Underground water pollution tracing method and system based on sewage pipeline data

Abstract

The invention relates to the technical field of pollution tracing, in particular to an underground water pollution tracing method and system based on sewage pipeline data, and the method comprises the steps: obtaining the water flow and mineral dissolution content of a monitoring well; acquiring all suspected downstream monitoring wells of each monitoring well; analyzing the fluctuation similarity of the water flow and combining with the mineral dissolution content to obtain a plurality of monitoring wells contained in each underground river reach; the intersection condition of the underground river reach is analyzed to obtain a plurality of tide suspected communication points and a plurality of marked wells thereof; the high water flow date of each marked well of each tide suspected communication point is obtained; judging the independence of the trend of the mineral dissolution content to obtain a plurality of tidal well channels and communicated river reaches thereof; and connecting an underground river section for pollution tracing. The invention aims to solve the influence of unclear upstream and downstream of an underground river and well channels existing between different underground river reaches on traceability, and realizes accurate groundwater pollution traceability.

Description

Technical Field

[0001] The present invention relates to the technical field of pollution source tracing, and particularly to a method and system for tracing groundwater pollution based on sewage pipeline data. Background Art

[0002] Groundwater is the main water resource to ensure the life and production of global residents, and its sustainability and water use safety directly affect social development and residents' health. The groundwater resources in karst area cities account for more than 70% of the total urban water resources. Therefore, when groundwater is polluted, it seriously affects the urban water use safety. The main reason for urban groundwater pollution is the leakage of sewage pipes. Therefore, the tracing of groundwater pollution in karst area cities mainly uses sewage pipelines as the data basis for tracing. By isotopic tracing of groundwater, the sewage pipelines passed by groundwater are judged, and finally the sewage pipelines with sewage leakage are determined.

[0003] Different groundwater layers form non-interfering water layers driven by gravity, density difference and heat. However, domestic and industrial water in karst area cities mainly rely on pumping groundwater by drilling wells. Drilling wells will connect multiple different levels of groundwater layers in the karst area. If the groundwater in one layer is polluted due to the leakage of sewage pipes, the interconnection of the multi-layer water structure will affect multiple water layers, making other water layers also have water pollution, resulting in difficulty in determining the pollution source and increasing the difficulty of tracing the pollution source. Summary of the Invention

[0004] The present invention provides a method and system for tracing groundwater pollution based on sewage pipeline data to solve the existing problems.

[0005] The method and system for tracing groundwater pollution based on sewage pipeline data of the present invention adopt the following technical solutions: In the first aspect, an embodiment of the present invention provides a method for tracing groundwater pollution based on sewage pipeline data, and the method includes the following steps: Using the positions of the monitoring wells of groundwater and the positions of the sewage pipelines and their respective inspection wells to construct a sewage pipeline map; collecting the water flow rate and mineral dissolution content of the monitoring wells at each sampling moment every day; Analyzing the peak-shift correlation of the water flow rates between the monitoring wells to obtain all suspected downstream monitoring wells of each monitoring well; analyzing the similarity of the water flow rate fluctuations at short distances between each monitoring well and its respective suspected downstream monitoring wells, and combining the co-variation of the mineral dissolution content increment and the flowing distance, to obtain several monitoring wells included in each underground river section; Connecting the monitoring wells included in each underground river section in the sewage pipeline map to obtain an underground river section pipe network map; analyzing the intersection conditions of the underground river sections to obtain several tidal suspected connection points and their several marked wells; screening the dates when each marked well is higher than its daily average water flow rate to obtain the high water flow dates of each marked well of each tidal suspected connection point; Judge the independence of the trends of the mineral dissolution contents of all marked wells at each suspected tidal connection point on all high water flow dates, and obtain several tidal well channels and their connected river sections; Connect all the connected river sections of the same tidal well channel in the underground river section pipe network diagram to obtain several through river sections, and conduct pollution source tracing through the intersection of the through river sections and each sewage pipeline and its inspection points.

[0006] Preferably, the specific steps for all suspected downstream monitoring wells of each monitoring well include: Utilize the water flow rates of each monitoring well at each sampling moment every day to construct the historical water flow rate sequence of each monitoring well; Denote any one monitoring well as the target monitoring well, and denote any one monitoring well other than the target monitoring well as the first monitoring well; Perform dynamic time warping on the historical water flow rate sequences of the target monitoring well and the first monitoring well to obtain the matching water flow rate of each water flow rate in the historical water flow rate sequence of the target monitoring well in the historical water flow rate sequence of the first monitoring well; If a water flow rate in the historical water flow rate sequence of the target monitoring well and its matching water flow rate in the historical water flow rate sequence of the first monitoring well satisfy one-to-one matching, denote this water flow rate in the historical water flow rate sequence of the target monitoring well as a fluctuating characteristic water flow rate of the target monitoring well; Calculate the time interval between each fluctuating characteristic water flow rate of the target monitoring well and its matching water flow rate in the historical water flow rate sequence of the first monitoring well, and denote it as the peak shift time difference between each fluctuating characteristic water flow rate of the target monitoring well and the first monitoring well; Denote the number of positive peak shift time differences among all the peak shift time differences between the fluctuating characteristic water flow rates of the target monitoring well and the first monitoring well as the positive peak shift value between the target monitoring well and the first monitoring well, and denote the number of negative peak shift time differences among all the peak shift time differences between the fluctuating characteristic water flow rates of the target monitoring well and the first monitoring well as the negative peak shift value between the target monitoring well and the first monitoring well; If the positive peak shift value between the target monitoring well and the first monitoring well is less than the negative peak shift value, denote the first monitoring well as a suspected downstream monitoring well of the target monitoring well.

