An ecological management method and system for flood disaster prevention and control in coastal cities

Abstract

The present application relates to the technical field of ecological governance, and in particular to an ecological governance method and system for flood disaster prevention and control in coastal cities. An ecological governance method for flood disaster prevention and control in coastal cities, including determining the optimal layout location of an ecological depression and constructing an ecological depression; monitoring the water level information and rainfall information of the ecological depression through a water level sensor and a rainfall sensor respectively, analyzing the water level information and rainfall information in real time and automatically adjusting the opening state of an adjustable drain outlet, specifically including: performing data processing on the water level information and rainfall information to obtain the current water level height and the current average rainfall intensity of the ecological depression as two independent variable inputs of a logistic regression model; using a logistic regression model, a likelihood function and a gradient descent method to determine the opening state of an adjustable drain outlet, and being able to automatically adjust the drainage strategy according to real-time environmental changes.

Description

Technical Field

[0001] The present application relates to the technical field of ecological management, and in particular to an ecological management method and system for preventing and controlling flooding disasters in coastal cities. Background Art

[0002] In traditional urban drainage systems, hard drains and pipes are usually used to quickly drain rainwater and surface water. Although these systems are effective in the short term, they are often unable to quickly handle large amounts of water in extreme weather such as heavy rains and tides, causing urban flooding. Due to the special geographical location, coastal cities are more susceptible to rising sea levels and tidal changes, exacerbating flooding problems. In addition, hard drainage facilities have a significant negative impact on the urban environment and ecosystem, such as destroying natural landscapes, reducing green space, and reducing biodiversity.

[0003] In recent years, ecological engineering has gradually gained attention, including the use of natural ecosystems to manage and treat urban stormwater. As an ecological engineering measure, ecological swales can temporarily store water and promote natural infiltration, which helps reduce runoff and improve groundwater recharge. However, existing ecological swale systems often lack intelligent management and regulation capabilities and cannot automatically adjust drainage strategies according to real-time environmental changes. Summary of the invention

[0004] In order to automatically adjust the drainage strategy according to real-time environmental changes, the present application provides an ecological management method and system for flood disaster prevention and control in coastal cities.

[0005] On the first aspect, the present application provides an ecological management method for preventing and controlling flooding disasters in coastal cities.

[0006] An ecological management method for flood disaster prevention and control in coastal cities, comprising:

[0007] Determine the best layout location for ecological swales and build them;

[0008] The water level information and rainfall information of the ecological depression are monitored by water level sensors and rainfall sensors respectively, and the water level information and rainfall information are analyzed in real time to automatically adjust the opening state of the adjustable drain outlet, including:

[0009] The water level information and rainfall information were processed to obtain the current water level height and the current average rainfall intensity of the ecological depression as two independent variable inputs of the logistic regression model;

[0010] The logistic regression model, likelihood function and gradient descent method are used to determine the opening state of the adjustable drain outlet, including:

[0011] Build a logistic regression model:

[0012] Z=β0+β1θ1+β2θ2

[0013] P(Y=1|X)=1 / (1+e -z )

[0014] Among them, Z represents the sum of the linear weight values ​​after the water level and the average rainfall intensity are superimposed, β0, β1, and β2 represent the logistic regression coefficients of the sample, and the initialization values ​​of the logistic regression coefficients β0, β1, and β2 are randomly set, θ1 represents the current water level, θ2 represents the average rainfall intensity, P(Y=1|X) represents the probability that Y is 1 when X is given, X is the characteristic vector of the sample, and Y is the characteristic value corresponding to the opening state of the adjustable drain outlet, 0≤P≤1, Y=1 indicates that the adjustable drain outlet is fully open, and Y=0 indicates that the adjustable drain outlet is fully closed;

[0015] The characteristic values ​​of historical water level height, historical average rainfall intensity and corresponding opening state are collected as samples, and the samples contain n groups of data. The samples are input into the logistic regression model, and the logistic regression coefficient of the logistic regression model is corrected by using the likelihood function and log-likelihood function.

