Intelligent water conservancy-oriented drainage basin flood forecasting system based on capacity expansion of flood storage and detention area subsections

Abstract

The invention discloses an intelligent water conservancy-oriented drainage basin flood forecasting system based on capacity expansion of a flood storage and detention area, relates to the technical field of intelligent water conservancy flood prevention forecasting and early warning, and aims to solve the problem of flood simulation forecasting errors caused by distortion of a water level-volume curve under a low storage capacity condition when internal subsections of a flood storage and detention area are started or partially outburst. The system comprises a main riverway hydrodynamic simulation forecasting module, a flood storage and detention area starting judgment module, a flood storage and detention area topology analysis module and a flood storage and detention area subsection expansion simulation module. The main river channel hydrodynamic simulation forecasting module adopts a hydrodynamic model to carry out flood simulation forecasting, the flood storage and detention area starting judgment module judges whether a flood storage and detention area is started or not according to user input data and a main river channel simulation result, and the flood storage and detention area topology analysis module determines the connection and capacity expansion sequence of each independent branch. The flood storage and detention area subsection capacity expansion simulation module realizes subsection capacity expansion simulation by dynamically calculating the outer boundary and the internal flood diversion flow, and calculation is scientific and efficient.

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 and retarding areas by distribution. Background Technique

[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 and retarding areas can effectively relieve the flood control pressure of the downstream river channels by storing excess water volume and reducing the flow velocity during flood peaks. However, the operation of flood detention and retarding 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 and retarding areas, the overall basin hydrodynamic model is based on the Saint-Venant Equations and can comprehensively depict the non-linear 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 couple the main river channel hydrodynamic model with the water volume balance model of the flood detention area. 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 significant curve distortion under low storage conditions. Such deviations not only directly affect the calculation accuracy of the flood diversion flow, but also weaken the reliability of the overall flood forecasting 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: A main river channel hydrodynamic simulation and forecasting module, a flood detention area activation discrimination module, a flood detention area topology analysis module, and a flood detention area sectional expansion simulation module; The main river channel hydrodynamic simulation and forecasting module is used to carry out main river channel flood simulation and forecasting by using a hydrodynamic model, support the activation discrimination of the flood detention area, and serve the dynamic calculation of the flood diversion flow for activating the flood detention area; The flood detention area activation discrimination module 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, in combination with the main river channel hydrodynamic simulation; The flood detention area topology analysis module is used to determine the connectivity information and expansion application order of each independent section of the flood detention area based on the spatial information and activation information of the activated flood detention area, in combination with the topology analysis method; The flood detention area sectional expansion simulation module is used to carry out dynamic calculation of the outer boundary and internal flood diversion flow for the activated flood detention area, and realize the process simulation of the sectional expansion of the flood detention area.

[0008] Furthermore, the main river channel hydrodynamic simulation and forecasting module is used to carry out numerical simulation of the main river channel water flow evolution based on the flood flow process at the upstream boundary of the basin, the flood flow process in the main river channel section, and the water level - flow relationship curve at the downstream boundary, and provide the time variation process of hydraulic elements such as water level, flow rate, and flow velocity at the hydrological stations along the main river channel; If there is an activated flood detention area in the system, during the simulation of each time step, the flood diversion flow at the outer boundary gates and breaches of the lateral flood detention area is deducted from the main channel storage, and the main channel water level information is provided to serve the dynamic calculation of the flood diversion flow at the outer boundary levee breach; For the upstream boundary of the basin and the inflow from the main 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 with the time process of hydraulic elements at hydrological stations, 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 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.

[0009] 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; The main discrimination conditions include: if the system user inputs the flood detention area activation information, including the activated outer boundary levee gates, flood diversion flow and timing, and the distribution of outer boundary levee breaches, it is determined that the flood detention area is in the activated state; otherwise, it turns to the secondary discrimination conditions; The secondary discrimination conditions include: the flood diversion flow at the gates and breaches of the lateral flood detention area of the main channel is set to zero, and the main channel hydrodynamic simulation and forecasting module is applied to obtain the hydraulic elements of the main channel hydrological stations, and evaluate whether the peak water level or flow at the flood control control stations 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, and the activated gates and flood diversion flow are determined according to the flood detention area design data, and the activation time is the time when the hydraulic elements first reach the activation value; otherwise, the flood detention area is set to the non-activated state.

[0010] Furthermore, the flood detention area topology analysis module is used to divide the activated flood detention area into multiple independent parts based on the spatial distribution of internal dikes, and determine the water level - volume curve of each independent part based on the flood detention area topographic data; Based on the dike elevation, clarify the potential strong connectivity and connectivity direction of any adjacent parts. For the dikes with elevations lower than the elevation of the outer boundary levee of the flood detention area, connection occurs under the overtopping condition when the water level on at least one side of the dike is higher than the dike elevation, and the connectivity direction is from the high-water side part to the low-water side part; Based on the distribution of activated dike gates and the specified dike breach distribution in the user input, clarify the potential weak connectivity and connectivity direction of any adjacent parts. The weak connectivity includes gate flood diversion connectivity and breach breach connectivity, and the connectivity direction is from the high-water side part to the low-water side part.