[0007] Preferably, the specific steps for several monitoring wells included in each underground river section include: Denote the inverse proportional normalization value of the position distance between each monitoring well and its respective suspected downstream monitoring wells as the spatial difference weight between each monitoring well and its respective suspected downstream monitoring wells; Analyze the approximation of the water flow rate trends of each monitoring well and its respective suspected downstream monitoring wells at each sampling moment every day, and combine the spatial difference weights between each monitoring well and its respective suspected downstream monitoring wells to obtain the water flow rate fluctuation similarity between each monitoring well and its respective suspected downstream monitoring wells; Analyze the differences in the mineral dissolution content of each monitoring well and its suspected downstream monitoring wells at each sampling time of each day, and combine the spatial difference weights of each monitoring well and its suspected downstream monitoring wells, which is denoted as the connection degree of the solution products between each monitoring well and its suspected downstream monitoring wells; Based on the similarity of water flow fluctuations and the connection degree of solution products between each monitoring well and its suspected downstream monitoring wells, obtain the connection possibility between each monitoring well and its suspected downstream monitoring wells. The connection possibility is in a direct proportional relationship with both the similarity of water flow fluctuations and the connection degree of solution products; Among all the suspected downstream monitoring wells of each monitoring well, the suspected downstream monitoring well with the highest connection possibility is denoted as the judged downstream monitoring well of each monitoring well; Preset a connection threshold. When the connection possibility between a monitoring well and its judged downstream monitoring well is greater than or equal to the connection threshold, this monitoring well is denoted as the first monitoring well of an underground river section, and the judged downstream monitoring well is denoted as the second monitoring well of this underground river section; Take the current judged downstream monitoring well as a new monitoring well, and obtain the new judged downstream monitoring well of the new monitoring well, and so on, until there is no judged downstream monitoring well for the new monitoring well, so as to obtain all the monitoring wells included in this underground river section.

[0008] Preferably, the specific steps of the similarity of water flow fluctuations include: Denote any suspected downstream monitoring well of the target monitoring well as the second monitoring well; for the target monitoring well and the second monitoring well, obtaining the similarity of water flow fluctuations between the target monitoring well and the second monitoring well includes: Denote the inverse normalization value of the DTW distance after dynamic time warping of the historical water flow sequences of the target monitoring well and the second monitoring well as the water flow trend approximation degree of the target monitoring well and the second monitoring well; Denote the product of the water flow trend approximation degree of the target monitoring well and the second monitoring well and the spatial difference weight of the target monitoring well and the second monitoring well as the similarity of water flow fluctuations between the target monitoring well and the second monitoring well.

[0009] Preferably, the specific steps of the connection degree of solution products include: Denote the sum of the differences in the mineral dissolution content of the target monitoring well and the second monitoring well at each sampling time of each day as the mineral dissolution content increment of the target monitoring well and the second monitoring well; Denote the product of the inverse normalization value of the mineral dissolution content increment and the spatial difference weight of the target monitoring well and the second monitoring well as the connection degree of solution products between the target monitoring well and the second monitoring well.

[0010] Preferably, analyzing the intersection situation of the underground river section to obtain several tidal suspected connection points and their several marked wells includes: Obtain the intersection points of all underground river sections and the corresponding underground river sections for each intersection point in the underground river network diagram; If the distance between the positions of multiple intersection points is less than or equal to the preset position distance threshold, record the centroid of these multiple intersection points as a suspected tidal connection point, and the suspected tidal connection point inherits the corresponding underground river sections of these multiple intersection points; If the distance between one intersection point and the positions of all other intersection points is greater than the preset position distance threshold, record this intersection point as a suspected tidal connection point, and the suspected tidal connection point inherits the corresponding underground river section of this intersection point; Among all the monitoring wells of each underground river section corresponding to each suspected tidal connection point, record the monitoring well with the shortest distance from the suspected tidal connection point as the corresponding marked well for each suspected tidal connection point.

[0011] Preferably, the specific steps for the high water flow date include: Obtain the average value of the water flow at all sampling times of all days for each marked well of each suspected tidal connection point, and record it as the daily average water flow of each marked well of each suspected tidal connection point; Obtain the average value of the water flow at all sampling times of each day for each marked well of each suspected tidal connection point, and record it as the average water flow of each marked well of each suspected tidal connection point on each day; Record the dates when the average water flow of each marked well of each suspected tidal connection point is greater than the daily average water flow as the high water flow dates of each marked well of each suspected tidal connection point.

[0012] Preferably, the specific steps for the several tidal well channels and their connected river sections include: Use the mineral dissolution content at each sampling time of all marked wells of each suspected tidal connection point during all high water flow dates to construct the mineral dissolution matrix of each suspected tidal connection point; Calculate the covariance matrix of the mineral dissolution matrix of each suspected tidal connection point, and obtain the eigenvectors of the covariance matrix through the principal component analysis algorithm; Arrange the eigenvalues of the eigenvectors of the covariance matrix in descending order, and record it as the descending sequence of principal components of each suspected tidal connection point; Record the difference between the eigenvalue of each eigenvector and the eigenvalue of the next eigenvector in the descending sequence of principal components of each suspected tidal connection point as the principal component decision coefficient of each eigenvector of each suspected tidal connection point; Record the serial number of the eigenvector with the largest principal component decision coefficient in the descending sequence of principal components as the number of principal component directions of the mineral dissolution matrix of each suspected tidal connection point; If the number of principal component directions of the mineral dissolution amount matrix of each suspected tidal connection point is greater than or equal to the number of marked wells of each suspected tidal connection point, mark this suspected tidal connection point as a tidal well channel, and mark the underground river section corresponding to the marked well of this suspected tidal connection point as the connected river section of this tidal well channel.

[0013] Preferably, connect all the connected river sections of the same tidal well channel in the underground river section pipe network diagram to obtain several through river sections. Pollution source tracing through the intersection of the through river sections and each sewage pipeline and its inspection points includes: Connect all the connected river sections of the same tidal well channel in the underground river section pipe network diagram to obtain several through river sections; Regard both the through river sections and the underground river sections as traceable rivers. Mark all the sewage pipelines that intersect with the existing polluted traceable rivers as suspected sewage pipelines. Mark the nearest inspection point upstream of the suspected sewage pipeline at the intersection position of the polluted traceable river and each suspected sewage pipeline as the tracer inspection point of each suspected sewage pipeline; Start from the suspected sewage pipeline at the most downstream of the polluted traceable river. Inject isotopes at the tracer inspection point of the most downstream suspected sewage pipeline, and monitor the tracer in the monitoring well closest to this tracer inspection point. If the tracer is detected, mark this tracer inspection point as the leakage inspection point; if the tracer is not detected, then judge the suspected sewage pipeline adjacent upstream of the polluted traceable river until the leakage inspection point is obtained.

[0014] In a second aspect, the present invention also proposes a groundwater pollution source tracing system based on sewage pipeline data. The system includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the above method are implemented.