[0016] Construct the likelihood function L(β):

[0017]

[0018] Where n represents the sample size, Y i represents the characteristic value corresponding to the opening state of the adjustable drain corresponding to the i-th group of data in the sample, X i Represents the characteristic vector of the i-th group of data in the sample; P(Y i =1|X i ) represents a given feature vector X i The eigenvalue Y is obtained when i =1, if Y i is 1, then the output P(Y i =1|X i ), otherwise output 1-P(Y i =1|X i );β is the logistic regression coefficient, and β∈β0,β1,β2;

[0019] The likelihood function L(β) is used to measure the matching degree between the opening state of the adjustable drain outlet and the water level height and the average rainfall intensity. The likelihood function L(β) is taken logarithmically to obtain the logarithmic likelihood function l(β). The formula of the logarithmic likelihood function l(β) is:

[0020]

[0021] in, Indicates that when the eigenvalue Yi =1, the value is 1, otherwise it is 0; Indicates that when the eigenvalue Y i =0, the value is 0, otherwise it is 1;

[0022] Use the log-likelihood function l(β) to output the logistic regression coefficient β m,j , β m,j is the logistic regression coefficient of the mth eigenvector at the jth iteration, and the logistic regression coefficient of the logistic regression model is determined by the gradient descent method;

[0023]

[0024] Among them, j represents the number of iterations, α represents the learning rate, and y i represents the actual eigenvalue corresponding to the i-th group of data, z i represents the sum of the linear weight values ​​after the superposition of the water level height and the average rainfall intensity of the i-th group, x im Represents the mth eigenvector of the i-th group of data in the sample;

[0025] Until the converged logistic regression coefficients β0, β1, β2 are output and substituted into the logistic regression model to obtain a converged logistic regression model;

[0026] The current water level and the current average rainfall intensity are input into the convergent logistic regression model, the probability P1 corresponding to the current adjustable drain outlet and the eigenvalue Y1 corresponding to the probability P1 are calculated, and the opening of the adjustable drain outlet is adjusted according to the probability P1 and the eigenvalue Y1.

[0027] Optionally, an ecological management method for preventing and controlling flooding disasters in coastal cities further includes:

[0028] Design the ecological depression into a concave or funnel shape;

[0029] Local water-resistant plants are planted in the ecological depression, shrubs or small trees are planted on the edge of the ecological depression, and herbaceous plants are planted in the central area of ​​the ecological depression.

[0030] Optionally, determining the optimal layout position of the ecological depression and constructing the ecological depression includes:

[0031] Use drone-mounted cameras and / or lidar to obtain terrain elevation data of flood-prone areas in coastal cities;

[0032] Convert terrain elevation data into 3D point cloud data;

[0033] Generate digital elevation model data from 3D point cloud data to obtain 3D topographic maps of flood-prone areas;

[0034] Obtain meteorological data, and determine and construct ecological depressions through meteorological data and three-dimensional topographic maps, including:

[0035] Based on the digital elevation model data, the slope of the flood-prone area is calculated by the difference method to obtain a three-dimensional topographic map of the flood-prone area in the coastal city, and to identify low-lying areas, slope changes and potential water flow paths, so as to determine the optimal layout location of the ecological depression. The calculation formula is as follows:

[0036]

[0037]

[0038] Where k represents the slope of the flood-prone area, z1 represents the elevation value of one point in the digital elevation model data, z2 represents the elevation value of another point in the digital elevation model data, z1-z2 represents the elevation difference between adjacent points, d represents the horizontal distance between adjacent points, and Δr represents the slope between adjacent points;

[0039] The soil permeability coefficient formula is used to evaluate the soil permeability and water retention capacity. After calculating the soil permeability coefficient, the soil type suitable for water storage and infiltration is selected and laid on the ecological depression. The soil permeability coefficient calculation formula is as follows:

[0040]

[0041] Among them, K represents the permeability coefficient of the soil, Q represents the amount of infiltrated water, L represents the length of the infiltration path, A represents the infiltration area, t represents the infiltration time, and H represents the water head difference;

[0042] Calculate the water storage capacity and drainage rate of the bio-swale to ensure the bio-swale operates properly under extreme weather conditions;

[0043] The water storage capacity of the ecological depression is calculated as follows:

[0044] V=a*h

[0045] Among them, V represents the water storage capacity of the ecological depression, a represents the area of ​​the ecological depression, and h represents the average depth of the ecological depression;

[0046] The calculation formula for the drainage rate of the ecological depression is as follows:

[0047]

[0048] Among them, v represents the drainage rate of the ecological depression, V1 represents the drainage volume of the ecological depression, and T represents the drainage time of the ecological depression.

