River and lake ecological environment threshold determination method

Abstract

The invention discloses a river and lake ecological environment threshold value determination method, which comprises the following steps of: determining a spatial range of an ecological threshold value evaluation region based on a drainage basin and a region boundary line, and dividing river and lake land and water ecological function subareas, water system afflux or outflow points, visible drain outlets and population distribution; determining an ecological threshold value of each water quality index according to an ecological corresponding model, determining a safety range of each water quality parameter through a confidence interval of a multiple regression model, and determining a joint critical value of the water quality parameters through discriminant analysis; the river and lake ecological water quality threshold value is determined through real-time data acquisition and analysis, so that water quality management and ecological protection are scientifically guided, and data accuracy and reliability are ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of river and lake ecological environment protection and restoration, and specifically relates to a method for determining a river and lake ecological environment threshold. Background Art

[0002] The threshold of river and lake ecological environment refers to the critical value that various environmental factors (such as water quality, ecological flow, connectivity, etc.) can withstand in river and lake ecosystems. When the changes in these environmental factors exceed the threshold, the structure, function and stability of the water ecosystem will be significantly affected, causing damage to the ecosystem or even collapse. At present, my country's river and lake ecological environment is still facing huge challenges. Pollution emissions, over-exploitation, alien species and climate change have prominent impacts, which seriously threaten the health of rivers and lakes and the sustainable development of the economy and society.

[0003] In the sustainable development of rivers and lakes, the determination of ecological environment thresholds plays an important role. Water environment quality is one of the important indicators for judging the health of river and lake ecosystems. Compared with other indicators (such as food chain, biodiversity, energy and material cycle, etc.), water quality is an indicator that is easier to obtain. At present, the determination of important water quality parameters (such as chemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus, etc.) mainly relies on manual sampling and laboratory testing, which generally cannot reflect the water quality of the entire river (lake). In addition, the detection cycle is long, the cost is high, and the real-time performance is poor, which is not conducive to the determination of the threshold of river and lake ecological environment. In addition, the health of river and lake ecosystems is a comprehensive concept, involving various indicators of multiple factors such as water quality, aquatic organisms, hydrology, and coastal ecological environment, but there is currently a lack of effective methods for systematic analysis and prediction. Summary of the invention

[0004] In view of the shortcomings of the existing river and lake ecological environment threshold confirmation, the present invention provides a river and lake ecological environment threshold determination method, which determines the river and lake ecological environment threshold through real-time data acquisition and analysis to scientifically guide water quality management, ecological protection and restoration work.

[0005] The solution adopted by the present invention to solve the technical problem is: a method for determining the threshold value of the ecological environment of rivers and lakes, comprising the following steps:

[0006] Step 1: Based on the watershed and regional boundaries, determine the spatial scope of the ecological threshold assessment area, and divide the river and lake water and land ecological function zones, water system inflow or outflow points, visible sewage outlets, population distribution, etc.;

[0007] Step 2: Deploy multi-parameter online real-time water quality monitoring equipment at the inflow or outflow points of river and lake systems in the assessment area, visible sewage outlets, densely populated areas, and other water areas; use visual self-rotating laser scanning equipment and intelligent monitoring systems to monitor the biological information of the main rivers and major lakes in the area;

[0008] Step 3: Obtain information on historical water quality, biology, hydrometeorology, flow, river-lake connectivity, etc. in the assessment area, combine multi-source real-time monitoring data, build a dynamic data set of river and lake ecological environment, and display ecosystems at risk;

[0009] Step 4: Through monitoring and numerical simulation, determine the environmental variables that affect the health of river and lake ecosystems. Environmental variables include water quality indicators, biological indicators, ecological flow, river-lake connectivity, etc., and identify ecosystems close to critical thresholds; Figure 8 As shown,

[0010] Step 5: Use the Pearson correlation coefficient method to establish a correlation matrix of environmental variables that affect the health of river and lake ecosystems; analyze the degree and direction of correlation between environmental variables and ecological services through different environmental variable correlation matrices, and establish an ecosystem service model. Ecosystem services include water supply, carbon and nitrogen cycles, ecosystem health, biodiversity, etc.; evaluate the relationship between environmental variables and between environmental variables and ecosystem health through the ecosystem service model;

[0011] Step 6: According to the ecosystem service model, determine the ecological and environmental thresholds of each indicator in the assessment area and show the cost of crossing the threshold; determine the uncertainty area of ​​each indicator through the confidence interval of the multivariate regression model, including the starting point of the indicator in the uncertainty area (F 0 ), turning point of indicators affecting ecosystem functions (threshold F 1 ) and the indicator point at which ecosystem function becomes irreversible (F 2 ), and the joint critical values ​​of the ecological environment of different indicators are determined by discriminant analysis.