[0015] The beneficial effects of the technical solution of the present invention are as follows: The present invention constructs a sewage pipeline map by using the positions of groundwater monitoring wells, sewage pipelines and their respective inspection wells; obtains the water flow rate and mineral dissolution content of the monitoring wells at each sampling time of each day; analyzes the peak-shifting correlation of the water flow rate between the monitoring wells to obtain all suspected downstream monitoring wells of each monitoring well; achieves obtaining the downstream monitoring wells of the monitoring wells by analyzing the water flow peak-shifting relationship between the monitoring wells; analyzes the similarity of the water flow rate fluctuations at short distances between each monitoring well and its respective suspected downstream monitoring wells, and combines the co-variation of the mineral dissolution content increment and the flowing distance to obtain several monitoring wells included in each underground river section; by analyzing the similarity of the water flow rate fluctuations in the same underground river section and the characteristic that the increase in the dissolved mineral content of adjacent monitoring wells in the same river channel is small under short-distance flow, connects the monitoring wells to obtain several underground river sections; connects the monitoring wells included in each underground river section in the sewage pipeline map to obtain an underground river section pipe network map; analyzes the intersection conditions of the underground river sections to obtain several suspected tidal connection points and their several marked wells; after graphically processing the position information of the underground river sections, determines their intersection points as suspected tidal connection points, which serve as the basis for the position coordinates of analyzing the tidal well channels; screens the dates when each marked well is higher than its daily average water flow rate to obtain the high-water flow dates of each marked well of each suspected tidal connection point; uses the blending characteristics of different river sections caused by the tidal well channels under large water volume conditions to screen the high-water flow dates of each river channel; determines the independence of the trends of the mineral dissolution content of all marked wells of each suspected tidal connection point on all high-water flow dates to obtain several tidal well channels and their connected river sections; by analyzing the independence of the trends of the mineral dissolution content in the water flow of the marked wells corresponding to the same suspected tidal connection point, determines the consistency between the independent trend and the number of underground river sections to determine whether the suspected tidal connection point belongs to a tidal well channel; connects all the connected river sections of the same tidal well channel in the underground river section pipe network map to obtain several through river sections, and conducts pollution source tracing through the intersection conditions of the through river sections and each sewage pipeline and its inspection points. The present invention aims to solve the problem that the upstream and downstream of underground rivers are not clear and the influence of well channels between different underground river sections on source tracing, and realizes accurate groundwater pollution source tracing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a flowchart of the steps of the groundwater pollution source tracing method based on sewage pipeline data of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, detail the specific implementation manners, structures, features, and effects of the groundwater pollution source tracing method and system based on sewage pipeline data proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0020] The following will specifically describe the specific solutions of the groundwater pollution source tracing method and system based on sewage pipeline data provided by the present invention in conjunction with the accompanying drawings.

[0021] Please refer to Figure 1 , which shows the step flowchart of the groundwater pollution source tracing method based on sewage pipeline data provided by an embodiment of the present invention. The method includes the following steps: Step S001: Construct a sewage pipeline map using the positions of the groundwater monitoring wells, the sewage pipeline, and the positions of each inspection well; collect the water flow rate and mineral dissolution content of the monitoring wells at each sampling moment every day.

[0022] Since the sewage pipeline is installed artificially, an inspection well will be set at regular intervals underground. When tracing the pollution source, if it is suspected that a certain section of the sewage pipeline leaks, an isotope tracer is put into the corresponding upstream inspection well to determine whether the corresponding isotope appears in the underground river, thereby determining the location of the leakage point; and this embodiment is for groundwater pollution source tracing based on sewage pipeline data, so first, the positions of the sewage pipeline and each inspection well need to be collected and obtained.

[0023] Specifically, obtain the orientation of the sewage pipeline and the geographical locations of each inspection well on the sewage pipeline through the public information of the municipal drainage management department to construct the original sewage pipeline map. In the original sewage pipeline map of this embodiment, the positions of each inspection well are described by their longitude and latitude coordinates. Other embodiments may use other methods to represent.

[0024] When tracing the source of groundwater pollution, it is usually necessary to obtain the locations of each underground river, and obtain water samples from each underground river through sampling for isotope analysis. However, in this process, due to the complex structures of underground caves, water layers, and rivers in karst area cities, when the existing ground penetrating radar method is used to detect underground river channels and caves, due to the influence of radar penetration depth and underground structure, the detection depth is relatively small, usually less than 50 meters. And there are multiple layers of underground rivers in karst cities, and multiple underground rivers intersect, so there are multiple underground rivers at the same depth in different positions, making it difficult to determine the underground river to which each position belongs from the groundwater layers that can be monitored.

[0025] Therefore, in this embodiment, by sampling and monitoring the groundwater that can be monitored, and then analyzing the correlation between the water samples of monitoring wells at different positions, the monitorable points belonging to each underground river are obtained. Since the pipe diameter of the river channel of the same underground river is fixed, compared with surface water, its flow rate is related to the speed, and the groundwater in the karst area is rich in , and other carbonate dissolution products. Therefore, after selecting the positions of the monitoring wells in this embodiment, the water flow rate and mineral dissolution content at the sampling nodes of each monitoring well are obtained.

[0026] Specifically, use ground penetrating radar to detect the locations where groundwater exists in the karst area, and drill monitoring wells at the locations where groundwater can be detected; In the preset historical sampling range, obtain the water flow rate and mineral dissolution content of each monitoring well at each sampling moment every day. It should be noted that in this embodiment, the historical sampling range is taken as the most recent month, and the sampling moment is at 1-hour sampling intervals. Among them, the water flow rate is obtained by installing water flow sensors in each monitoring well to obtain the water flow rate at each sampling moment, and after extracting water samples from the monitoring wells at each sampling moment, use the ion concentration detection method to obtain the concentration of each monitoring well at each sampling moment every day, which is recorded as the mineral dissolution content of each monitoring well at each sampling moment every day.

[0027] Furthermore, map the positions of each monitoring well to the original sewage pipeline diagram to obtain the sewage pipeline diagram.

[0028] Step S002: Analyze the peak-shift correlation of the water flow rates between the monitoring wells to obtain all suspected downstream monitoring wells of each monitoring well; analyze the similarity of the fluctuations of the water flow rates at short distances between each monitoring well and its respective suspected downstream monitoring wells, and combine the co-variation of the mineral dissolution content increment and the flowing distance to obtain several monitoring wells included in each underground river section.

[0029] For each monitoring well, since the pipe diameter of the underground river channel is fixed, when the water volume upstream changes, the water volume downstream will change accordingly. Therefore, for two adjacent monitoring wells belonging to the same underground river section, the change situation of their water flow rates will be the same after a certain time interval. Therefore, in this embodiment, by correlating the peak staggering of the water flow rates between different monitoring wells, the suspected downstream monitoring wells suspected to belong to each monitoring well are determined.