[0049] Optionally, an ecological management method for preventing and controlling flooding disasters in coastal cities further includes:

[0050] Regularly calibrate water level sensors and rainfall sensors;

[0051] Regularly clean up the debris in the ecological depression and manage the local water-resistant plants, shrubs, small trees and herbaceous plants in the ecological depression.

[0052] On the second aspect, the present application provides an ecological management system for preventing and controlling flood disasters in coastal cities.

[0053] An ecological management system for flood disaster prevention and control in coastal cities, applied to an ecological management method for flood disaster prevention and control in coastal cities as described in the first aspect, comprising: an ecological depression, a local control unit, a water level sensor installed in the ecological depression, a rainfall sensor, a control valve and an adjustable drain outlet, the local control unit is connected to the water level sensor, the rainfall sensor and the control valve respectively, the control valve is installed on the adjustable drain outlet, and the adjustable drain outlet is connected to the urban drainage network;

[0054] The local control unit is used to obtain water level information and rainfall information, and control the control valve based on the water level information and rainfall information to determine the opening state of the adjustable drain outlet.

[0055] Optionally, an ecological management system for flood disaster prevention and control in coastal cities also includes a central data server, and the local control unit is communicatively connected to the central data server. The central data server has data processing and analysis functions and can generate and display data reports.

[0056] In summary, this application at least includes the following beneficial technical effects:

[0057] 1. An ecological management system for flood disaster prevention and control in coastal cities includes ecological depressions, local control units, water level sensors, rainfall sensors, control valves and adjustable drains. These components work together to achieve effective collection, storage and intelligent discharge of rainwater in key urban areas, reduce human intervention, and can automatically adjust drainage strategies according to real-time environmental changes, thereby ensuring that coastal cities can effectively prevent flood disasters when facing extreme weather events. At the same time, the system not only integrates the concept of ecological engineering, but also introduces intelligent control technology, which optimizes drainage efficiency through real-time monitoring and automatic adjustment, while maintaining ecological friendliness and urban aesthetics.

[0058] 2. The central data server has data processing and analysis functions, and can generate reports based on the collected data to provide decision support for the prevention and response of flood disasters in coastal cities. In addition, the central data server can also display real-time monitoring data and historical data analysis results through the user interface, which is convenient for operators to monitor and manage.

[0059] 3. The vegetation planting strategy for the ecological depression can ensure water retention and natural infiltration in the ecological depression. These plants can not only absorb more water, but also strengthen the soil structure and improve the soil's resistance to erosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a flowchart of an ecological management method for preventing and controlling flooding disasters in coastal cities in an embodiment of the present application.

[0061] Figure 2 This is a control principle diagram of an ecological management system for preventing and controlling flooding disasters in coastal cities in an embodiment of the present application.

[0062] Explanation of the reference numerals: 1. Local control unit; 2. Water level sensor; 3. Rainfall sensor; 4. Control valve; 5. Adjustable drain outlet; 6. Central data server. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0064] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to be used as limitations to the present application. As used in the specification and the appended claims of the present application, the singular expressions "one", "a kind of", "said", "above", "the" and "this" are intended to also include plural expressions, unless there is a clear contrary indication in its context. It should also be understood that the term "and / or" used in the present application refers to and includes any or all possible combinations of one or more listed items. The term "exemplary" means "used as an example, embodiment or illustrative", and any embodiment described as "exemplary" here does not need to be interpreted as being superior to or better than other embodiments. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as implying or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can expressly or implicitly include one or more of these features, and in the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0065] In a first aspect, an embodiment of the present application provides an ecological management method for preventing and controlling flooding disasters in coastal cities.

[0066] refer to Figure 1 , an ecological management method for flood disaster prevention and control in coastal cities, comprising the following steps:

[0067] S102: Determine the optimal layout location of the ecological depression and construct the ecological depression.

[0068] A detailed assessment of the topographic conditions in areas with high risk of urban flooding is conducted to determine the best layout location for ecological depressions before they are constructed. Generally speaking, ecological depressions are located in areas with high risk of urban flooding, such as low-lying areas, densely built areas, or areas with weak infrastructure.

