Lake and reservoir water ecological health assessment technical method

Abstract

The invention relates to the technical field of ecological health assessment, and discloses a lake and reservoir water ecological health assessment technical method, which comprises the following steps: S1, acquiring survey monitoring data of a lake and a reservoir, including biological data and water quality data, and constructing a lake and reservoir water ecological index system; s2, determining a score level according to a total standard score value of each hierarchical level index score of the lake and reservoir water ecological index system; and S3, determining the water ecological health level of the lake and the reservoir based on the score value corresponding to each score level. According to the invention, a comprehensive lake and reservoir water ecological index system is constructed based on various biological data and water quality data. The index system comprises multiple levels such as phytoplankton, zooplankton and organic matter, the ecological health state of the lake or reservoir can be comprehensively evaluated from multiple dimensions, and the limitation of single index evaluation is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of ecological health assessment, and in particular, relates to a technical method for evaluating the ecological health of lakes and reservoirs. Background Art

[0002] Water ecological restoration is a higher-level water ecological protection measure that needs to be taken after the water environment quality has been improved to a certain extent. Water ecological health assessment is a prerequisite for the formulation of water ecological restoration strategies and is also a necessary means to consider the effectiveness of water ecological restoration.

[0003] As important water resources and ecosystems, lakes and reservoirs are of great significance for maintaining water ecological balance, water supply security and biodiversity protection. With the acceleration of industrialization and urbanization, the ecological environment of water bodies is facing increasingly severe pressure, especially water pollution, changes in biological communities and habitat degradation, making the water ecological health of lakes and reservoirs more prominent. Therefore, how to scientifically and effectively evaluate the water ecological health of lakes and reservoirs has become an important topic in the field of water environment management and ecological protection.

[0004] At present, water ecological health assessment technology mainly relies on water quality monitoring data and analysis of biological community characteristics. Common assessment indicators include water quality indicators (such as dissolved oxygen, ammonia nitrogen, total phosphorus, chlorophyll a content, etc.) and biological indicators (such as phytoplankton and zooplankton population, diversity index, biomass, etc.). These single indicator assessment methods are often difficult to fully reflect the comprehensive health status of lake or reservoir water ecosystems.

[0005] Existing water ecological health assessment methods generally use weighted scoring methods, but in practical applications, the hierarchy of the assessment system, the diversity of indicators, and the comprehensive analysis of data often present certain difficulties. In addition, how to reasonably quantify and normalize each indicator and conduct an effective comprehensive assessment based on the importance and weight of different indicators remains a challenge in current assessment technology.

[0006] In this context, the accuracy and comprehensiveness of water ecological health assessments for lakes and reservoirs need to be improved and enhanced. A water ecological health assessment method that can comprehensively consider multiple levels of indicators and perform scientific weighting is needed to more accurately and comprehensively reflect the ecological health status of water bodies. By constructing a multi-level and multi-dimensional water ecological indicator system and combining it with modern data analysis technology, it can provide a scientific basis for water ecological protection and water quality management, and help relevant departments to promptly detect ecological risks and take effective measures.

[0007] Therefore, the multi-level comprehensive evaluation system based on biological, chemical indicators and environmental data can effectively integrate various types of data and provide new technical support and theoretical basis for the monitoring and management of the water ecological health status of lakes and reservoirs.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is: A technical method for evaluating the water ecological health of lakes and reservoirs comprises the following steps: Step S1: Obtain survey and monitoring data of lakes and reservoirs, including biological data and water quality data, and construct a water ecological indicator system for lakes and reservoirs; Step S2: Determine the score level according to the total standard score value of the indicators at each hierarchical level of the lake and reservoir water ecological indicator system; Step S3: Determine the water ecological health level of lakes and reservoirs based on the score values ​​corresponding to each score level.

