Method and system for evaluating influence intensity of water transfer project on regulation and storage lake ecosystem

Abstract

The invention discloses a method and system for evaluating the influence intensity of a water transfer project on a regulation and storage lake ecosystem, and relates to the technical field of ecosystem function evaluation, and the method comprises the steps: collecting functional indexes of a lake ecosystem during a water transfer period and a non-water transfer period; performing standardization processing on the function indexes, clustering the processed function indexes, and allocating a weight to each cluster; the processed function indexes are compared with a preset function threshold value, the function indexes larger than the function threshold value serve as effective functions, the effective functions are multiplied by the corresponding weight to serve as the performance level of the effective functions, and the weighted average value of all the effective functions is calculated to serve as the multifunctionality of the lake ecosystem. And the influence of the water transfer project is evaluated through the multifunctionality in the water transfer period and the non-water transfer period. According to the method, the function indexes of the lake ecosystem are integrated, the trade-off relationship among different functions is considered, the relative importance of different function indexes is determined through clustering weighting, and the accuracy of the evaluation result of the influence of the water transfer project is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ecosystem function assessment, and more specifically to a method and system for assessing the intensity of the impact of a water diversion project on a regulating lake ecosystem. Background Art

[0002] Under the dual pressures of economic development and climate change, the demand for freshwater resources in human society has risen sharply, especially the uneven distribution of water resources, which has made the problem of insufficient water supply more serious. As a key measure to optimize water resource allocation, inter-basin water transfer projects have been proven to effectively alleviate the water supply pressure in water-scarce areas. Over the past few decades, my country has built and put into operation many water transfer projects, which have effectively improved the water shortage problem in water-scarce areas. However, water transfer projects have caused significant human intervention in the lakes along the route during the water transfer process, causing them to gradually change from a natural state to a regulation lake under artificial control, which in turn affects water quality and biodiversity, causing the various ecological functions of the lakes to suffer varying degrees of degradation. Therefore, quantitatively evaluating the intensity of the impact of water transfer projects on the ecosystem of regulation lakes is of vital importance for guiding future water resource allocation and management, ensuring the sustainable use of freshwater resources and the sound function of lake ecosystems.

[0003] The existing evaluation of the impact of water diversion projects on the ecosystem of regulating lakes mostly relies on water quality indicators to quantify lake functions, such as carbon, nitrogen, and phosphorus nutrient concentrations. During the water diversion period, the shortening of the water exchange cycle promotes the nutrient cycle and water purification of the lake. Therefore, the evaluation results based on water quality indicators generally believe that water diversion projects are beneficial to improving lake functions. However, a small number of evaluations on biological functions have found that water diversion projects may lead to reduced lake functions. For example, high-speed water flow during water diversion limits the colonization of submerged plants, thereby reducing the primary productivity of the lake; frequent hydraulic exchange promotes the miniaturization of plankton and benthic animals, which in turn affects the predatory behavior of fish and reduces the secondary productivity of the lake. The hydrological and ecological effects caused by water diversion projects are multifaceted. Only considering the evaluation results of water quality indicators or specific biological groups can only reflect the one-sided functions of the ecosystem, which limits our accurate understanding of the full play of the ecological functions of regulating lakes. Multifunctionality refers to the ability of an ecosystem to provide multiple functions at the same time, and can integrate the performance levels of different functions to achieve accurate quantification of ecosystem functions. By comprehensively considering multiple factors such as water quality, biology, and habitat environment, and calculating the weighted multifunctionality of regulating lakes based on the trade-off relationship between different functions, we can more accurately assess the impact of water diversion projects on the ecosystem of regulating lakes, thereby providing a scientific basis and data support for the formulation of future water resources allocation and optimization management measures, and promoting the sustainable management of water resources and the long-term health of ecosystems.

