is calculated using the gate hole flow formula, and the flow rate is multiplied by the time step length and merged into the inner flood storage and detention area; then the calculation rationality check is carried out: if the water level of the inner flood storage and detention area exceeds the water level of the outer main river channel at the end of the time step, the water level of the inner flood storage and detention area is limited to the water level of the outer main river channel, and the breach flow rate at the current time step is updated;

[0038] For the internal dike breach specified by the system user, in a time step of the partial storage routing in the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water levels of the branches on both sides of the internal dike, it is judged whether the breach flow in the current time step is free outflow or submerged outflow, and the gate hole flow formula is used to calculate the breach flow rate. The flow rate is deducted from the storage of the branch on the high water level side multiplied by the time step length, and then merged into the storage of the branch with low water level; then the calculation rationality check is carried out: if the water level of the branch on the high side at the beginning of the time step is lower at the end of the time step, the water levels of the branches on both sides are limited to be the same, and the breach flow rate of the current time step is updated at the same time.

[0039] Furthermore, the inter-bank and overbank simulation unit is used to perform the following calculations:

[0040] Determine whether the overflow at the current time step is a free outflow or a submerged outflow, use the weir flow formula to calculate the overflow flow, deduct the flow from the high-side branch storage of the inter-dike water level by the time step length, and merge it into the low-level branch storage; then carry out the calculation rationality check: if the water level of the high-side branch at the beginning of the time step is lower than the inter-dike elevation at the end of the time step, then limit the water level of the high-side branch to the minimum elevation of the inter-dike, and update the overflow flow at the current time step, then carry out the next judgment, if the water level of the high-side branch at the beginning of the time step is lower than the low-side branch at the beginning of the time step at the end of the time step, then limit the water levels of the branches on both sides to be the same, and update the overflow flow at the current time step.

[0041] Furthermore, the flood storage and detention area expansion simulation unit is used to perform the following calculations for the current time step and the current flood storage and detention area section in a loop:

[0042] Determine whether there is an enabled outer boundary dike gate or a specified outer boundary dike breach in this sub - section. If so, apply the gate hydraulics simulation unit and the breach development simulation unit respectively to calculate the flow rate through the outer boundary dike gate and the breach; otherwise, set it to the default value of 0. The calculation result is used as the inflow component of this sub - section;

[0043] Determine whether there is an electric drainage pump station in this sub - section. If so, apply the electric drainage pump station simulation unit to calculate the drainage flow rate of the pump station; otherwise, set it to the default value of 0. The calculation result is used as the outflow component of this sub - section;

[0044] Determine whether the strong connectivity condition of this sub - section is satisfied. If satisfied, apply the levee over - topping simulation unit to calculate the flow rate through the over - topping; otherwise, set it to the default value of 0. The calculation result is used as the outflow component of the sub - section with a higher initial water level and the inflow component of the sub - section with a lower initial water level among this sub - section and the adjacent sub - sections at the time step;

[0045] Determine whether the gate flood diversion connectivity in the weak connectivity condition of this sub - section is satisfied. If satisfied, apply the gate hydraulics simulation unit to calculate the flow rate through the gate; otherwise, set it to the default value of 0. The calculation result is used as the outflow component of the sub - section with a higher initial water level and the inflow component of the sub - section with a lower initial water level among this sub - section and the adjacent sub - sections at the time step;

[0046] Determine whether the breach - collapse connectivity in the weak connectivity condition of this sub - section is satisfied. If satisfied, apply the breach development simulation unit to calculate the development process and the flow rate through the breach; otherwise, set it to the default value of 0. The calculation result is used as the outflow component of the sub - section with a higher initial water level and the inflow component of the sub - section with a lower initial water level among this sub - section and the adjacent sub - sections at the time step;

[0047] Carry out storage calculation for this sub - section based on the principle of water balance to calculate the storage volume of the sub - section at the end of the time step: , where V 0 is the initial storage volume of the sub - section at the time step, V 1 is the storage volume of the sub - section at the end of the time step, INQ i are the inflow components, OTQ j are the outflow components, Δ t is the time step length; Based on the storage volume V 1 of the sub - section at the end of the time step and the water level - volume curve of the sub - section, use the interpolation method to obtain the water level Z 1 at the end of the time step of the sub - section.

[0048] The present invention has the following beneficial effects: A basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas of the present invention can not only quickly generate simulation forecast results on the premise of ensuring calculation efficiency, but also accurately present the internal water flow dynamic characteristics of flood detention areas under various complex operation scenarios, including the comprehensive impacts of sectional activation, levee breach failure, and gate-pump project scheduling. By accurately simulating the linkage process between the main river channel and flood detention areas through multi-module coupling, the simulation accuracy of flood evolution and the decision-making support ability for scheduling are improved. The dual discrimination mechanism combined with rationality verification realizes intelligent decision-making for the activation of flood detention areas and compatibility with multiple scenarios, enhancing the flexibility and practicality of the system. Based on the sectional expansion modeling of levees, the sectional regulation process of flood detention areas is finely simulated, contributing to the optimization of storage capacity and the precise control of flood risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0050] Figure 1 Structural diagram of the basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas of the present invention;

[0051] Figure 2 Application flow chart of the basin flood forecasting system for intelligent water conservancy based on the sectional expansion of flood detention areas of the present invention;

[0052] Figure 3 Forecast water levels of the flood control control station of the main river channel before and after the activation of the flood detention area in the embodiment of the present invention;

[0053] Figure 4 Schematic diagram of the application of sectional expansion after the activation of the flood detention area in the embodiment of the present invention.

