An ecological restoration method for eutrophic water body based on aquatic plants

Abstract

This invention discloses a method for ecological restoration of eutrophic water bodies based on aquatic plants. This invention relates to the field of water body ecological restoration technology. The invention includes: S1, acquiring water body planar information and drawing a sampling point coordinate distribution map, collecting real-time depth torque data to obtain a sequence of adjacent differences, and simultaneously recording the angle deflection of the drive end; S2, determining the initial and final points of the medium boundary based on the torque difference sequence, correcting the preset sampling points, and simultaneously collecting medium data and, based on the dynamic classification of pollution levels for total nitrogen and total phosphorus, performing targeted progressive restoration operations such as oxygenation, planting submerged plants, and stratified dredging. This invention improves the accuracy of sampling and classification, and can efficiently improve the water quality of eutrophic water bodies.

Description

Technical Field

[0001] This invention relates to the field of aquatic ecological restoration technology, specifically to a method for ecological restoration of eutrophic water bodies based on aquatic plants. Background Technology

[0002] Eutrophication refers to water pollution caused by excessive levels of nutrients such as nitrogen and phosphorus in water bodies. Its essence is due to the imbalance between the input and output of nutrients. Large amounts of nutrients such as nitrogen and phosphorus required by organisms enter slow-flowing water bodies such as lakes, rivers, and bays, causing algae and other plankton to multiply rapidly, leading to a decrease in dissolved oxygen, deterioration of water quality, and mass mortality of fish and other organisms. This results in an imbalance in the distribution of species in the aquatic ecosystem, with the unchecked growth of a single species, causing the entire aquatic ecosystem to become unbalanced and gradually lead to its extinction.

[0003] When restoring the ecology of eutrophic water bodies, the main principles adopted are external source interception, internal source treatment, ecological restoration, and long-term management. This ensures that all domestic sewage and industrial wastewater are included in the pipe network and discharged into sewage treatment plants in compliance with standards. It also reduces the use of chemical fertilizers and pesticides, constructs ecological ditches and buffer zones in farmland to intercept agricultural non-point source pollution, and uses "sponge city" measures such as grassed swales, sunken green spaces, and rain gardens to purify and retain initial rainwater carrying large amounts of pollutants.

[0004] When carrying out ecological restoration of eutrophic water bodies, it is necessary to assess the eutrophication indicators in the water body in order to select appropriate ecological restoration methods. This requires water body sampling. To ensure the accuracy of the assessment of eutrophication indicators, it is necessary to conduct comprehensive sampling and assessment of different water layers, sludge, etc. However, at present, it is not easy to determine the sludge depth when sampling sludge, which affects the sludge sampling depth classification and leads to deviations in the assessment indicators.

[0005] Therefore, there is an urgent need for an ecological restoration method for eutrophic water bodies based on aquatic plants. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an ecological restoration method for eutrophic water bodies based on aquatic plants, which solves the problems of difficulty in determining the depth of sludge sampling and deviation in the assessment of eutrophication indicators.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for ecological restoration of eutrophic water bodies based on aquatic plants, comprising: S1. Obtain the current water body plane information, draw the sampling point coordinate distribution map, and collect the sampling device depth torque data in real time. Calculate the depth torque difference between adjacent time points in time sequence to form a complete depth torque difference sequence, and synchronously record the drive end angle deflection corresponding to each time point. S2. Determine the initial and final points of the media boundary based on the depth-torque difference sequence, correct the sampling points preset by the sampling device, record the corresponding data of the media obtained through the corrected sampling points, classify the eutrophication indicators in the obtained media data, and perform water body ecological restoration operations.

[0008] As a further aspect of the present invention, the specific rules for determining the initial point of the medium boundary are as follows: set a comparison threshold and a number of consecutive judgments N. If there are N consecutive torque differences in the depth torque difference sequence that are not within the comparison threshold and the difference in the angle deflection of the drive end at adjacent times is not 0, then extract the first difference that is not within the comparison threshold, obtain the depth torque data that is used as the minuend when calculating the difference, record the angle deflection of the drive end corresponding to the depth torque data, and record it as the initial point of the medium boundary.