[0010] As a preferred embodiment of the present invention, in step 1, the biological indicator includes chlorophyll a, the chlorophyll a content of phytoplankton is directly calculated according to the detection value, the dry weight biomass of zooplankton, the wet weight biomass of zooplankton, the number of zooplankton individuals, the zooplankton group composition, the zooplankton diversity, the existing biomass of zooplankton, the zooplankton diversity index, the zooplankton energy ratio, and the chlorophyll a content of zooplankton are calculated according to the dry weight biomass of the zooplankton species, and the calculation formula is as follows: zooplankton dry weight biomass = ∑(∑ωi×bi); zooplankton wet weight biomass = zooplankton dry weight biomass × (1+water content), wherein the zooplankton wet weight biomass is capitalized as W; the number of zooplankton individuals = ∑ni = 1ωi×bi×number magnification factor, where the number of zooplankton individuals is N; zooplankton diversity composition = Shannon diversity index, where the zooplankton diversity composition is D; zooplankton energy quality = zooplankton community energy × zooplankton biomass, where the zooplankton energy quality is E; zooplankton dry weight biomass = ∑(∑ωi×Wij), zooplankton wet weight biomass = zooplankton dry weight biomass × (1+W water content), zooplankton individual number = ∑ni = 1ωi×Wij×Vnumber magnification factor × P, zooplankton diversity = ∑ni = 1ωi×Wij×S, zooplankton energy = Bj; Chlorophyll a content is calculated using sample detection value.

[0011] As a preferred embodiment of the present invention, the method for constructing the water ecological health evaluation system includes the following steps: S1: obtaining a survey evaluation matrix based on the first-level indicators in the water ecological indicator system of lakes and reservoirs: wherein xi,j is the value of the jth indicator of the first-level indicators, n is the number of first-level indicators, and the score value of each indicator is in the range of [0,1]; obtaining a survey evaluation matrix based on the second-level indicators of the water ecological indicator system of lakes and reservoirs: wherein m is the number of second-level indicators, and the score value of each indicator is in the range of [0,1], j and k represent the jth and kth second-level indicators and the total score, k=1,…,m; wherein the first-level indicators in the water ecological indicator system of lakes and reservoirs include phytoplankton indicators, zooplankton indicators and organic matter indicators, phytoplankton indicators include phytoplankton chlorophyll a content, phytoplankton chlorophyll a content, phytoplankton diversity, phytoplankton density indicators, and organic matter indicators include the inverse of transparency, sediment suspended sediment, sediment dissolved oxygen, sediment ammonia nitrogen, sediment total phosphorus and sediment Total nitrogen index, zooplankton index includes zooplankton group index, zooplankton biomass, zooplankton diversity, zooplankton energy, zooplankton individual number, zooplankton wet weight biomass, zooplankton dry weight biomass, zooplankton energy quality and zooplankton density index; S2: Normalize the survey and evaluation matrix to obtain the normalized matrix of the first-level index: Among them, A′i,j is the value obtained after normalization of the first-level index; Normalize the survey and evaluation matrix of each second-level index to obtain the normalized matrix of the second-level index A normalized matrix: where A′m,k is the normalized value of the second-level indicators; S3: The weights for calculating the weighted scores of the first-level indicators are: where wi is the weight of the i-th indicator in the first-level indicators, w1…n are the weights of all indicators in the first level, and w∑=1; the weights for calculating the weighted scores of the second-level indicators, j represents the j-th indicator; where the second-level weight matrix is: A′m×m=(wj2×A′m,n)m×n, where wj2 is the weight of the j-th indicator in the second level, and w∑2=1.