[0004] Therefore, how to quickly and comprehensively calculate the multifunctionality of lake ecosystems in order to assess the impact intensity of water diversion projects on regulating lake ecosystems is an issue that technicians in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a method and system for evaluating the intensity of the impact of water diversion projects on the ecosystem of regulating lakes. Through cluster analysis, 16 functional indicators of lake ecosystems are classified and weighted, the trade-off relationship between different functions is comprehensively considered and the multifunctionality of lake ecosystems is accurately quantified. The weighted multifunctionality is scientifically used to evaluate the intensity of the impact of water diversion projects on the ecosystem of regulating lakes.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for assessing the impact intensity of water diversion projects on the ecosystem of regulating lakes, including:

[0008] Collect water quality and biological samples of lake ecosystems during water transfer and non-water transfer periods to determine functional indicators;

[0009] The functional indicators are subjected to outlier elimination and standardization processing, the processed functional indicators are clustered, the number of clusters and the functional indicators contained in each cluster are determined, and an equal weight is assigned to each cluster, and the weight of each functional indicator in the cluster is also equal;

[0010] Preset an effective function threshold, compare the processed function index with the function threshold, take the processed function index greater than the function threshold as an effective function, multiply the effective function by the weight corresponding to the effective function to obtain the performance level of the effective function, and calculate the weighted average of all effective functions to obtain the multifunctionality of the lake ecosystem;

[0011] The impact intensity of water diversion projects on the regulating lake ecosystem is evaluated by the multifunctionality during the water diversion period and the non-water diversion period.

[0012] Preferably, the functional indicators specifically include: total phosphorus concentration, total nitrogen concentration, total organic carbon concentration, dissolved oxygen concentration, transparency, aquatic plant cover, bacterial abundance, aquatic plant biomass, phytoplankton density, rotifer biomass, microshell biomass, benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass, and herbivorous fish biomass.

[0013] Preferably, in the standardization process, the total phosphorus concentration and the total nitrogen concentration are standardized according to the reference value, and the calculation formula is as follows:

[0014]

[0015] Among them, x is the detection value, x std is the baseline value.

[0016] Preferably, other functional indicators except total phosphorus concentration and total nitrogen concentration are calculated using the forward standardization method, and the calculation formula is as follows:

[0017]

[0018] Among them, x is the detection value, x min is the minimum value, x max is the maximum value.

[0019] Preferably, the calculation formula of the multifunctionality specifically includes:

[0020]

[0021] Where MF is the multifunctionality, F is the total number of functions, and f i is the normalized value of function i, t is the effective function threshold, r i is the discriminant function.

[0022] Preferably, the water quality indicators include transparency, dissolved oxygen, total phosphorus concentration, total nitrogen concentration and total organic carbon concentration. When the water quality indicators are collected, the transparency is measured using a Secchi disk at the sampling point, and the dissolved oxygen is measured using a multi-parameter water quality meter; a plexiglass water sampler is used to collect 1L of water sample 0.5m below the water surface, which is refrigerated at 4°C and brought back to the laboratory for determination of total nitrogen, total phosphorus and total organic carbon concentrations. The total nitrogen concentration is determined by alkaline potassium persulfate digestion ultraviolet spectrophotometry, the total phosphorus concentration is determined by flow injection-ammonium molybdate spectrophotometry, and the total organic carbon concentration is determined by combustion oxidation-non-dispersive infrared absorption.

[0023] Preferably, the bacterial abundance is determined by collecting 1 L of water sample using a plexiglass water sampler, filtering with a 0.22 μm filter membrane and storing at -80°C, and then performing high-throughput sequencing in a laboratory to determine the bacterial abundance.

[0024] Preferably, the phytoplankton density is collected by using a plexiglass water sampler to collect 1L of water sample, immediately adding 15mL of Lugol's iodine solution for fixation, taking 0.1mL with a micropipette, observing and counting all phytoplankton cells under a microscope, and taking an average value.

[0025] Preferably, the rotifer biomass is collected by: collecting 1L of water sample, immediately adding 15mL of Lugol's iodine solution for fixation, standing for 48 hours, concentrating to 20mL by multiple siphoning, taking 1mL of sample with a micropipette, counting the whole piece under a microscope and taking the average value, and converting the biomass by the volume method.

[0026] A system for assessing the impact intensity of water diversion projects on the ecosystem of regulating lakes, including:

[0027] The indicator collection module collects functional indicators corresponding to water quality and biological samples of lake ecosystems during water diversion and non-water diversion periods;

[0028] A weight allocation module is used to remove outliers and standardize the functional indicators, cluster the processed functional indicators, determine the number of clusters and the functional indicators contained in each cluster, and allocate equal weights to each cluster, and the weights of each functional indicator in the cluster are also equal;

[0029] A multifunctionality calculation module is provided, wherein an effective function threshold is preset, the processed functional index is compared with the functional threshold, the processed functional index greater than the functional threshold is taken as an effective function, the effective function is multiplied by the weight corresponding to the effective function to obtain the performance level of the effective function, and the weighted average value of all effective functions is calculated as the multifunctionality of the lake ecosystem;

[0030] The impact intensity evaluation module evaluates the impact intensity of the water diversion project on the regulating lake ecosystem through the multifunctionality during the water diversion period and the non-water diversion period.

