Fresh water ecosystem damage evaluation method and system

Abstract

The invention discloses a fresh water ecosystem damage evaluation method and system.The method comprises the steps that firstly, evaluation indexes are determined, an evaluation system is constructed, then an ecological evaluation baseline A is determined based on the evaluation system, and the ecological evaluation baseline A comprises the steps that the ecological evaluation baselines A1 of the indexes are determined through a 25% / 75% quantile method and a trisection method respectively and verified mutually; and constructing a fresh water ecological baseline database based on existing data, and supplementing an ecological evaluation baseline A2 of an index which cannot be covered. On the basis of the ecological evaluation base line A, calculating a total ecological damage index of water ecology, and finally, corresponding to a water ecological damage degree grade, so as to finish evaluation; according to the method, multiple ecological element indexes are comprehensively considered to construct the index system so as to highlight the local damage condition of ecological system components, and the 25% / 75% quantile method and the trisection method are adopted to determine the ecological base line and verify each other, so that the reliability of the ecological base line is improved, the calculation error of a single means is reduced, and the accuracy of an evaluation result is further improved. Therefore, the method is high in accuracy.

Description

Technical Field

[0001] The invention relates to ecological assessment means, belongs to the field of freshwater ecological assessment, and in particular to a freshwater ecosystem damage assessment method and system. Background Art

[0002] Ecological environmental damage refers to the adverse changes in environmental elements such as the atmosphere, surface water, groundwater, soil, forests, and biological elements such as plants, animals, and microorganisms caused by environmental pollution and ecological destruction, as well as the degradation of ecosystem functions composed of the above elements. Freshwater ecosystems have become the most widespread place for ecological damage incidents, directly or indirectly causing a large amount of freshwater ecological damage.

[0003] The quantification of the value of ecological damage is a difficult point in the definition of ecological environmental compensation. The main reason is the lack of a systematic ecological damage evaluation index system, which makes it difficult to accurately quantify the degree of damage to the ecological environment. Therefore, the scientific quantification of the degree of ecological environmental damage is an important prerequisite and key link for improving the ecological environmental compensation system. In order to solve this problem, the existing technology has used reference point method to qualitatively evaluate the damage to grassland environment and the control area method to evaluate the probability of damage to polluted soil environment. However, due to the late start of research on ecological environmental damage assessment, there are few systematic damage assessments for freshwater ecology. In addition, since the functions and services of the ecosystem are synergistically provided by its various components, the independent evaluation of a single ecological indicator in the past cannot objectively reflect the actual damage status of the ecosystem, resulting in low accuracy of the evaluation results. Therefore, there is an urgent need for a more accurate method to solve the above-mentioned defects in the existing technology. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects and problems of low accuracy in the prior art and to provide a freshwater ecosystem damage assessment method and system with high accuracy.

[0005] To achieve the above objectives, the technical solution of the present invention is: a method for assessing damage to freshwater ecosystems, comprising:

[0006] S1. Determine the freshwater ecological damage assessment indicators and construct a freshwater ecosystem assessment system based on the analytic hierarchy process;

[0007] S2. Based on the freshwater ecosystem assessment system, determine the ecological assessment baseline A; the ecological assessment baseline A includes the following parts:

[0008] Part I: Determine the ecological evaluation baseline A1 of the indicator using the 25% / 75% quantile method and the three-point method and verify each other;

[0009] Part II: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological assessment baseline A2 for indicators that cannot be covered by the ecological assessment baseline A1;

[0010] S3. Calculate the overall ecological damage index of water ecology based on the ecological assessment baseline A;

[0011] S4. Match the overall ecological damage index of water ecology with the degree of water ecological damage, determine the degree of water ecological damage corresponding to the overall ecological damage index of water ecology, and complete the evaluation of the degree of water ecological damage in the target area.

[0012] In step S2, the ecological assessment baseline A1 specifically includes:

[0013] S21. Obtain ecological data samples corresponding to the freshwater ecological damage assessment indicators in the freshwater ecosystem assessment system and construct a water ecological data set; and based on the number of samples in the water ecological data set, calculate the ecological data using any of the following methods:

[0014] The first method: if the number of samples is ≥ 9, proceed to step S22 to determine the ecological evaluation baseline of the indicator using the 25% / 75% quantile method and the three-point method;

[0015] The second method: if the number of samples is less than 9, the freshwater ecological baseline database is used to assign values ​​and determine the ecological evaluation baseline of the indicator;

[0016] S22. Based on the 25% / 75% quantile method and the three-part method, the response of each indicator in the water ecological data set to interference is compared with the preset standard basis; the comparison result includes any one of the following:

[0017] The first type: if the indicator responds to interference by increasing, the 25% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the smallest 1 / 3 data is used as the second ecological evaluation baseline;

[0018] The second type: if the indicator responds to the disturbance by decreasing, the 75% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the largest 1 / 3 data is used as the second ecological evaluation baseline;

[0019] S23, comparing the first ecological evaluation baseline with the second ecological evaluation baseline, determining a low value and a high value between the two, and then comparing the difference between the low value and the high value; the comparison result includes any one of the following:

[0020] The first type: if the low value × 1.25 < the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is large, and the outliers in the water ecological data set need to be removed, and step S22 is performed again until the low value × 1.25 ≥ the high value;

[0021] The second type: if the low value × 1.25 ≥ the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is small, and step S24 is performed;

[0022] S24. Based on the box plot method, the ecological data samples of the 25% / 75% quantile method and the three-point method are used as reference points, and the overlap of the interquartile ranges of the reference points and the damaged points is scored to determine the environmental pressure discrimination ability of the freshwater ecological damage assessment indicators corresponding to the first ecological assessment baseline and the second ecological assessment baseline;

[0023] The reference point of the 25% / 75% quantile method is the first 25% or the last 25% of the ecological data samples; the reference point of the three-part method is the 1 / 3 ecological data samples with the largest value or the 1 / 3 ecological data samples with the smallest value;

[0024] The judgment result includes any of the following:

[0025] The first method: if the ecological data sample of the indicator does not have the ability to distinguish environmental pressure, the freshwater ecological baseline database is used to assign a value to the indicator;

[0026] The second type: if the ecological data sample of the indicator has the ability to distinguish environmental pressure, proceed to step S25;

[0027] S25. Compare the number of freshwater ecological damage assessment indicators with environmental pressure discrimination capabilities determined by the 25% / 75% quantile method and the three-point method, and select the group with the larger number of indicators as the ecological assessment baseline A1; if the number is the same, select the average of the 25% / 75% quantile method and the three-point method as the ecological assessment baseline A1.

[0028] In step S24, the scoring rules are as follows:

[0029] If the interquartile ranges of the reference point and the damaged point do not overlap, the score is 3; if the interquartile ranges of the reference point and the damaged point partially overlap, but their medians are outside the interquartile range of the other party, the score is 2; if only one median of the reference point or the damaged point is within the interquartile range of the other party, the score is 1; if the medians of the reference point and the damaged point are both within the interquartile range of the other party, the score is 0;

[0030] Based on the above scoring rules, if the score of a reference point is ≥2, it means that the reference point has the ability to distinguish environmental pressure; if the score of a reference point is <2, it means that the reference point’s ability to distinguish environmental pressure is insufficient.

[0031] In step S21, if the number of ecological data samples corresponding to the freshwater ecological damage assessment index is ≥ 9 groups, it is necessary to check whether there are outliers in the ecological data samples; if there are outliers, it is necessary to remove the outliers and then construct them into a water ecological data set.