[0012] As a preferred embodiment of the present invention, the constructed lake and reservoir water ecological evaluation index system also includes third-level indicators. According to the third-level indicators in the lake and reservoir water ecological evaluation system, a survey and evaluation matrix is ​​obtained: wherein P=p1…pm, p1 is total phosphorus, p2 is total nitrogen, p3 is ammonia nitrogen, p4 is soluble silicon, and m is the total number of third-level indicator items; the survey and evaluation matrix of each indicator of the third level is normalized to obtain a normalized matrix: wherein B′i,j is the value obtained after normalization of the third-level indicator; the weight of the weighted score of the third-level indicator is calculated, and s represents the sth indicator; wherein the third-level weight matrix is ​​B′n×m=(ws3×B′i,j)n×m, wherein ws3 is the weight of the sth indicator of the third level, and w∑3=1.

[0013] As a preferred embodiment of the present invention, in step 2, determining the scoring level according to the total standard score value of the indicators at each hierarchical level of the water ecological indicator system of lakes and reservoirs includes: setting the first-level scoring level for the first-level indicators: for the second-level indicators, setting the scoring level of the second-level indicators respectively, and setting the total standard score of all second-level indicators under the indicator to S21, including: S1: if the second-level indicator belongs to the first level, otherwise enter S2 and S3; S2: if the second-level indicator belongs to the second level, otherwise enter S3; S3: if the second-level indicator belongs to the third level, otherwise enter S4; S4: if the second-level indicator belongs to the fourth level, otherwise it belongs to the fifth level; setting the third-level scoring level for the third-level indicators, the scoring level of the third-level indicators is the same as the method of setting the scoring level of the second-level indicators.

[0014] As a preferred embodiment of the present invention, in step 3, based on the score values ​​corresponding to each score level, determining the water ecological health level of lakes and reservoirs includes the following steps: calculating the corresponding first-level indicator total score, second-level indicator total score and third-level indicator total score according to the normalized matrices of the first-level indicators, the second-level indicators and the third-level indicators, respectively, expressed as: first-level indicator total score = A′1×F1×I1; second-level indicator total score = A′2×F2×I2; wherein F1 is the first-level weight matrix, and I1 is the inverse of the first-level weight. Diagonal element matrix, F2 is the second-level weight matrix, I2 is the reciprocal diagonal element matrix of the second-level weights; the total score of the third-level indicators = B′i×G1×J1, among which, matrix G1 is the third-level weight matrix, and J1 is the reciprocal diagonal element matrix of the third-level weights; the water ecological health level of lakes and reservoirs is determined according to the total score of the first-level indicators, the second-level indicator scores and the third-level indicator scores; among which, the score values ​​corresponding to the water ecological health level of lakes and reservoirs are between 60-95, and the grades are excellent, good, general, poor and very poor respectively.

[0015] As a preferred embodiment of the present invention, the lake and reservoir water ecological health assessment system also includes water quality evaluation indicators, and the lake and reservoir water ecological health level is determined based on the acquired water quality monitoring data; the water quality evaluation indicators include ammonia nitrogen, pH value, dissolved oxygen, volatile phenols, permanganate index, chemical oxygen demand, total phosphorus content, total nitrogen content, dissolved oxygen saturation rate / %, and transparency.

[0016] Compared with the prior art, the present invention has the following beneficial effects: Based on a variety of biological data and water quality data, the present invention constructs a comprehensive lake and reservoir water ecological index system. The index system includes multiple levels such as phytoplankton, zooplankton and organic matter, which can comprehensively evaluate the ecological health status of lakes or reservoirs from multiple dimensions, avoiding the limitations of single indicator evaluation.

[0017] By constructing a survey evaluation matrix and performing normalization, the evaluation results of each ecological indicator can be uniformly converted into standardized scores, thereby ensuring the objectivity and scientificity of the evaluation results. This method allows the health assessment of different lakes or reservoirs to be compared and analyzed through unified standards, and has high universality and applicability.

[0018] This method can reflect the ecological health status of lakes or reservoirs in real time through classification based on score levels, making the ecological health assessment results more timely and dynamic, facilitating the monitoring of water ecological change trends and providing decision-making support for ecological environmental protection.