[0031] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method and system for evaluating the impact intensity of water diversion projects on the ecosystem of regulating lakes. Starting from the difference in ecological functions of regulating lakes during the water diversion period and the non-water diversion period, the changes in ecological function indicators of lakes in different periods are comprehensively investigated; by integrating key factors such as water quality, biological communities, and habitat environment, cluster analysis is used to deeply reveal the trade-off relationship and relative weight between various ecological functions; the effective function threshold discrimination method is used to calculate the weighted multifunctionality of regulating lakes in different periods, and then the impact intensity of water diversion projects on the ecosystem of regulating lakes is evaluated. The technical characteristics and advantages of the present invention are mainly reflected in the following three aspects:

[0032] (1) Comprehensiveness: The present invention not only focuses on water quality indicators, but also covers multiple dimensions such as biological communities and habitat environments, involving seven major ecological functions such as nutrient cycling, system metabolism, primary production, secondary production, underwater light intensity, microbial abundance and habitat complexity, ensuring the comprehensiveness and accuracy of the assessment results.

[0033] (2) Scientificity: This paper uses cluster analysis to deeply explore the intrinsic connections and relative weights among different ecological functions, avoiding the subjective interference of human empowerment and ensuring the scientificity and rationality of the evaluation method.

[0034] (3) Practicality: The present invention adopts the effective function threshold discrimination method to calculate the weighted multifunctionality, which provides a quantitative assessment of the ecological impact of water diversion projects and enhances the application value of the present invention in actual water resources management and ecological protection work. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0036] Figure 1 A flow chart of the method for calculating the multifunctionality of lake ecosystems based on functional clustering provided by the present invention;

[0037] Figure 2 The scree plot of 16 functional indicators of the case lake based on the elbow method provided by the present invention;

[0038] Figure 3 The cluster analysis dendrogram and weight distribution results of 16 functional indicators of the case lake provided by the present invention;

[0039] Figure 4 The calculation results of the multifunctionality of the lake ecosystem in the case lake provided by the present invention during the water diversion period and the non-water diversion period. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The embodiment of the present invention discloses a method for evaluating the intensity of the impact of a water diversion project on a regulating lake ecosystem. Figure 1 As shown, including:

[0042] Collect water quality and biological samples of lake ecosystems during water transfer and non-water transfer periods to determine functional indicators;

[0043] The functional indicators are subjected to outlier elimination and standardization processing, and the processed functional indicators are clustered to determine the number of clusters and the functional indicators contained in each cluster, and an equal weight is assigned to each cluster, and the weight of each functional indicator within the cluster is also equal;

[0044] Preset an effective function threshold, compare the processed function index with the function threshold, take the processed function index greater than the function threshold as the effective function, multiply the effective function by the weight corresponding to the effective function to obtain the performance level of the effective function, and calculate the weighted average of all effective functions to obtain the multifunctionality of the lake ecosystem;

[0045] The impact intensity of water diversion projects on the regulating lake ecosystem is evaluated through the multifunctionality during the water diversion period and the non-water diversion period.

[0046] In a specific embodiment, the detection data after removing outliers is standardized to the interval [0, 1].

[0047] In a specific embodiment, the effective function threshold is 0.5, and k-means cluster analysis is performed on all indicators. Each cluster is assigned an equal weight, and the weight of each functional indicator in the cluster is also equal. The results are shown in Figure 2 and Figure 3 According to the scree plot and classification tree, the number of clusters is determined to be 3. Cluster 1 includes total phosphorus, total nitrogen, total organic carbon, transparency, vegetation cover, rotifer biomass and microshell biomass, and the weight of each indicator is 0.14. Cluster 2 includes dissolved oxygen, aquatic plant biomass, phytoplankton density and bacterial abundance, and the weight of each indicator is 0.25. Cluster 3 includes benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass and herbivorous fish biomass, and the weight of each indicator is 0.2. The total weight is 2.98. The specific weight is calculated by dividing the indicator weight by the total weight.