[0032] In step S3, the calculation formula for calculating the overall ecological damage index of the water ecology is as follows:

[0033] TEDI=TEDI 1 ×0.3+TEDI 2 ×0.7;

[0034] Among them: TEDI is the overall ecological damage index of water ecology, TEDI 1 TEDI is the environmental quality damage index. 2 is the ecological function damage index, 0.3 and 0.7 are weights;

[0035]

[0036] Among them: TEDI i For TEDI 1 or TEDI 2 The ecological damage index of the ith sub-goal in the evaluation system of freshwater ecosystems is S, which is the number of criteria or indicators in the evaluation system of freshwater ecosystems. i is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system, CEDI i is the ecological damage index of the ith criterion in the freshwater ecosystem assessment system, n is the number of criteria or indicators that lack ecological data samples in the freshwater ecosystem assessment system, and W ni is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system that lacks ecological data samples. i is the ecological damage index of the ith indicator in the freshwater ecosystem assessment system, T i is the measured value of the ith indicator, B i is the ecological evaluation baseline of the ith indicator.

[0037] In step S1, the freshwater ecosystem evaluation system includes: a target layer, a sub-target layer, a criterion layer, and an indicator layer;

[0038] The target layer includes the overall ecological damage index;

[0039] The sub-target layers include environmental quality damage index and ecological function damage index;

[0040] The criteria layer includes comprehensive water quality, sediment pollution status, phytoplankton integrity, zooplankton integrity, benthic zoo integrity, fish integrity, biological production capacity, and water supply capacity;

[0041] The indicator layer includes water pH, water transparency, total nitrogen concentration in water, total phosphorus concentration in water, concentration of permanganate index in water, dissolved oxygen content in water, total nitrogen concentration in sediment, total phosphorus concentration in sediment, heavy metal ecological risk index, phytoplankton Margalef index, phytoplankton Shannon index, phytoplankton Pielou index, total phytoplankton density, proportion of cyanobacteria density, proportion of diatom density, zooplankton Margalef index, zooplankton Shannon index, zooplankton Pielou index, proportion of rotifer density, benthic zoo Margalef index, benthic zoo Shannon index, benthic zoo Pielou index, benthic zoo BPI index, fish retention index, ratio of water transparency to water depth, annual water storage capacity of lakes and reservoirs, ecological flow satisfaction of rivers, and drinking water compliance rate.

[0042] The ecosystem assessment system construction module is used to determine the freshwater ecological damage assessment indicators and construct a freshwater ecosystem assessment system based on the analytic hierarchy process;

[0043] The ecological assessment baseline confirmation module is used to determine the ecological assessment baseline A based on the freshwater ecosystem assessment system; the ecological assessment baseline A includes the following parts:

[0044] Part I: Determine the ecological evaluation baseline A1 of the indicator using the 25% / 75% quantile method and the three-point method and verify each other;

[0045] Part II: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological assessment baseline A2 for indicators that cannot be covered by the ecological assessment baseline A1;

[0046] The ecological damage index confirmation module is used to calculate the overall ecological damage index of the water ecology based on the ecological assessment baseline A;

[0047] The ecological damage degree evaluation module is used to correspond the overall ecological damage index of water ecology with the water ecological damage degree level, determine the water ecological damage degree level corresponding to the overall ecological damage index of water ecology, and complete the evaluation of the water ecological damage degree in the target area.

[0048] Preferably, the content of the ecological assessment baseline confirmed by the ecological assessment baseline confirmation module can be found in the corresponding part of Example 1;

[0049] Preferably, the content of the ecological damage degree evaluation module evaluating the ecological damage degree can be found in the corresponding part of Example 1;

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. In a freshwater ecosystem damage assessment method and system of the present invention, the method first determines the assessment index and constructs a freshwater ecosystem assessment system, and then determines the ecological assessment baseline A based on the freshwater ecosystem assessment system, which includes the ecological assessment baseline A1 of the indicators determined by the 25% / 75% quantile method and the three-part method and mutually verified; and the freshwater ecological baseline database is constructed based on the existing data, and the ecological assessment baseline A2 of the indicators that cannot be covered by the ecological assessment baseline A1 is supplemented; then, based on the ecological assessment baseline A, the overall ecological damage index of the water ecology is calculated, and finally the water ecological damage degree level is corresponded to complete the assessment; in the application of this design, a variety of ecological element indicators are comprehensively considered to construct an indicator system to highlight the local damage of the ecosystem components, and the 25% / 75% quantile method and the three-part method are used to determine the ecological baseline and mutually verified to improve the reliability of the ecological baseline, reduce the calculation error of a single means, and further improve the accuracy of the evaluation results. Therefore, the accuracy of the present invention is relatively high.

[0052] 2. In a freshwater ecosystem damage assessment method and system of the present invention, the method adopts the 25% / 75% quantile method and the three-part method to determine the ecological assessment baseline of the indicator, and conducts mutual verification; in the application of this design, the method pays more attention to the distribution of the middle part of the data, eliminates the excessive interference of extreme values ​​on the ecological baseline, so that the distribution trend of ecological data can be grasped from a macro perspective, and the similar results obtained by the two methods are mutually verified, which greatly enhances the credibility of the ecological baseline results.

[0053] 3. In the method and system for evaluating damage to a freshwater ecosystem of the present invention, the established freshwater ecosystem evaluation system includes a target layer, a sub-target layer, a criterion layer, and an indicator layer, and further clarifies various potential influencing factors in the criterion layer and the indicator layer, such as comprehensive water quality, sediment pollution status, phytoplankton and animal integrity, pH fish retention index, etc. In the application of this design, the system not only pays attention to the environment and function of the ecosystem, but also makes the evaluation content more accurate, and can highlight the local damage of the ecosystem components, so as to more effectively identify specific ecological and environmental problems and their causes, and provide decision makers with clearer intervention directions for compensation and restoration of the ecosystem. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a flow chart of the method steps of the present invention.

[0055] Figure 2 It is one of the freshwater ecosystem evaluation system tables in the present invention.

[0056] Figure 3It is one of the freshwater ecosystem evaluation system tables in the present invention.

[0057] Figure 4 It is one of the freshwater ecosystem evaluation system tables in the present invention.

[0058] Figure 5 It is a schematic diagram of the ecological baseline calculation process in the present invention.

[0059] Figure 6 This is a distribution map of the Honghu sampling points in Example 1 of the present invention.

[0060] Figure 7 It is a schematic diagram of the ecological assessment baseline of Honghu Lake and Weihe River in Example 1 of the present invention.

[0061] Figure 8 It is a schematic diagram of the environmental pressure discrimination capability analysis of the Honghu reference point in Example 1 of the present invention.

[0062] Fig. 9 It is a schematic diagram of the water ecosystem damage index of Honghu Lake in Example 1 of the present invention.

[0063] Fig.10 It is a schematic diagram of the water ecosystem damage index of the Weihe River in Example 1 of the present invention.

[0064] Fig.11 It is a schematic diagram of sensitivity analysis of the criterion factors of the Honghu Lake and Weihe River ecosystem damage assessment index system in Example 1 of the present invention.

[0065] Fig.12 It is a schematic diagram of the system structure of the present invention.

[0066] Fig.13 This is a schematic diagram of the freshwater ecological baseline database in Example 1 of the present invention.