[0019] The assessment method uses standardized and simplified calculation formulas and steps, which are easy to operate and implement in practice. Through systematic processes and clear steps, it can provide efficient and convenient technical support for relevant departments and scientific research institutions, and promote the regular assessment and management of the water ecological health status of lakes and reservoirs.

[0020] This method is applicable to the health assessment of various lake and reservoir ecosystems, and can be widely used in water quality monitoring, ecological environmental protection, resource management and other fields. Its assessment results are not only helpful for scientific research, but also provide data support and scientific basis for ecological restoration, environmental governance, policy formulation, etc.

[0021] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In the attached picture: Figure 1 This is a flow chart of a technical method for assessing the water ecological health of lakes and reservoirs. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments are clearly and completely described, and the following embodiments are used to illustrate the present invention.

[0024] A technical method for evaluating the water ecological health of lakes and reservoirs comprises the following steps: Step S1: Obtain survey and monitoring data of lakes and reservoirs, including biological data and water quality data, and construct a water ecological indicator system for lakes and reservoirs; Step S2: Determine the score level according to the total standard score value of the indicators at each hierarchical level of the lake and reservoir water ecological indicator system; Step S3: Determine the water ecological health level of lakes and reservoirs based on the score values ​​corresponding to each score level.

[0025] Furthermore, in step 1, the biological indicators include chlorophyll a, and the chlorophyll a content of phytoplankton is directly calculated according to the detection value. The dry weight biomass of zooplankton, the wet weight biomass of zooplankton, the number of zooplankton individuals, the composition of zooplankton groups, the diversity of zooplankton, the existing biomass of zooplankton, the zooplankton diversity index, and the energy-to-quality ratio of zooplankton are calculated according to the dry weight biomass of zooplankton species. The calculation formula is as follows: zooplankton dry weight biomass = ∑(∑ωi×bi); zooplankton wet weight biomass = zooplankton dry weight biomass × (1+water content), wherein the capital letter of zooplankton wet weight biomass is W; the number of zooplankton individuals = ∑ni = 1ωi×b i×number magnification factor, where the number of zooplankton individuals is N; zooplankton diversity composition = Shannon diversity index, where the zooplankton diversity composition is D; zooplankton energy quality = zooplankton community energy × zooplankton biomass, where the zooplankton energy quality is E; zooplankton dry weight biomass = ∑(∑ωi×Wij), zooplankton wet weight biomass = zooplankton dry weight biomass × (1+W water content), zooplankton individual number = ∑ni = 1ωi×Wij×Vnumber magnification factor × P, zooplankton diversity = ∑ni = 1ωi×Wij×S, zooplankton energy = Bj; the chlorophyll a content was calculated using the sample detection value.

[0026] Furthermore, the method for constructing the water ecological health evaluation system includes the following steps: S1: obtaining a survey and evaluation matrix based on the first-level indicators in the water ecological indicator system of lakes and reservoirs: wherein xi,j is the value of the jth indicator of the first-level indicators, n is the number of first-level indicators, and the score value of each indicator is in the range of [0,1]; obtaining a survey and evaluation matrix based on the second-level indicators of the water ecological indicator system of lakes and reservoirs: wherein m is the number of second-level indicators, the score value of each indicator is in the range of [0,1], j and k represent the jth and kth second-level indicators and the total score, k=1,…,m; wherein, the first-level indicators in the water ecological indicator system of lakes and reservoirs include phytoplankton indicators, zooplankton indicators and organic matter indicators, phytoplankton indicators include phytoplankton chlorophyll a content, phytoplankton chlorophyll a content, phytoplankton diversity, and phytoplankton density indicators, and organic matter indicators include the inverse of transparency, sediment suspended sediment, sediment dissolved oxygen, sediment ammonia nitrogen, sediment total phosphorus and sediment total nitrogen indicators. , zooplankton indicators include zooplankton group indicators, zooplankton biomass, zooplankton diversity, zooplankton energy, zooplankton individual number, zooplankton wet weight biomass, zooplankton dry weight biomass, zooplankton energy quality and zooplankton density indicators; S2: Normalize the survey and evaluation matrix to obtain the normalized matrix of the first-level indicators: Among them, A′i,j is the value obtained after normalization of the first-level indicators; Normalize the survey and evaluation matrix of each second-level indicator to obtain the normalized matrix of the second-level indicators Matrix: A′m,k is the normalized value of the second-level indicators; S3: The weights for calculating the weighted scores of the first-level indicators are: wi is the weight of the i-th indicator in the first-level indicators, w1…n are the weights of all indicators in the first level, and w∑=1; the weights for calculating the weighted scores of the second-level indicators, j represents the j-th indicator; the second-level weight matrix is: A′m×m=(wj2×A′m,n)m×n, wj2 is the weight of the j-th indicator in the second level, and w∑2=1.