[0009] As a further aspect of the present invention, the specific operation for determining the endpoint of the medium boundary is as follows: Set a fixed deflection increment, deflection growth value and data sampling frequency, synchronously collect the angle deflection, depth torque and tilt angle deflection of the drive end, and initialize the deflection counter and the maximum deflection number threshold. The deflection growth value = real-time length of the sampling ruler × sin(fixed deflection increment). The tilt angle deflection action is executed according to a fixed deflection increment to generate a continuous deflection sequence. After each deflection is completed, the angle is kept stable for a preset time, and the drive end angle deflection and depth torque at the corresponding deflection angle are recorded. If the angle deflection at the drive end increases continuously and the difference between adjacent increases is less than or equal to the deflection growth value, and the corresponding depth torque continuously meets the preset threshold, then it is determined to be bottoming out. At this time, the angle deflection at the drive end when the deflection action is not performed is extracted as the media boundary endpoint.

[0010] As a further aspect of the present invention, if the angle deflection at the drive end continuously increases and the difference between adjacent increases is greater than the deflection growth value, then the difference between the adjacent increase difference and the deflection growth value and the corresponding adjacent growth coefficient are calculated, and the uncorrected angle deflection L and the total deflection angle α corresponding to the maximum growth coefficient are obtained. These are then substituted into the formulas K=L×cosα and A=L×sinα to calculate the corrected angle deflection K and the corrected length A, and K is taken as the endpoint of the medium boundary.

[0011] As a further aspect of the present invention, the specific operation for obtaining the adjacent growth coefficient is as follows: Obtain the driving end angle deflection recorded during the deflection of the sampling ruler, and calculate the difference between two adjacent driving end angle deflections, i.e., the adjacent increase difference. For each adjacent increase difference, subtract the corresponding deflection growth value to obtain the comparison sequence q, and calculate the i-th adjacent growth coefficient = (q i+1 -qi ) / q i ; The real-time length of the sampling ruler when calculating the corresponding deflection growth value refers to the length of the sampling ruler before a single deflection action occurs.

[0012] As a further aspect of the present invention, the specific steps for correcting the pre-set sampling points of the sampling device are as follows: Using the preset sampling point as the origin, the effective direction of the sampling ruler around the obstacle is taken as the horizontal lateral movement direction, and the correction length A calculated at the end of the medium boundary is taken as the fixed lateral movement length. The horizontal lateral movement operation is performed, and the end of the lateral movement is the preliminary correction sampling point. Obtain the correction drive end angle deflection information K corresponding to the media boundary endpoint, control the operation of the drive end of the sampling device, and make the actual depth of the sampling ruler completely consistent with K. Initiate the tilt angle rotation action, collect the deflection torque during the rotation process in real time, and calculate the drive end angle deflection = rotation angle × deflection growth value coefficient, and update the drive end angle in real time. If the rotation angle remains constant but the deflection torque continues to increase within N consecutive intervals, stop the rotation immediately, record the current total rotation angle and end point position, subtract the fixed adjustment amount s from the correction drive end angle deflection K and re-enter it, restart the rotation action until the torque no longer continues to increase, and locate the accurate position of the obstacle edge. If the rotation angle and deflection torque both change continuously within N consecutive intervals, then the rotation action continues. If the rotation angle continues to change within N consecutive intervals and the end point of the sampling ruler returns to the initial sampling line, then the rotation action should be stopped immediately, and the current preliminary correction sampling point is the final correction sampling point.

[0013] As a further aspect of the present invention, the continuous change in the rotation angle refers to the angle in the tilt angle rotation action continuously decreasing towards the initial sampling line; the continuous change in the deflection torque refers to the deflection torque fluctuating non-constantly within the resistance threshold range corresponding to the current target medium, without unidirectional continuous increase or decrease.

[0014] As a further aspect of the present invention, the specific steps for classifying eutrophication indicators in the acquired medium data are as follows: Base samples were collected from uncontaminated areas of the target water body, and the background levels of total nitrogen and total phosphorus in the samples were measured and denoted as TN0 and TP0, respectively. Based on the critical nutrient concentration for algal blooms in the target water body, calibrated grading thresholds were set: the threshold values ​​for mild and moderate algal blooms were TN1 = TN0 + TN0. min TP1 = TP0 + TP min The threshold between moderate and severe cases is TN2 = TN0 + TN maxTP2 = TP0 + TP max ; among which, TN min TN max These are the lower and upper limits of total nitrogen, i.e., TN. min <TN max TP min TP max These are the lower and upper limits of total phosphorus, i.e., TP. min <TP max ; Obtain the actual measured values ​​of TN and TP in the medium data: if TN < TN1 and TP < TP1, it is judged as light pollution; if TN1 ≤ TN < TN2 and TP1 ≤ TP < TP2, it is judged as moderate pollution; if TN ≥ TN2 and TP ≥ TP2, it is judged as heavy pollution.