[0067] In the figure: ecosystem assessment system construction module 1, ecological assessment baseline confirmation module 2, ecological damage index confirmation module 3, ecological damage degree assessment module 4. DETAILED DESCRIPTION

[0068] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0069] Embodiment 1:

[0070] See also Figure 1 , a method for assessing damage to freshwater ecosystems, comprising:

[0071] S1. Determine the freshwater ecological damage assessment indicators and construct a freshwater ecosystem assessment system based on the analytic hierarchy process;

[0072] In the application, the selection of evaluation indicators is the premise of building an evaluation indicator system. In this scheme, according to the framework requirements of water ecological damage evaluation in relevant guidelines and literature, the evaluation content including water environment, aquatic organisms and water ecological functions is formulated; at the same time, the indicators are selected based on the following principles: (1) Systematicity: the indicators are required to be able to scientifically and comprehensively reflect the health and function of water ecology; (2) Measurability: the degree of excellence of the indicators can be analyzed and compared through data quantification; (3) Accessibility: the indicators can obtain sufficient data based on existing literature or can obtain data quickly through ecological surveys; (4) Non-repetitiveness: that is, the same indicators are not calculated or evaluated repeatedly. Based on the above evaluation content and selection principles, a total of 28 specific indicators were selected for the construction of freshwater ecosystem evaluation system.

[0073] Then the evaluation contents and indicators were classified and integrated. In this scheme, the analytic hierarchy process (AHP) was used to construct the freshwater ecosystem evaluation system. Finally, the target layer was defined as the overall ecological damage index (T). Considering that many functions of the ecosystem are actually provided by organisms, aquatic organisms were incorporated into the ecological function, and the target layer was divided into two sub-targets, namely the environmental quality damage index (T1) and the ecological function damage index (T2). The environmental quality damage index was further divided into two criteria (C1-C2) and nine indicators (I1-I9), and the ecological function damage index had six criteria (C3-C8) and 19 indicators (I10-I28). Among them, the indicators used to evaluate non-drinking water sources (mainly rivers and lakes) are I1-I27, and the indicators used to evaluate drinking water sources (mainly reservoirs) are I1-I28. After the construction of the index system is completed, the judgment matrix is ​​constructed for the sub-target layer, the criterion layer, and the index layer, and the factors in the judgment matrix are compared with each other through the expert evaluation method to determine their relative importance and complete the weight scoring. After the judgment matrix passes the consistency test, the geometric mean of the weights of each factor is taken as its final weight. Compared with the existing ecological health and ecological integrity evaluation systems, the ecological damage evaluation system constructed by this plan not only focuses on the environment and function of the ecosystem, but also has more accurate evaluation content and can highlight the local damage of the ecosystem components, so as to more effectively identify specific ecological and environmental problems and their causes, and provide decision makers with clearer intervention directions for compensation and restoration of the ecosystem.

[0074] For the specific freshwater ecosystem evaluation system, the response of each indicator to disturbance, data acquisition method and setting basis, please refer to Figure 2-Figure 4 .

[0075] S2. Based on the freshwater ecosystem assessment system, determine the ecological assessment baseline A; the ecological assessment baseline A includes the following parts:

[0076] Part 1: Determine the ecological evaluation baseline A1 of the indicators by using the 25% / 75% quantile method and the three-point method respectively and verify each other; Part 2: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological evaluation baseline A2 of the indicators that cannot be covered by the ecological evaluation baseline A1;

[0077] In application, the determination of ecological baseline is one of the core issues of ecological damage assessment. According to relevant standard documents, the priority of the methods for determining indicator baselines is historical data method, control area method, environmental quality standard benchmark method, and special research method. Among them, both the historical data method and the control area method require the use of data before environmental pollution or ecological damage occurs, and select the 10% or 90% quantile (indicators whose values ​​increase and decrease due to interference) of historical or control area data as the baseline; however, due to long-term development activities, some water bodies may have been irreversibly transformed by human beings for a certain period of time, and there is a problem of insufficient effective historical data due to the lack of indicators and frequency of water monitoring in the past. Therefore, it is not realistic to strictly follow the historical data method and control area method in the standard to formulate ecological baselines. In addition, the current ecological environmental damage events are mainly caused by short-term ecological damage or illegal production and discharge, rather than long-term production activities; it is only necessary to select sample points with good ecological environment from the water bodies where ecological environmental damage appraisal is carried out as reference points to formulate ecological baselines, so as to quickly and accurately identify the source of damage and the scope of damage in the damaged water bodies. If the ecological evaluation baseline A of the indicator can be determined by the 25% / 75% quantile method and the three-part method, then the ecological evaluation baseline A1 will be used as the ecological evaluation baseline A; if the ecological evaluation baseline A of the indicator cannot be determined by the 25% / 75% quantile method and the three-part method, then after the ecological evaluation baseline A1 is determined, a freshwater ecological baseline database will be constructed based on the existing data, and the ecological evaluation baseline A2 of the indicators that cannot be covered by the ecological evaluation baseline A1 will be supplemented, and the ecological evaluation baseline A1 and the ecological evaluation baseline A2 will be combined to determine the ecological evaluation baseline A.

[0078] Therefore, the ecological assessment baseline for ecological damage identification needs to be re-established based on relevant standards and actual needs. Finally, the 25% / 75% quantile and the three-point method are used together as the method for calculating the indicator ecological assessment baseline. The calculation process is shown in Figure 5 The freshwater ecological baseline database can be found at Fig.13 :

[0079] S21. Obtain ecological data samples corresponding to the freshwater ecological damage assessment indicators in the freshwater ecosystem assessment system and construct a water ecological data set; and based on the number of samples in the water ecological data set, calculate the ecological data using any of the following methods:

[0080] The first method: if the number of samples is ≥ 9, proceed to step S22 to determine the ecological evaluation baseline of the indicator using the 25% / 75% quantile method and the three-point method;

[0081] The second method: if the number of samples is less than 9, the freshwater ecological baseline database is used to assign values ​​and determine the ecological evaluation baseline of the indicator;

[0082] Furthermore, if the number of ecological data samples corresponding to the freshwater ecological damage assessment index is ≥ 9 groups, it is necessary to check whether there are outliers in the ecological data samples; if there are outliers, it is necessary to remove the outliers and then construct them into a water ecological data set.

[0083] S22. Based on the 25% / 75% quantile method and the three-part method, the response of each indicator in the water ecological data set to interference is compared with the preset standard basis; the comparison result includes any one of the following:

[0084] The first type: if the indicator responds to interference by increasing, the 25% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the smallest 1 / 3 data is used as the second ecological evaluation baseline;

[0085] The second type: if the indicator responds to the disturbance by decreasing, the 75% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the largest 1 / 3 data is used as the second ecological evaluation baseline;

[0086] S23, comparing the first ecological evaluation baseline with the second ecological evaluation baseline, determining a low value and a high value between the two, and then comparing the difference between the low value and the high value; the comparison result includes any one of the following:

[0087] The first type: if the low value × 1.25 < the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is large, and the outliers in the water ecological data set need to be removed, and step S22 is performed again until the low value × 1.25 ≥ the high value;

[0088] The second type: if the low value × 1.25 ≥ the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is small, and step S24 is performed;

[0089] S24. Based on the box plot method, the ecological data samples of the 25% / 75% quantile method and the three-point method are used as reference points, and the overlap of the interquartile ranges of the reference points and the damaged points is scored to determine the environmental pressure discrimination ability of the freshwater ecological damage assessment indicators corresponding to the first ecological assessment baseline and the second ecological assessment baseline;

[0090] Furthermore, if the interquartile ranges of the reference point and the damaged point do not overlap, the score is 3; if the interquartile ranges of the reference point and the damaged point partially overlap, but the medians of each are outside the interquartile range of the other, the score is 2; if only one median of the reference point or the damaged point is within the interquartile range of the other, the score is 1; if the medians of the reference point and the damaged point are both within the interquartile range of the other, the score is 0;

[0091] Based on the above scoring rules, if the score of a reference point is ≥2, it means that the reference point has the ability to distinguish environmental pressure; if the score of a reference point is <2, it means that the reference point’s ability to distinguish environmental pressure is insufficient.