[0011] Furthermore, the flood detention area sub - section expansion simulation module includes: an electric drainage pump station simulation unit, a sluice gate hydraulic simulation unit, a breach development simulation unit, an intermediate dike over - topping simulation unit, and a flood detention area sub - section expansion simulation unit; 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 area sub - section storage 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 - section storage calculation, subtract the sub - section storage from the storage volume of the sub - section where the pump station is located according to the designed drainage flow of the pump station corresponding to the sub - section water level multiplied by the time step length; then carry out a calculation rationality check: if the sub - section storage is less than zero, force it to be assigned as zero, and at the same time update the pump station drainage flow of the current time step; The sluice gate hydraulic simulation unit is used to quantitatively reflect the flow - through effect of enabling the outer boundary dike sluice gates and the internal intermediate dike sluice gates in the flood detention area sub - section storage calculation; The breach development simulation unit is used to quantitatively reflect the development process and flow - through effect of the outer boundary dike breach and the internal intermediate dike breach in the flood detention area sub - section storage calculation; The intermediate dike over - topping simulation unit is used to quantitatively reflect the flow - through effect of the intermediate dike over - topping in the flood detention area sub - section storage calculation; in a time step of the flood detention area sub - section storage calculation, combine the sub - section water levels on both sides of the intermediate dike to judge whether the high - side sub - section water level exceeds the intermediate dike elevation. If it exceeds, carry out the intermediate dike over - topping simulation; The flood detention area sub - section expansion simulation unit is used to incorporate the new sub - sections involved in the continuous propagation of the stored water volume after the flood detention area is enabled into the calculation domain, realize the simulation of the step - by - step expansion process of the flood detention area, and provide the storage volume and water level process of each sub - section; According to the initial storage volume and water level of each flood detention area sub - section input by the system user, carry out an outer - loop calculation within the simulation time range with the user - specified time step; then traverse each independent sub - section of the flood detention area and carry out an inner - loop calculation.

[0012] The sluice gate hydraulic simulation unit is used to perform the following calculations: For each enabled outer boundary dike sluice gate in the flood detention area, in a time step of the flood detention area sub - section storage calculation, if the current time step has not reached the flood diversion timing input by the system user, the sluice gate flow - through flow is zero, otherwise the sluice gate flow - through flow is the flood diversion flow input by the user; then carry out a calculation rationality check: 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, update the sluice gate flow - through flow of the current time step with the limit that the total storage volume rises to the designed volume; For each flood storage and detention area's sluice gate opening between the dikes, clarify the gate project dimensions, the number of gates to be opened and the opening degree under different water level conditions according to the gate operation management regulations; at one time step of the flood storage and detention area's sectional regulation and storage calculation, combined with the sectional water levels on both sides of the internal dike, judge whether the current time step's dike gate outflow is free outflow or submerged outflow, calculate the gate outflow discharge using the sluice opening flow formula, deduct the product of the outflow discharge and the time step length from the storage volume of the higher water level side section, and merge it into the storage volume of the lower water level side section; then carry out the rationality verification of the calculation: if the water level of the higher water level side section at the beginning of the time step is lower at the end of the time step, then limit the water levels of both sections to be equal, and at the same time update the current time step's gate outflow discharge.

[0013] Furthermore, the breach development simulation unit is used for the following calculations: At one time step of the flood storage and detention area's sectional regulation and storage calculation, simulate the development process of the outer boundary dike breach and the internal dike breach specified by the system user, and the simulation control equations are: = , = ; 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 velocity v 、the high side water levels upstream and downstream of the breach Z us 、the low side water level Z ds of the quantitative relationship; is the breach depth H evolution and the breach width B 、the breach depth H 、the breach velocity v 、the high side water levels upstream and downstream of the breach Z us 、the low side water level Z ds of the quantitative relationship; the quantitative relationship is specified by the system user according to experience; For the outer boundary dike breach specified by the system user, at one time step of the flood storage and detention area's sectional regulation and storage calculation, based on the current time step's breach width B 、the 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 sub-region, determine whether the current time-step breach outflow belongs to free outflow or submerged outflow, calculate the breach outflow discharge using the sluice opening outflow formula, and multiply the outflow discharge by the time-step length and incorporate it into the inner flood storage and detention sub-region; subsequently, conduct a calculation rationality check: if the water level of the inner flood storage and detention sub-region at the end of the time-step exceeds the water level of the outer main river channel, then limit the water level of the inner flood storage and detention sub-region to the water level of the outer main river channel, and simultaneously update the current time-step breach outflow discharge; For the internal dike breach specified by the system user, in one time-step of the flood storage and detention sub-region regulation calculation, based on the breach width B and breach depth H at the current time-step, combined with the water levels of the two sub-regions on both sides of the internal dike, determine whether the current time-step breach outflow belongs to free outflow or submerged outflow, calculate the breach outflow discharge using the sluice opening outflow formula, deduct the outflow discharge multiplied by the time-step length from the storage volume of the sub-region with the higher water level, and incorporate it into the storage volume of the sub-region with the lower water level; subsequently, conduct a calculation rationality check: if the water level of the sub-region with the higher water level at the beginning of the time-step is lower at the end of the time-step, then limit the water levels of the two sub-regions to be equal, and simultaneously update the current time-step breach outflow discharge.