[0069] The design should take full account of the terrain and drainage requirements, determine the best location and shape of the depression through terrain surveys, and use the advantages of natural terrain to achieve the natural collection and flow of rainwater. When evaluating the location of an ecological depression, a series of key geographical and environmental data needs to be collected and analyzed, mainly including terrain elevation data, soil type, rainfall data, surface runoff, the effectiveness of the existing drainage system, and vegetation coverage.

[0070] First, high-precision cameras and / or lidars carried by drones are used to obtain terrain elevation data of flood-prone areas in coastal cities. Then, the terrain elevation data (i.e., images) taken by the drones are converted into three-dimensional point cloud maps through photogrammetry technology. Point cloud processing software is then used to filter, denoise, and interpolate the point cloud to generate a high-precision digital elevation model (DEM), thereby obtaining a three-dimensional topographic map of flood-prone areas in coastal cities, identifying low-lying areas, slope changes, and potential water flow paths, and determining the optimal layout location of ecological depressions to ensure that they can effectively collect and store rainwater while reducing pressure on existing drainage systems.

[0071] Specifically, based on the digital elevation model data, the slope of the flood-prone area is calculated by the difference method. The calculation formula is as follows:

[0072]

[0073]

[0074] Among them, k represents the slope of the area prone to flooding disasters, z1 represents the elevation value of one point in the digital elevation model data, z2 represents the elevation value of another point in the digital elevation model data, z1-z2 represents the elevation difference between adjacent points, d represents the horizontal distance between adjacent points, and Δr represents the slope between adjacent points.

[0075] Afterwards, the soil permeability and water retention capacity are evaluated by the soil permeability coefficient formula. After calculating the soil permeability coefficient, the soil type suitable for water storage and infiltration is selected and laid on the ecological depression. The soil permeability coefficient calculation formula is as follows:

[0076]

[0077] Among them, K represents the permeability coefficient of the soil, Q represents the amount of infiltrated water, L represents the length of the infiltration path, A represents the infiltration area, t represents the infiltration time, and H represents the water head difference.

[0078] Afterwards, the water storage capacity and drainage rate of the eco-swale were calculated to ensure the proper functioning of the eco-swale under extreme weather conditions.

[0079] The water storage capacity of the ecological depression is calculated as follows:

[0080] V=a*h

[0081] Among them, V represents the water storage capacity of the ecological depression, a represents the area of ​​the ecological depression, and h represents the average depth of the ecological depression;

[0082] The calculation formula for the drainage rate of the ecological depression is as follows:

[0083]

[0084] Among them, v represents the drainage rate of the ecological depression, V1 represents the drainage volume of the ecological depression, and T represents the drainage time of the ecological depression.

[0085] S104: respectively monitoring the water level information and rainfall information of the ecological depression through the water level sensor and the rainfall sensor, analyzing the water level information and the rainfall information in real time, and automatically adjusting the opening state of the adjustable drain outlet.

[0086] First, the water level sensor 2 obtains the water level information of the ecological depression and sends the water level information to the local control unit 1. The rainfall sensor 3 obtains the rainfall information of the ecological depression and sends the rainfall information to the local control unit 1. After that, the local control unit 1 can obtain the water level information and rainfall information. After the local control unit 1 obtains the water level information and rainfall information, the original current water level height and the original average rainfall intensity can be obtained.

[0087] First, the local control unit 1 is used to clean the original current water level and the original average rainfall intensity. Data cleaning includes removing noise and outliers. Noise removal means that the original current water level and the original average rainfall intensity may contain noise due to sensor failure, environmental interference and other factors. If a water level reading suddenly jumps to an unreasonable high value (such as from 0.5m to 5m), it is considered to be noise. The local control unit 1 needs to identify and eliminate such abnormal readings and use the sliding average filter method to smooth the data. The removal of outliers is caused by extreme weather events or sensor damage, and is replaced by the average of the previous and next values. For example, when counting the average rainfall intensity in the past hour, if a reading is as high as 1000mm / h, it should be regarded as an outlier and processed.