[0054] Illustration: 1 - Main river channel hydrodynamic simulation and forecasting module; 2 - Flood detention area activation discrimination module; 3 - Flood detention area topology analysis module; 4 - Flood detention area sectional expansion simulation module; 41 - Electric drainage pump station simulation unit; 42 - Gate hydraulics simulation unit; 43 - Breach development simulation unit; 44 - Levee overtopping simulation unit; 45 - Flood detention area sectional expansion simulation unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0055] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. The following will detail the technical solutions provided by each embodiment of the present invention with reference to the drawings.

[0056] Please refer to Figure 1 , the basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention areas in the present invention includes: a main river channel hydrodynamic simulation and forecasting module 1, a flood detention area activation discrimination module 2, a flood detention area topology analysis module 3, and a flood detention area expansion simulation module 4.

[0057] The main river channel hydrodynamic simulation and forecasting module 1 is used to carry out flood simulation and forecasting of the main river channel by using a hydrodynamic model, support the activation discrimination of flood detention areas, and serve the dynamic calculation of the flood diversion flow for activating flood detention areas.

[0058] Specifically, the main river channel hydrodynamic simulation and forecasting module 1 is used to carry out numerical simulation of the water flow evolution of the main river channel based on the flood flow process at the upstream boundary of the basin, the flood flow process in the main river channel interval, and the water level - flow relationship curve at the downstream boundary, and provide the time - varying process of hydraulic elements such as water level, flow rate, and flow velocity at hydrological stations along the main river channel; if there are activated flood detention areas in the system, at each time step of the simulation calculation, subtract the flood diversion flow of the outer boundary sluices and breaches of the lateral flood detention areas from the main river channel storage, and provide the main river channel water level information to serve the dynamic calculation of the flood diversion flow at the outer boundary dike breaches; for the incoming water at the upstream boundary of the basin and in the main river channel interval, if it is the measured flow process, carry out basin flood simulation analysis, and if it is the forecast flow process, carry out basin flood forecasting and early warning, and combine the time process of hydraulic elements at hydrological stations, warning and guaranteed water levels to provide flood over - warning or over - guarantee warning; for carrying out numerical simulation of water flow evolution, if there are developed sandbars and mid - channel bars in the main river channel, use a two - dimensional hydrodynamic model based on the shallow water equations to reflect the complex water flow field; otherwise, use a one - dimensional hydrodynamic model based on the Saint - Venant equations to save computational cost.

[0059] The flood detention area activation discrimination module 2 is used to judge whether the lateral flood detention areas of the main river channel are activated and the activation information according to the flood detention area activation information input by the system user in combination with the main river channel hydrodynamic simulation.

[0060] Specifically, the flood detention area activation discrimination module 2 is used to judge whether the flood detention area is activated according to the main discrimination conditions and secondary discrimination conditions, and determine the activation information.

[0061] The main discrimination conditions include: If the system user inputs the flood storage and detention area activation information, including the sluice gates at the outer boundary main dike, the flood diversion flow rate and timing, and the distribution of breaches in the outer boundary main dike, then it is determined that the flood storage and detention area is in the activated state; otherwise, it turns to the secondary discrimination conditions.

[0062] The secondary discrimination conditions include: The flood diversion flow rates of the sluice gates and breaches in the flood storage and detention area beside the main river channel are set to zero. The hydrodynamic simulation and forecasting module of the main river channel is applied to obtain the hydraulic elements of the hydrological stations in the main river channel, and it is evaluated whether the peak flood level or flow rate of the flood control station corresponding to the flood storage and detention area exceeds the activation value in the design data of the flood storage and detention area; if it exceeds, the flood storage and detention area is set to the activated state, and the activated sluice gates and flood diversion flow rates are determined according to the design data of the flood storage and detention area, and the activation time is the time when the hydraulic elements first reach the activation value; otherwise, the flood storage and detention area is set to the non-activated state.

[0063] The flood storage and detention area topology analysis module 3 is used to determine the connectivity information and the order of expansion application of each independent part of the flood storage and detention area based on the spatial information and activation information of the activated flood storage and detention area, combined with the topology analysis method.

[0064] Specifically, the flood storage and detention area topology analysis module 3 is used for the activated flood storage and detention area. Based on the spatial distribution of the internal intermediate dikes, the flood storage and detention area is divided into multiple independent parts, and the water level - volume curves of each independent part are determined based on the topographic data of the flood storage and detention area; based on the elevation of the intermediate dikes, the potential strong connectivity and connection direction between any adjacent parts are clarified. For the intermediate dikes with elevations lower than the elevation of the outer boundary main dike of the flood storage and detention area, connection occurs under the condition of overtopping when the water level on at least one side of the intermediate dike is higher than the elevation of the intermediate dike, and the connection direction is from the high - water - side part to the low - water - side part; based on the distribution of the activated intermediate dike sluice gates and the specified distribution of intermediate dike breaches input by the user, the potential weak connectivity and connection direction between any adjacent parts are clarified. The weak connectivity includes flood diversion connection through sluice gates and breach - collapse connection, and the connection direction is from the high - water - side part to the low - water - side part.