[0030] Preferably, the specific steps for analyzing the peak staggering correlation of the water flow rates between the monitoring wells and obtaining all the suspected downstream monitoring wells of each monitoring well include: Using the water flow rate of each monitoring well at each sampling moment every day, construct the historical water flow rate sequence of each monitoring well; Perform time series alignment on the historical water flow rate sequences of each monitoring well and other monitoring wells, and obtain the matching water flow rates of each water flow rate in the historical water flow rate sequence of each monitoring well in the historical water flow rate sequences of other monitoring wells; Analyze the time series misalignment relationship between each water flow rate in the historical water flow rate sequence of each monitoring well and the matching water flow rates in the historical water flow rate sequences of other monitoring wells, and obtain all the suspected downstream monitoring wells of each monitoring well.

[0031] Specifically, using the water flow rate of each monitoring well at each sampling moment every day, constructing the historical water flow rate sequence of each monitoring well specifically includes: Denote the sequence composed of the water flow rates of each monitoring well at each sampling moment every day as the historical water flow rate sequence of each monitoring well.

[0032] Further, performing time series alignment on the historical water flow rate sequences of each monitoring well and other monitoring wells, and obtaining the matching water flow rates of each water flow rate in the historical water flow rate sequence of each monitoring well in the historical water flow rate sequences of other monitoring wells specifically includes: It should be noted that there is a peak staggering correlation in the historical water flow rate sequences of the suspected upstream and downstream monitoring wells in the same river section, that is, the change peaks of their water flow rates are approximately the same at different times. Therefore, by performing time series alignment on the suspected upstream and downstream monitoring wells and judging the alignment situation of the aligned matching times, all the suspected downstream monitoring wells of each monitoring well can be obtained.

[0033] Denote any one monitoring well as the target monitoring well, and denote any one monitoring well other than the target monitoring well as the first monitoring well; Perform dynamic time warping on the historical water flow rate sequences of the target monitoring well and the first monitoring well, and obtain the matching water flow rates of each water flow rate in the historical water flow rate sequence of the target monitoring well in the historical water flow rate sequence of the first monitoring well; Similarly, obtain the matching water flow rates of each water flow rate in the historical water flow rate sequence of each monitoring well in the historical water flow rate sequences of other monitoring wells.

[0034] Further, by analyzing the time - sequence misalignment relationship between each water flow rate in the historical water flow rate sequence of each monitoring well and the matching water flow rate in the historical water flow rate sequences of each other monitoring well, all suspected downstream monitoring wells of each monitoring well are obtained, specifically including: Count the positive and negative quantities of the time intervals after one - to - one matching of each water flow rate in the historical water flow rate sequence of each monitoring well and the matching water flow rate in the historical water flow rate sequences of each other monitoring well, and record them as the positive misalignment peak value and negative misalignment peak value of each monitoring well with respect to each other monitoring well; It should be noted that since there are many - to - one matching situations in dynamic time warping, mainly for sequences with unobvious change trends, these situations are not considered in this embodiment during the analysis.

[0035] If the positive misalignment peak value of a monitoring well with respect to another monitoring well (excluding this monitoring well) is less than the negative misalignment peak value, then record the other monitoring well (excluding this monitoring well) as the suspected downstream monitoring well of this monitoring well.

[0036] As an example, for the target monitoring well and the first monitoring well, the steps to obtain the positive misalignment peak value and negative misalignment peak value of the target monitoring well and the first monitoring well are as follows: If a water flow rate in the historical water flow rate sequence of the target monitoring well and its matching water flow rate in the historical water flow rate sequence of the first monitoring well meet one - to - one matching, record this water flow rate in the historical water flow rate sequence of the target monitoring well as a fluctuating characteristic water flow rate of the target monitoring well; Calculate the time interval between each fluctuating characteristic water flow rate of the target monitoring well and its matching water flow rate in the historical water flow rate sequence of the first monitoring well, and record it as the misalignment time difference between each fluctuating characteristic water flow rate of the target monitoring well and the first monitoring well; the time interval is the result of subtracting the time of the matching water flow rate in the historical water flow rate sequence of the first monitoring well from the time of the water flow rate in the historical water flow rate sequence of the target monitoring well; It should be noted that when the misalignment time difference is negative, it means that when the water flow rate in the historical water flow rate sequence of the target monitoring well undergoes the same change as the matching water flow rate in the historical water flow rate sequence of the first monitoring well, it is before the time sequence of the matching water flow rate in the historical water flow rate sequence of the first monitoring well, indicating that the first monitoring well is downstream of the target monitoring well.

[0037] Further, among the misalignment time differences between all the fluctuating characteristic water flow rates of the target monitoring well and the first monitoring well, record the number of positive misalignment time differences as the positive misalignment peak value of the target monitoring well and the first monitoring well, and record the number of negative misalignment time differences as the negative misalignment peak value of the target monitoring well and the first monitoring well.

[0038] Preferably, the specific steps for obtaining several monitoring wells included in each underground river section by analyzing the similarity of water flow fluctuations at short distances between each monitoring well and its respective suspected downstream monitoring wells, and combining the co-variation of the increment of mineral dissolution content and the flow-through distance are as follows: The inverse proportional normalization value of the positional distance between each monitoring well and its respective suspected downstream monitoring well is denoted as the spatial difference weight between each monitoring well and its respective suspected downstream monitoring well; Analyze the approximation of the water flow trends at each sampling moment of each day between each monitoring well and its respective suspected downstream monitoring wells, and combine the spatial difference weights between each monitoring well and its respective suspected downstream monitoring wells to obtain the similarity of water flow fluctuations between each monitoring well and its respective suspected downstream monitoring wells; Analyze the difference in the mineral dissolution content at each sampling moment of each day between each monitoring well and its respective suspected downstream monitoring wells, and combine the spatial difference weights between each monitoring well and its respective suspected downstream monitoring wells, which is denoted as the degree of connection of the solution products between each monitoring well and its respective suspected downstream monitoring wells; Integrate the similarity of water flow fluctuations and the degree of connection of solution products between each monitoring well and its respective suspected downstream monitoring wells to obtain the connection possibility between each monitoring well and its respective suspected downstream monitoring wells, and the connection possibility is in a direct proportional relationship with both the similarity of water flow fluctuations and the degree of connection of solution products; Connect each monitoring well and its respective suspected downstream monitoring wells through the connection possibility to obtain several monitoring wells included in each underground river section.