[0014] Furthermore, the dike overtopping simulation unit is used to perform the following calculations; Determine whether the current time-step dike overtopping outflow belongs to free outflow or submerged outflow, calculate the dike overtopping outflow discharge using the weir outflow formula, deduct the outflow discharge multiplied by the time-step length from the storage volume of the sub-region with the higher dike water level, and incorporate it into the storage volume of the sub-region with the lower water level; subsequently, conduct a calculation rationality check: if the water level of the sub-region with the higher dike water level at the beginning of the time-step is lower than the dike elevation at the end of the time-step, then limit the water level of the higher sub-region to be at least as low as the dike elevation, and simultaneously update the current time-step dike overtopping outflow discharge, and then conduct the next judgment. If the water level of the sub-region with the higher dike water level at the beginning of the time-step is lower than the water level of the sub-region with the lower dike water level at the beginning of the time-step at the end of the time-step, then limit the water levels of the two sub-regions to be equal, and simultaneously update the current time-step dike overtopping outflow discharge.

[0015] Furthermore, the flood storage and detention sub-region expansion simulation unit, for the current time-step and the current flood storage and detention sub-region, the loop body is used to perform the following calculations: Determine whether there is an enabled outer boundary dike sluice or a specified outer boundary dike breach in this sub-region. If so, apply the sluice hydraulics simulation unit and the breach development simulation unit respectively to calculate the outflow discharges of the outer boundary dike sluice 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; Determine whether there is an electric drainage pump station in this sub-region. If so, apply the electric drainage pump station simulation unit to calculate the pump drainage discharge; otherwise, set it to the default value of 0; the calculation results are used as the outflow components of this sub-region; Determine whether the strong connectivity condition of this sub - region is satisfied. If it is satisfied, apply the levee over - topping simulation unit to calculate the over - flow discharge of the over - topping; otherwise, set it to the default value of 0. The calculation results are used as the out - flow components of the sub - region with the higher initial water level and the in - flow components of the sub - region with the lower initial water level among this sub - region and its adjacent sub - regions at the time step. Determine whether the flood diversion connectivity in the weak connectivity condition of this sub - region is satisfied. If it is satisfied, apply the gate hydraulics simulation unit to calculate the over - flow discharge of the gate; otherwise, set it to the default value of 0. The calculation results are used as the out - flow components of the sub - region with the higher initial water level and the in - flow components of the sub - region with the lower initial water level among this sub - region and its adjacent sub - regions at the time step. Determine whether the breach - collapse connectivity in the weak connectivity condition of this sub - region is satisfied. If it is satisfied, apply the breach development simulation unit to calculate the development process and over - flow discharge of the breach; otherwise, set it to the default value of 0. The calculation results are used as the out - flow components of the sub - region with the higher initial water level and the in - flow components of the sub - region with the lower initial water level among this sub - region and its adjacent sub - regions at the time step. Carry out storage 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 of the sub - region at the end of the time step, INQ i are the in - flow components, OTQ j are the out - flow components, Δ t is the time step length; based on the storage volume V 1 of the sub - region at the end of the time step 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.

[0016] The present invention has the following beneficial effects: A basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and retention areas by sub - regions of the present invention can not only quickly generate simulation and forecasting results on the premise of ensuring calculation efficiency, but also accurately present the internal water flow dynamic characteristics of flood detention and retention areas under various complex application scenarios, including the comprehensive influence of enabling by sub - regions, levee breach and destruction, and gate - pump project scheduling. Through the precise simulation of the linkage process between the main river channel and flood detention and retention areas by multi - module coupling, the accuracy of flood evolution simulation and the ability to support scheduling decisions are improved. The dual discrimination mechanism combined with rationality verification realizes the intelligent decision - making and multi - scenario compatibility for the activation of flood detention and retention areas, enhancing the flexibility and practicality of the system. The sub - region expansion modeling based on the levee topology finely simulates the step - by - step storage process of flood detention and retention areas, contributing to the optimization of storage capacity and the precise control of flood risks. Description of the Drawings

[0017] To more clearly illustrate the technical solution 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.

[0018] Figure 1 Structural diagram of the basin flood forecasting system for the present invention's intelligent water conservancy based on the sectional expansion of flood detention and retarding areas; Figure 2 Application flow chart of the basin flood forecasting system for the present invention's intelligent water conservancy based on the sectional expansion of flood detention and retarding areas; Figure 3 Forecast water levels of the flood control control station on the main river channel before and after the activation of the flood detention and retarding area in the embodiment of the present invention; Figure 4 Schematic diagram of the application situation of sectional expansion after the activation of the flood detention and retarding area in the embodiment of the present invention.

[0019] Illustration: 1 - Main river channel hydrodynamic simulation and forecasting module; 2 - Flood detention and retarding area activation discrimination module; 3 - Flood detention and retarding area topology analysis module; 4 - Flood detention and retarding area sectional expansion simulation module; 41 - Electric drainage pump station simulation unit; 42 - Hydraulic simulation unit at the sluice; 43 - Breach development simulation unit; 44 - Levee overtopping simulation unit; 45 - Flood detention and retarding area sectional expansion simulation unit. Detailed implementation manners

[0020] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the 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 them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention. The following will describe in detail the technical solutions provided by each embodiment of the present invention with reference to the drawings.