[0027] Furthermore, the constructed lake and reservoir water ecological evaluation index system also includes third-level indicators. According to the third-level indicators in the lake and reservoir water ecological evaluation system, the survey and evaluation matrix is ​​obtained: wherein P = p1…pm, p1 is total phosphorus, p2 is total nitrogen, p3 is ammonia nitrogen, p4 is soluble silicon, and m is the total number of third-level indicator items; the survey and evaluation matrix of each indicator of the third level is normalized to obtain a normalized matrix: wherein B′i,j is the normalized value of the third-level indicator; the weight of the weighted score of the third-level indicator is calculated, and s represents the sth indicator; wherein the third-level weight matrix is ​​B′n×m=(ws3×B′i,j)n×m, wherein ws3 is the weight of the sth indicator of the third level, and w∑3=1.

[0028] Furthermore, the scoring level is determined according to the total standard score of the indicators at each hierarchical level of the water ecological indicator system of lakes and reservoirs, including: setting the first-level scoring level for the first-level indicators; setting the scoring level of the second-level indicators for the second-level indicators respectively, and setting the total standard score of all the second-level indicators under the indicator to S21, including: S1: if then the second-level indicator belongs to the first level, otherwise enter S2 and S3; S2: if then the second-level indicator belongs to the second level, otherwise enter S3; S3: if then the second-level indicator belongs to the third level, otherwise enter S4; S4: if then the second-level indicator belongs to the fourth level, otherwise it belongs to the fifth level; setting the third-level scoring level for the third-level indicators, the scoring level of the third-level indicators is the same as the method of setting the scoring level of the second-level indicators.

[0029] Furthermore, in step 3, based on the score values ​​corresponding to each score level, determining the water ecological health level of lakes and reservoirs includes the following steps: calculating the corresponding first-level indicator total score, second-level indicator total score and third-level indicator total score according to the normalized matrices of the first-level indicators, the second-level indicators and the third-level indicators, respectively, expressed as: first-level indicator total score = A′1×F1×I1; second-level indicator total score = A′2×F2×I2; where F1 is the first-level weight matrix, I1 is the reciprocal diagonal element of the first-level weight prime matrix, F2 is the second-level weight matrix, I2 is the reciprocal diagonal element matrix of the second-level weight; the total score of the third-level indicators = B′i×G1×J1, among which, the matrix G1 is the third-level weight matrix, and J1 is the reciprocal diagonal element matrix of the third-level weight; the water ecological health level of lakes and reservoirs is determined according to the total score of the first-level indicators, the second-level indicator scores and the third-level indicator scores; among which, the score values ​​corresponding to the water ecological health level of lakes and reservoirs are between 60-95, and the grades are excellent, good, general, poor and very poor respectively.

[0030] Furthermore, the lake and reservoir water ecological health assessment system also includes water quality evaluation indicators, which determine the water ecological health level of lakes and reservoirs based on the acquired water quality monitoring data; water quality evaluation indicators include ammonia nitrogen, pH value, dissolved oxygen, volatile phenols, permanganate index, chemical oxygen demand, total phosphorus content, total nitrogen content, dissolved oxygen saturation rate / %, and transparency.