[0039] Specifically, analyzing the approximation of the water flow trends at each sampling moment of each day between each monitoring well and its respective suspected downstream monitoring wells, and combining the spatial difference weights between each monitoring well and its respective suspected downstream monitoring wells, the specific method for obtaining the similarity of water flow fluctuations between each monitoring well and its respective suspected downstream monitoring wells includes: As an example, any one of the suspected downstream monitoring wells of the target monitoring well is denoted as the second monitoring well; for the target monitoring well and the second monitoring well, obtaining the similarity of water flow fluctuations between the target monitoring well and the second monitoring well includes: The inverse proportional normalization value of the DTW distance after dynamic time warping of the historical water flow sequences of the target monitoring well and the second monitoring well is denoted as the approximation degree of the water flow trends of the target monitoring well and the second monitoring well; The product of the approximation degree of the water flow trends of the target monitoring well and the second monitoring well and the spatial difference weight between the target monitoring well and the second monitoring well is denoted as the similarity of water flow fluctuations between the target monitoring well and the second monitoring well.

[0040] It should be noted that the DTW distance can reflect the difference in the change trends of historical water flow sequences. The smaller the value, the smaller the difference. When the distance between a monitoring well and its suspected downstream monitoring well is closer and the difference in the water flow change trends is smaller, the approximation degree of the water flow trends between the monitoring well and its suspected downstream monitoring well. Among them, obtaining the DTW distance by dynamic time warping is a well-known existing technology and will not be elaborated in this embodiment.

[0041] Furthermore, analyze the difference in the mineral dissolution content at each sampling moment of each day between each monitoring well and its respective suspected downstream monitoring wells, and combine the spatial difference weights between each monitoring well and its respective suspected downstream monitoring wells, which is denoted as the degree of connection of the solution products between each monitoring well and its respective suspected downstream monitoring wells, specifically including: It should be noted that since the mineral dissolution content in the underground river is constantly increasing in adjacent monitoring wells due to the scouring of the water flow on the karst area, in this embodiment, by analyzing the co-variation of the mineral dissolution content increment and the flowing distance, the degree of connection of the solution products between each monitoring well and its respective suspected downstream monitoring wells is obtained.

[0042] Among them, co-variation means the common parameter change of the mineral dissolution content increment and the flowing distance. As the flowing distance changes, the mineral dissolution content increment can also produce a certain co-variation effect. It can be understood that the mineral dissolution content increment represents the change difference of the mineral dissolution content, and the flowing distance characterizes the feature of the position distance. Therefore, based on the values of the two, the co-calculation of the degree of connection of the solution products can be realized.

[0043] As an example, for the target monitoring well and the second monitoring well, obtaining the degree of connection of the solution products between the target monitoring well and the second monitoring well includes: Denote the sum of the differences in the mineral dissolution content at each sampling moment of each day between the target monitoring well and the second monitoring well as the mineral dissolution content increment between the target monitoring well and the second monitoring well; Denote the product of the inverse normalization value of the mineral dissolution content increment and the spatial difference weight between the target monitoring well and the second monitoring well as the degree of connection of the solution products between the target monitoring well and the second monitoring well.

[0044] Among them, the degree of connection of the solution products represents the degree of association between the target monitoring well and the second monitoring well in terms of solution products.

[0045] It should be noted that when the mineral dissolution content increment between two monitoring wells is smaller and the distance is closer, it is more likely that they belong to two monitoring wells on the same underground river section.

[0046] In the embodiments of the present invention, since the above includes "the inverse normalization value of the positional distance between each monitoring well and its respective suspected downstream monitoring wells is denoted as the spatial difference weight between each monitoring well and its respective suspected downstream monitoring wells", that is, the spatial difference weight has a distance feature. Therefore, the flow-through distance can be characterized by the spatial difference weight. The larger the value of the spatial difference weight, the closer the positional distance, further indicating a higher value of the degree of connection of the solution products.

[0047] Also, the smaller the increment of the mineral dissolution content, the smaller the difference in the mineral dissolution content between the two monitoring wells at different sampling times, indicating a higher similarity in the change of the mineral dissolution content between the two monitoring wells in time series, that is, a higher degree of connection of the solution products.

[0048] Furthermore, by integrating the water flow fluctuation similarity and the degree of connection of the solution products between each monitoring well and its respective suspected downstream monitoring wells, the connection possibility between each monitoring well and its respective suspected downstream monitoring wells is obtained. The connection possibility is in a direct proportional relationship with both the water flow fluctuation similarity and the degree of connection of the solution products, specifically including: As an example, taking the target monitoring well and the second monitoring well as a monitoring well group, obtaining the connection possibility between the target monitoring well and the second monitoring well includes: Denote the second norm of the water flow fluctuation similarity and the degree of connection of the solution products of the monitoring well group as the connection possibility of the monitoring well group.

[0049] That is to say, the target monitoring well and the second monitoring well have the characteristic of water flow fluctuation similarity and also have the characteristic of the degree of connection of the solution products. The two characteristics are integrated through the calculation method of the second norm to obtain the connection possibility of the monitoring well group.

[0050] Furthermore, by connecting each monitoring well and its respective suspected downstream monitoring wells through the connection possibility, obtaining the several monitoring wells included in each underground river section includes: Denote the suspected downstream monitoring well with the greatest connection possibility among all the suspected downstream monitoring wells of each monitoring well as the judged downstream monitoring well of each monitoring well; Preset a connection threshold. When the connection possibility between a monitoring well and its judged downstream monitoring well is greater than or equal to the connection threshold, denote this monitoring well as the first monitoring well of an underground river section, and denote the judged downstream monitoring well as the second monitoring well of this underground river section; Take the current judged downstream monitoring well as the new monitoring well, obtain the new judged downstream monitoring well of the new monitoring well, and so on, until there is no longer a judged downstream monitoring well for the new monitoring well, to obtain all the monitoring wells included in this underground river section.

[0051] It should be noted that in this embodiment, the connection threshold is described by taking 0.6 as an example.

[0052] As an example, among the connection possibilities between the target monitoring well and all its suspected downstream monitoring wells, the suspected downstream monitoring well with the greatest connection possibility is denoted as the third monitoring well; if the connection possibility between the target monitoring well and the third monitoring well is greater than or equal to the connection threshold, the target monitoring well is denoted as the first monitoring well of an underground river section, the third monitoring well is denoted as the second monitoring well of this underground river section, and the second monitoring well is used as the new target monitoring well to obtain the judgment downstream monitoring well of the new target monitoring well, and so on until there is no judgment downstream monitoring well for the new target monitoring well, so as to obtain all the monitoring wells included in this underground river section.