[0065] The flood storage and detention area sub - part expansion simulation module 4 is used to carry out dynamic calculations of the outer boundary and internal flood diversion flow rates for the activated flood storage and detention area, and to realize the process simulation of the step - by - step expansion of the flood storage and detention area.

[0066] Specifically, the flood storage and detention area sub - part expansion simulation module 4 includes: an electric drainage pump station simulation unit 41, a sluice gate hydraulics simulation unit 42, a breach development simulation unit 43, an intermediate dike overtopping simulation unit 44, and a flood storage and detention area sub - part expansion simulation unit 45.

[0067] The electric drainage pumping station simulation unit 41 is used to quantitatively reflect the drainage effect of the electric drainage pumping station in the sectional regulation and calculation of the flood detention area; according to the operation and management regulations of each electric drainage pumping station in the flood detention area, the designed drainage flow under different water level conditions is determined; in a time step of the sectional regulation and calculation of the flood detention area, from the storage volume of the section where the pumping station is located, the designed drainage flow of the pumping station corresponding to the section water level is multiplied by the time step length, and the section storage volume is deducted; then, a calculation rationality check is carried out: if the section storage volume is less than zero, it is forced to be assigned zero, and at the same time, the drainage flow of the pumping station at the current time step is updated.

[0068] The gate hydraulics simulation unit 42 is used to quantitatively reflect the flow-through effect of enabling the outer boundary dike gates and the internal inter-dike gates in the sectional regulation and calculation of the flood detention area.

[0069] Specifically, the gate hydraulics simulation unit 42 is used to perform the following calculations: for each enabled outer boundary dike gate in the flood detention area, in a time step of the sectional regulation and calculation of the flood detention area, if the current time step has not reached the flood diversion timing input by the system user, the gate flow-through flow is zero, otherwise the gate flow-through flow is the flood diversion flow input by the user; then, a calculation rationality check is carried out: if the total storage volume of the flood detention area at the end of the time step exceeds the designed volume of the flood detention area, the gate flow-through flow at the current time step is updated with the limit that the total storage volume rises to the designed volume.

[0070] For each enabled inter-dike gate in the flood detention area, the gate project dimensions, the number of gates opened and the opening degree under different water level conditions are determined according to the gate operation and management regulations; in a time step of the sectional regulation and calculation of the flood detention area, combined with the sectional water levels on both sides of the internal inter-dike, it is judged whether the inter-dike gate flow-through at the current time step is free out-flow or submerged out-flow, and the gate flow-through flow is calculated using the gate orifice flow formula, the flow-through flow multiplied by the time step length is deducted from the storage volume of the section with the higher water level, and is incorporated into the storage volume of the section with the lower water level; then, a calculation rationality check is carried out: if the water level of the section with the higher water level at the beginning of the time step is lower at the end of the time step, the water levels of both sections are limited to be equal, and at the same time, the gate flow-through flow at the current time step is updated.

[0071] The breach development simulation unit 43 is used to quantitatively reflect the development process and flow-through effect of the outer boundary dike breach and the internal inter-dike breach in the sectional regulation and calculation of the flood detention area.

[0072] Specifically, the breach development simulation unit 43 is used to perform the following calculations: in a time step of the sectional regulation and calculation of the flood detention area, the development processes of the outer boundary dike breach and the internal inter-dike breach specified by the system user are simulated, and the simulation control equations are:

[0073] = , = ;

[0074] Among them, Bis the breach width; H is the breach depth; The width of the breach B Evolution and breach width B , breach depth H , breach flow rate v , high side water level upstream and downstream of breach Z us , low side water level Z ds Quantitative relationship of The depth of breach H Evolution and breach width B , breach depth H , breach flow rate v , high side water level upstream and downstream of breach Z us , low side water level Z ds The quantitative relationship is specified by the system user based on experience;

[0075] For the breach of the outer boundary levee specified by the system user, in a time step of the partial storage routing of the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water level of the outer main river channel and the water level of the inner flood storage and detention area, it is judged whether the breach flow at the current time step is free outflow or submerged outflow, and the breach flow rate is calculated using the gate hole flow formula, and the flow rate is multiplied by the time step length and merged into the inner flood storage and detention area; then the calculation rationality check is carried out: if the water level of the inner flood storage and detention area exceeds the water level of the outer main river channel at the end of the time step, the water level of the inner flood storage and detention area is limited to the water level of the outer main river channel, and the breach flow rate at the current time step is updated;

[0076] For the internal dike breach specified by the system user, in a time step of the partial storage routing in the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water levels of the branches on both sides of the internal dike, it is judged whether the breach flow in the current time step is free outflow or submerged outflow, and the gate hole flow formula is used to calculate the breach flow rate. The flow rate is deducted from the storage of the branch on the high water level side multiplied by the time step length, and then merged into the storage of the branch with low water level; then the calculation rationality check is carried out: if the water level of the branch on the high side at the beginning of the time step is lower at the end of the time step, the water levels of the branches on both sides are limited to be the same, and the breach flow rate of the current time step is updated at the same time.

[0077] The inter-levee and overbank simulation unit 44 is used to quantitatively reflect the flow effect of the inter-levee and overbank in the partial storage calculation of the flood storage and detention area; in a time step of the partial storage calculation of the flood storage and detention area, combined with the partial water levels on both sides of the inter-levee, it is judged whether the high-side partial water level exceeds the inter-levee elevation, and if so, the inter-levee and overbank simulation is carried out.