[0092] The reference point of the 25% / 75% quantile method is the first 25% or the last 75% of the ecological data samples; the reference point of the three-part method is the 1 / 3 ecological data samples with the largest value or the 1 / 3 ecological data samples with the smallest value;

[0093] The judgment result includes any of the following:

[0094] The first method: if the ecological data sample of the indicator does not have the ability to distinguish environmental pressure, the freshwater ecological baseline database is used to assign a value to the indicator;

[0095] The second type: if the ecological data sample of the indicator has the ability to distinguish environmental pressure, proceed to step S25;

[0096] S25. Compare the number of freshwater ecological damage assessment indicators with environmental pressure discrimination capabilities determined by the 25% / 75% quantile method and the three-point method, and select the group with the larger number of indicators as the ecological assessment baseline A1; if the number is the same, select the average of the 25% / 75% quantile method and the three-point method as the ecological assessment baseline A1.

[0097] S3. Based on the final ecological assessment baseline A, calculate the overall ecological damage index of the water ecology;

[0098] In this scheme, according to the constructed freshwater ecosystem damage assessment system, a relevant calculation method is set to calculate the total ecological damage index (TEDI) of the water ecology; the calculation formula of the total ecological damage index of the water ecology is as follows:

[0099] TEDI=TEDI 1 ×0.3+TEDI 2 ×0.7;

[0100] Among them: TEDI is the overall ecological damage index of water ecology, TEDI 1 TEDI is the environmental quality damage index. 2 is the ecological function damage index, 0.3 and 0.7 are weights;

[0101]

[0102] Among them: Among them: TEDI i For TEDI 1 or TEDI 2 The ecological damage index of the ith sub-goal in the evaluation system of freshwater ecosystems is S, which is the number of criteria or indicators in the evaluation system of freshwater ecosystems. i is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system, CEDI i is the ecological damage index of the ith criterion in the freshwater ecosystem assessment system, n is the number of criteria or indicators that lack ecological data samples in the freshwater ecosystem assessment system, and W ni is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system that lacks ecological data samples. i is the ecological damage index of the ith indicator in the freshwater ecosystem assessment system, T i is the measured value of the ith indicator, B i is the ecological evaluation baseline of the ith indicator.

[0103] S4. Match the overall ecological damage index of water ecology with the degree of water ecological damage, determine the degree of water ecological damage corresponding to the overall ecological damage index of water ecology, and complete the evaluation of the degree of water ecological damage in the target area.

[0104] In this scheme, the degree of water ecological damage is graded according to the size of the ecological damage index. The larger the value, the higher the degree of ecological damage. Specifically, if TEDI < 1.2, it means that the degree of water ecological damage in the target area is not damaged; if 1.2 ≤ TEDI < 1.5, it means that the degree of water ecological damage in the target area is slightly damaged; if 1.5 ≤ TEDI < 2, it means that the degree of water ecological damage in the target area is moderately damaged; if TEDI ≥ 2, it means that the degree of water ecological damage in the target area is severely damaged.

[0105] By matching the calculated overall ecological damage index of water ecology with the degree of water ecological damage in the target area, the degree of water ecological damage in the target area can be evaluated.

[0106] Note: Figure 2-Figure 4 In the freshwater ecosystem evaluation system table: a means it is only used to evaluate lakes and reservoirs; b means it is only used to evaluate rivers; c means it is only used to evaluate reservoirs or lakes designated as water sources.

[0107] In formulas (1) and (2), NIRI is the comprehensive ecological risk of heavy metals. The potential ecological risk of heavy metal i, and They are The maximum and average values ​​of is the toxicity coefficient of heavy metal i, C i is the actual concentration of heavy metal i, S i is the environmental background value of heavy metal i; in formulas (3), (4) and (5), N is the sum of the number of individuals of all species in the community, S is the total number of species in the community, and Pi is the proportion of individuals belonging to the i-th species in the sample; in formula (6), P D is the percentage of cyanobacteria density, D D is the density of cyanobacteria, D P is the total density of phytoplankton; in formula (7), P c is the density ratio of diatoms, D C is the diatom density, D P is the total density of phytoplankton; in formula (8), P R is the density ratio of rotifers, D R is the rotifer density, D Z is the total density of zooplankton; in formula (9), n 1 is the number of oligochaetes, leeches and chironomid larvae, 2 is a constant set to avoid the numerator or denominator having a value of 0, n 2 is the number of individuals of polychaetes, crustaceans, and other aquatic insects except chironomid larvae, n 3 is the number of molluscs, see the relevant ecological environment standard HJ 1295-2023 for details; in formula (10), FOEI is the fish stock index, FO is the number of fish species measured (excluding alien species), and FE is the number of fish species monitored in the waters before 1980. Since the result of this indicator is a relative value, if the FE of the water area cannot be obtained, the current number of fish species in the water area (excluding alien species) can be used instead; in formula (11), W S is the annual storage capacity of the lake, S is the lake area, ΔH is the difference between the normal water level and the water level required for the minimum ecological water demand, n is the number of water re-storage times, which refers to the frequency of repeated water storage and drainage in the river within a year, and n=1.5 in normal water years; the ecological flow satisfaction is the percentage of the measured daily flow of the river section to the multi-year average flow in the corresponding period.

[0108] Based on the above scheme, Honghu Lake and Weihe River are selected as application cases of lakes and rivers in this embodiment. Among them, Honghu Lake is located on the north bank of the middle reaches of the Yangtze River and is the seventh largest freshwater lake in China. Honghu Lake has a subtropical humid monsoon climate, with an average annual temperature of 16.6℃, a precipitation of about 1,300 mm, and the rainy season accounts for 77% of the annual precipitation. Honghu Lake has ecological functions such as flood control, irrigation, aquatic product supply and biodiversity protection. The Weihe River is the largest tributary of the Yellow River, with a total length of 818 kilometers, flowing through Gansu, Ningxia and Shaanxi. The Weihe River Basin has a temperate continental climate, with an average annual temperature of 6-14℃ and an annual precipitation of about 500 mm, with precipitation mainly concentrated in summer. The Weihe River has functions such as irrigation, flood control and water supply, and is an important water source for the Guanzhong Plain in Shaanxi. However, in the past few decades, due to human activities and climate change, the runoff of Honghu Lake and Weihe River has decreased year by year, and seasonal dry-up has occurred in some sections of the river. Therefore, the dramatic changes in Honghu Lake and Weihe River reflect the ecological succession characteristics of typical water bodies under the background of human disturbance. Taking them as assessment areas can provide reference for the identification and evaluation of damage to freshwater ecosystems.