[0015] As a further aspect of the present invention, if the pollution is mild, oxygenation equipment is installed in the key flow areas of the water body; if the pollution is moderate, submerged plants are planted on the basis of oxygenation treatment for mild pollution; if the pollution is severe, environmentally friendly bottom sediment dredging equipment is used to remove the polluted bottom sediment in layers on the basis of moderate pollution.

[0016] As a further embodiment of the present invention, the oxygenation equipment includes an aerator, an aeration boat, and a fountain; the submerged plants include Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum.

[0017] This invention provides a method for ecological restoration of eutrophic water bodies based on aquatic plants, which has the following advantages compared with existing technologies: (1) This invention accurately determines the initial and final points of the medium boundary by combining the depth torque difference sequence with the angle deflection of the drive end. At the same time, the sampling points are corrected by horizontal lateral movement and rotation detection, effectively avoiding the interference of obstacles and ensuring that the collected medium data can truly reflect the characteristics of water body and bottom sediment pollution. (2) The present invention is based on the background value of the base sample of the unpolluted area of ​​the target water body and combined with the critical nutrient concentration of algal bloom to set a dynamic classification threshold, so that the pollution classification is more in line with the actual situation of the target water body and avoids the classification deviation caused by the fixed threshold. (3) The present invention adopts a graded and progressive remediation strategy, matching corresponding physical oxygenation, ecological planting and layered dredging methods according to different pollution levels, so as to achieve synergistic effect of nutrient salt reduction and ecological restoration. Attached Figure Description

[0018] Figure 1 This is a flowchart of the steps of the present invention; Figure 2 This is a schematic diagram of the device of the present invention; Figure 3 This is a schematic diagram of the swinging sampling ruler of the present invention; Figure 4 This is a schematic diagram of the modified sampling points of the present invention; Figure 5 This is a schematic diagram of the sampling ruler swingback of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1-5 As shown, the present invention provides a method for ecological restoration of eutrophic water bodies based on aquatic plants; As an embodiment of this application, the specific steps include the following: S1. Obtain the current water body plane information, draw the sampling point coordinate distribution map, and obtain the depth torque and drive end angle deflection of the sampling device at the corresponding sampling point at the corresponding time. Calculate the depth torque difference X between the previous and next time points. S2. Determine the initial and final points of the media boundary based on the difference in depth torque X, correct the sampling points preset by the sampling device, record the corresponding data of the media obtained at the corrected sampling points, and perform water body ecological restoration operations based on the eutrophication index in the obtained media data.

[0021] As a second embodiment of this application, it is implemented based on the first embodiment, except that this embodiment includes: S1. Obtain the current water body plane information and draw the sampling point coordinate distribution map; Natural water bodies exhibit significant heterogeneity in their planar regions, with substantial differences in water flow velocity, sediment type, and pollution levels across different areas. Without a standardized coordinate distribution map, sampling point placement would be random, resulting in collected media data failing to reflect the true extent of water pollution. Meanwhile, drawing a coordinate distribution map enables spatial calibration of sampling points, ensuring that each sampling point's media data has a unique spatial coordinate correspondence. Real-time acquisition of the depth torque data of the sampling device, calculation of the depth torque difference between adjacent time points in chronological order, forming a complete depth torque difference sequence; The depth torque data at a single moment can only reflect the instantaneous resistance at a certain depth of the sampling ruler and cannot determine the trend of resistance change. The core feature of the medium boundary is the qualitative change of resistance. This qualitative change is not a sudden change in the torque value at a single moment, but a continuous and regular change in resistance. Synchronously record the angle deflection of the drive end at each point in time; The angle deflection at the drive end is a direct quantitative indicator of the sampling depth, while the torque difference sequence can only reflect when the resistance changes qualitatively, but cannot pinpoint the depth at which the resistance changes qualitatively. Synchronous recording can achieve a one-to-one accurate correlation between the torque difference change and the sampling depth.