[0012] The multi-parameter online real-time water quality monitoring equipment in step 2 includes a hull, a controller, a data storage module, a wireless transceiver module and an underwater detection device. The hollow tube is vertically installed on the hull, and the hollow tube can be vertically lifted and extended into the water. The underwater detection device includes a device block and a lifting drive mechanism. The device block is mounted on the submerged part of the hollow tube. The device block is provided with a plurality of detection cavities vertically penetrating the device block. Each detection cavity is provided with an electrode detection mechanism. The electrode detection mechanism includes a sealing column, a detection electrode, a piston, a sealing assembly and a sealing plate. The sealing column is vertically installed on the inner top wall of the detection cavity. The detection electrode is fixedly installed on the bottom surface of the sealing column and is connected to the controller. The detection electrodes in each motor detection mechanism are of different types. The controller is connected to the data storage module for storing the results detected by the detection electrode. The controller is connected to the wireless transceiver module for transmitting the detected real-time water quality data; the piston is matched and installed in the detection cavity below the sealing column, and the piston is provided with a perforation matching the sealing column. The blocking component is matched and installed on the bottom surface of the piston, and the blocking component will automatically block the bottom of the perforation when the detection electrode does not pass through the perforation. The blocking plate is arranged in parallel and spaced below the device block and is coaxially arranged with the corresponding detection cavity. The blocking plate is connected to the piston. When the controller drives the piston to lift the blocking plate through the lifting drive mechanism, so that the detection electrode passes through the blocking component through the perforation and extends into the detection cavity below the piston, the blocking plate will seal against the bottom surface of the device block to block the bottom of the detection cavity.

[0013] The blocking assembly includes a hinged shaft, a blocking door and a torsion spring. The blocking door is hingedly installed on the bottom of the piston on one side of the perforation through the hinged shaft. The torsion spring is matched and installed on the hinged shaft. In a natural state, the torsion spring will drive the blocking plate to flip toward the perforated side and seal with the bottom surface of the piston to block the bottom of the perforation.

[0014] The top of the detection cavity is provided with an opening, and a cover plate is fixed on the top of the sealing column. The cover plate is fixedly installed on the top of the device block by bolts to seal the top opening of the detection cavity, and the sealing column passes through the top opening of the detection cavity and extends into the detection cavity.

[0015] A plurality of connecting rods are evenly spaced along the circumference of the sealing plate surface outside the perforation, one end of the connecting rod is vertically connected to the bottom surface of the piston, and the other end of the connecting rod extends downward to form a device block and is vertically connected to the upper end surface of the sealing plate.

[0016] The piston driving device includes a high-pressure fan fixedly installed on the hull and connected to the controller. An electric-controlled valve connected to the controller is installed at the output end of the high-pressure fan. The output end of the electric-controlled valve is connected to a gas diverter. The number of outlets of the gas diverter is the same as the number of detection cavities, and they are connected to the chambers above the pistons in the corresponding detection cavities through air pipes.

[0017] The water quality indicators in step 4 include pH value, conductivity, COD, ammonia nitrogen, total phosphorus, total nitrogen, etc., and the biological indicators include fish species data, water / shore plant coverage, etc.

[0018] The multi-parameter online real-time water quality monitoring equipment in step 2 is used to detect water quality data, and the real-time water quality data includes real-time pH, real-time conductivity, real-time COD, real-time ammonia nitrogen, real-time total phosphorus, and real-time total nitrogen.

[0019] Real-time dissolved oxygen data, real-time ammonia nitrogen data and real-time nitrate data; the real-time biological data includes the types and quantities of real-time phytoplankton and zooplankton.

[0020] The ecosystem service model in step 5 is a multiple linear regression model, and the ecosystem service model is:

[0021] y=β 0 +β 1 x 1 +β 2 x 2 +…+β n x n +∈

[0022] where x 1 , x 2 , ...x n is the water quality index to be investigated, β 0 is the intercept, β 1 , β 2 , ... β n is the Pearson correlation coefficient corresponding to the water quality index, and ∈ is the error term.

[0023] The spatial scope of the ecological threshold assessment in step 1 includes information such as the regional / watershed boundaries within the assessment scope and the water volume and pollution migration location on the boundaries, water system connectivity characteristics, river and lake distribution, sewage outlets, population distribution, etc.

[0024] Beneficial effects of the invention: The method for determining the threshold value of the river and lake ecological environment provided by the invention has the following beneficial effects:

[0025] 1. The present invention provides a method for determining the threshold value of the ecological environment of rivers and lakes. Through multi-parameter online real-time water quality monitoring equipment, visual self-rotating laser scanning equipment and intelligent monitoring system, it can obtain water quality and biological data of the assessment area in real time, ensure the timeliness and dynamism of the data, provide a basis for accurate analysis, and provide a basis for scientific decision-making by selecting and analyzing key water quality indicators of water body ecological health.

[0026] 2. The method for determining the ecological environment threshold of rivers and lakes provided by the present invention can simulate the impact of different indicators on the ecosystem through the ecosystem service model, provide a scientific prediction tool, and enhance the understanding of the response of the ecosystem; the multivariate analysis method is used to determine the safe range and critical value of the ecological threshold of each indicator, ensuring the scientificity and reliability of the ecological threshold, and can effectively guide water quality management and ecological protection.