[0021] Please refer to Figure 1 , the basin flood forecasting system for the present invention's intelligent water conservancy based on the sectional expansion of flood detention and retarding areas includes: a main river channel hydrodynamic simulation and forecasting module 1, a flood detention and retarding area activation discrimination module 2, a flood detention and retarding area topology analysis module 3, and a flood detention and retarding area sectional expansion simulation module 4.

[0022] 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 discrimination of the activation of the flood detention and retarding area, and serve the dynamic calculation of the flood diversion flow for activating the flood detention and retarding area.

[0023] Specifically, 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 discharge process at the upstream boundary of the basin, the flood discharge process in the main river channel interval, and the water level-discharge 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; if there is an enabled flood detention area in the system, at each time step of the simulation calculation, subtract the flood diversion flow at the outer boundary sluice and breach of the side flood detention area from the main river channel storage, and provide the main river channel water level information for the dynamic calculation of the flood diversion flow at the outer boundary dike breach; 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, if it is the forecast flow process, carry out basin flood forecasting and early warning, and combine the time process of hydraulic elements at the hydrological stations, warning and guarantee water levels to provide flood over-warning or over-guarantee warning; for the numerical simulation of water flow evolution, if there are 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 overhead.

[0024] The flood detention area activation discrimination module 2 is used to judge whether the side flood detention area of 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 main river channel hydrodynamic simulation.

[0025] 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.

[0026] The main discrimination conditions include: if the system user inputs the flood detention area activation information, including the enabled outer boundary dike sluice, flood diversion flow and timing, and the distribution of outer boundary dike breaches, it is determined that the flood detention area is in the activated state; otherwise, it is transferred to the secondary discrimination conditions.

[0027] The secondary discrimination conditions include: setting the flood diversion flow at the sluice and breach of the side flood detention area of the main river channel to zero, obtaining the hydraulic elements of the main river channel hydrological stations by applying the main river channel hydrodynamic simulation and forecasting module, and evaluating whether the peak water level or flow rate of the flood control station corresponding to the flood detention area exceeds the activation value in the flood detention area design data; if it exceeds, set the flood detention area to the activated state, and the enabled sluice and flood diversion flow are determined according to the flood detention area design data, and the activation time is the time when the hydraulic elements first reach the activation value; otherwise, set the flood detention area to the non-activated state.

[0028] The flood detention area topology analysis module 3 is used to determine the connectivity information and expansion application order of each independent part of the flood detention area based on the spatial information and activation information of the enabled flood detention area and combined with the topology analysis method.

[0029] Specifically, the flood storage and detention area topology analysis module 3 is used for the enabled flood storage and detention area. Based on the spatial distribution of the internal dikes, the flood storage and detention area is divided into multiple independent sections. Based on the topographic data of the flood storage and detention area, the water level - volume curve of each independent section is determined. Based on the dike elevation, the potential strong connectivity and connection direction between any adjacent sections are clarified. For the dikes with elevations lower than the elevation of the outer boundary dike of the flood storage and detention area, when the water level on at least one side of the dike is higher than the dike elevation, connection occurs under the condition of dike overtopping, and the connection direction is from the high - water - level section to the low - water - level section. Based on the distribution of enabled dike gates and the specified dike breach distribution in the user input, the potential weak connectivity and connection direction between any adjacent sections are clarified. The weak connectivity includes flood diversion connection through gates and breach connection due to dike breakage, and the connection direction is from the high - water - level section to the low - water - level section.

[0030] The flood storage and detention area section expansion simulation module 4 is used for the enabled flood storage and detention area to carry out dynamic calculation of the outer boundary and internal flood diversion flow, and realize the process simulation of the step - by - step expansion of the flood storage and detention area by section.

[0031] Specifically, the flood storage and detention area section expansion simulation module 4 includes: an electric drainage pump station simulation unit 41, a gate hydraulics simulation unit 42, a breach development simulation unit 43, a dike overtopping simulation unit 44, and a flood storage and detention area section expansion simulation unit 45.

[0032] 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 storage and detention area section regulation calculation. According to the operation and management regulations of each electric drainage pump station in the flood storage and detention area, the designed drainage flow under different water level conditions is clarified. In a time step of the flood storage and detention area section regulation calculation, from the storage volume of the section where the pump station is located, according to the designed drainage flow of the pump station corresponding to the section water level multiplied by the time step length, the section storage volume is deducted. Subsequently, 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 current time step pump station drainage flow is updated.

[0033] The gate hydraulics simulation unit 42 is used to quantitatively reflect the flow - through effect of the enabled outer boundary dike gates and internal dike gates in the flood storage and detention area section regulation calculation.

[0034] Specifically, the gate hydraulics simulation unit 42 is used to perform the following calculations: for each enabled outer boundary dike gate in the flood storage and detention area, in a time step of the flood storage and detention area section regulation calculation, 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. 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 current time step gate flow - through flow is updated with the limit that the total storage volume rises to the designed volume. For each flood storage and detention area's floodgate at the embankment between the flood storage and detention areas, the engineering dimensions of the floodgate, the number of floodgates opened and the opening degree under different water level conditions are specified according to the floodgate operation management regulations; in one time step of the flood storage and detention area's sectional regulation and storage calculation, combined with the sectional water levels on both sides of the internal embankment, it is judged whether the flow through the floodgate at the embankment between the flood storage and detention areas 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 through the floodgate is deducted from the storage volume of the higher water level side by multiplying it by the time step length 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 at the same time, the flow rate through the floodgate at the current time step is updated.