[0088] After data cleaning, normalization is performed. Normalization helps improve the convergence speed and performance of the logistic regression model. For water level data, it is assumed that the maximum value of the water level data is 2m (the value is determined based on the previous maximum water level) and the minimum value is 0m. Taking the water level reading of 0.3m as an example, the normalized value is (0.3-0) / (1-0)=0.3. For rainfall intensity data, the maximum value is based on the maximum value in the past records, and the normalization method is similar to that of water level data.

[0089] After the local control unit 1 performs the above data processing on the original current water level and the original average rainfall intensity, the current water level and the current average rainfall intensity of the ecological depression can be obtained as two independent variable inputs of the logistic regression model.

[0090] Through the above detailed data cleaning, conversion and normalization processing steps, the system can ensure the accuracy of the current water level height and average rainfall intensity input into the logistic regression model, thereby improving the accuracy and efficiency of logistic regression model training and prediction.

[0091] Then, the opening state of the adjustable drain outlet 5 is determined by using a logistic regression model, a likelihood function and a gradient descent method, specifically including:

[0092] Build a logistic regression model:

[0093] Z=β0+β1θ1+β2θ2

[0094] P(Y=1|X)=1 / (1+e -z )

[0095] Wherein, Z represents the sum of the linear weight values ​​after the water level and the average rainfall intensity are superimposed, β0, β1, and β2 represent the logistic regression coefficients of the sample, and the initialization values ​​of the logistic regression coefficients β0, β1, and β2 are randomly set, θ1 represents the current water level, θ2 represents the average rainfall intensity, P(Y=1|X) represents the probability that Y is 1 given X, X is the characteristic vector of the sample, and Y is the characteristic value corresponding to the opening state of the adjustable drain outlet 5, 0≤P≤1, Y=1 indicates that the adjustable drain outlet 5 is fully opened, and Y=0 indicates that the adjustable drain outlet 5 is fully closed;

[0096] The characteristic values ​​of historical water level height, historical average rainfall intensity and corresponding opening state are collected as samples, and the samples contain n groups of data. The samples are input into the logistic regression model, and the logistic regression coefficient of the logistic regression model is corrected by using the likelihood function and log-likelihood function.

[0097] Construct the likelihood function L(β):

[0098]

[0099] Where n represents the sample size, Y i represents the characteristic value corresponding to the opening state of the adjustable drain outlet 5 corresponding to the i-th group of data in the sample, X i Represents the characteristic vector of the i-th group of data in the sample; P(Y i =1|X i ) represents a given feature vector X i The eigenvalue Y is obtained when i =1, if Y i is 1, then the output P(Y i =1|X i ), otherwise output 1-P(Y i =1|X i );β is the logistic regression coefficient, and β∈β0,β1,β2;

[0100] The likelihood function L(β) is used to measure the matching degree between the opening state of the adjustable drain outlet 5 and the water level height and the average rainfall intensity. The likelihood function L(β) is logarithmically taken to obtain the logarithmic likelihood function l(β). The formula of the logarithmic likelihood function l(β) is:

[0101]

[0102] in, Indicates that when the eigenvalue Y i =1, the value is 1, otherwise it is 0; Indicates that when the eigenvalue Y i =0, the value is 0, otherwise it is 1;

[0103] Use the log-likelihood function l(β) to output the logistic regression coefficient β m,j , β m,j is the logistic regression coefficient of the mth eigenvector at the jth iteration, and the logistic regression coefficient of the logistic regression model is determined by the gradient descent method;

[0104]

[0105] Among them, j represents the number of iterations, α represents the learning rate, and y i represents the actual eigenvalue corresponding to the i-th group of data, z i represents the sum of the linear weight values ​​after the superposition of the water level height and the average rainfall intensity of the i-th group, x im Represents the mth eigenvector of the i-th group of data in the sample;

[0106] Until the converged logistic regression coefficients β0, β1, and β2 are output, and substituted into the logistic regression model, a converged logistic regression model is obtained. Specifically, when the loss function value is less than 0.01, it is considered that the convergence condition is met.

[0107] The current water level and the current average rainfall intensity are input into the convergent logistic regression model, the probability P1 corresponding to the current adjustable drain outlet 5 and the eigenvalue Y1 corresponding to the probability P1 are calculated, and the opening of the adjustable drain outlet 5 is adjusted according to the probability P1 and the eigenvalue Y1.