[0027] 3. Through the unique multi-parameter online real-time water quality monitoring, errors in the detection process are avoided. It can simultaneously detect multiple water quality indicators of water bodies at the same depth in the same area, obtain water quality data in real time, improve detection efficiency and data accuracy, ensure the authenticity and accuracy of the data, and provide a reliable data base for subsequent analysis and decision-making. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the underwater detection device of the present invention.

[0029] Figure 2 It is a schematic diagram of the device block structure of the present invention.

[0030] Figure 3 It is a structural schematic diagram of the electrode detection mechanism of the present invention.

[0031] Figure 4 It is a schematic diagram of the piston structure of the present invention.

[0032] Figure 5 It is a schematic diagram of the use process of the underwater detection device of the present invention.

[0033] Figure 6 It is a schematic diagram of an example result icon of the present invention.

[0034] Figure 7 It is a schematic diagram of the evaluation area division of the present invention.

[0035] Figure 8 It is a schematic diagram of the uncertainty area of ​​the present invention.

[0036] Fig. 9 It is a schematic diagram of data obtained by the present invention through the dynamic data set of ecological environment.

[0037] Fig.10 Schematic diagram of the correlation coefficient matrix of Example 1 of the present invention.

[0038] Fig.11 It is a schematic diagram of the prediction results of the ecological response y of Example 1 of the present invention.

[0039] Fig.12 It is a schematic diagram of the structure of the cleaning and pressure relief mechanism of the present invention.

[0040] Fig.13It is a schematic diagram of the setting position of the underwater detection device of the present invention.

[0041] Numbers in the figure: 1 is the hull, 2 is the hollow tube, 3 is the device block, 31 is the detection chamber, 32 is the air hole, 4 is the sealing column, 41 is the cover plate, 42 is the limit block, 5 is the detection electrode, 6 is the piston, 61 is the perforation, 62 is the pointed square column, 63 is the elastic reset assembly, 631 is the guide plate, 632 is the connecting rod, 633 is the top spring, 634 is the limit plate, 64 is the installation groove, 65 is the suction channel, 66 is the water inlet, 67 is the water pumping hole, 68 is the negative pressure hole, 69 is the flushing hole, 7 is the blocking assembly, 71 is the hinge shaft, 72 is the blocking door, 8 is the blocking plate, 81 is the connecting rod, and 9 is the underwater detection device. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0043] Example 1

[0044] This embodiment provides a method for determining a river and lake ecological environment threshold, comprising the following steps:

[0045] Step 1, such as Figure 7 As shown in the figure, based on the watershed and regional boundaries, the spatial scope of the ecological threshold assessment area is determined, and the water and land ecological functional zones of rivers, lakes, water system confluence or outflow points, visible sewage outlets, and population distribution are divided. When determining the ecological water quality thresholds of rivers and lakes, specific analysis and processing can be carried out according to the characteristics of different regions, making the ecological threshold assessment more scientific and reasonable.

[0046] Step 2: Deploy multi-parameter online real-time water quality monitoring equipment at the inflow or outflow points of the river and lake systems in the assessment area, visible sewage outlets, densely populated areas and other water areas; use visual self-rotating laser scanning equipment and intelligent monitoring systems to monitor the biological information of the main rivers and lakes in the area, and obtain real-time water quality data and real-time biological information in each area;

[0047] like Figure 1-5 As shown, the multi-parameter online real-time water quality monitoring equipment used in this embodiment includes a hull 1, a controller, a data storage module, a wireless transceiver module and an underwater detection device. The hollow tube 2 is vertically installed on the hull 1, and the hollow tube 2 can be vertically lifted and extended into the water. There are many methods for controlling the lifting and extending of the hollow tube 2 into the water. For example: a lifting frame is provided on one side of the hull 1, and a winch is installed on the top of the lifting frame. The hollow tube 2 is vertically slidably installed in the lifting frame, and the top of the hollow tube 2 is connected to the traction end of the winch traction rope. When the winch releases the traction rope, the bottom end of the hollow tube 2 will rely on its own weight to descend along the lifting frame and extend into the water.

[0048] The underwater detection device 9 includes a device block 3 and a lifting drive mechanism. The lifting drive mechanism is matched and installed in the hull 1. The device block 3 is mounted on the submerged part of the hollow tube 2. When the hollow tube 2 is extended into the water, the device block 3 will follow the downward movement of the hollow tube 2 and be immersed in the water. A plurality of detection cavities 31 are evenly arranged in the device block 3 along the circumferential direction. The detection cavity 31 penetrates the device block 3 vertically downward. An electrode detection mechanism is arranged in each detection cavity 31 for performing different types of water quality detection on the water body.

[0049] The electrode detection mechanism includes a sealing column 4, a detection electrode 5, a piston 6, a sealing assembly 7 and a sealing plate 8. The sealing column 4 is vertically installed on the inner top wall of the detection chamber 31. The detection electrode 5 is fixedly installed in the middle of the bottom surface of the sealing column 4 and is connected to the controller. There are many ways to install the sealing column 4. For example, the top of the detection chamber 31 is provided with an opening, and a cover plate 41 is fixed on the top of the sealing column 4. The cover plate 41 is fixed to the top of the device block 3 by bolts to seal the top opening of the detection chamber 31, and the sealing column 4 passes through the top opening of the detection chamber 31 and extends into the detection chamber 31.