[0035] 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 embankment breach in the flood storage and detention area's sectional regulation and storage calculation.

[0036] Specifically, the breach development simulation unit 43 is used to perform the following calculations: in one time step of the flood storage and detention area's sectional regulation and storage calculation, the development process of the breach of the outer boundary dike and the internal embankment breach specified by the system user is simulated, and the simulation control equations are: = , = ; 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 water levels on both the upstream and downstream sides of the breach Z us 、the low 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 water levels on both the upstream and downstream sides of the breach Z us 、the low 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 dike specified by the system user, in one time step of the flood storage and detention area's sectional regulation and storage calculation, based on the breach width B 、the breach depth H, combined with the water level of the outer main river channel and the water levels of the inner flood storage and detention sub-areas, determine whether the current time-step breach flow is free outflow or submerged outflow, calculate the breach flow rate using the orifice flow formula, and multiply the flow rate by the time-step length and incorporate it into the inner flood storage and detention sub-areas; subsequently, conduct a calculation rationality check: if the water level of the inner flood storage and detention sub-areas at the end of the time-step exceeds the water level of the outer main river channel, then limit the water level of the inner flood storage and detention sub-areas to the water level of the outer main river channel, and at the same time update the current time-step breach flow rate; For the internal dike breach specified by the system user, in one time-step of the flood storage and detention sub-area regulation and calculation, based on the breach width B and the breach depth H at the current time-step, combined with the water levels of the two sub-areas on both sides of the internal dike, determine whether the current time-step breach flow is free outflow or submerged outflow, calculate the breach flow rate using the orifice flow formula, deduct the product of the flow rate and the time-step length from the storage volume of the sub-area with the higher water level, and incorporate it into the storage volume of the sub-area with the lower water level; subsequently, conduct a calculation rationality check: if the water level of the sub-area with the higher water level at the beginning of the time-step is lower at the end of the time-step, then limit the water levels of the two sub-areas to be equal, and at the same time update the current time-step breach flow rate.

[0037] The dike overtopping simulation unit 44 is used to quantitatively reflect the overtopping flow effect of the dike in the flood storage and detention sub-area regulation and calculation; in one time-step of the flood storage and detention sub-area regulation and calculation, combined with the water levels of the two sub-areas on both sides of the dike, determine whether the water level of the higher sub-area exceeds the dike elevation, and if it exceeds, conduct dike overtopping simulation.

[0038] Specifically, the dike overtopping simulation unit 44 is used to perform the following calculations; determine whether the current time-step overtopping flow is free outflow or submerged outflow, calculate the overtopping flow rate using the weir flow formula, deduct the product of the flow rate and the time-step length from the storage volume of the sub-area with the higher water level on the dike, and incorporate it into the storage volume of the sub-area with the lower water level; subsequently, conduct a calculation rationality check: if the water level of the sub-area with the higher water level at the beginning of the time-step is lower than the dike elevation at the end of the time-step, then limit the water level of the higher sub-area to be at least as low as the dike elevation, and at the same time update the current time-step overtopping flow rate, and then conduct the next judgment. If the water level of the sub-area with the higher water level at the beginning of the time-step is lower than the water level of the sub-area with the lower water level at the beginning of the time-step at the end of the time-step, then limit the water levels of the two sub-areas to be equal, and at the same time update the current time-step overtopping flow rate.

[0039] The flood storage and detention sub-area expansion simulation unit 45 is used to incorporate the new sub-areas 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 step-by-step expansion process of the flood storage and detention area, and provide the storage volume and water level processes of each sub-area; according to the initial storage volume and water level of each flood storage and detention sub-area input by the system user, conduct an outer loop calculation within the simulation time range at the user-specified time-step length; then traverse each independent sub-area of the flood storage and detention area and conduct an inner loop calculation.

[0040] Specifically, for the current time step and the current flood storage and detention sub - area division, the flood storage and detention sub - area division expansion simulation unit 45 has a loop body for performing the following calculations: Determine whether there is an enabled outer boundary dike gate or a specified outer boundary dike breach in this division. If so, apply the gate hydraulics simulation unit 42 and the breach development simulation unit 43 respectively to calculate the flow - through discharge of 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 division; Determine whether there is an electric drainage pumping station in this division. If so, apply the electric drainage pumping station simulation unit 41 to calculate the drainage discharge of the pumping station; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of this division; Determine whether the strong - connectivity condition of this division is satisfied. If so, apply the levee over - topping simulation unit 44 to calculate the flow - through discharge of the over - topping; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of the division with a higher initial water level and the inflow component of the division with a lower initial water level among this division and its adjacent divisions at the current time step; Determine whether the gate flood - diversion connectivity in the weak - connectivity condition of this division is satisfied. If so, apply the gate hydraulics simulation unit 42 to calculate the flow - through discharge of the gate; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of the division with a higher initial water level and the inflow component of the division with a lower initial water level among this division and its adjacent divisions at the current time step; Determine whether the breach - break connectivity in the weak - connectivity condition of this division is satisfied. If so, apply the breach development simulation unit 43 to calculate the development process and the flow - through discharge of the breach; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of the division with a higher initial water level and the inflow component of the division with a lower initial water level among this division and its adjacent divisions at the current time step; Carry out storage and regulation calculation for this division based on the principle of water balance to calculate the storage volume of the division at the end of the time step: , where V 0 is the initial storage volume of the division at the time step, V 1 is the storage volume at the end of the division 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 division at the end of the time step and the division water level - volume curve, use the interpolation method to obtain the water level Z 1 at the end of the division time step.