[0048] Taking 0.5 as the functional threshold, the standardized value higher than the functional threshold is the effective function, the standardized value multiplied by the corresponding weight is the performance level of the effective function, and the weighted average of all effective functions is the multifunctionality of the lake ecosystem. The calculation results are shown in Figure 4 , the multifunctionality in the water regulation period and the non-water regulation period was 0.66±0.08 and 0.67±0.09, respectively.

[0049] Preferably, the functional indicators specifically include: total phosphorus concentration, total nitrogen concentration, total organic carbon concentration, dissolved oxygen concentration, transparency, aquatic plant cover, bacterial abundance, aquatic plant biomass, phytoplankton density, rotifer biomass, microshell biomass, benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass, and herbivorous fish biomass. A certain regulating lake is located in the northern inland of my country, with an average water depth of 2.5 meters and a total water storage capacity of 300 million cubic meters. These include seven main ecological functions: nutrient cycling, represented by total phosphorus and total nitrogen concentrations; ecosystem metabolism, represented by dissolved oxygen and total organic carbon; primary production of lakes, represented by aquatic plant biomass and phytoplankton density; secondary production of lakes, represented by rotifer biomass, microshell biomass, benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass, and herbivorous fish biomass; underwater light intensity, represented by the depth of the photic zone; water body microbial abundance, represented by bacterial abundance; and habitat complexity, represented by vegetation cover.

[0050] Since 2013, with the implementation of the water diversion project, the lake has been diverting water from December to May of the following year, and the amount of water diverted has increased year by year. As of now, the cumulative amount of water diverted has exceeded 5 billion cubic meters. According to the progress of water diversion, the lake ecology survey was carried out in the water diversion period (April) and the non-water diversion period (July), 30 sampling points were set up, water quality and biological samples were collected, and each sampling point was repeated 3 times to test the following 16 functional indicators: total phosphorus concentration, total nitrogen concentration, total organic carbon concentration, dissolved oxygen concentration, transparency, aquatic plant cover, bacterial abundance, aquatic plant biomass, phytoplankton density, rotifer biomass, microshell biomass, benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass, and herbivorous fish biomass. The test results are shown in Table 1.

[0051] Table 1 Test results of 16 indicators of lakes

[0052]

[0053]

[0054] Preferably, in the standardization process, the total phosphorus concentration and the total nitrogen concentration are standardized according to the reference value, and the calculation formula is as follows:

[0055]

[0056] Among them, x is the detection value, xstd is the reference value. According to the requirements for Class III lake water quality in the National Surface Water Quality Standard (GB3838-2002), the reference values ​​of total phosphorus and total nitrogen are 0.05 mg / L and 1.0 mg / L respectively.

[0057] Preferably, other functional indicators except total phosphorus concentration and total nitrogen concentration are calculated using the forward standardization method, and the calculation formula is as follows:

[0058]

[0059] Among them, x is the detection value, xmin is the minimum value, and xmax is the maximum value.

[0060] Preferably, the calculation formula of multifunctionality specifically includes:

[0061]

[0062] Among them, MF is multifunctionality, F is the total number of functions, fi is the standardized value of function i, t is the effective function threshold (generally 0.5), and ri is the discriminant function.

[0063] The impact intensity of water diversion project on regulating lake ecosystem was evaluated according to the weighted multifunctionality in water diversion period and non-water diversion period. The multifunctionality in water diversion period and non-water diversion period were 0.66±0.08 and 0.67±0.09 respectively. There was no significant difference in weighted multifunctionality of the regulating lake in different periods, indicating that the impact intensity of water diversion project on regulating lake ecosystem was not great.

[0064] Preferably, the water quality indicators include transparency, dissolved oxygen, total phosphorus concentration, total nitrogen concentration and total organic carbon concentration. When collecting water quality indicators, a Secchi disk is used to measure transparency at the sampling point, and a multi-parameter water quality meter (YSIPro Plus, YSI Company, USA) is used to measure dissolved oxygen; a 1L water sample is collected from 0.5m below the water surface using a plexiglass water sampler, which is refrigerated at 4°C and brought back to the laboratory for determination of total nitrogen, total phosphorus and total organic carbon concentrations. The total nitrogen concentration is determined by alkaline potassium persulfate digestion ultraviolet spectrophotometry (HJ 636-2012), the total phosphorus concentration is determined by flow injection-ammonium molybdate spectrophotometry (HJ 671-2013), and the total organic carbon concentration is determined by combustion oxidation-non-dispersive infrared absorption method (HJ 501-2009).