[0050] And the detection electrode 5 in each motor detection mechanism is of different types. The detection electrode 5 is an existing water quality detection electrode 5 or a water quality detection sensor, which is used to perform different types of water quality detection. The controller is connected to the data storage module to store the results detected by the detection electrode 5. The controller is connected to the wireless transceiver module to transmit the detected real-time water quality data; the piston 6 is matched and installed in the detection cavity 31 below the sealing column 4, and the piston 6 is provided with a perforation matching the sealing column 4. When the piston 6 lifts the sealing column 4 and inserts it into the perforation, the sealing column 4 will The sealing member 7 is matched and installed on the bottom surface of the piston 6, and the sealing member 7 will automatically block the bottom of the perforation when the detection electrode 5 does not pass through the perforation. There are many types of sealing members 7. The sealing member 7 of this embodiment includes a hinge shaft 71, a blocking door 72 and a torsion spring. The blocking door 72 is hingedly installed on the bottom of the piston 6 on one side of the perforation through the hinge shaft 71. The torsion spring is matched and installed on the hinge shaft 71. In the natural state, the torsion spring will drive the sealing plate 8 to flip toward the perforation side and seal with the bottom surface of the piston 6 to block the bottom of the perforation.

[0051] The blocking plate 8 is arranged in parallel and at intervals below the device block 3 and is coaxially arranged with the corresponding detection chamber 31. The blocking plate 8 is connected to the piston 6. When the controller drives the piston 6 to lift the blocking plate 8 through the lifting drive mechanism, so that the detection electrode 5 passes through the blocking assembly 7 through the perforation and extends into the detection chamber 31 below the piston 6, the blocking plate 8 will seal against the bottom surface of the device block 3 to block the bottom of the detection chamber 31, and when the piston 6 is lifted, the river and lake water will enter the detection chamber 31 on the lower side of the piston 6 as a river and lake water sample for detection.

[0052] There are many ways to connect the sealing plate 8 to the piston 6. For example, a plurality of connecting rods 81 are evenly spaced along the circumference of the sealing plate 8 on the outside of the perforation. One end of the connecting rod 81 is vertically connected to the bottom surface of the piston 6. The other end of the connecting rod 81 extends downward out of the device block 3 and is vertically connected to the upper end surface of the sealing plate 8. When the piston 6 rises and falls, the connecting plate will be driven to rise and fall synchronously.

[0053] The piston 6 driving device includes a high-pressure fan fixedly mounted on the hull 1 and connected to the controller. An electric-controlled valve connected to the controller is installed at the output end of the high-pressure fan. The output end of the electric-controlled valve is connected to a gas diverter. The number of outlets of the gas diverter is the same as the number of detection chambers 31, and they are connected to the chambers above the piston 6 in the corresponding detection chambers 31 through air pipes. Specifically:

[0054] The end of the sealing column 4 away from the piston 6 is matched with a limit block 42, and the inner wall of the detection chamber 31 on one side of the limit block 42 is provided with an air hole 32, and the air hole 32 is located above the limit block 42. The outer opening of the air hole 32 is connected with an air pipe, and the tail end of the air pipe extends through the hollow tube 2 to the outlet corresponding to the gas diverter on the hull 1 to be connected. The length dimension of the sealing column 4 below the limit block 42 is greater than the thickness dimension of the piston 6. When the piston 6 is lifted and inserted on the sealing column 4, and continues to be lifted along the sealing column 4 to contact the limit block 42, the blocking plate 8 will synchronously contact with the bottom surface of the device block 3 to seal the bottom of the detection chamber 31. In this process, the bottom end of the sealing column 4 can extend downward from the piston 6 so that the detection electrode 5 installed at the bottom end of the sealing column 4 can penetrate into the detection chamber 31 below the piston 6 and immerse in the river and lake water body;

[0055] When the controller controls the high-pressure fan to rotate forward to extract the air in the detection chamber 31 above the piston 6, negative pressure will be generated in the detection chamber 31 above the piston 6, driving the piston 6 to move upward. When the piston 6 is matched and inserted into the sealing sleeve, the sealing column 4 will seal the hole in the middle of the piston 6, so that when the detection electrode 5 pushes the sealing component 7 open, the piston 6 can still be driven by the negative pressure to continue to be lifted and contact the limit block 42. Conversely, when the controller controls the high-pressure fan to rotate in the opposite direction to inject high-pressure air into the detection chamber 31 above the piston 6, the injected high-pressure air will push the piston 6 downward to move the detected river and lake water out of the detection chamber 31.

[0056] During use, when the piston 6 is lifted, the lake and river water will be drawn into the detection chamber 31. When the measuring electrode passes through the perforation through the sealing assembly 7 and extends into the detection chamber 31 below the piston 6 and is immersed in the water body, the sealing plate 8 will seal the bottom of the detection chamber 31. At this time, the perforation on the piston 6 is blocked by the sealing column 4, thereby sealing the detection chamber 31 below the piston 6 as an independent sealed chamber. Since the types of detection electrodes 5 are different in each motor detection mechanism, the controller can simultaneously perform different types of water quality detection on river and lake water in the same partition, depth and time period through each detection electrode 5, obtain real-time water quality data, improve data authenticity and accuracy, and avoid errors.