[0022] S2. Determine the initial and final points of the medium boundary based on the depth torque difference sequence, correct the sampling points preset by the sampling device, and record the corresponding data of the medium obtained through the corrected sampling points. The specific operation for determining the initial point of the medium boundary based on the depth torque difference sequence is as follows: Set the comparison threshold and the number of consecutive judgments N; In water sampling, the sampling rod often encounters minor disturbances such as entanglement with aquatic plants and water flow disturbance. A single torque difference fluctuation cannot distinguish whether it is a change in the medium or an disturbance. At the same time, whether the angle deflection of the drive end is stable is the key basis for judging whether the sampling rod can continue to go deeper. If there are N consecutive differences in the depth torque difference sequence that are not within the comparison threshold, and the driving end angle deflection of the corresponding time period is continuously changing, that is, the difference of the driving end angle deflection at adjacent times is not 0, then the first difference that is not within the comparison threshold is extracted, and the depth torque data used as the minuend when calculating the difference is obtained. The driving end angle deflection corresponding to the depth torque data is recorded and recorded as the initial point of the medium boundary. Then, water sampling is continued. If the torque difference continues to exceed the threshold, it indicates that the resistance encountered by the sampling ruler has undergone a qualitative change. However, if the angle of the drive end continues to change, it indicates that the sampling ruler can continue to go deeper, eliminating the possibility of obstacles blocking it. At this time, the minuend depth torque corresponding to the first difference exceeding the threshold is exactly the critical state when the sampling ruler just enters the new medium, which can be used as the initial point of medium boundary. If there are N consecutive differences in the depth torque difference sequence that are all within the comparison threshold, then water sampling will continue. When the torque difference continues to fluctuate within the comparison threshold, it indicates that the resistance experienced by the sampling ruler has not changed significantly. It is likely that it has encountered non-medium-change interference such as entanglement of aquatic plants or slight water flow disturbance. If sampling is interrupted at this time, it will lead to the breakage of the sampling process. After determining the initial point of the media boundary, the specific operation for determining the end point of the media boundary is as follows: Set a fixed deflection increment, deflection growth value and data sampling frequency, synchronously collect the angle deflection, depth torque and tilt angle deflection of the drive end, and initialize the deflection counter and the maximum deflection number threshold. The deflection growth value = real-time length of the sampling ruler × sin(fixed deflection increment). The tilt angle deflection action is executed according to a fixed deflection increment to generate a continuous deflection sequence. After each deflection is completed, the angle is kept stable for a preset time, and the drive end angle deflection and depth torque at the corresponding deflection angle are recorded. By gradually deflecting in fixed deflection increments, we can avoid missing the obstacle edge or bottoming signal by deflecting a large angle at one time, thus achieving the accuracy of gradual detection. At the same time, maintaining a stable preset time after each deflection is to eliminate the instantaneous mechanical fluctuations caused by the deflection action and ensure that the recorded drive end angle deflection and depth torque are the true stable values ​​under that deflection angle. If the angle deflection at the drive end increases continuously and the difference between adjacent increases is less than or equal to the deflection growth value, and the corresponding depth torque continuously meets the preset threshold, then it is determined to be bottoming out. At this time, the angle deflection at the drive end when the deflection action is not performed is extracted as the media boundary endpoint. The continuous increase in the angle deflection at the drive end and the difference between adjacent increases being less than or equal to the deflection growth value indicate that the actual elongation of the sampling ruler during deflection meets the requirement of constant end depth, and no extra elongation occurs, meaning that it has not bypassed the obstacle. From another perspective, the continuous satisfaction of the depth torque with the stability threshold indicates that the resistance experienced by the sampling ruler has no sudden change, meaning that the resistance will not change with the deflection after touching the bottom. The simultaneous satisfaction of these two conditions is the key to bottom-touching judgment. If only the angle is satisfied, it may be due to uneven medium, while if only the torque is stable, it may be due to an obstacle blocking the way. If the angle deflection at the drive end increases continuously and the difference between adjacent increases is greater than the deflection growth value, calculate the difference between the adjacent increase difference and the deflection growth value