Claims

1. A technical method for evaluating the water ecological health of lakes and reservoirs, characterized in that: The steps include: Step S1: Obtain survey and monitoring data of lakes and reservoirs, including biological data and water quality data, and construct a water ecological indicator system for lakes and reservoirs; Step S2: Determine the score level according to the total standard score value of the indicators at each hierarchical level of the lake and reservoir water ecological indicator system; Step S3: Determine the water ecological health level of lakes and reservoirs based on the score values ​​corresponding to each score level.

2. A lake and reservoir water ecological health assessment technical method according to claim 1, characterized in that: In step 1, the biological index includes chlorophyll a, the chlorophyll a content of phytoplankton is directly calculated according to the detection value, the dry weight biomass of zooplankton, the wet weight biomass of zooplankton, the number of zooplankton individuals, the composition of zooplankton groups, the diversity of zooplankton, the existing biomass of zooplankton, the diversity index of zooplankton, and the energy-to-quality ratio of zooplankton. The chlorophyll a content of zooplankton is calculated according to the dry weight biomass of zooplankton species, and the calculation formula is as follows: zooplankton dry weight biomass = ∑(∑ωi×bi); zooplankton wet weight biomass = zooplankton dry weight biomass × (1+water content), wherein the capital letter of zooplankton wet weight biomass is W; the number of zooplankton individuals = ∑ni = 1ωi×bi× Number magnification factor, where the number of zooplankton individuals is N; Zooplankton diversity composition = Shannon diversity index, where the zooplankton diversity composition is D; Zooplankton energy quality = Zooplankton community energy × Zooplankton biomass, where the zooplankton energy quality is E; Zooplankton dry weight biomass = ∑(∑ωi×Wij), Zooplankton wet weight biomass = Zooplankton dry weight biomass × (1+W water content), Zooplankton individual number = ∑ni = 1ωi×Wij×V Number magnification factor × P, Zooplankton diversity = ∑ni = 1ωi×Wij×S, Zooplankton energy = Bj; Chlorophyll a content is calculated using sample detection values.

3. A lake and reservoir water ecological health assessment technical method according to claim 1, characterized in that: The method for constructing the water ecological health evaluation system includes the following steps: S1: obtaining a survey and evaluation matrix based on the first-level indicators in the water ecological indicator system of lakes and reservoirs: wherein xi,j is the value of the jth indicator of the first-level indicators, n is the number of first-level indicators, and the score value of each indicator is in the range of [0,1]; obtaining a survey and evaluation matrix based on the second-level indicators of the water ecological indicator system of lakes and reservoirs: wherein m is the number of second-level indicators, and the score value of each indicator is in the range of [0,1], j and k represent the jth and kth second-level indicators and the total score, k=1,…,m; wherein, the first-level indicators in the water ecological indicator system of lakes and reservoirs include phytoplankton indicators, zooplankton indicators and organic matter indicators, phytoplankton indicators include phytoplankton chlorophyll a content, phytoplankton chlorophyll a content, phytoplankton diversity, and phytoplankton density indicators, organic matter indicators include the inverse of transparency, sediment suspended sediment, sediment dissolved oxygen, sediment ammonia nitrogen, sediment total phosphorus and sediment total nitrogen indicators, and plankton Animal indicators include zooplankton group indicators, zooplankton biomass, zooplankton diversity, zooplankton energy, zooplankton individual number, zooplankton wet weight biomass, zooplankton dry weight biomass, zooplankton energy quality and zooplankton density indicators; S2: Normalize the survey and evaluation matrix to obtain the normalized matrix of the first-level indicators: where A′i,j is the value obtained after normalization of the first-level indicators; Normalize the survey and evaluation matrix of each second-level indicator to obtain the normalized matrix of the second-level indicators Matrix: A′m,k is the normalized value of the second-level indicators; S3: The weights for calculating the weighted scores of the first-level indicators are: wi is the weight of the i-th indicator in the first-level indicators, w1…n are the weights of all indicators in the first level, and w∑=1; the weights for calculating the weighted scores of the second-level indicators, j represents the j-th indicator; the second-level weight matrix is: A′m×m=(wj2×A′m,n)m×n, wj2 is the weight of the j-th indicator in the second level, and w∑2=1.