[0057] Step three: Obtain information on historical water quality, biology, hydrometeorology, flow, river-lake connectivity, etc. in the assessment area, and build a dynamic data set of river and lake ecological environment by combining real-time monitoring data from multi-parameter online real-time water quality monitoring equipment with visual self-rotating laser scanning equipment and intelligent monitoring systems; and display risky ecosystems. There are many types of historical water quality data and historical biological data for each sub-division of rivers and lakes. For example, historical water quality data and historical biological data for each sub-division of rivers and lakes can be obtained through public data from environmental protection departments of public institutions or hydrological monitoring stations.

[0058] Step 4: Determine the environmental variables that affect the health of river and lake ecosystems through monitoring and numerical simulation. Environmental variables include water quality indicators, biological indicators, ecological flow, river-lake connectivity, etc., identify ecosystems close to critical thresholds. Water quality indicators include but are not limited to pH value, conductivity, COD, ammonia nitrogen, total phosphorus, total nitrogen, etc. Select multiple indicators based on regional characteristics. Biological indicators include fish species data, water / shore plant coverage, etc.

[0059] The water quality data of each region is obtained through the dynamic data set of ecological environment, and the water quality data of each region is analyzed to determine the impact of each environmental variable on the ecological environment health of each region, so as to provide a scientific basis for the subsequent determination of ecological thresholds; the water quality data analysis of each region includes one or more of time series analysis, spatial analysis, correlation analysis and multivariate analysis. Through time series analysis, the changing trends of water quality indicators in different time periods are analyzed. For example, the temperature data of river, lake, water and land ecological function zones are obtained through the dynamic data set of ecological environment, and a time series diagram of the temperature of river, lake, water and land ecological function zones is drawn according to the obtained data. The changing trends of the temperature of river, lake, water and land ecological function zones in different time periods are judged through the time series diagram;

[0060] Through spatial analysis, water quality data from different regions are compared to identify differences between regions. For example, pH data of each region is obtained through the dynamic ecological environment data set, and box plots are drawn based on the pH data of each region for comparison. Through correlation analysis, the relationship between water quality indicators and between water quality indicators and ecological health status is evaluated. For example, data on dissolved oxygen and ammonia nitrogen in the water and land ecological functional zoning of rivers, lakes and land are obtained through the dynamic ecological environment data set, and the Pearson correlation coefficient of dissolved oxygen and ammonia nitrogen is calculated to evaluate the linear relationship and correlation between the two water quality indicators. Multivariate analysis is used to evaluate the comprehensive impact of various water quality indicators on ecological health. For example, a multivariate regression model is established to predict the impact of dissolved oxygen on water quality health.

[0061] Step 5: Use the Pearson correlation coefficient method to establish a correlation matrix of environmental variables that affect the health of river and lake ecosystems; analyze the degree and direction of correlation between environmental variables and ecological services through different environmental variable correlation matrices, and establish an ecosystem service model. Ecosystem services include water supply, carbon and nitrogen cycles, ecosystem health, biodiversity, etc.; evaluate the relationship between environmental variables and between environmental variables and ecosystem health through the ecosystem service model;

[0062] Example 1

[0063] To understand the water quality indicators (x i ) and the ecological response (y), as well as the correlation between various water quality indicators, the Pearson correlation coefficient method was used to obtain the correlation coefficient matrix under certain specific conditions, such as Figure 1 As shown. The value of the correlation coefficient is [-1,1]. When the value is negative, it represents a negative correlation. The closer it is to -1, the greater the correlation is. When it is -1, it is a negative linear correlation. When the value is positive, it represents a positive correlation. The closer it is to 1, the greater the correlation is. When it is 1, it is a positive linear correlation. Figure 1 The "*" in the represents the degree of significance, and the more the number, the more significant it is. In general, when |r|≥0.8, it represents a high correlation; when 0.5≤|r|<0.8, it represents a moderate correlation; when 0.3≤|r|<0.5, it represents a low correlation; when |r|<0.3, it may represent no correlation.

[0064] like Fig.10 As shown in the figure, except for τ and y, which are positively correlated, the other indicators such as R, P, N, k 0 The correlation coefficients of P, R, and N are all negatively correlated with y, that is, the larger the value, the smaller y is, and the more unfavorable the ecological conditions are. According to the size of the correlation coefficient, the degree of correlation between each factor and y can be determined. Specifically, P, R, and N are highly correlated with y, and k 0 、M 3 , τ is moderately correlated with y, M 2 、M 4 Low correlation with y, Mx 、M 1 There is no correlation with y.

[0065] Remove irrelevant and low-correlated factors and establish a fitting model (multiple regression model) between the ecological response y value and its high and medium correlation factors. The results are shown in formula 1, and the relationship between the actual y value and the fitted value is given. The results are shown in Figure 2 As shown in the figure, the average absolute error of the fitting results is 0.016, and the average relative error is 7.64%, and the fitting accuracy is relatively high.