[0041] The following details the application process of the basin flood forecasting system for intelligent water conservancy based on flood storage and detention sub - area division expansion with specific cases.

[0042] The A flood detention and retarding area is an important part of the flood control system of the X River and undertakes the major task of storing and diverting the excess flood of the X River. The basic information of the A flood detention and retarding 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 retarding area is as follows: 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 retarding areas; depending on the safety needs of key protected objects, the A flood detention and retarding area and other flood detention and retarding areas are used first, and other surrounding flood detention and retarding areas are successively used.

[0043] 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 control level of 34.4 m. Now, the basin flood forecasting system based on the sectional expansion of flood detention and retarding areas for intelligent water conservancy of the present invention is applied to carry out the basin flood forecasting for the main channel of the X River and the basin of the A flood detention and retarding area 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.

[0044] Please refer to Figures 2 to 4 , Figure 4 The upper middle number in it is the water depth distribution map of the A flood detention and retarding area. The arrow indicates the flood diversion gate. The pink line segment indicates the internal dike in the flood detention and retarding area. The application process of the basin flood forecasting system based on the sectional expansion of flood detention and retarding areas for intelligent water conservancy of the present invention is as follows: I. Data acquisition 1.1. Obtain the basic information of the flood detention and retarding area, such as the design data, topographic data, dike distribution and elevation, characteristic parameters of internal sluice pumps and operation management regulations of the A flood detention and retarding area.

[0045] Based on the design data of the A flood detention and retarding area, it is clear that there is a total of 1 dike gate on the outer boundary of the flood detention and retarding area, and the designed flood diversion flow is 3,630 m³ / s; the elevation data of the internal dikes are clarified; the spatial distribution, starting water level threshold and designed drainage flow of the internal dike drainage pumping stations are clarified; the spatial distribution, design parameters and operation methods of the internal dike gates are clarified. The design parameters include width, height, opening height, etc.

[0046] 1.2. Obtain the flood flow process at the upstream boundary and the water level-flow relationship curve at the downstream boundary.

[0047] Obtain the forecast incoming water process of the upstream D Hydrological Station in the basin and the forecast incoming water process in the main channel section of the X River as the upper boundary conditions for flood forecasting; Obtain the water level-flow relationship curve of the downstream E Hydrological Station in the basin as the lower boundary condition for flood forecasting.

[0048] 1.3. Obtain the flood detention and retarding area activation information input by the system user; The flood detention and retention area activation information input by the system user, including the requirement to activate the outer boundary dike gate, the flood diversion flow rate is taken as the designed flood diversion flow rate of the gate, the flood diversion flow rate is 3,630 m³ / s, and the flood diversion activation time is 9:00 on July 24th; activate the main gates of the intermediate dike, 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 dike.

[0049] 1.4. Obtain the initial storage volume and water level of each section of the flood detention and retention area input by the system user.

[0050] II. Apply the main river channel hydrodynamic simulation and forecasting module Under the condition of not activating the A flood detention and retention area, based on the one-dimensional hydrodynamic model of the main channel of the X River, combined with the incoming water process forecasted by the upstream D hydrological station, the incoming water process forecasted in the X River reach, and the water level-discharge relationship curve of the downstream E hydrological station, calculate the time-varying processes of water level, discharge, and flow velocity and other elements at the C hydrological station, the flood control control station of the main channel of the X River. Through model calculation, the forecasted water level at the C hydrological station exceeds the flood control water level of 34.4 m and reaches 34.66 m.

[0051] III. Apply the flood detention and retention area activation discrimination module Apply the flood detention and retention area activation discrimination module, and based on the activation information of the A flood detention and retention area input by the user, confirm that the flood detention and retention area is in the activated state.

[0052] IV. Apply the flood detention and retention area topology analysis module Based on the distribution of the intermediate dikes inside the A flood detention and retention area, divide it into independent sections, generate the water level-volume curve, and determine the strong and weak connectivity and directions between the sections.

[0053] Based on the distribution and elevation data of the intermediate dikes in the A flood detention and retention area, divide the A flood detention and retention area into 3 independent sections, the west section, the middle section, and the east section, and independently quantify the water level-volume curve of each section based on the Digital Elevation Model (DEM) data. Among them, the outer boundary dike gate is located in the middle section.

[0054] Apply the flood detention and retention area topology analysis module, combined with the spatial distribution information of the intermediate dike gates inside, and obtain the following connectivity information inside the flood detention and retention area: Strong connectivity: Connectivity under overtopping conditions between the middle section and the east section, and connectivity under overtopping conditions between the middle section and the west section; Connectivity direction: All from the high-water side section to the low-water side section; Weak connectivity: Connectivity through flood diversion at the intermediate dike gate between the middle section and the east section; Connectivity direction: From the high-water side section to the low-water side section.