[0065] Preferably, the bacterial abundance is determined by collecting 1 L of water sample using a plexiglass water sampler, filtering with a 0.22 μm filter membrane and storing at -80°C, and then performing high-throughput sequencing in the laboratory to determine the bacterial abundance.

[0066] Preferably, when collecting the phytoplankton density, 1 L of water sample is collected using a plexiglass water sampler, 15 mL of Lugol's iodine solution is immediately added for fixation, 0.1 mL is taken with a micropipette, and all phytoplankton cells are counted under a microscope to obtain an average value.

[0067] Preferably, the collection of rotifer biomass includes: collecting 1L of water sample, immediately adding 15mL of Lugol's iodine solution for fixation, standing for 48 hours, concentrating to 20mL by multiple siphoning, taking 1mL of sample with a micropipette, counting the whole piece under a microscope and taking the average value, and converting the biomass by the volume method.

[0068] When collecting microshell biomass, collect 20L of water sample, filter and concentrate it through No. 25 plankton net, put it into 100mL polyethylene bottle, add 1.5mL Lugol's iodine solution immediately to fix it, use micropipette to draw 5mL and count under microscope, calculate the total number of multiple counting results, and convert it into biomass by volume method;

[0069] When collecting the coverage and biomass of aquatic plants, a 1m×1m sample square was placed at the sampling point to estimate the coverage of aquatic plants. All plants in the sample square were cut from the base of the emergent plants with a sickle, and a waterweed quantitative clamp (opening area of ​​0.25m 2 ) Collect floating plants, floating leaf plants and submerged plants, and weigh them to obtain biomass;

[0070] Benthic animal biomass: Use an opening area of ​​1 / 16m 2 The Peterson mud sampler was used to quantitatively collect mud three times, and the samples were washed several times in a 40-mesh sieve. After the sludge was washed off, it was poured into a white porcelain plate for sorting. The sorted benthic animal samples were fixed in a 75% ethanol solution and weighed to obtain the biomass.

[0071] Fish biomass includes carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass and herbivorous fish biomass. Place traps at appropriate locations at sampling points. Collect samples from the traps after 12 hours, record the type, number and weight of the fish, and calculate the fish biomass using the following formula:

[0072] B = (C × d) / (v × t × a × q);

[0073] Where B is the fish biomass in a single survey in the ground cage (gm -2 ), C is the catch of a single cage device, a is the mesh area of ​​the cage (m 2 ), t is the time of cage placement, v is the average flow velocity of regional water (mh -1 ), d is the average water depth (m), q is the fishing efficiency, which is set to 0.5;

[0074] A system for assessing the impact intensity of water diversion projects on the ecosystem of regulating lakes, including:

[0075] The indicator collection module collects functional indicators corresponding to water quality and biological samples of lake ecosystems during water diversion and non-water diversion periods;

[0076] The weight allocation module removes outliers and standardizes the functional indicators, clusters the processed functional indicators, determines the number of clusters and the functional indicators contained in each cluster, assigns equal weights to each cluster, and the weights of each functional indicator in the cluster are also equal;

[0077] The multifunctionality calculation module presets an effective function threshold, compares the processed functional index with the functional threshold, takes the processed functional index greater than the functional threshold as the effective function, multiplies the effective function by the weight corresponding to the effective function to obtain the performance level of the effective function, and calculates the weighted average of all effective functions to obtain the multifunctionality of the lake ecosystem;

[0078] The impact intensity assessment module evaluates the impact intensity of water diversion projects on the regulating lake ecosystem through the multifunctionality during the water diversion period and the non-water diversion period.

[0079] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0080] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for assessing the impact intensity of a water diversion project on a regulating lake ecosystem, characterized in that: include: Collect water quality and biological samples of lake ecosystems during water transfer and non-water transfer periods to determine functional indicators; The functional indicators are subjected to outlier elimination and standardization processing, the processed functional indicators are clustered, the number of clusters and the functional indicators contained in each cluster are determined, and an equal weight is assigned to each cluster, and the weight of each functional indicator in the cluster is also equal; Preset an effective function threshold, compare the processed function index with the function threshold, take the processed function index greater than the function threshold as an effective function, multiply the effective function by the weight corresponding to the effective function to obtain the performance level of the effective function, and calculate the weighted average of all effective functions to obtain the multifunctionality of the lake ecosystem; The impact intensity of water diversion projects on the regulating lake ecosystem is evaluated by the multifunctionality during the water diversion period and the non-water diversion period.

2. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 1, characterized in that: The functional indicators specifically include: total phosphorus concentration, total nitrogen concentration, total organic carbon concentration, dissolved oxygen concentration, transparency, aquatic plant cover, bacterial abundance, aquatic plant biomass, phytoplankton density, rotifer biomass, microshell biomass, benthic animal biomass, carnivorous fish biomass, omnivorous fish biomass, filter-feeding fish biomass, and herbivorous fish biomass.

3. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: In the standardization process, the total phosphorus concentration and the total nitrogen concentration are standardized according to the reference value, and the calculation formula is as follows: Among them, x is the detection value, x std is the benchmark value.

4. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: The other functional indicators except total phosphorus concentration and total nitrogen concentration were calculated using the forward standardization method, and the calculation formula is as follows: Among them, x is the detection value, x min is the minimum value, x max is the maximum value.

5. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 1, characterized in that: The calculation formula of the multifunctionality specifically includes: Where MF is the multifunctionality, F is the total number of functions, and f i is the normalized value of function i, t is the effective function threshold, r i is the discriminant function.

6. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: Water quality indicators include transparency, dissolved oxygen, total phosphorus concentration, total nitrogen concentration and total organic carbon concentration. When the water quality indicators are collected, the transparency is measured using a Secchi disk at the sampling point, and the dissolved oxygen is measured using a multi-parameter water quality meter. A plexiglass water sampler is used to collect 1L of water sample 0.5m below the water surface, which is refrigerated at 4°C and brought back to the laboratory for determination of total nitrogen, total phosphorus and total organic carbon concentrations. The total nitrogen concentration is determined by alkaline potassium persulfate digestion ultraviolet spectrophotometry, the total phosphorus concentration is determined by flow injection-ammonium molybdate spectrophotometry, and the total organic carbon concentration is determined by combustion oxidation-non-dispersive infrared absorption method.

7. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: The bacterial abundance was determined by collecting 1 L of water sample using a plexiglass water sampler, filtering with a 0.22 μm filter membrane and storing at -80°C, and then performing high-throughput sequencing in the laboratory to determine the bacterial abundance.

8. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: When collecting the phytoplankton density, 1L of water sample was collected using a plexiglass water sampler, 15mL of Lugol's iodine solution was immediately added for fixation, 0.1mL was taken using a micropipette, and all phytoplankton cells were counted under a microscope to obtain an average value.

9. The method for evaluating the impact intensity of a water diversion project on a regulating lake ecosystem according to claim 2, characterized in that: The rotifer biomass collection process includes: collecting 1L of water sample, immediately adding 15mL of Lugol's iodine solution for fixation, standing for 48 hours, concentrating to 20mL by multiple siphoning, taking 1mL of sample with a micropipette, counting the whole piece under a microscope and taking the average value, and converting the biomass by the volume method.

10. A system for assessing the impact intensity of a water diversion project on a regulating lake ecosystem, using a method for assessing the impact intensity of a water diversion project on a regulating lake ecosystem as claimed in any one of claims 1 to 9, characterized in that: include: The indicator collection module collects functional indicators corresponding to water quality and biological samples of lake ecosystems during water diversion and non-water diversion periods; A weight allocation module is used to remove outliers and standardize the functional indicators, cluster the processed functional indicators, determine the number of clusters and the functional indicators contained in each cluster, and allocate equal weights to each cluster, and the weights of each functional indicator in the cluster are also equal; A multifunctionality calculation module is provided, wherein an effective function threshold is preset, the processed functional index is compared with the functional threshold, the processed functional index greater than the functional threshold is taken as an effective function, the effective function is multiplied by the weight corresponding to the effective function to obtain the performance level of the effective function, and the weighted average value of all effective functions is calculated as the multifunctionality of the lake ecosystem; The impact intensity evaluation module evaluates the impact intensity of the water diversion project on the regulating lake ecosystem through the multifunctionality during the water diversion period and the non-water diversion period.

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