[0066] β=0.7-0.529R-0.024P+0.033N+0.058T-0.003M 3 +1.146τ (1)

[0067] Where: y is the ecological response value (such as ecosystem health status, number of fish species); R is COD content, mg / L; P is total phosphorus content, mg / L; N is ammonia nitrogen content, mg / L; T is water temperature, °C; M 3 is the conductivity of other water quality indicators, mS / m; τ is the dissolved oxygen content.

[0068] The ecological response prediction can be carried out according to formula (1). The prediction results are as follows: Fig.11 As shown in the figure, the closer y is to 1, the healthier the ecosystem is, and vice versa, the more fragile the ecosystem is.

[0069] Example 2

[0070] It can be seen from formula (1) that the ecological response model is a multiple linear regression model, and the ecosystem service model is:

[0071] y=β 0 +β 1 x 1 +β 2 x 2 +…+β n x n +∈

[0072] where x 1 , x 2 , ...x n is the water quality index to be investigated, β 0 is the intercept, β 1 , β 2 , …β n is the Pearson correlation coefficient corresponding to the water quality standard, and ∈ is the error term.

[0073] The data in Table 1 were obtained through the ecological environment dynamics dataset, including three water quality parameters: dissolved oxygen (DO), pH value, and nitrogen concentration (N), as well as the number of fish species (Fish Species) as ecological responses.

[0074] Obtained through the ecological environment dynamics dataset Fig. 9 The data in Table 1 include three water quality parameters, namely dissolved oxygen (DO), pH value and nitrogen concentration (N), as well as the number of fish species (Fish Species) as ecological responses.

[0075] According to the data in Table 1, the form of the ecosystem service model in Table 1 is:

[0076] y=β 0 +β 1 DO+β 2 pH+β 3 N+∈

[0077] The regression coefficients were calculated using the least squares method (OLS):

[0078] β 0 =2.5,β 1 =2.0,β 2 =1.5,β 3 =-1.0.

[0079] The ecosystem service model in Table 1 is:

[0080] y=2.5+2.0DO+1.5pH+1.0N+∈

[0081] Apply the ecosystem service model formula in Table 1 to predict new water quality indicators, for example:

[0082] If DO=6.5mg / L, pH=7.0, N=0.7mg / L, the predicted number of fish species is:

[0083] y=2.5+2.0×6.5+1.5×7.0-1.0×0.7y=2.5+2.0×6.5+1.5×7.0-1.0×0.7

[0084] y=2.5+13.0+10.5-0.7y=2.5+13.0+10.5-0.7

[0085] y≈25.3y≈25.3

[0086] By establishing an ecosystem service model, it can help workers understand and predict the impact of changes in water quality parameters on the ecosystem, providing a scientific basis for environmental management and protection.

[0087] Step 6: According to the ecosystem service model, determine the ecological and environmental thresholds of each indicator in the assessment area and show the cost of crossing the threshold; determine the uncertainty area of ​​each indicator through the confidence interval of the multivariate regression model, such as Figure 8As shown, the indicator starting point (F 0 ), turning point of indicators affecting ecosystem functions (threshold F 1 ) and the indicator point at which ecosystem function becomes irreversible (F 2 ), and the joint critical values ​​of the ecological environment of different indicators are determined by discriminant analysis, for example:

[0088] According to the ecosystem service model of Example 2: y = 2.5 + 2.0 DO + 1.5 pH + 1.0 N + ∈

[0089] like Figure 6 As shown, assuming the confidence interval is 95%, the safety range of each water quality parameter is determined by the confidence interval of the multiple regression model: dissolved oxygen (DO): 5.0-8.0 mg / L; pH value: 6.5-7.5; nitrogen concentration (N): 0.5-1.0 mg / L.

[0090] Hypothetical discriminant analysis shows that the parameter combination when the ecosystem begins to be significantly negatively affected is: DO <4.0 mg / L, pH <6.0, N >1.5 mg / L.

[0091] Therefore, based on the results of discriminant analysis, the joint critical points of each water quality parameter were determined: the critical value of dissolved oxygen (DO) was 4.0 mg / L, the critical value of pH was 6.0, and the critical value of nitrogen concentration (N): 1.5 mg / L.

[0092] Example 2

[0093] The difference between Example 2 and Example 1 is that Fig.12 As shown, a cleaning pressure relief mechanism is matched inside the piston 6, and the cleaning pressure relief mechanism includes a tip square column 62 and an elastic reset component 63. A mounting groove 64 matching the tip square column is provided on the outer ring surface of the piston 6 in the circumferential direction. The tip square column is matched and installed in the mounting groove 64 and can slide radially along the inner wall of the mounting groove. The tip of the tip owner is set outward, and the elastic reset component is installed in the mounting groove on the inner side of the tip square column and connected to the tip square column. The elastic reset member will drive the tip square column box to slide back into the mounting groove in a natural state; a suction channel 65 is provided inwardly at the tip of the tip square column, and a water inlet 66 penetrating the tip square column is provided upward at the inner end of the suction channel. A water pumping hole 67 connected to the mounting groove is vertically provided on the upper end surface of the piston above the mounting groove. The position of the water pumping hole matches the water inlet of the suction channel, and when the tip square column retracts into the mounting groove, the tip square column outside the water inlet of the suction channel blocks and blocks the bottom opening of the water pumping hole;