[0108] In layman's terms, the logistic regression model is trained using the historical water level, the historical average rainfall intensity and the corresponding opening of the adjustable drain 5 as the training set. The model parameters are continuously adjusted through the gradient descent algorithm to minimize the loss function. The goal is to learn a decision boundary that divides the data into two categories: "open the adjustable drain valve" and "close the adjustable drain valve".

[0109] During the real-time prediction process, if the predicted state of the adjustable drain outlet 5 is inconsistent with the current actual state, a control signal is sent to the system, and the local control unit 1 then performs the corresponding operation of opening or closing the adjustable drain outlet 5, that is, re-controlling the control valve 4.

[0110] At the same time, the local control unit 1 can also record the predicted results and actual execution status of each drainage operation to form feedback data, and regularly evaluate the performance of the logistic regression model. If it is found that the prediction accuracy has decreased, the new feedback data and new historical data are used to retrain the logistic regression model, and the model version in the local control unit 1 is updated.

[0111] In an optional embodiment of the present application, an ecological management method for flood disaster prevention in coastal cities also includes designing the ecological depression into a concave or funnel shape. Since the bottom of the concave or funnel shape is low, the natural terrain can be used to promote rainwater collection, and the water storage capacity of the ecological depression can be increased, thereby reducing surface runoff and reducing the risk of flooding in coastal cities, while facilitating the discharge of rainwater from the adjustable drain port 5.

[0112] In an optional embodiment of the present application, an ecological management method for flood disaster prevention and control in coastal cities also includes planting plants in ecological depressions. Specifically, local water-resistant plants are planted inside the ecological depression, taller plants such as shrubs or small trees are planted on the edges, and herbaceous plants such as grasses or low flowering plants are planted in the central area. The porosity of the soil is increased by the root system of plants, thereby improving permeability. The edges of tall plants form a barrier, which reduces the speed of water flow, prolongs the residence time of water in the soil, and promotes water infiltration. Herbaceous plants effectively improve the water storage capacity due to their dense root system and high water absorption, and together they enhance the natural infiltration and water storage efficiency of the ecological depression.

[0113] In an optional embodiment of the present application, an ecological management method for preventing and controlling flooding disasters in coastal cities also includes regularly calibrating the water level sensor 2 and the rainfall sensor 3 to ensure that the collected data has high accuracy and reliability, thereby reducing the impact of errors on drainage decisions.

[0114] In an optional implementation of the present application, an ecological management method for flood disaster prevention and control in coastal cities also includes: regularly cleaning up debris in ecological depressions, and managing local water-resistant plants, tall plants, and herbaceous plants in ecological depressions. Specifically, formulate and implement regular inspection and maintenance plans, such as establishing a debris cleaning procedure, regularly removing fallen leaves, garbage, and other debris that may affect drainage in ecological depressions; formulate a vegetation management plan, including pruning, fertilizing, and pest and disease control, to maintain healthy growth and optimal functional status of plants.

[0115] This embodiment also provides an ecological management system for preventing and controlling flood disasters in coastal cities.

[0116] refer to Figure 2 An ecological management system for flood disaster prevention and control in coastal cities includes: an ecological depression, a local control unit 1, a water level sensor 2 installed in the ecological depression, a rainfall sensor 3, a control valve 4 and an adjustable drain outlet 5.

[0117] The local control unit 1 is respectively connected to the water level sensor 2, the rainfall sensor 3 and the control valve 4. The control valve 4 is installed on the adjustable drain outlet 5. The adjustable drain outlet 5 is connected to the urban drainage network. When the water storage capacity of the ecological depression is exceeded, the water will gradually be discharged into the urban drainage network.

[0118] The local control unit 1 is used to obtain water level information and rainfall information, and control the control valve 4 based on the water level information and rainfall information to determine the opening of the adjustable drain outlet 5, thereby automatically adjusting the drainage strategy according to real-time environmental changes.

[0119] The adjustable drain port 5 is made of corrosion-resistant material to extend its service life, and has a structure to prevent backflow to ensure that no sewage will flow back to the ecological depression during the drainage process. The control valve 4 is a mechanical device connected to the adjustable drain port 5, which can adjust the adjustable drain port 5 according to the rainfall intensity and rainfall amount to control the drainage amount.