[0078] Specifically, the overtopping simulation unit 44 of the intermediate dike is used for the following calculations: determining whether the overtopping flow at the current time step is free outfall or submerged outfall, calculating the overtopping flow rate using the weir flow formula, deducting the product of the overtopping flow rate and the time step length from the storage volume on the high side of the intermediate dike water level, and incorporating it into the storage volume on the low side of the water level; subsequently, a calculation rationality check is carried out: if the water level on the high side of the initial water level of the time step is lower than the intermediate dike elevation at the end of the time step, the water level on the high side is limited to drop to the intermediate dike elevation at least, and at the same time, the overtopping flow rate of the current time step is updated, and then the next judgment is carried out. If the water level on the high side of the initial water level of the time step is lower than the water level on the low side of the initial water level of the time step at the end of the time step, the water levels on both sides are limited to be flush, and at the same time, the overtopping flow rate of the current time step is updated.

[0079] The flood storage and detention area sub-region expansion simulation unit 45 is used to incorporate the new sub-regions involved in the continuous propagation of the stored water volume after the flood storage and detention area is activated into the calculation domain, realize the simulation of the gradual expansion process of the flood storage and detention area by sub-region, and provide the storage volume and water level process of each sub-region; according to the initial storage volume and water level of each sub-region of the flood storage and detention area input by the system user, in the simulation time range with the user-specified time step length, an outer loop calculation is carried out; then each independent sub-region of the flood storage and detention area is traversed to carry out an inner loop calculation.

[0080] Specifically, for the current time step and the current sub-region of the flood storage and detention area, the loop body of the flood storage and detention area sub-region expansion simulation unit 45 is used for the following calculations:

[0081] Determine whether there is an activated outer boundary dike gate or a specified outer boundary dike breach in this sub-region. If so, apply the gate hydraulics simulation unit 42 and the breach development simulation unit 43 respectively to calculate the overtopping flow rates of the outer boundary dike gate and the breach; otherwise, set it to the default value of 0; the calculation results are used as the inflow components of this sub-region;

[0082] Determine whether there is an electric drainage pump station in this sub-region. If so, apply the electric drainage pump station simulation unit 41 to calculate the drainage flow rate of the pump station; otherwise, set it to the default value of 0; the calculation results are used as the outflow components of this sub-region;

[0083] Determine whether the strongly connected condition of this sub-region is satisfied. If satisfied, apply the overtopping simulation unit 44 of the intermediate dike to calculate the overtopping flow rate; otherwise, set it to the default value of 0; the calculation results are used as the outflow components of this sub-region and the inflow components of the sub-region with the higher initial water level of the time step among this sub-region and the adjacent sub-regions at the same time;

[0084] Determine whether the gate flood diversion connection in the weakly connected condition of this sub-region is satisfied. If satisfied, apply the gate hydraulics simulation unit 42 to calculate the overtopping flow rate of the gate; otherwise, set it to the default value of 0; the calculation results are used as the outflow components of this sub-region and the inflow components of the sub-region with the higher initial water level of the time step among this sub-region and the adjacent sub-regions at the same time;

[0085] Judge whether the breach connection in the weak connectivity condition of this sub - region is satisfied. If it is satisfied, apply the breach development simulation unit 43 to calculate the development process of the breach and the flow rate passing through the breach; otherwise, set it to the default value 0. The calculation results are used as the outflow components of the sub - region with a higher initial water level and the inflow components of the sub - region with a lower initial water level in this sub - region and the adjacent sub - regions at the time step.

[0086] Carry out storage regulation calculation for this sub - region based on the principle of water balance, and calculate the storage volume of the sub - region at the end of the time step: , where V 0 is the initial storage volume of the sub - region at the time step, V 1 is the storage volume at the end of the time step of the sub - region, INQ i are the inflow components, OTQ j are the outflow components, Δ t is the time step length; based on the storage volume V 1 at the end of the time step of the sub - region and the water level - volume curve of the sub - region, use the interpolation method to obtain the water level Z 1 at the end of the time step of the sub - region.

[0087] The application process of the basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage sub - regions of the present invention is described in detail below with specific cases.

[0088] The A flood detention and storage area is an important part of the flood control system of the X River, undertaking the major task of diverting and storing the excess flood of the X River. The basic information of the A flood detention and storage area is as follows: the designed flood storage level is 35.37 m, the area is 269.55 km², the effective flood storage volume is 1.504 billion m³, and the cultivated land area is 176,000 mu. The operation method of the A flood detention and storage area is: if the water level of the C hydrological station, the flood control control station of the X River, reaches 34.4 m and continues to rise, flood diversion measures need to be taken in the nearby flood detention and storage areas; depending on the safety needs of key protected objects, first use flood detention and storage areas such as the A flood detention and storage area, and then use other surrounding flood detention and storage areas successively.

[0089] In the flood season of 2020, a basin - wide major flood occurred in the X River Basin. Especially in July, the water level of the C hydrological station exceeded the flood control level of 34.4 m. Now apply the basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage sub - regions of the present invention to carry out basin flood forecasting for the main channel of the X River and the A flood detention and storage area basin from July to August. The main channel of the X River is the section from the upstream D hydrological station to the downstream E hydrological station.