[0094] A negative pressure hole 68 matching the mounting groove is radially provided on the inner wall of the detection chamber 31 on the same side of the mounting groove, and the orifice of the negative pressure hole away from the mounting groove is matched and connected with a negative pressure suction mechanism, and when the piston is vertically lowered to the limit position, the mounting groove and the negative pressure hole overlap and connect; the negative pressure suction mechanism includes a negative pressure machine matched and installed on the hull, and the suction end of the negative pressure machine is matched and installed with an electric control valve, which is connected to the orifice of the negative pressure hole away from the mounting groove through a negative pressure pipe; a flushing hole and a vent are matched on the inner wall of the detection chamber 31 on one side of the air hole, and the flushing hole and the vent are arranged at the same height as the air hole 32, and the outer orifice of the vent is connected with a pressure equalizing pipe, and the other end of the pressure equalizing pipe extends to the hull, and is matched and installed with a control valve connected to the controller for controlling the opening and closing of the vent.

[0095] The flushing hole is matched and connected with a flushing water supply component, which is an existing water supply mechanism, including a flushing water supply component including a storage tank installed on the hull, in which clean water is stored, and a high-pressure water pump is matched and installed on the drainage section of the storage tank, and a drain valve is matched and installed on the drainage end of the high-pressure water pump, and the drain valve is connected to the flushing hole, and the negative pressure machine, the electric control valve, the drain valve and the high-pressure water pump are all connected to the controller; when in use, after the water quality monitoring is completed, the controller will control the control valve to close, and then control the drain valve and the high-pressure water pump to open, and the high-pressure water pump will draw clean water through the drain valve and the flushing hole and discharge it into the detection chamber 31 above the piston. As the clean water is injected, the piston 6 will be pushed down, and when the piston moves downward to the limit When the mounting groove is in the negative pressure hole, it overlaps and connects with the negative pressure hole. The controller will control the control valve to open, and then control the drain valve and the high-pressure water pump to close. At this time, the detection motor at the bottom of the sealing column 4 is immersed in clean water, thereby realizing the cleaning of the detection electrode. After the cleaning is completed after soaking for a certain period of time, the controller controls the control valve and the negative pressure machine to open. When the negative pressure machine is working, negative pressure will be generated in the negative pressure hole, thereby driving the pointed square column to extend outward to match the mounting groove and insert into the negative pressure hole to fix the height of the piston. When the pointed end is driven to extend to the limit length, the water inlet of the suction channel on the pointed square column overlaps and is connected with the water pumping hole, so that the suction end of the negative pressure machine is connected with the detection cavity above the piston, so that it can suck and discharge the clean water in the detection cavity above the piston.

[0096] There are various structures of the elastic reset component. The elastic reset component in this embodiment includes a guide plate 631 fixedly installed in the installation groove, an axial hole is provided in the middle of the guide plate, and a connecting rod 632 is slidably installed. One end of the connecting rod is fixedly connected to the tip square column, and the other end of the connecting rod is matched and installed with a limit plate 634. A top spring 633 is matched and mounted on the connecting rod between the limit plate and the guide plate. In a natural state, the top spring will push the limit plate inward to drive the connecting rod to drive the tip square column to retract inward, so that the tip square column contacts the guide plate and completely retracts into the installation groove.

[0097] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A method for determining the threshold value of river and lake ecological environment, characterized in that: The following steps are involved: Step 1: Based on the watershed and regional boundaries, determine the spatial scope of the ecological threshold assessment area, and divide the river and lake water and land ecological function zones, water system inflow or outflow points, visible sewage outlets, and population distribution; Step 2: Deploy multi-parameter online real-time water quality monitoring equipment at the inflow or outflow points of river and lake systems in the assessment area, visible sewage outlets, and waters in densely populated areas; use visual self-rotating laser scanning equipment and intelligent monitoring systems to monitor the biological information of the main rivers and major lakes in the area; Step 3: Obtain historical water quality, biology, hydrometeorology, flow, and river-lake connectivity information in the assessment area, and combine the real-time monitoring data of multi-parameter online real-time water quality monitoring equipment with visual self-rotating laser scanning equipment and intelligent monitoring systems to construct a dynamic data set of river and lake ecological environment and display the ecosystems at risk; Step 4: Determine the environmental variables that affect the health of river and lake ecosystems through monitoring and numerical simulation. Environmental variables include water quality indicators, biological indicators, ecological flow, river-lake connectivity, and identify ecosystems close to critical thresholds; Step 5: Use the Pearson correlation coefficient method to establish a correlation matrix of environmental variables that affect the health of river and lake ecosystems; (Analyze the degree and direction of correlation between environmental variables and ecological services through different environmental variable correlation matrices) Establish an ecosystem service model, and use the ecosystem service model to evaluate the relationship between environmental variables and between environmental variables and ecosystem health status; Step six: Based on the ecosystem service model, determine the ecological and environmental thresholds of each indicator in the assessment area and show the cost of crossing the threshold. Determine the uncertainty area of ​​each indicator through the confidence interval of the multivariate regression model, including the indicator starting point F0 in the uncertainty area, the indicator turning point threshold F1 that affects the ecosystem function, and the indicator point F2 where the ecosystem function is irreversible. Discriminant analysis is used to determine the joint critical values ​​of the ecological environment of different indicators.