[0120] In an optional embodiment of the present application, an ecological management system for flood disaster prevention and control in coastal cities also includes a central data server 6. The local control unit 1 is communicatively connected to the central data server 6. The central data server 6 has data processing and analysis functions and can generate and display data reports.

[0121] The various variations and specific examples in the methods provided in the above embodiments are also applicable to an ecological management system for flood disaster prevention and control in coastal cities in the present embodiment. Through the above detailed description of an ecological management method for flood disaster prevention and control in coastal cities, technical personnel in this field can clearly know the implementation method of an ecological management system for flood disaster prevention and control in coastal cities in the present embodiment. For the sake of brevity of the specification, it will not be described in detail here.

[0122] As described above, the above embodiments are only used to introduce the technical solution of the present application in detail, but the description of the above embodiments is only used to help understand the method and core idea of ​​the present application and should not be understood as limiting the present application. Any changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. An ecological management method for flood disaster prevention and control in coastal cities, characterized in that: include: Determine the best layout location for ecological swales and build them; The water level information and rainfall information of the ecological depression are respectively monitored by a water level sensor (2) and a rainfall sensor (3), the water level information and rainfall information are analyzed in real time, and the opening state of the adjustable drain outlet (5) is automatically adjusted, specifically including: The water level information and rainfall information were processed to obtain the current water level height and the current average rainfall intensity of the ecological depression as two independent variable inputs of the logistic regression model; The opening state of the adjustable drain outlet (5) is determined by using a logistic regression model, a likelihood function and a gradient descent method, specifically including: Build a logistic regression model: Z=β0+β1θ1+β2θ2 P(Y=1|X)=1 / (1+e -z ) Wherein, Z represents the sum of the linear weight values ​​after the water level and the average rainfall intensity are superimposed, β0, β1, and β2 represent the logistic regression coefficients of the sample, and the initialization values ​​of the logistic regression coefficients β0, β1, and β2 are randomly set, θ1 represents the current water level, θ2 represents the average rainfall intensity, P(Y=1|X) represents the probability that Y is 1 given X, X is the characteristic vector of the sample, and Y is the characteristic value corresponding to the opening state of the adjustable drain (5), 0≤P≤1, Y=1 represents that the adjustable drain (5) is fully opened, and Y=0 represents that the adjustable drain (5) is fully closed; The characteristic values ​​of historical water level height, historical average rainfall intensity and corresponding opening state are collected as samples, and the samples contain n groups of data. The samples are input into the logistic regression model, and the logistic regression coefficient of the logistic regression model is corrected by using the likelihood function and log-likelihood function. Construct the likelihood function L(β): Where n represents the sample size, Y i represents the characteristic value corresponding to the opening state of the adjustable drain outlet (5) corresponding to the i-th group of data in the sample, X i Represents the characteristic vector of the i-th group of data in the sample; P(Y i =1|X i ) represents a given feature vector X i The eigenvalue Y is obtained when i =1, if Y i is 1, then the output P(Y i =1|X i ), otherwise output 1-P(Y i =1|X i );β is the logistic regression coefficient, and β∈β0,β1,β2; The likelihood function L(β) is used to measure the matching degree between the opening state of the adjustable drain outlet (5) and the water level height and the average rainfall intensity. The likelihood function L(β) is logarithmically calculated to obtain the logarithmic likelihood function l(β). The formula of the logarithmic likelihood function l(β) is: in, Indicates that when the eigenvalue Y i =1, the value is 1, otherwise it is 0; Indicates that when the eigenvalue Y i =0, the value is 0, otherwise it is 1; Use the log-likelihood function l(β) to output the logistic regression coefficient β m,j , β m,j is the logistic regression coefficient of the mth eigenvector at the jth iteration, and the logistic regression coefficient of the logistic regression model is determined by the gradient descent method; Among them, j represents the number of iterations, α represents the learning rate, and y i represents the actual eigenvalue corresponding to the i-th group of data, z i represents the sum of the linear weight values ​​after the superposition of the water level height and the average rainfall intensity of the i-th group, x im Represents the mth eigenvector of the i-th group of data in the sample; Until the converged logistic regression coefficients β0, β1, β2 are output and substituted into the logistic regression model to obtain a converged logistic regression model; The current water level and the current average rainfall intensity are input into a convergent logistic regression model, the probability P1 corresponding to the current adjustable drain outlet (5) and the eigenvalue Y1 corresponding to the probability P1 are calculated, and the opening of the adjustable drain outlet (5) is adjusted according to the probability P1 and the eigenvalue Y1.