4. A lake and reservoir water ecological health assessment technical method according to claim 3, characterized in that: The constructed lake and reservoir water ecological evaluation index system also includes third-level indicators. According to the third-level indicators in the lake and reservoir water ecological evaluation system, the survey and evaluation matrix is ​​obtained: wherein P = p1…pm, p1 is total phosphorus, p2 is total nitrogen, p3 is ammonia nitrogen, p4 is soluble silicon, and m is the total number of third-level indicator items; the survey and evaluation matrix of each indicator of the third level is normalized to obtain a normalized matrix: wherein B′i,j is the normalized value of the third-level indicator; the weight of the weighted score of the third-level indicator is calculated, and s represents the sth indicator; wherein the third-level weight matrix is ​​B′n×m=(ws3×B′i,j)n×m, wherein ws3 is the weight of the sth indicator of the third level, and w∑3=1.

5. A lake and reservoir water ecological health assessment technical method according to claim 3, characterized in that: In step 2, the scoring level is determined according to the total standard score value of the indicators at each hierarchical level of the water ecological indicator system of lakes and reservoirs, including: setting the first-level scoring level for the first-level indicators; for the second-level indicators, setting the scoring level of the second-level indicators respectively, and setting the total standard score of all second-level indicators under the indicator to S21, including: S1: if then the second-level indicator belongs to the first level, otherwise enter S2 and S3; S2: if then the second-level indicator belongs to the second level, otherwise enter S3; S3: if then the second-level indicator belongs to the third level, otherwise enter S4; S4: if then the second-level indicator belongs to the fourth level, otherwise it belongs to the fifth level; setting the third-level scoring level for the third-level indicators, the scoring level of the third-level indicators is the same as the method of setting the scoring level of the second-level indicators.

6. A lake and reservoir water ecological health assessment technical method according to claim 3, characterized in that: In step 3, based on the score values ​​corresponding to each scoring level, determining the water ecological health level of lakes and reservoirs includes the following steps: calculating the corresponding first-level indicator total score, second-level indicator total score and third-level indicator total score according to the normalized matrices of the first-level indicators, the second-level indicators and the third-level indicators, respectively, expressed as: first-level indicator total score = A′1×F1×I1; second-level indicator total score = A′2×F2×I2; where F1 is the first-level weight matrix, and I1 is the reciprocal diagonal element matrix of the first-level weight , F2 is the second-level weight matrix, I2 is the reciprocal diagonal element matrix of the second-level weight; the total score of the third-level indicators = B′i×G1×J1, where the matrix G1 is the third-level weight matrix, and J1 is the reciprocal diagonal element matrix of the third-level weight; the water ecological health level of lakes and reservoirs is determined according to the total score of the first-level indicators, the second-level indicator scores and the third-level indicator scores; among them, the score values ​​corresponding to the water ecological health level of lakes and reservoirs are between 60-95, and the grades are excellent, good, general, poor and very poor respectively.

7. A lake and reservoir water ecological health assessment technical method according to claim 1, characterized in that: The lake and reservoir water ecological health assessment system also includes water quality evaluation indicators, which determine the water ecological health level of lakes and reservoirs based on the acquired water quality monitoring data; water quality evaluation indicators include ammonia nitrogen, pH value, dissolved oxygen, volatile phenols, permanganate index, chemical oxygen demand, total phosphorus content, total nitrogen content, dissolved oxygen saturation rate / %, and transparency.

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