[0109] like Figure 6 As shown in the figure, S1-S50 are the sampling points of the water ecological samples of Honghu Lake for evaluation; the water ecological data of Weihe River were collected from the literature. Among them, the collection and detection steps of Honghu Lake water samples are as follows: use a plexiglass water sampler to collect 1L of water samples from the surface, middle and bottom layers of the same sampling point, respectively, and use a multi-parameter water quality meter (EXO2; USA) to detect (pH), dissolved oxygen (DO) and chlorophyll a on-site after sufficient mixing. Use a Secchi disk and a plumb bob to measure transparency (SD) and water depth (WD) on-site, respectively. Then take 500mL of the mixed sample and seal it in a polyvinyl chloride plastic bottle for storage, and send it to the laboratory within 24 hours. According to the "Water and Wastewater Monitoring Methods", the total nitrogen (TN), total phosphorus (TP), and permanganate index (COD M n). The steps for collecting and testing sediments are as follows: Use a Peterson sampler (1 / 32m 2) Sediment samples were collected three times at one sampling point. After the samples were thoroughly mixed, 500 g were taken and stored in sealed bags. After the samples were air-dried, they were sieved through a 180-mesh sieve to determine STN and STN. The detection of heavy metals was as follows: As was determined by atomic fluorescence spectrometry (DZ / T0279.13-2016), Hg was determined by cold atomic fluorescence spectrometry (DZ / T0279.17-2016), Cr, Ni, Cu, Zn, Cd, and Pb were determined by aqua regia extraction-inductively coupled plasma mass spectrometry (HJ803-2016), and Mn was determined by inductively coupled plasma atomic emission spectrometry (DZ / T0279.2-2016). The collection and identification process of biological samples was as follows: The collection and concentration of phytoplankton and zooplankton were consistent with the previous research of the research team, and the main references were used for identification; for benthic animals, a Peterson mud sampler (1 / 32m 2 ) 3 mud samples were collected, and their pretreatment, selection, fixation and identification were referred to the literature; fish were collected using 3 layers of gill nets (50m×1.8m) and ground traps (20m×0.3m×0.4m), and the samples were fixed with 5% formaldehyde to prepare specimens. All biological specimens were identified to species as much as possible, and those that could not be completely identified were identified to genus.

[0110] Based on the baseline determination method of this scheme, the baselines of Honghu Lake water ecological indicators I1 to I26 were calculated using both the 3-point method and the 25% / 75% quantile. The results are shown in Figure 7 .

[0111] The box plot was drawn to test the discrimination ability of the reference point environmental pressure used in the 3-point method and the 25% / 75% quantile method. The results are shown in Figure 8 .

[0112] According to the results, the scores of indicators I1 to I26 at the reference point used in the 3-point method are all 3, which has a good ability to distinguish environmental pressure. The scores of indicators I1 to I26 at the reference point used in the 25% / 75% quantile are also all 3, which has a good ability to distinguish environmental pressure. This shows that the number of indicators with sufficient environmental pressure discrimination ability determined by the reference points used in the 3-point method and the 25% / 75% quantile method is the same, so the ecological baseline of indicators I1 to I26 is the average of the baselines determined by these two methods. In addition, since indicator I27 is the annual water storage capacity, it cannot be obtained based on the 3-point method and the 25% / 75% quantile method. It is calculated according to the formula (11) in the water supply capacity based on the multi-year water level data of Honghu Lake. The results are shown in Figure 7At the same time, the ecological baseline of the Weihe River was calculated using the same method. Among them, indicators I1 to I6, I9 to I13, I16 to I16, I21 to I23, I25 to I27 are the average values ​​of the baselines determined by the 3-point method and the 25% / 75% quantile method. Since the data volume of indicators I7, I8, I14, I15, and I24 is insufficient, the environmental quality standard benchmark and the freshwater ecological baseline data constructed by existing studies are used to assign values.

[0113] Based on the constructed freshwater ecosystem assessment system, ecosystem damage assessments were completed for Honghu Lake and Weihe River.

[0114] The results of Honghu Lake can be found in Fig. 9 The results show that the average TEDI of Honghu Lake in June 2022 was 1.35, with a minimum of 0.90 and a maximum of 2.98. In terms of damage degree, the number of samples with mild damage was the largest, accounting for 52.0% of the total number of samples; followed by samples with no damage and severe damage, accounting for 27.0% and 16.0% respectively; the number of samples with severe damage was the smallest, accounting for 4.0%. In terms of damage contribution, the contribution of the ecological function damage index was higher than that of the environmental quality damage index, which was mainly manifested in the following aspects: (1) the ecological function damage index (average TEDI = 1.39) was higher than the environmental quality damage index (average TEDI = 1.28); (2) the frequency of moderate and severe damage to ecological functions (a total of 26.0%) was higher than that of environmental quality (a total of 6.0%). Specifically, the damage to ecological functions mainly stems from the damage to biological production capacity, phytoplankton integrity, benthic animal integrity, and zooplankton integrity, with average CEDIs of 2.06, 1.69, 1.46, and 1.44, respectively; while the damage to environmental quality mainly stems from the comprehensive water quality (average CEDI = 1.33) affected by SD, TP, and DO (average IEDIs of 1.62, 1.48, and 1.43, respectively).

[0115] The results of Weihe River can be found in Fig.10The average TEDI of the Weihe River from April 2017 to January 2018 was 4.03, with a minimum of 1.22 and a maximum of 9.49. In terms of damage degree, the most sample points suffered severe damage, accounting for 75.0% of the total number of sample points; the remaining 25.0% of the sample points suffered mild damage. In terms of damage contribution, the contribution of the ecological function damage index is still higher than that of the environmental quality damage index, which is mainly manifested in: (1) The ecological function damage index (average TEDI = 4.40) is higher than the environmental quality damage index (average TEDI = 2.99); (2) The frequency of severe damage to ecological function (75.0%) is higher than that of environmental quality (58.3%). Specifically, the damage to ecological functions mainly comes from the damage to phytoplankton integrity, zooplankton integrity and water supply capacity, with average CEDIs of 6.11, 5.74 and 5.40 respectively; while the damage to environmental quality mainly comes from the sediment pollution state (average CEDI = 3.24), followed by SD and TP in the comprehensive water quality (average IEDIs of 3.44 and 3.08 respectively).

[0116] Furthermore, the indicators screened in this plan cover water quality, sediment environment, aquatic biological integrity and ecological functions. However, in practical applications, due to the limitations of objective conditions such as evaluation cycle, detection technology, and investigation funds, it may not be possible to fully obtain the evaluation indicators provided by this study. At the same time, considering that the indicators covered by certain criteria (such as various indicators under the phytoplankton integrity criterion) are obtained simultaneously. Therefore, this plan analyzes the sensitivity and applicability of factors with relatively high data acquisition difficulty from the perspective of the criterion layer. Among them, the sensitivity analysis is based on the Morris method, which is completed by the R package "sensitivity". The results are as follows Fig.11 As shown in the figure, the more to the right the factor is, the more sensitive it is to the evaluation model, and the more to the top the factor is, the stronger its interaction with other factors is; in other words, the factors located to the upper right of the diagonal are more sensitive to the model results. Among them, there are three criterion factors that are sensitive to the water ecological damage index in Honghu Lake, including C1 (comprehensive water quality), C5 (benthic animal integrity), and C7 (biological production capacity); there are four criterion factors that are sensitive to the water ecological damage index in Weihe River, namely C1 (comprehensive water quality), C3 (phytoplankton integrity), C4 (zooplankton integrity) and C7 (biological production capacity). Therefore, in the future damage assessment of freshwater ecosystems, even if all indicators cannot be obtained due to conditions, the indicator data covered by these criteria should be guaranteed to be obtained first.

[0117] In addition, this study further tested the influence of criterion layer factors on TEDI to determine its applicability in this index system. First, five criteria with high data acquisition difficulty were selected, including C2 (sediment pollution status), C3 (phytoplankton integrity), C4 (zooplankton integrity), C5 (benthic animal integrity), and C6 (fish integrity); then, in the process of calculating TEDI, 1 to 3 criterion factors were removed in turn and TEDI' was calculated; then, the correlation (R) between TEDI and TEDI' linear fitting equation was further calculated. 2 ) and root mean square error (RMSE) are used to evaluate the accuracy of TEDI'. In order to ensure the credibility of the results, this scheme is based on the simultaneous satisfaction of R 2 >0.9 and RMSE <0.1 are considered sufficient evaluation accuracy. When ignoring the criteria C3 / C4 / C6, C2 and C3 / C3 and C6, and C2, C5, C6, the accuracy requirements can be met (0.9063≤R 2 ≤0.9917, 0.0224≤RMSE≤0.0991; when the criteria C2 / C5 / C6, C2 and C5 / C2 and C6 / C5 and C6, and C2, C5 and C6 are not considered, the accuracy requirements can be met (0.9824≤R 2 ≤0.9976, 0.0184≤RMSE≤0.0606). Since a high evaluation accuracy can still be obtained without considering these criteria in the process of ecosystem damage assessment, these criteria can be regarded as having high applicability.