[0053] Step S003: Connect the monitoring wells included in each underground river section in the sewage pipeline diagram to obtain an underground river section pipe network diagram; analyze the intersection conditions of the underground river sections to obtain several tidal suspected connection points and their several marked wells; screen the dates when each marked well is higher than its average daily water flow to obtain the high water flow dates of each marked well of each tidal suspected connection point; judge the independence of the trends of the mineral dissolution contents of all the marked wells of each tidal suspected connection point on all high water flow dates to obtain several tidal well channels and their connected river sections.

[0054] Due to the complex structure of the groundwater layer in the karst area with natural channels, and the main water use in karst area cities being groundwater, there are connected well channels between the multi-layer underground water structures, resulting in the exchange of water flow and ions between different water layers. These well channels are mainly divided into constant-through well channels and tidal well channels. The constant-through well channels are caused by the collapse of karst caves and artificial well drilling, directly connecting the underground river sections of different water layers; the other is the tidal well channel, which is usually at the high position of the river course of the underground river section, or due to the pressure difference between the penetrated underground river sections, resulting in the inability to carry out large water volume and ion exchange by gravity flow.

[0055] For the upper and lower underground river sections penetrated by the tidal well channel, when the water flow of the upper underground river section increases, due to the increased water flow burden and rising water level of the upper river section, the water of the upper underground river section will enter the lower underground river section; and when tracing the source of groundwater pollution, the tidal well channel makes the pollution manifestation characteristics of isotope tracing incoherent. Therefore, in this embodiment, by analyzing the intersection conditions of different underground rivers, and then analyzing the flow trend conditions of the intersecting underground rivers on high water flow dates, several tidal well channels and their connected river sections are obtained.

[0056] Specifically, in the sewage pipeline diagram, connect the monitoring wells in the order of the underground river sections to which they belong to obtain an underground river section pipe network diagram.

[0057] It should be noted that tidal well channels will only appear when underground river sections intersect at the same location. Therefore, analyze the intersection conditions of the underground river sections to obtain tidal suspected connection points and their several marked wells.

[0058] Preferably, the specific steps for analyzing the confluence of the underground river section to obtain several suspected tidal connection points and their several marker wells are as follows: Obtain all the confluence points of the underground river sections and the corresponding underground river sections in the underground river section pipe network diagram; screen all the confluence points to obtain several suspected tidal connection points and their corresponding underground river sections; Among all the monitoring wells of each underground river section corresponding to each suspected tidal connection point, the monitoring well with the closest distance to the suspected tidal connection point is recorded as each marker well of each suspected tidal connection point.

[0059] It should be noted that since the flowing area of the underground river section may be relatively large, although multiple underground river sections do not converge at the same location, the positions of their confluence points are close. Therefore, in this embodiment, the close confluence points are screened to obtain the suspected tidal connection points.

[0060] Specifically, screening all the confluence points to obtain several suspected tidal connection points and their corresponding underground river sections includes: If the distance between multiple confluence points is less than or equal to the preset position distance threshold, the centroid of these multiple confluence points is recorded as a suspected tidal connection point, and the suspected tidal connection point inherits the corresponding underground river sections of these multiple confluence points; If the distance between a confluence point and the positions of all other confluence points is greater than the preset position distance threshold, the confluence point is recorded as a suspected tidal connection point, and the suspected tidal connection point inherits the corresponding underground river section of the confluence point.

[0061] It should be noted that in this embodiment, the position distance threshold is described by taking 2 kilometers as an example.

[0062] Preferably, the specific steps for screening the dates when each marker well is higher than its average daily water flow rate to obtain the high water flow dates of each marker well of each suspected tidal connection point include: Obtain the average value of the water flow rates of each marker well of each suspected tidal connection point at all sampling moments on all days, and record it as the average daily water flow rate of each marker well of each suspected tidal connection point; Obtain the average value of the water flow rates of each marker well of each suspected tidal connection point at all sampling moments on each day, and record it as the average water flow rate of each marker well of each suspected tidal connection point on each day; Record the dates when the average water flow rate of each marker well of each suspected tidal connection point is greater than the average daily water flow rate as the high water flow dates of each marker well of each suspected tidal connection point.

[0063] It should be noted that the paths through which the water flows in each underground river section are different. During the flow in the underground river section, the rocks will be dissolved, so that the flowing water contains dissolved minerals. Since the river channels in the same underground river section are the same, while the river channels in different underground river sections are different, the content of dissolved minerals in the same underground river section has the same trend, and the changing trends of minerals in different underground river sections are different. Then, if the trends of the dissolved mineral content in the marker wells corresponding to multiple underground river sections of a suspected tidal connection point are independent of each other, it indicates that there is no water flow mixing caused by well channels. When the number of independent changing trends of the dissolved mineral content is less than the number of underground river sections corresponding to the suspected tidal connection point, it indicates that there is water flow mixing, that is, there is a well channel at this suspected tidal connection point.

[0064] Preferably, the specific steps for judging the independence of the trends of the dissolved mineral content of all marker wells at each suspected tidal connection point on all high water flow dates and obtaining several tidal well channels and their connected river sections are as follows: Using the dissolved mineral content at each sampling moment of all marker wells at each suspected tidal connection point on all high water flow dates, construct the dissolved mineral amount matrix of each suspected tidal connection point; It should be noted that the dissolved mineral amount matrix is a three-dimensional matrix. The X-axis is the serial number of the marker well, the Y-axis is the high water flow date of each marker well, and the Z-axis is the dissolved mineral content at each sampling moment of each marker well on each high water flow date.

[0065] Calculate the covariance matrix of the dissolved mineral amount matrix of each suspected tidal connection point, and obtain the eigenvectors of the covariance matrix through the principal component analysis algorithm; It should be noted that the calculation of the covariance matrix and its eigenvectors of the dissolved mineral amount matrix, as well as the principal component analysis algorithm, are well-known existing technologies, and will not be elaborated in this embodiment; Arrange the eigenvalues of the eigenvectors of the covariance matrix in descending order, denoted as the descending sequence of the principal components of each suspected tidal connection point; For each suspected tidal connection point, in the descending sequence of the principal components, record the difference between the eigenvalue of each eigenvector and the eigenvalue of the next eigenvector as the principal component decision coefficient of each eigenvector of each suspected tidal connection point; Record the serial number of the eigenvector with the largest principal component decision coefficient in the descending sequence of the principal components as the number of principal component directions of the dissolved mineral amount matrix of each suspected tidal connection point; If the number of principal component directions of the dissolved mineral amount matrix of each suspected tidal connection point is greater than or equal to the number of marker wells at each suspected tidal connection point, record this suspected tidal connection point as a tidal well channel, and record the underground river section corresponding to the marker well of this suspected tidal connection point as the connected river section of this tidal well channel.