[0090] Please refer to Figures 2 to 4 , Figure 4 The upper - middle number in is the water depth distribution map of the A flood detention and storage area. The arrow indicates the flood diversion gate. The pink line segment indicates the internal dike in the flood detention and storage area. The application process of the basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage sub - regions of the present invention is as follows:

[0091] I. Data Acquisition

[0092] 1.1 Obtain basic information of the flood storage and detention area, such as the design data, topographic data, distribution and elevation of the intermediate dikes, characteristic parameters of the internal sluice pumps, and operation management regulations of Area A flood storage and detention area.

[0093] Based on the design data of Area A flood storage and detention area, it is clear that there is a total of 1 sluice at the outer boundary dike of the flood storage and detention area, with a designed flood diversion flow rate of 3630 m³ / s; the elevation data of the internal intermediate dikes are determined; the spatial distribution, starting water level threshold, and designed drainage flow rate of the electric drainage pump stations on the internal intermediate dikes are determined; the spatial distribution, design parameters, and operation modes of the sluices on the internal intermediate dikes are determined. The design parameters include width, height, opening height, etc.

[0094] 1.2 Obtain the flood flow process at the upstream boundary and the water level - flow relationship curve at the downstream boundary.

[0095] Obtain the forecast incoming water process of Hydrological Station D in the upper reaches of the basin and the forecast incoming water process of the main channel section of River X as the upper boundary conditions for flood forecasting;

[0096] Obtain the water level - flow relationship curve of Hydrological Station E in the lower reaches of the basin as the lower boundary condition for flood forecasting.

[0097] 1.3 Obtain the flood storage and detention area activation information input by the system user;

[0098] The flood storage and detention area activation information input by the system user includes the requirement to activate the sluice at the outer boundary dike, the flood diversion flow rate is taken as the designed flood diversion flow rate of the sluice, the flood diversion flow rate is 3630 m³ / s, and the flood diversion activation time is 9:00 on July 24th; activate the main sluices of the intermediate dikes, and the activation method is that the gates are gradually opened to full opening when the upstream section is expected to reach the elevation of the intermediate dikes.

[0099] 1.4 Obtain the initial storage volume and water level of each section of the flood storage and detention area input by the system user.

[0100] II. Apply the main channel hydrodynamic simulation and forecasting module

[0101] Under the condition of not activating Area A flood storage and detention area, based on the one - dimensional hydrodynamic model of the main channel of River X, combined with the forecast incoming water process of Hydrological Station D in the upper reaches, the forecast incoming water process of the River X section, and the water level - flow relationship curve of Hydrological Station E in the lower reaches, calculate the time - varying processes of water level, flow rate, and flow velocity of Hydrological Station C, the flood control station of the main channel of River X. Through model calculation, the forecast water level of Hydrological Station C exceeds the flood control water level of 34.4 m and reaches 34.66 m.

[0102] III. Apply the flood storage and detention area activation discrimination module

[0103] Apply the flood storage and detention area activation discrimination module to confirm that the flood storage and detention area is in the activated state based on the activation information of Area A flood storage and detention area input by the user.

[0104] IV. Applying the topological analysis module of flood storage and detention areas

[0105] Based on the distribution of internal dikes in Flood Storage and Detention Area A, it is divided into independent sub - areas, and the water level - volume curve is generated to determine the strong and weak connections and directions between the sub - areas.

[0106] Based on the dike distribution and elevation data in Flood Storage and Detention Area A, Flood Storage and Detention Area A is divided into three independent sub - areas: the west sub - area, the middle sub - area, and the east sub - area. Based on the Digital Elevation Model (DEM) data, the water level - volume curve of each sub - area is independently quantified. Among them, the sluice at the outer boundary dike is located in the middle sub - area.

[0107] Applying the topological analysis module of flood storage and detention areas, combined with the spatial distribution information of internal dike sluices, the connectivity information inside the flood storage and detention area is obtained as follows:

[0108] Strong connection: There is a connection under over - topping conditions between the middle sub - area and the east sub - area, and there is a connection under over - topping conditions between the middle sub - area and the west sub - area;

[0109] Connection direction: All are from the sub - area on the high - water side to the sub - area on the low - water side;

[0110] Weak connection: There is a connection through flood diversion at the dike sluice between the middle sub - area and the east sub - area;

[0111] Connection direction: From the sub - area on the high - water side to the sub - area on the low - water side.

[0112] V. Coupled application of the main river channel hydrodynamic simulation and prediction module and the flood storage and detention area sub - area expansion simulation module

[0113] Coupled application of the main river channel hydrodynamic simulation and prediction module and the flood storage and detention area sub - area expansion simulation module: At each calculation time step within the simulation time range from July to August, the calculation time step is 60 seconds, and the calculations of the main river channel hydrodynamic simulation module and the flood storage and detention area sub - area expansion simulation module are carried out simultaneously. Among them, for the main river channel hydrodynamic simulation module, the flood diversion flow at the sluice of the outer boundary dike of the flood storage and detention area is obtained as the lateral outflow.