[0118] For the first time, this plan has constructed an ecological environmental damage assessment system for freshwater ecosystems. In terms of assessment content, this assessment system has 1 goal, 2 sub-goals, 8 criteria, and 28 indicators from top to bottom, covering environmental quality and ecological functions. The selected indicators can not only meet the principles of systematicity, measurability, accessibility, and non-repetitiveness required for ecosystem assessment, but also apply to different types of freshwater ecosystems, and set weights for each level through expert scoring. Therefore, the assessment content can objectively reflect the damaged state of the ecosystem. On the ecological baseline, both the requirements of relevant standards and the judicial appraisal needs in public interest environmental litigation are referred to, specifically: the minimum number of samples (9) is higher than the requirements of relevant standards (5); the sample points with better ecological environment in the assessment waters are preferred as reference points to calculate the baseline, and the results of the methods provided by relevant standards (environmental quality standard benchmarks and special research) are used as alternative baselines. This design combined with relevant standards and legal needs makes the baseline have a strong reference value in practical applications such as environmental public interest litigation. In terms of applicability, the ecosystem damage assessment of Honghu Lake and Weihe River was empirically verified by this evaluation system, respectively, proving its applicability in different types of freshwater ecosystems. At the same time, in order to cope with the situation where all indicator data cannot be obtained, the study proposed a preferred list of different criteria combinations and their priorities through sensitivity and applicability analysis. Data verification based on real environments enhances the credibility and practicality of the evaluation system, and the flexible evaluation content design ensures that more accurate evaluation results can be obtained in the case of insufficient data, which further enhances the applicability of the evaluation system. In summary, the ecosystem damage assessment system is sufficiently reasonable in terms of evaluation content, evaluation criteria and applicability, has the potential to be widely used in different freshwater ecosystems, and is suitable for promotion to more water ecological environment damage assessments.

[0119] In addition, the ecological damage assessment system has both similarities and differences compared with the existing ecological health and ecological integrity assessment systems. The similarities are that the assessment contents are similar, both include environmental indicators and biological indicators, and environmental indicators are in a secondary position. The main differences are two points: first, the assessment contents of ecological damage and ecological health include ecological functions in addition to environmental and biological indicators, while ecological integrity assessment does not; second, the baseline division standards are inconsistent. The baseline of ecological damage assessment is the better level in the evaluated waters. In contrast, the baseline used in ecological integrity assessment is the natural or historical state without interference, while the baseline of ecological health is the optimal value that can be achieved or the recognized standard value. Due to the differences in assessment content and baselines, the assessment systems of these three ecosystems have different scopes of application. Specifically, ecological damage assessment is applicable to ecosystems that need ecological compensation due to ecological damage caused by unreasonable production activities, ecological health assessment is more applicable to ecosystems that meet ecological service needs after restoration due to human pollution or destruction, and ecological integrity assessment is applicable to natural ecosystems with fragile ecology. Therefore, ecological damage assessment is different from ecological health and ecological integrity assessment. Its focus is on quantifying the negative impact of human activities on ecosystems, especially providing a basis for ecological compensation and restoration within the legal framework.

[0120] Embodiment 2:

[0121] See also Fig.12 , a freshwater ecosystem damage assessment system, including:

[0122] Ecosystem evaluation system construction module 1 is used to determine the freshwater ecological damage evaluation indicators and construct a freshwater ecosystem evaluation system based on the analytic hierarchy process;

[0123] The ecological assessment baseline confirmation module 2 is used to determine the ecological assessment baseline A based on the freshwater ecosystem assessment system; the ecological assessment baseline A includes the following parts:

[0124] Part I: Determine the ecological evaluation baseline A1 of the indicator using the 25% / 75% quantile method and the three-point method and verify each other;

[0125] Part II: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological assessment baseline A2 for indicators that cannot be covered by the ecological assessment baseline A1;

[0126] Furthermore, the ecological assessment baseline confirmation module 2 confirms the ecological assessment baseline according to the following steps:

[0127] S21. Obtain ecological data samples corresponding to the freshwater ecological damage assessment indicators in the freshwater ecosystem assessment system and construct a water ecological data set; and based on the number of samples in the water ecological data set, calculate the ecological data using any of the following methods:

[0128] The first method: if the number of samples is ≥ 9, proceed to step S22 to determine the ecological evaluation baseline of the indicator using the 25% / 75% quantile method and the three-point method;

[0129] The second method: if the number of samples is less than 9, the freshwater ecological baseline database is used to assign values ​​and determine the ecological evaluation baseline of the indicator;

[0130] S22. Based on the 25% / 75% quantile method and the three-part method, the response of each indicator in the water ecological data set to interference is compared with the preset standard basis; the comparison result includes any one of the following:

[0131] The first type: if the indicator responds to interference by increasing, the 25% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the smallest 1 / 3 data is used as the second ecological evaluation baseline;

[0132] The second type: if the indicator responds to the disturbance by decreasing, the 75% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the largest 1 / 3 data is used as the second ecological evaluation baseline;

[0133] S23, comparing the first ecological evaluation baseline with the second ecological evaluation baseline, determining a low value and a high value between the two, and then comparing the difference between the low value and the high value; the comparison result includes any one of the following:

[0134] The first type: if the low value × 1.25 < the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is large, and the outliers in the water ecological data set need to be removed, and step S22 is performed again until the low value × 1.25 ≥ the high value;

[0135] The second type: if the low value × 1.25 ≥ the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is small, and step S24 is performed;

[0136] S24. Based on the box plot method, the ecological data samples of the 25% / 75% quantile method and the three-point method are used as reference points, and the overlap of the interquartile ranges of the reference points and the damaged points is scored to determine the environmental pressure discrimination ability of the freshwater ecological damage assessment indicators corresponding to the first ecological assessment baseline and the second ecological assessment baseline;

[0137] The reference point of the 25% / 75% quantile method is the first 25% or the last 25% of the ecological data samples; the reference point of the three-part method is the 1 / 3 ecological data samples with the largest value or the 1 / 3 ecological data samples with the smallest value;

[0138] The judgment result includes any of the following:

[0139] The first method: if the ecological data sample of the indicator does not have the ability to distinguish environmental pressure, the freshwater ecological baseline database is used to assign a value to the indicator;

[0140] The second type: if the ecological data sample of the indicator has the ability to distinguish environmental pressure, proceed to step S25;

[0141] S25. Compare the number of freshwater ecological damage assessment indicators with environmental pressure discrimination capabilities determined by the 25% / 75% quantile method and the three-point method, and select the group with the larger number of indicators as the ecological assessment baseline A1; if the number is the same, select the average of the 25% / 75% quantile method and the three-point method as the ecological assessment baseline A1.