2. The method for determining the river and lake ecological environment threshold according to claim 1, characterized in that: The multi-parameter online real-time water quality monitoring equipment in step 2 includes a hull, a controller, a data storage module, a wireless transceiver module and an underwater detection device. The hollow tube is vertically installed on the hull, and the hollow tube can be vertically lifted and extended into the water. The underwater detection device includes a device block and a lifting drive mechanism. The device block is mounted on the submerged part of the hollow tube. The device block is provided with a plurality of detection cavities vertically penetrating the device block. Each detection cavity is provided with an electrode detection mechanism. The electrode detection mechanism includes a sealing column, a detection electrode, a piston, a sealing assembly and a sealing plate. The sealing column is vertically installed on the inner top wall of the detection cavity. The detection electrode is fixedly installed on the bottom surface of the sealing column and is connected to the controller. The detection electrodes in each motor detection mechanism are of different types. The controller is connected to the data storage module for storing the results detected by the detection electrode. The controller is connected to the wireless transceiver module for transmitting the detected real-time water quality data; the piston is matched and installed in the detection cavity below the sealing column, and the piston is provided with a perforation matching the sealing column. The blocking component is matched and installed on the bottom surface of the piston, and the blocking component will automatically block the bottom of the perforation when the detection electrode does not pass through the perforation. The blocking plate is arranged in parallel and spaced below the device block and is coaxially arranged with the corresponding detection cavity. The blocking plate is connected to the piston. When the controller drives the piston to lift the blocking plate through the lifting drive mechanism, so that the detection electrode passes through the blocking component through the perforation and extends into the detection cavity below the piston, the blocking plate will seal against the bottom surface of the device block to block the bottom of the detection cavity.

3. The method for determining the river and lake ecological environment threshold according to claim 2 is characterized in that: The blocking assembly includes a hinged shaft, a blocking door and a torsion spring. The blocking door is hingedly installed on the bottom of the piston on one side of the perforation through the hinged shaft. The torsion spring is matched and installed on the hinged shaft. In a natural state, the torsion spring will drive the blocking plate to flip toward the perforated side and seal with the bottom surface of the piston to block the bottom of the perforation.

4. The method for determining the river and lake ecological environment threshold according to claim 2, characterized in that: The top of the detection cavity is provided with an opening, and a cover plate is fixed on the top of the sealing column. The cover plate is fixedly installed on the top of the device block by bolts to seal the top opening of the detection cavity, and the sealing column passes through the top opening of the detection cavity and extends into the detection cavity.

5. The method for determining the river and lake ecological environment threshold according to claim 2, characterized in that: A plurality of connecting rods are evenly spaced along the circumference of the sealing plate surface outside the perforation, one end of the connecting rod is vertically connected to the bottom surface of the piston, and the other end of the connecting rod extends downward to form a device block and is vertically connected to the upper end surface of the sealing plate.

6. The method for determining the river and lake ecological environment threshold according to claim 2, characterized in that: The piston driving device includes a high-pressure fan fixedly installed on the hull and connected to the controller. An electric-controlled valve connected to the controller is installed at the output end of the high-pressure fan. The output end of the electric-controlled valve is connected to a gas diverter. The number of outlets of the gas diverter is the same as the number of detection cavities, and they are connected to the chambers above the pistons in the corresponding detection cavities through air pipes.

7. The method for determining the river and lake ecological environment threshold according to claim 1, characterized in that: The water quality indicators in step 4 include pH value, conductivity, COD, ammonia nitrogen, total phosphorus, and total nitrogen, and the biological indicators include fish species data and water / shore plant coverage.

8. The method for determining the river and lake ecological environment threshold according to claim 1, characterized in that: The multi-parameter online real-time water quality monitoring equipment in step 2 is used to detect water quality data, and the real-time water quality data includes real-time pH, conductivity, COD, ammonia nitrogen, total phosphorus, and total nitrogen.

9. The method for determining the river and lake ecological environment threshold according to claim 1, characterized in that: The ecosystem service model in step 5 is a multiple linear regression model, and the ecosystem service model is: y=β0+β1x1+β2x2+…+β n x n +∈ where x1, x2, ... x n is the water quality index under investigation, β0 is the intercept, β1, β2, ... β n is the Pearson correlation coefficient corresponding to the water quality index, and ∈ is the error term.

10. The method for determining the river and lake ecological environment threshold according to claim 1, characterized in that: The spatial scope of the ecological threshold assessment in step 1 includes the regional / watershed boundaries within the assessment scope, as well as the water volume and pollution migration locations on the boundaries, water system connectivity characteristics, river and lake distribution, sewage outlets, and population distribution information.

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