[0114] For the flood storage and detention area sub - area expansion simulation module, an outer - loop calculation is carried out with a user - specified time step of 60 seconds within the simulation time range from July to August; an inner - loop calculation is carried out by traversing each independent sub - area of the flood storage and detention area;

[0115] For the current time step and the current sub - area of the flood storage and detention area, the loop body includes the following calculation steps;

[0116] Judge whether there is an enabled sluice at the outer boundary dike of this sub - area. If so, apply the sluice hydraulics simulation unit 42 to calculate the flow rate through the sluice at the outer boundary dike; otherwise, set it to the default value of 0; the calculation result is used as the inflow component of this sub - area.

[0117] Determine whether there is a drainage pumping station in this sub - section. If so, apply the drainage pumping station simulation unit 41 to calculate the drainage flow rate of the pumping station; otherwise, set it to the default value 0; the calculation result is used as the outflow component of this sub - section.

[0118] Determine whether the strongly connected condition of this sub - section is satisfied. If so, apply the dike over - topping simulation unit 44 to calculate the overflow flow rate of the over - topped dike; otherwise, set it to the default value 0; the calculation result is used as the outflow component of the sub - section with a higher initial water level and the inflow component of the sub - section with a lower initial water level among this sub - section and the adjacent sub - sections at the time step.

[0119] Determine whether the flood - diversion connection in the weakly connected condition of this sub - section is satisfied. If so, apply the gate hydraulics simulation unit 42 to calculate the overflow flow rate of the gate; otherwise, set it to the default value 0; the calculation result is used as the outflow component of the sub - section with a higher initial water level and the inflow component of the sub - section with a lower initial water level among this sub - section and the adjacent sub - sections at the time step.

[0120] Carry out storage - regulation calculation for this sub - section based on the principle of water balance, and calculate the storage volume of the sub - section at the end of the time step: , where V 0 is the initial storage volume of the sub - section at the time step, V 1 is the storage volume of the sub - section at the end of the time step, INQ i are the inflow components, OTQ j are the outflow components, Δ t is the time step length; based on the storage volume V 1 of the sub - section at the end of the time step and the water level - volume curve of the sub - section, use the interpolation method to obtain the water level Z 1 of the sub - section at the end of the time step.

[0121] VI. System Application Effect

[0122] Based on the flood - storage and detention area activation information input by the system user, compare the predicted flood processes at Hydrological Station C on the main channel of River X before and after the activation of Flood - storage and Detention Area A, and investigate the application process of the sub - section expansion of Flood - storage and Detention Area A. It is found through comparison that after the activation of Flood - storage and Detention Area A, the peak flood level at Hydrological Station C drops to 34.39 m, which is lower than the flood control water level of 34.4 m.

[0123] The embodiments of the present invention described above do not constitute a limitation on the protection scope of the present invention.

Claims

1. A basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas by distribution, characterized in that, Including: The main river channel hydrodynamic simulation and forecasting module (1), the flood detention area activation discrimination module (2), the flood detention area topology analysis module (3), and the flood detention area sub - division expansion simulation module (4); The main river channel hydrodynamic simulation and forecasting module (1) is used to carry out flood simulation and forecasting of the main river channel by using a hydrodynamic model, support the activation discrimination of the flood detention area, and serve the dynamic calculation of the flood discharge for activating the flood detention area; The flood detention area activation discrimination module (2) is used to judge whether the flood detention area beside the main river channel is activated and the activation information according to the flood detention area activation information input by the system user and combined with the hydrodynamic simulation of the main river channel; the flood detention area activation discrimination module (2) is used to judge whether the flood detention area is activated according to the main discrimination conditions and secondary discrimination conditions, and determine the activation information; The main discrimination conditions include: if the system user inputs the flood detention area activation information, including the outer boundary dike gate, flood discharge and timing of activation, and the distribution of dike breaches at the outer boundary, then it is determined that the flood detention area is in an activated state; otherwise, turn to the secondary discrimination conditions; The secondary discrimination conditions include: the flood discharge of the flood detention area beside the main river channel at the gate and the breach is set to zero, the hydrodynamic elements of the main river channel hydrological station are obtained by applying the main river channel hydrodynamic simulation and forecasting module, and it is evaluated whether the peak water level or flow of the flood control control station corresponding to the flood detention area exceeds the activation value in the flood detention area design data; if it exceeds, the flood detention area is set to the activated state, the activated gate and flood discharge are determined according to the flood detention area design data, and the activation time is the time when the hydrodynamic elements first reach the activation value; otherwise, the flood detention area is set to the non - activated state; The flood detention area topology analysis module (3) is used to determine the connectivity information and expansion application order of each independent sub - division of the flood detention area based on the spatial information and activation information of the activated flood detention area, combined with the topology analysis method; The flood detention area sub - division expansion simulation module (4) is used to carry out dynamic calculation of the outer boundary and internal flood discharge of the activated flood detention area, and realize the process simulation of the step - by - step expansion of the flood detention area; the flood detention area sub - division expansion simulation module (4) includes: the electric drainage pump station simulation unit (41), the gate hydraulic simulation unit (42), the breach development simulation unit (43), the dike over - topping simulation unit (44), and the flood detention area sub - division expansion simulation unit (45); The electric drainage pump station simulation unit (41) is used to quantitatively reflect the drainage effect of the electric drainage pump station in the flood detention area sub - division regulation and calculation; according to the operation and management regulations of each electric drainage pump station in the flood detention area, clarify the designed drainage flow under different water level conditions; in a time step of the flood detention area sub - division regulation and calculation, subtract the sub - division storage from the storage of the sub - division where the pump station is located according to the designed drainage flow of the pump station corresponding to the sub - division water level multiplied by the time step length; then carry out calculation rationality verification: if the sub - division storage is less than zero, it is forced to be assigned zero, and at the same time, update the current time step pump station drainage flow; The gate hydraulic simulation unit (42) is used to quantitatively reflect the flow - through effect of the activated outer boundary dike gate and the internal dike gate in the flood detention area sub - division regulation and calculation; The breach development simulation unit (43) is used to quantitatively reflect the development process and the flow-through effect of the breach of the outer boundary dike and the internal intermediate dike during the sectional regulation and calculation in the flood detention area; The overtopping simulation unit of the intermediate dike (44) is used to quantitatively reflect the flow-through effect of the overtopping of the intermediate dike during the sectional regulation and calculation in the flood detention area; at a time step of the sectional regulation and calculation in the flood detention area, in combination with the sectional water levels on both sides of the intermediate dike, it is judged whether the water level of the high-side section exceeds the elevation of the intermediate dike. If it exceeds, the overtopping simulation of the intermediate dike is carried out; The sectional expansion simulation unit of the flood detention area (45) is used to incorporate the new sections involved in the continuous propagation of the water storage volume after the flood detention area is activated into the calculation domain, realize the simulation of the sectional expansion process of the flood detention area, and provide the water storage volume and water level process of each section; According to the initial water storage volume and water level of each section of the flood detention area input by the system user, an outer loop calculation is carried out within the simulation time range with the time step specified by the user; then each independent section of the flood detention area is traversed to carry out an inner loop calculation.

2. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 1, characterized in that, The main river channel hydrodynamic simulation and forecasting module (1) is used to carry out numerical simulation of the water flow evolution in the main river channel based on the flood flow process at the upstream boundary of the basin, the flood flow process in the main river channel reach, and the downstream boundary water level-discharge relationship curve, and provide the time-varying process of hydraulic elements such as water level, discharge, and flow velocity at the hydrological stations along the main river channel; If there is an activated flood detention area in the system, at each time step of the simulation calculation, the flood diversion discharge of the outer boundary sluice and breach of the side flood detention area is deducted from the main river channel storage, and the main river channel water level information is provided to serve the dynamic calculation of the flood diversion discharge of the outer boundary dike breach; For the inflow from the upstream boundary of the basin and the main river channel reach, if it is the measured flow process, the basin flood simulation analysis is carried out. If it is the forecast flow process, the basin flood forecasting and early warning are carried out. Combining the time process of hydraulic elements at the hydrological stations, the warning and guarantee water levels, flood over-warning or over-guarantee warning are provided; For the numerical simulation of water flow evolution, if there are sandbars and mid-channel bars developed in the main river channel, a two-dimensional hydrodynamic model based on the shallow water equations is adopted; otherwise, a one-dimensional hydrodynamic model based on the Saint-Venant equations is adopted.

3. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 1, characterized in that, The flood detention area topology analysis module (3) is used for the activated flood detention area. Based on the spatial distribution of the internal intermediate dikes, the flood detention area is divided into multiple independent sections, and the water level-volume curve of each independent section is determined based on the topographic data of the flood detention area; Based on the elevation of the intermediate dike, the potential strong connectivity and the connectivity direction of any adjacent sections are clarified. For the intermediate dike with an elevation lower than the elevation of the outer boundary dike of the flood detention area, connection occurs under the overtopping condition when the water level on at least one side of the intermediate dike is higher than the elevation of the intermediate dike, and the connectivity direction is from the high-water-side section to the low-water-side section; Based on the distribution of the activated intermediate dike sluices and the specified distribution of intermediate dike breaches input by the user, the potential weak connectivity and the connectivity direction of any adjacent sections are clarified. The weak connectivity includes the flood diversion connection through the sluice and the breach connection due to the breach, and the connectivity direction is from the high-water-side section to the low-water-side section.

4. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 1, characterized in that, The sluice hydraulics simulation unit (42) is used to perform the following calculations: For each floodgate at the outer boundary dike of the flood detention area, during one time step of the distributed storage and regulation calculation in the flood detention area, if the current time step has not reached the flood diversion timing input by the system user, the flow rate through the floodgate is zero; otherwise, the flow rate through the floodgate is the flood diversion flow rate input by the user. Subsequently, a calculation rationality check is carried out: if the total storage volume in the flood detention area at the end of the time step exceeds the designed volume of the flood detention area, the flow rate through the floodgate at the current time step is updated with the limit that the total storage volume rises to the designed volume. For each floodgate at the internal dike in the flood detention area, the engineering dimensions of the floodgate and the number and opening degree of the floodgate under different water level conditions are specified according to the gate operation management regulations. During one time step of the distributed storage and regulation calculation in the flood detention area, combined with the distributed water levels on both sides of the internal dike, it is judged whether the flow through the floodgate at the current time step is free outflow or submerged outflow, and the flow rate through the floodgate is calculated using the orifice flow formula. The flow rate multiplied by the time step length is deducted from the storage volume of the higher water level side, and is incorporated into the storage volume of the lower water level side. Subsequently, a calculation rationality check is carried out: if the water level of the higher water level side at the beginning of the time step is lower at the end of the time step, the water levels on both sides are limited to be equal, and the flow rate through the floodgate at the current time step is updated simultaneously.

5. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 1, characterized in that, The breach development simulation unit (43) is used for the following calculations: During one time step of the distributed storage and regulation calculation in the flood detention area, the development process of the breach of the outer boundary dike and the internal dike specified by the system user is simulated. The simulation control equation: ； Among them, B is the breach width; H is the breach depth; is the breach width B evolution and the breach width B , the breach depth H , the breach flow velocity v , the high-side water levels upstream and downstream of the breach Z us , the low-side water level Z ds quantitative relationship; is the breach depth H evolution and the breach width B , the breach depth H , the breach flow velocity v , the high-side water levels upstream and downstream of the breach Z us , the low-side water level Z ds quantitative relationship; The quantitative relationship is specified by the system user according to experience; For the breach of the outer boundary levee specified by the system user, in a time step of the partial storage routing of the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water level of the outer main river channel and the water level of the inner flood storage and detention area, it is judged whether the breach flow at the current time step is free outflow or submerged outflow, and the breach flow rate is calculated using the gate hole flow formula, and the flow rate is multiplied by the time step length and merged into the inner flood storage and detention area; then the calculation rationality check is carried out: if the water level of the inner flood storage and detention area exceeds the water level of the outer main river channel at the end of the time step, the water level of the inner flood storage and detention area is limited to the water level of the outer main river channel, and the breach flow rate at the current time step is updated; For the internal dike breach specified by the system user, in a time step of the partial storage routing in the flood storage area, the breach width based on the current time step B , breach depth H , combined with the water levels of the branches on both sides of the internal dike, it is judged whether the breach flow in the current time step is free outflow or submerged outflow, and the gate hole flow formula is used to calculate the breach flow rate. The flow rate is deducted from the storage of the branch on the high water level side multiplied by the time step length, and then merged into the storage of the branch with low water level; then the calculation rationality check is carried out: if the water level of the branch on the high side at the beginning of the time step is lower at the end of the time step, the water levels of the branches on both sides are limited to be the same, and the breach flow rate of the current time step is updated at the same time.

6. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and retention areas according to claim 1, characterized in that The overtopping simulation unit (44) of the internal dike is used for the following calculations; Judge whether the overtopping flow at the current time step is free outflow or submerged outflow, calculate the overtopping flow rate using the weir flow formula, deduct the flow rate multiplied by the time step length from the storage volume of the higher water level side of the internal dike, and incorporate it into the storage volume of the lower water level side. Subsequently, a calculation rationality check is carried out: if the water level of the higher water level side at the beginning of the time step is lower than the elevation of the internal dike at the end of the time step, the water level of the higher side is limited to drop to the elevation of the internal dike at least, and the overtopping flow rate at the current time step is updated simultaneously. Subsequently, the next judgment is carried out. If the water level of the higher water level side at the beginning of the time step is lower than the water level of the lower water level side at the beginning of the time step at the end of the time step, the water levels on both sides are limited to be equal, and the overtopping flow rate at the current time step is updated simultaneously.

7. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood storage and detention areas according to claim 1, characterized in that, The distributed expansion simulation unit (45) of the flood detention area is a loop body for the current time step and the current distributed flood detention area, and is used for the following calculations: Judge whether there is an enabled floodgate at the outer boundary dike or a specified breach of the outer boundary dike in this division. If so, the gate hydraulics simulation unit (42) and the breach development simulation unit (43) are respectively applied to calculate the flow rates through the floodgate and the breach of the outer boundary dike; otherwise, it is set to the default value 0. The calculation result is used as the inflow component of this division; Judge whether there is an electric drainage pump station in this division. If so, the electric drainage pump station simulation unit (41) is applied to calculate the drainage flow rate of the pump station; otherwise, it is set to the default value 0. The calculation result is used as the outflow component of this division; Judge whether the strongly connected condition of this division is satisfied. If so, the overtopping simulation unit (44) of the internal dike is applied to calculate the overtopping flow rate; otherwise, it is set to the default value 0. The calculation result is used as the outflow component of the division with the higher initial water level and the inflow component of the division with the lower initial water level among this division and the adjacent divisions at the same time step. Determine whether the flood diversion connection in the weak connectivity condition of this sub - section is satisfied. If it is satisfied, apply the gate hydraulics simulation unit (42) to calculate the flow rate through the gate; otherwise, set it to the default value of 0. The calculation results are used as the outflow component of the sub - section with a higher initial water level at the time step and the inflow component of the sub - section with a lower initial water level in both this sub - section and the adjacent sub - section; Determine whether the breach connection in the weak connectivity condition of this sub - section is satisfied. If it is satisfied, apply the breach development simulation unit (43) to calculate the development process and flow rate through the breach; otherwise, set it to the default value of 0. The calculation results are used as the outflow component of the sub - section with a higher initial water level at the time step and the inflow component of the sub - section with a lower initial water level in both this sub - section and the adjacent sub - section; Based on the water balance principle, a regulation calculation is carried out for this sub - section, and the storage volume of the sub - section at the end of the time step is calculated as follows: , where V 0 is the initial storage volume of the sub - section time step, V 1 is the storage volume at the end of the sub - section time step, INQ i is each inflow component, OTQ j is each outflow component, Δ t is the time step length; Based on the storage volume V 1 at the end of the sub - section time step and the sub - section water level - volume curve, the water level Z 1 at the end of the sub - section time step is obtained by interpolation method.

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