[0142] Ecological damage index confirmation module 3, used to calculate the overall ecological damage index of water ecology based on the ecological assessment baseline A;

[0143] Furthermore, the ecological damage index confirmation module 3 is used to confirm the ecological damage index according to the following method:

[0144] The calculation formula for calculating the overall ecological damage index of water ecology is as follows:

[0145] TEDI=TEDI 1 ×0.3+TEDI 2 ×0.7;

[0146] Among them: TEDI is the overall ecological damage index of water ecology, TEDI 1 TEDI is the environmental quality damage index. 2 is the ecological function damage index, 0.3 and 0.7 are weights;

[0147]

[0148]

[0149] Among them: TEDI i For TEDI 1 or TEDI 2 The ecological damage index of the ith sub-goal in the evaluation system of freshwater ecosystems is S, which is the number of criteria or indicators in the evaluation system of freshwater ecosystems. i is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system, CEDI i is the ecological damage index of the ith criterion in the freshwater ecosystem assessment system, n is the number of criteria or indicators that lack ecological data samples in the freshwater ecosystem assessment system, and W ni is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system that lacks ecological data samples.i is the ecological damage index of the ith indicator in the freshwater ecosystem assessment system, T i is the measured value of the ith indicator, B i is the ecological evaluation baseline of the ith indicator;

[0150] The ecological damage degree evaluation module 4 is used to correspond the overall ecological damage index of the water ecology with the water ecological damage degree level, determine the water ecological damage degree level corresponding to the overall ecological damage index of the water ecology, and complete the evaluation of the water ecological damage degree in the target area.

[0151] Furthermore, the ecological damage degree evaluation module 4 is used to evaluate the ecological damage degree according to the following method:

[0152] The water ecological damage degree of the target area can be evaluated by matching the calculated overall ecological damage index of the water ecology with the water ecological damage degree level of the target area;

[0153] The water ecological damage degree levels of the target area include the following:

[0154] If TEDI is less than 1.2, it means that the water ecological damage level in the target area is not damaged;

[0155] If 1.2≤TEDI<1.5, it means that the water ecological damage degree of the target area is slight damage;

[0156] If 1.5≤TEDI<2, it means that the water ecological damage level in the target area is moderate;

[0157] If TEDI ≥ 2, it means that the degree of water ecological damage in the target area is severe;

[0158] Among them: TEDI is the overall ecological damage index of water ecology.

[0159] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for assessing damage to a freshwater ecosystem, characterized in that: include: S1. Determine the freshwater ecological damage assessment indicators and construct a freshwater ecosystem assessment system based on the analytic hierarchy process; S2. Based on the freshwater ecosystem assessment system, determine the ecological assessment baseline A; the ecological assessment baseline A includes the following parts: Part I: Determine the ecological evaluation baseline A1 of the indicator using the 25% / 75% quantile method and the three-point method and verify each other; Part II: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological assessment baseline A2 for indicators that cannot be covered by the ecological assessment baseline A1; S3. Calculate the overall ecological damage index of water ecology based on the ecological assessment baseline A; S4. Match the overall ecological damage index of water ecology with the degree of water ecological damage, determine the degree of water ecological damage corresponding to the overall ecological damage index of water ecology, and complete the evaluation of the degree of water ecological damage in the target area.

2. The freshwater ecosystem damage assessment method according to claim 1, characterized in that: In step S2, the ecological assessment baseline A1 specifically includes: S21. Obtain ecological data samples corresponding to the freshwater ecological damage assessment indicators in the freshwater ecosystem assessment system and construct a water ecological data set; and based on the number of samples in the water ecological data set, calculate the ecological data using any of the following methods: The first method: if the number of samples is ≥ 9, proceed to step S22 to determine the ecological evaluation baseline of the indicator using the 25% / 75% quantile method and the three-point method; The second method: if the number of samples is less than 9, the freshwater ecological baseline database is used to assign values ​​and determine the ecological evaluation baseline of the indicator; S22. Based on the 25% / 75% quantile method and the three-part method, the response of each indicator in the water ecological data set to interference is compared with the preset standard basis; the comparison result includes any one of the following: The first type: if the indicator responds to interference by increasing, the 25% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the smallest 1 / 3 data is used as the second ecological evaluation baseline; The second type: if the indicator responds to the disturbance by decreasing, the 75% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the largest 1 / 3 data is used as the second ecological evaluation baseline; S23, comparing the first ecological evaluation baseline with the second ecological evaluation baseline, determining a low value and a high value between the two, and then comparing the difference between the low value and the high value; the comparison result includes any one of the following: The first type: if the low value × 1.25 < the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is large, and the outliers in the water ecological data set need to be removed, and step S22 is performed again until the low value × 1.25 ≥ the high value; The second type: if the low value × 1.25 ≥ the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is small, and step S24 is performed; S24. Based on the box plot method, the ecological data samples of the 25% / 75% quantile method and the three-point method are used as reference points, and the overlap of the interquartile ranges of the reference points and the damaged points is scored to determine the environmental pressure discrimination ability of the freshwater ecological damage assessment indicators corresponding to the first ecological assessment baseline and the second ecological assessment baseline; The reference point of the 25% / 75% quantile method is the first 25% or the last 25% of the ecological data samples; the reference point of the three-part method is the 1 / 3 ecological data samples with the largest value or the 1 / 3 ecological data samples with the smallest value; The judgment result includes any of the following: The first method: if the ecological data sample of the indicator does not have the ability to distinguish environmental pressure, the freshwater ecological baseline database is used to assign a value to the indicator; The second type: if the ecological data sample of the indicator has the ability to distinguish environmental pressure, proceed to step S25; S25. Compare the number of freshwater ecological damage assessment indicators with environmental pressure discrimination capabilities determined by the 25% / 75% quantile method and the three-point method, and select the group with the larger number of indicators as the ecological assessment baseline A1; if the number is the same, select the average of the 25% / 75% quantile method and the three-point method as the ecological assessment baseline A1.

3. The freshwater ecosystem damage assessment method according to claim 2, characterized in that: In step S24, the scoring rules are as follows: If the interquartile ranges of the reference point and the damaged point do not overlap, the score is 3; if the interquartile ranges of the reference point and the damaged point partially overlap, but their medians are outside the interquartile range of the other party, the score is 2; if only one median of the reference point or the damaged point is within the interquartile range of the other party, the score is 1; if the medians of the reference point and the damaged point are both within the interquartile range of the other party, the score is 0; Based on the above scoring rules, if the score of a reference point is ≥2, it means that the reference point has the ability to distinguish environmental pressure; if the score of a reference point is <2, it means that the reference point’s ability to distinguish environmental pressure is insufficient.

4. The freshwater ecosystem damage assessment method according to claim 2, characterized in that: In step S21, if the number of ecological data samples corresponding to the freshwater ecological damage assessment index is ≥ 9 groups, it is necessary to check whether there are outliers in the ecological data samples; if there are outliers, it is necessary to remove the outliers and then construct them into a water ecological data set.

5. The freshwater ecosystem damage assessment method according to claim 1, characterized in that: In step S3, the calculation formula for calculating the overall ecological damage index of the water ecology is as follows: TEDI=TEDI1×0.3+TEDI2×0.7; Among them: TEDI is the overall ecological damage index of water ecology, TEDI1 is the environmental quality damage index, TEDI2 is the ecological function damage index, and 0.3 and 0.7 are weights; Among them: TEDI i is the ecological damage index of the i-th sub-objective in TEDI1 or TEDI2, S is the number of criteria or indicators in the freshwater ecosystem assessment system, and W i is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system, CEDI i is the ecological damage index of the ith criterion in the freshwater ecosystem assessment system, n is the number of criteria or indicators that lack ecological data samples in the freshwater ecosystem assessment system, and W ni is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system that lacks ecological data samples. i is the ecological damage index of the ith indicator in the freshwater ecosystem assessment system, T i is the measured value of the ith indicator, B i is the ecological evaluation baseline of the ith indicator.