[0066] When the number of principal component directions of the mineral dissolution amount matrix at each suspected tidal connection point is greater than or equal to the number of marked wells at each suspected tidal connection point, it indicates that there is no blending of the carbonate solution products in the underground river sections corresponding to the marked wells at each suspected tidal connection point, and the change trends between the carbonate solution products are independent of each other; conversely, it indicates that there is blending of the carbonate solution products at this suspected tidal connection point, resulting in a reduction in independent features, thus proving the existence of a tidal well channel at this suspected tidal connection point.

[0067] Step S004: Connect all the connected river sections of the same tidal well channel in the underground river section pipe network diagram to obtain several through-connected river sections, and conduct pollution source tracing through the intersection situation of the through-connected river sections, each sewage pipeline, and its inspection points.

[0068] Currently, the tracing of groundwater pollution is mainly achieved through the isotope tracing method. Isotopes are injected into the inspection well closest to the upstream of the suspected leaking sewage pipeline, and then samples are taken from the monitoring wells in the underground river section at this location to analyze whether isotopes are contained therein. If they exist, it indicates that sewage leakage has occurred here; otherwise, the sewage leakage in the upstream is further judged, thereby realizing the tracing of groundwater pollution.

[0069] In this embodiment, through the underground river section pipe network diagram, the tidal well channels and connected river sections between the underground river sections are analyzed, so that when conducting sewage source tracing, the underground river sections connected by the tidal well channels can be connected, avoiding the source tracing error caused by the tidal well channels.

[0070] Specifically, in the underground river section pipe network diagram, all the connected river sections of the same tidal well channel are connected to obtain several through-connected river sections; Both the through-connected river sections and the underground river sections are regarded as traceable rivers. All the sewage pipelines that intersect with the existing polluted traceable rivers are recorded as suspected sewage pipelines, and the inspection point closest to the upstream of the suspected sewage pipeline at the intersection position of the polluted traceable river and each suspected sewage pipeline is recorded as the tracer inspection point of each suspected sewage pipeline; Starting from the suspected sewage pipeline at the most downstream of the polluted traceable river, isotopes are injected at the tracer inspection point of the most downstream suspected sewage pipeline, and the tracer is monitored in the monitoring well closest to this tracer inspection point. If the tracer is monitored, this tracer inspection point is recorded as the leakage inspection point; if the tracer is not monitored, it is judged towards the suspected sewage pipeline adjacent to the upstream of the polluted traceable river until the leakage inspection point is obtained, proving that pollution exists at this tracer inspection point, and realizing the tracing of groundwater pollution.

[0071] Another embodiment of the present invention provides a groundwater pollution source tracing system based on sewage pipeline data. The system includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the above method steps S001 to S004 are implemented.

[0072] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for tracing the source of groundwater pollution based on sewage pipeline data, characterized in that The method includes the following steps: Construct a sewage pipeline map using the locations of groundwater monitoring wells, sewage pipelines, and their inspection wells; collect the water flow and mineral dissolution content of the monitoring wells at each sampling time of each day. Analyze the peak-shift correlation of the water flow between the monitoring wells to obtain all suspected downstream monitoring wells of each monitoring well; analyze the similarity of the water flow fluctuations at short distances between each monitoring well and its suspected downstream monitoring wells, and combine the co-variation of the mineral dissolution content increment and the flowing distance to obtain several monitoring wells included in each underground river section. Connect the monitoring wells included in each underground river section in the sewage pipeline map to obtain an underground river section pipe network map; analyze the intersection conditions of the underground river sections to obtain several suspected tidal connection points and their several marked wells; screen the dates when each marked well is higher than its average daily water flow to obtain the high water flow dates of each marked well of each suspected tidal connection point. Judge the independence of the trends of the mineral dissolution content of all marked wells of each suspected tidal connection point on all high water flow dates to obtain several tidal well channels and their connected river sections. Connect all the connected river sections of the same tidal well channel in the underground river section pipe network map to obtain several through river sections, and conduct pollution source tracing through the intersection conditions of the through river sections and each sewage pipeline and its inspection points.

2. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein The specific steps for all suspected downstream monitoring wells of each monitoring well include: Construct a historical water flow sequence for each monitoring well using the water flow of each monitoring well at each sampling time of each day. Denote any one monitoring well as the target monitoring well, and denote any one monitoring well other than the target monitoring well as the first monitoring well. Perform dynamic time warping on the historical water flow sequences of the target monitoring well and the first monitoring well to obtain the matching water flow of each water flow in the historical water flow sequence of the target monitoring well in the historical water flow sequence of the first monitoring well. If a water flow in the historical water flow sequence of the target monitoring well and its matching water flow in the historical water flow sequence of the first monitoring well satisfy one-to-one matching, denote this water flow in the historical water flow sequence of the target monitoring well as a fluctuation characteristic water flow of the target monitoring well. Calculate the time interval between each fluctuation characteristic water flow of the target monitoring well and its matching water flow in the historical water flow sequence of the first monitoring well, and denote it as the peak-shift time difference between each fluctuation characteristic water flow of the target monitoring well and the first monitoring well. Denote the number of positive peak-shift time differences among all the peak-shift time differences between all the fluctuation characteristic water flows of the target monitoring well and the first monitoring well as the positive peak-shift value between the target monitoring well and the first monitoring well, and denote the number of negative peak-shift time differences among all the peak-shift time differences between all the fluctuation characteristic water flows of the target monitoring well and the first monitoring well as the negative peak-shift value between the target monitoring well and the first monitoring well. If the positive peak-shift value between the target monitoring well and the first monitoring well is less than the negative peak-shift value, denote the first monitoring well as a suspected downstream monitoring well of the target monitoring well.

3. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein The specific steps for several monitoring wells included in each underground river section include: Denote the inverse proportional normalization value of the position distance between each monitoring well and its suspected downstream monitoring wells as the spatial difference weight between each monitoring well and its suspected downstream monitoring wells. Analyze the approximation of the water flow trends of each monitoring well and its respective suspected downstream monitoring wells at each sampling time of each day, and combine the spatial difference weights of each monitoring well and its respective suspected downstream monitoring wells to obtain the similarity of water flow fluctuations between each monitoring well and its respective suspected downstream monitoring wells; Analyze the differences in the mineral dissolution content of each monitoring well and its respective suspected downstream monitoring wells at each sampling time of each day, and combine the spatial difference weights of each monitoring well and its respective suspected downstream monitoring wells, which is denoted as the degree of connection of the solution products between each monitoring well and its respective suspected downstream monitoring wells; Integrate the similarity of water flow fluctuations and the degree of connection of solution products between each monitoring well and its respective suspected downstream monitoring wells to obtain the connection possibility between each monitoring well and its respective suspected downstream monitoring wells. The connection possibility is in a direct proportional relationship with both the similarity of water flow fluctuations and the degree of connection of solution products; Among all the suspected downstream monitoring wells of each monitoring well, denote the suspected downstream monitoring well with the highest connection possibility as the judged downstream monitoring well of each monitoring well; Preset a connection threshold. When the connection possibility between a monitoring well and its judged downstream monitoring well is greater than or equal to the connection threshold, denote this monitoring well as the first monitoring well of an underground river section, and denote the judged downstream monitoring well as the second monitoring well of this underground river section; Take the current judged downstream monitoring well as the new monitoring well, and obtain the new judged downstream monitoring well of the new monitoring well, and so on, until there is no longer a judged downstream monitoring well for the new monitoring well, so as to obtain all the monitoring wells included in this underground river section.

4. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 3, wherein, The specific steps of the similarity of water flow fluctuations include: Denote any one of the suspected downstream monitoring wells of the target monitoring well as the second monitoring well; for the target monitoring well and the second monitoring well, obtaining the similarity of water flow fluctuations between the target monitoring well and the second monitoring well includes: Denote the inverse proportional normalization value of the DTW distance after dynamic time warping of the historical water flow sequences of the target monitoring well and the second monitoring well as the water flow trend approximation degree of the target monitoring well and the second monitoring well; Denote the product of the water flow trend approximation degree of the target monitoring well and the second monitoring well and the spatial difference weight of the target monitoring well and the second monitoring well as the similarity of water flow fluctuations between the target monitoring well and the second monitoring well.

5. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 4, wherein The specific steps of the degree of connection of solution products include: Denote the sum of the differences in the mineral dissolution content of the target monitoring well and the second monitoring well at each sampling time of each day as the mineral dissolution content increment of the target monitoring well and the second monitoring well; Denote the product of the inverse proportional normalization value of the mineral dissolution content increment and the spatial difference weight of the target monitoring well and the second monitoring well as the degree of connection of solution products between the target monitoring well and the second monitoring well.

6. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein The analysis of the intersection situation of the underground river section to obtain several tidal suspected connection points and their several marked wells includes: Obtain all the intersection points of the underground river sections and the corresponding underground river sections in the underground river section pipe network diagram; If the distance between the positions of multiple intersection points is less than or equal to the preset position distance threshold, denote the centroid of these multiple intersection points as a tidal suspected connection point, and the tidal suspected connection point inherits the corresponding underground river sections of these multiple intersection points; If the position distance between a junction point and all other junction points is greater than a preset position distance threshold, mark this junction point as a suspected tidal connection point, and the suspected tidal connection point inherits the corresponding underground river section of this junction point; Among all the monitoring wells of each underground river section corresponding to each suspected tidal connection point, mark the monitoring well with the closest position distance to the suspected tidal connection point as the respective marked well of each suspected tidal connection point.

7. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein The specific steps for the high water flow date include: Obtain the average value of the water flow rates of each marked well of each suspected tidal connection point at all sampling times on all days, and denote it as the daily average water flow rate of each marked well of each suspected tidal connection point; Obtain the average value of the water flow rates of each marked well of each suspected tidal connection point at all sampling times of each day, and denote it as the average water flow of each marked well of each suspected tidal connection point on each day; Mark the dates when the average water flow of each marked well of each suspected tidal connection point is greater than the daily average water flow rate as the high water flow dates of each marked well of each suspected tidal connection point.

8. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein The specific steps for the several tidal well channels and their connected river sections include: Utilize the mineral dissolution content of each marked well of each suspected tidal connection point at each sampling time during all high water flow dates to construct the mineral dissolution matrix of each suspected tidal connection point; Calculate the covariance matrix of the mineral dissolution matrix of each suspected tidal connection point, and obtain the eigenvectors of the covariance matrix through the principal component analysis algorithm; Arrange the eigenvalues of the eigenvectors of the covariance matrix in descending order, and denote it as the descending principal component sequence of each suspected tidal connection point; Denote the difference between the eigenvalue of each eigenvector and the eigenvalue of the next eigenvector in the descending principal component sequence of each suspected tidal connection point as the principal component decision coefficient of each eigenvector of each suspected tidal connection point; Denote the serial number of the eigenvector with the largest principal component decision coefficient in the descending principal component sequence as the number of principal component directions of the mineral dissolution matrix of each suspected tidal connection point; If the number of principal component directions of the mineral dissolution matrix of each suspected tidal connection point is greater than or equal to the number of marked wells of each suspected tidal connection point, mark this suspected tidal connection point as a tidal well channel, and mark the underground river section corresponding to the marked well of this suspected tidal connection point as the connected river section of this tidal well channel.

9. The method for tracing the source of groundwater pollution based on sewage pipeline data according to claim 1, wherein Pollution source tracing is carried out through the intersection situation of the connected river sections obtained by connecting all the connected river sections of the same tidal well channel in the underground river section pipeline network diagram and each sewage pipeline and its inspection points, including: Connect all the connected river sections of the same tidal well channel in the underground river section pipeline network diagram to obtain several through-connected river sections; Regard both the through-connected river sections and the underground river sections as traceable rivers. Denote all the sewage pipelines that intersect with the existing polluted traceable rivers as suspected sewage pipelines, and denote the nearest inspection point upstream of the suspected sewage pipeline at the intersection position of the polluted traceable river and each suspected sewage pipeline as the tracer inspection point of each suspected sewage pipeline; Starting from the suspected sewage pipeline at the farthest downstream of the traceable river with pollution, an isotope is placed at the tracer inspection point of the suspected sewage pipeline at the farthest downstream, and the tracer is monitored in the monitoring well closest to the tracer inspection point. If the tracer is detected, the tracer inspection point is marked as the leakage inspection point; if the tracer is not detected, it is judged towards the suspected sewage pipeline adjacent upstream of the traceable river with pollution until the leakage inspection point is obtained.

10. A groundwater pollution source tracing system based on sewage pipeline data, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the groundwater pollution tracing method based on sewage pipeline data according to any one of claims 1-9.

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