2. The ecological management method for flood disaster prevention and control in coastal cities as claimed in claim 1, characterized in that: Also includes: Design the ecological depression into a concave or funnel shape; Local water-resistant plants are planted in the ecological depression, shrubs or small trees are planted on the edge of the ecological depression, and herbaceous plants are planted in the central area of ​​the ecological depression.

3. The ecological management method for flood disaster prevention and control in coastal cities as claimed in claim 1, characterized in that: Determining the optimal layout location of the ecological depression and constructing the ecological depression includes: Use drone-mounted cameras and / or lidar to obtain terrain elevation data of flood-prone areas in coastal cities; Convert terrain elevation data into 3D point cloud data; Generate digital elevation model data from 3D point cloud data to obtain 3D topographic maps of flood-prone areas; Obtain meteorological data, and determine and construct ecological depressions through meteorological data and three-dimensional topographic maps, including: Based on the digital elevation model data, the slope of the flood-prone area is calculated by the difference method to obtain a three-dimensional topographic map of the flood-prone area in the coastal city, and to identify low-lying areas, slope changes and potential water flow paths, so as to determine the optimal layout location of the ecological depression. The calculation formula is as follows: Where k represents the slope of the flood-prone area, z1 represents the elevation value of one point in the digital elevation model data, z2 represents the elevation value of another point in the digital elevation model data, z2-z1 represents the elevation difference between adjacent points, d represents the horizontal distance between adjacent points, and Δr represents the slope between adjacent points; The soil permeability coefficient formula is used to evaluate the soil permeability and water retention capacity. After calculating the soil permeability coefficient, the soil type suitable for water storage and infiltration is selected and laid on the ecological depression. The soil permeability coefficient calculation formula is as follows: Among them, K represents the permeability coefficient of the soil, Q represents the amount of infiltrated water, L represents the length of the infiltration path, A represents the infiltration area, t represents the infiltration time, and H represents the water head difference; Calculate the water storage capacity and drainage rate of the bio-swale to ensure the bio-swale operates properly under extreme weather conditions; The water storage capacity of the ecological depression is calculated as follows: V=a*h Among them, V represents the water storage capacity of the ecological depression, a represents the area of ​​the ecological depression, and h represents the average depth of the ecological depression; The calculation formula for the drainage rate of the ecological depression is as follows: Among them, v represents the drainage rate of the ecological depression, V1 represents the drainage volume of the ecological depression, and T represents the drainage time of the ecological depression.

4. The ecological management method for flood disaster prevention and control in coastal cities as claimed in claim 2, characterized in that: Also includes: Regularly calibrate the water level sensor (2) and rainfall sensor (3); Regularly clean up the debris in the ecological depression and manage the local water-resistant plants, shrubs, small trees and herbaceous plants in the ecological depression.

5. An ecological management system for flood disaster prevention and control in coastal cities, applied to an ecological management method for flood disaster prevention and control in coastal cities as described in any one of claims 1 to 4, characterized in that: include: An ecological depression, a local control unit (1), a water level sensor (2) installed in the ecological depression, a rainfall sensor (3), a control valve (4) and an adjustable drain outlet (5), wherein the local control unit (1) is connected to the water level sensor (2), the rainfall sensor (3) and the control valve (4) respectively, the control valve (4) is installed on the adjustable drain outlet (5), and the adjustable drain outlet (5) is connected to an urban drainage network; The local control unit (1) is used to obtain water level information and rainfall information, and to control the control valve (4) based on the water level information and rainfall information to determine the opening state of the adjustable drain outlet (5).

6. The ecological management system for flood disaster prevention and control in coastal cities as claimed in claim 5 is characterized in that: It also includes a central data server (6). The local control unit (1) is in communication connection with the central data server (6). The central data server (6) has data processing and analysis functions and can generate and display data reports.

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