6. The freshwater ecosystem damage assessment method according to claim 5, characterized in that: In step S4, the water ecological damage level includes the following: If TEDI is less than 1.2, it means that the water ecological damage level in the target area is not damaged; If 1.2≤TEDI<1.5, it means that the water ecological damage degree of the target area is slight damage; If 1.5≤TEDI<, it means that the water ecological damage level in the target area is moderate; If TEDI ≥ 2, it means that the degree of water ecological damage in the target area is severe; Among them: TEDI is the overall ecological damage index of water ecology.

7. The freshwater ecosystem damage assessment method according to claim 1, characterized in that: In step S1, the freshwater ecosystem evaluation system includes: a target layer, a sub-target layer, a criterion layer, and an indicator layer; The target layer includes the overall ecological damage index; The sub-target layers include environmental quality damage index and ecological function damage index; The criteria layer includes comprehensive water quality, sediment pollution status, phytoplankton integrity, zooplankton integrity, benthic zoo integrity, fish integrity, biological production capacity, and water supply capacity; The indicator layer includes water pH, water transparency, total nitrogen concentration in water, total phosphorus concentration in water, concentration of permanganate index in water, dissolved oxygen content in water, total nitrogen concentration in sediment, total phosphorus concentration in sediment, heavy metal ecological risk index, phytoplankton Margalef index, phytoplankton Shannon index, phytoplankton Pielou index, total phytoplankton density, proportion of cyanobacteria density, proportion of diatom density, zooplankton Margalef index, zooplankton Shannon index, zooplankton Pielou index, proportion of rotifer density, benthic zoo Margalef index, benthic zoo Shannon index, benthic zoo Pielou index, benthic zoo BPI index, fish retention index, ratio of water transparency to water depth, annual water storage capacity of lakes and reservoirs, ecological flow satisfaction of rivers, and drinking water compliance rate.

8. A freshwater ecosystem damage assessment system, characterized in that: The system comprises: Ecosystem evaluation system construction module (1), used to determine freshwater ecological damage evaluation indicators and construct a freshwater ecosystem evaluation system based on the analytic hierarchy process; The ecological assessment baseline confirmation module (2) is used to determine the ecological assessment baseline A based on the freshwater ecosystem assessment system; the ecological assessment baseline A includes the following parts: Part I: Determine the ecological evaluation baseline A1 of the indicator using the 25% / 75% quantile method and the three-point method and verify each other; Part II: Construct a freshwater ecological baseline database based on existing data, and supplement the ecological assessment baseline A2 for indicators that cannot be covered by the ecological assessment baseline A1; The ecological damage index confirmation module (3) is used to calculate the overall ecological damage index of the water ecology based on the ecological assessment baseline A; The ecological damage degree evaluation module (4) is used to correspond the overall ecological damage index of the water ecology with the water ecological damage degree level, determine the water ecological damage degree level corresponding to the overall ecological damage index of the water ecology, and complete the evaluation of the water ecological damage degree of the target area.

9. The freshwater ecosystem damage assessment system according to claim 8, characterized in that: The ecological assessment baseline confirmation module (2) confirms the ecological assessment baseline A1 according to the following steps: S21. Obtain ecological data samples corresponding to the freshwater ecological damage assessment indicators in the freshwater ecosystem assessment system and construct a water ecological data set; and based on the number of samples in the water ecological data set, calculate the ecological data using any of the following methods: The first method: if the number of samples is ≥ 9, proceed to step S22 to determine the ecological evaluation baseline of the indicator using the 25% / 75% quantile method and the three-point method; The second method: if the number of samples is less than 9, the freshwater ecological baseline database is used to assign values ​​and determine the ecological evaluation baseline of the indicator; S22. Based on the 25% / 75% quantile method and the three-part method, the response of each indicator in the water ecological data set to interference is compared with the preset standard basis; the comparison result includes any one of the following: The first type: if the indicator responds to interference by increasing, the 25% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the smallest 1 / 3 data is used as the second ecological evaluation baseline; The second type: if the indicator responds to the disturbance by decreasing, the 75% percentile value of all ecological data samples of the indicator is used as the first ecological evaluation baseline, and the median of the largest 1 / 3 data is used as the second ecological evaluation baseline; S23, comparing the first ecological evaluation baseline with the second ecological evaluation baseline, determining a low value and a high value between the two, and then comparing the difference between the low value and the high value; the comparison result includes any one of the following: The first type: if the low value × 1.25 < the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is large, and the outliers in the water ecological data set need to be removed, and step S22 is performed again until the low value × 1.25 ≥ the high value; The second type: if the low value × 1.25 ≥ the high value, it means that the difference between the first ecological evaluation baseline and the second ecological evaluation baseline is small, and step S24 is performed; S24. Based on the box plot method, the ecological data samples of the 25% / 75% quantile method and the three-point method are used as reference points, and the overlap of the interquartile ranges of the reference points and the damaged points is scored to determine the environmental pressure discrimination ability of the freshwater ecological damage assessment indicators corresponding to the first ecological assessment baseline and the second ecological assessment baseline; The reference point of the 25% / 75% quantile method is the first 25% or the last 25% of the ecological data samples; the reference point of the three-part method is the 1 / 3 ecological data samples with the largest value or the 1 / 3 ecological data samples with the smallest value; The judgment result includes any of the following: The first method: if the ecological data sample of the indicator does not have the ability to distinguish environmental pressure, the freshwater ecological baseline database is used to assign a value to the indicator; The second type: if the ecological data sample of the indicator has the ability to distinguish environmental pressure, proceed to step S25; S25. Compare the number of freshwater ecological damage assessment indicators with environmental pressure discrimination capabilities determined by the 25% / 75% quantile method and the three-part method, and select the group with more indicators as the ecological assessment baseline A1; If the numbers are consistent, the average of the 25% / 75% quantile method and the three-point method is selected as the ecological assessment baseline A1.

10. The freshwater ecosystem damage assessment system according to claim 8, characterized in that: The ecological damage index confirmation module (3) is used to confirm the ecological damage index according to the following method: The calculation formula for calculating the overall ecological damage index of water ecology is as follows: TEDI=TEDI1×0.3+TEDI2×0.7; Among them: TEDI is the overall ecological damage index of water ecology, TEDI1 is the environmental quality damage index, TEDI2 is the ecological function damage index, and 0.3 and 0.7 are weights; Among them: TEDI i is the ecological damage index of the i-th sub-objective in TEDI1 or TEDI2, S is the number of criteria or indicators in the freshwater ecosystem assessment system, and W i is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system, CEDI i is the ecological damage index of the ith criterion in the freshwater ecosystem assessment system, n is the number of criteria or indicators that lack ecological data samples in the freshwater ecosystem assessment system, and W ni is the weight of the ith criterion or indicator in the freshwater ecosystem assessment system that lacks ecological data samples. i is the ecological damage index of the ith indicator in the freshwater ecosystem assessment system, T i is the measured value of the ith indicator, B i is the ecological evaluation baseline of the ith indicator; The ecological damage degree evaluation module (4) is used to evaluate the ecological damage degree of the target area according to the following method: The water ecological damage degree levels of the target area include the following: If TEDI is less than 1.2, it means that the water ecological damage level in the target area is not damaged; If 1.2≤TEDI<1.5, it means that the water ecological damage degree of the target area is slight damage; If 1.5≤TEDI<2, it means that the water ecological damage level in the target area is moderate; If TEDI ≥ 2, it means that the degree of water ecological damage in the target area is severe; Among them: TEDI is the overall ecological damage index of water ecology.

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