[0055] V. Coupled application of the main river channel hydrodynamic simulation and forecasting module and the flood detention and retention area section expansion simulation module Couple and apply the main river channel hydrodynamic simulation and forecasting module and the flood detention and retention area partial expansion simulation module: At each calculation time step within the simulation time range from July to August, with the calculation time step being 60 seconds, simultaneously conduct the calculations of the main river channel hydrodynamic simulation module and the flood detention and retention area partial expansion simulation module; among them, for the main river channel hydrodynamic simulation module, obtain the flood diversion flow rate at the sluice of the outer boundary dike of the flood detention and retention area as the lateral outflow.

[0056] For the flood detention and retention area partial expansion simulation module, conduct the outer loop calculation with the user-specified time step of 60 seconds within the simulation time range from July to August; traverse each independent part of the flood detention and retention area to conduct the inner loop calculation; For the current time step and the current part of the flood detention and retention area, the loop body includes the following calculation steps; Judge whether there is an enabled outer boundary dike sluice for this part. If so, apply the sluice hydraulics simulation unit 42 to calculate the flow rate through the outer boundary dike sluice; otherwise, set it to the default value of 0; the calculation result is used as the inflow component of this part. Judge whether there is an electric drainage pump station for this part. 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 result is used as the outflow component of this part. Judge whether the strong connectivity condition of this part is satisfied. If so, apply the levee overtopping simulation unit 44 to calculate the flow rate through the overtopping; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of the part with the higher initial water level at the current time step and the inflow component of the part with the lower initial water level among this part and the adjacent parts at the same time step. Judge whether the sluice flood diversion connectivity in the weak connectivity condition of this part is satisfied. If so, apply the sluice hydraulics simulation unit 42 to calculate the flow rate through the sluice; otherwise, set it to the default value of 0; the calculation result is used as the outflow component of the part with the higher initial water level at the current time step and the inflow component of the part with the lower initial water level among this part and the adjacent parts at the same time step. Conduct storage calculation for this part based on the water balance principle to calculate the storage volume of the part at the end of the time step: , where V 0 is the initial storage volume of the part at the time step, V 1 is the storage volume at the end of the time step of the part, 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 part and the water level - volume curve of the part, use the interpolation method to obtain the water level Z 1 at the end of the time step of the part.

[0057] VI. System application effect Based on the flood detention and retention area activation information input by the system user, a comparison of the predicted flood processes at Hydrological Station C on the main channel of River X before and after the activation of Flood Detention and Retention Area A was carried out, and the application process of the expansion of the distribution of Flood Detention and Retention Area A was investigated. Through comparison, it was found that after the activation of Flood Detention and Retention Area A, the peak flood level at Hydrological Station C dropped to 34.39 m, which is lower than the flood control level of 34.4 m.

[0058] The above-described embodiments of the present invention 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 sectional expansion of flood detention areas, 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 topology analysis module (3) is used to determine the connectivity information and the 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 and 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; 2. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood storage and detention areas according to claim 1, wherein 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 discharge process at the upstream boundary of the basin, the flood discharge process in the main river channel section, and the water level - discharge relationship curve at the downstream boundary, 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, deduct the flood discharge of the outer boundary sluice and breach of the flood detention area beside the main river channel from the main river channel storage, and provide the main river channel water level information to serve the dynamic calculation of the flood discharge of the outer boundary dike breach; For the incoming water at the upstream boundary of the basin and in the main river channel section, if it is the measured flow process, carry out basin flood simulation analysis; if it is the forecast flow process, carry out basin flood forecasting and early warning. Combine the time process of hydraulic elements at the hydrological stations, the warning and guarantee water levels to provide flood over - warning or over - guarantee warning; For carrying out numerical simulation of water flow evolution, if there are sandbars and mid - channel bars 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.

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 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 activated outer boundary dike sluice, flood discharge and timing, and the distribution of the outer boundary dike breach, then determine that the flood detention area is in the activated state; otherwise, turn to the secondary discrimination conditions; The secondary discrimination conditions include: set the flood discharge of the sluice and breach of the flood detention area beside the main river channel to zero, use the main river channel hydrodynamic simulation and forecasting module to obtain the hydraulic elements of the main river channel hydrological stations, and evaluate whether the peak water level or discharge of the flood control station corresponding to the flood detention area exceeds the activation value in the flood detention area design data; if it exceeds, set the flood detention area to the activated state, and the activated sluice and flood discharge are determined according to the flood detention area design data, 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.

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

5. 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 flood storage and detention area 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 overtopping dike simulation unit (44), and a flood storage and detention area part 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 storage and detention area part regulation and calculation; according to the operation and management regulations of each electric drainage pump station in the flood storage and detention area, the designed drainage flow under different water level conditions is clarified; in a time step of the flood storage and detention area part regulation and calculation, from the storage volume of the part where the pump station is located, according to the designed drainage flow of the pump station corresponding to the part water level multiplied by the time step length, the part storage volume is deducted; then a calculation rationality check is carried out: if the part storage volume is less than zero, it is forced to be assigned zero, and at the same time, the current time step pump station drainage flow is updated. The sluice gate hydraulics simulation unit (42) is used to quantitatively reflect the flow - passing effect of the enabled outer boundary dike sluice gates and internal dike sluice gates in the flood storage and detention area part regulation and calculation. The breach development simulation unit (43) is used to quantitatively reflect the development process and flow - passing effect of the outer boundary dike breach and internal dike breach in the flood storage and detention area part regulation and calculation. The overtopping dike simulation unit (44) is used to quantitatively reflect the flow - passing effect of overtopping dikes in the flood storage and detention area part regulation and calculation; in a time step of the flood storage and detention area part regulation and calculation, combined with the water levels of the two parts on both sides of the dike, it is judged whether the water level of the high - side part exceeds the dike elevation. If it exceeds, the overtopping dike simulation is carried out. The flood storage and detention area part expansion simulation unit (45) is used to incorporate the new parts involved in the continuous propagation of the stored water volume after the flood storage and detention area is enabled into the calculation domain, realize the simulation of the step - by - step expansion process of the flood storage and detention area, and provide the storage volume and water level process of each part. According to the initial storage volume and water level of each part 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 part of the flood storage and detention area is traversed to carry out an inner - loop calculation.

6. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 5, characterized in that, The sluice gate hydraulics simulation unit (42) is used to perform the following calculations: For each gate of the outer boundary levee that is activated in the flood storage and detention area, in a time step of the partial 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 gate flow rate is zero, otherwise the gate flow rate is the flood diversion flow rate input by the user; then the calculation rationality check is carried out: if the total storage capacity of the flood storage and detention area at the end of the time step exceeds the design capacity of the flood storage and detention area, the gate flow rate at the current time step is updated with the total storage capacity increasing to the design capacity; For each activated inter-dike gate in the flood storage and detention area, the gate engineering dimensions, the number of gates to be opened and the degree of opening under different water level conditions are clearly defined according to the gate operation management regulations; in a time step of the partial storage calculation of the flood storage and detention area, combined with the water levels of the branches on both sides of the internal inter-dike, it is determined whether the outflow at the inter-dike gate in the current time step is a free outflow or a submerged outflow, and the gate flow rate is calculated using the gate hole flow formula, the outflow flow rate is deducted from the storage of the branch on the high water level side multiplied by the time step length, and the flow rate is merged into the storage of the branch on the low water level; then a calculation rationality check is carried out: if the branch on the high side with a lower water level at the beginning of the time step is lower than the water level at the end of the time step, the water levels of the branches on both sides are limited to be flush, and the outflow flow at the gate in the current time step is updated.

7. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood storage and detention areas according to claim 5, characterized in that, The breach development simulation unit (43) is used to perform the following calculations: In a time step of partial storage and regulation calculation in the flood storage area, the development process of the outer boundary levee breach and the internal intermediate levee breach specified by the system user is simulated, and the simulation control equation is: = ， = ； Among them, B is the breach width; H is the breach depth; is the breach width B evolution and breach width B , breach depth H , breach flow velocity v , high-side water levels upstream and downstream of the breach Z us , low-side water level Z ds quantitative relationships; is the breach depth H evolution and breach width B , breach depth H , breach flow velocity v , high-side water levels upstream and downstream of the breach Z us , low-side water level Z ds quantitative relationships; The quantitative relationships are 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, at one time step of the flood storage and detention area's distributed regulation and routing calculation, based on the breach width B and breach depth H at the current time step, combined with the distributed water levels on both sides of the internal dike, determine whether the breach flow at the current time step is free outflow or submerged outflow, calculate the breach flow rate using the sluice orifice flow formula, deduct the product of the flow rate and the time step length from the storage volume of the higher water level side, and add it to the storage volume of the lower water level side; then conduct a rationality check on the calculation: 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, then limit the water levels on both sides to be equal, and at the same time update the breach flow rate at the current time step.

8. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 5, characterized in that The inter-bank and overbank simulation unit (44) is used to perform the following calculations: 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.

9. The basin flood forecasting system for intelligent water conservancy based on the expansion of flood detention and storage areas according to claim 5, characterized in that The flood storage and detention area expansion simulation unit (45) is a loop body for performing the following calculations for the current time step and the current flood storage and detention area section: Determine whether there is an enabled outer boundary levee gate or a designated outer boundary levee breach in the branch. If so, use the gate hydraulic simulation unit (42) and the breach development simulation unit (43) to calculate the flow rate of the outer boundary levee gate and breach respectively; otherwise, set the default value to 0; the calculation result is used as the inflow component of the branch; Determine whether there is an electric drainage pump station in the branch. If yes, use the electric drainage pump station simulation unit (41) to calculate the drainage flow of the pump station; otherwise, set the default value to 0; the calculation result is used as the outflow component of the branch; Determine whether the strong connectivity condition of the branch is satisfied. If so, use the inter-bank overbank simulation unit (44) to calculate the overbank flow rate. Otherwise, set the default value to 0. The calculation result is used as the outflow component of the branch with a higher initial water level in the time step and the inflow component of the branch with a lower initial water level in the time step in the adjacent branches. 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 simultaneously 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 among this sub - section and the adjacent sub - sections; 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 simultaneously 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 among this sub - section and the adjacent sub - sections; 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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