and the corresponding adjacent growth coefficient, obtain the uncorrected angle deflection L and the total deflection angle α corresponding to the maximum growth coefficient, substitute them into the formulas K=L×cosα and A=L×sinα to calculate the corrected angle deflection K and the corrected length A, and take K as the end point of the medium boundary. The continuous increase in the angle deflection at the drive end and the fact that the difference between adjacent increases is greater than the deflection growth value indicate that the actual elongation of the sampling ruler during deflection exceeds the requirement of a constant end depth. In other words, the sampling ruler has bypassed the obstacle and continues to penetrate deeper into the medium. At this point, calculating the difference between the adjacent increase difference and the deflection growth value, as well as the corresponding adjacent growth coefficient, is to locate the critical point where the obstacle has just been bypassed. The moment corresponding to the maximum growth coefficient is the instant when the sampling ruler breaks free from the obstacle and enters the normal medium. At this time, the uncorrected driving end angle deflection L is the total length in the deflected state. The formulas K=L×cosɑ and A=L×sinɑ are used for calculation because L is the oblique length after deflection, which needs to be corrected to the true depth in the vertical direction to ensure that the end point of the medium boundary reflects the vertical depth. The specific steps to obtain the adjacent growth coefficients are as follows: Obtain the driving end angle deflection recorded during the deflection of the sampling ruler, and calculate the difference between two adjacent driving end angle deflections, i.e., the adjacent increase difference. For each adjacent increase difference, subtract the corresponding deflection growth value to obtain the comparison sequence q, and calculate the i-th adjacent growth coefficient = (q i+1 -q i ) / q i ; The real-time length of the sampling ruler when calculating the corresponding deflection growth value refers to the length of the sampling ruler before a single deflection action occurs. The specific steps for correcting the pre-set sampling points of the sampling device are as follows: Using the preset sampling point as the origin, the effective direction of the sampling ruler around the obstacle is taken as the horizontal lateral movement direction, and the correction length A calculated at the end of the medium boundary is taken as the fixed lateral movement length. The horizontal lateral movement operation is performed, and the end of the lateral movement is the preliminary correction sampling point. When there is an obstacle below the preset sampling point, direct sampling will cause data distortion. In this case, a correction length A needs to be introduced. This value is the accurate horizontal distance to bypass the obstacle, and the effective direction to bypass the obstacle is the safe path verified by the previous deflection detection. By moving laterally with the preset sampling point as the origin, the spatial correlation between the correction point and the original sampling point can be ensured. Obtain the correction drive end angle deflection information K corresponding to the media boundary endpoint, control the operation of the drive end of the sampling device, so that the actual depth of the sampling ruler is completely consistent with K, and ensure that the end of the sampling ruler is always at the same media depth during the rotation process. The corrected drive end angle deflection K is the vertical depth of the media boundary endpoint. The core objective of rotary detection is to verify whether obstacles have been completely avoided within the same media layer. If the sampling ruler's depth is inconsistent with K, it will cause the end to enter other media, resulting in distorted torque data and making it impossible to accurately determine whether an obstacle has been contacted. Initiate the tilt angle rotation action (i.e., deflect in the opposite direction to the original preset sampling point), collect the deflection torque in real time during the rotation process, and calculate the drive end angle deflection = rotation angle × deflection growth value coefficient. Update the drive end angle in real time to ensure that the end of the sampling ruler rotates along a straight line and avoids depth deviation. The slewing motion deflects in the opposite direction of the original preset sampling point to verify whether the initial correction point has completely avoided the obstacle, while reducing the horizontal deviation from the original sampling point. Also, since the sampling ruler will generate arc motion when it rotates, if the drive end angle is not updated synchronously, the end will have a depth shift, causing the detection path to deviate from the target medium layer. If the rotation angle remains unchanged but the deflection torque continues to increase within N consecutive intervals, it indicates that the end of the sampling ruler has touched the edge of the obstacle. The rotation needs to be stopped immediately, and the current total rotation angle and end point position should be recorded. The fixed adjustment amount s (i.e., the fine-tuning value preset according to the medium density) should be subtracted from the correction drive end angle deflection K and then re-entered. The rotation action should be restarted until the torque no longer continues to increase, thus locating the accurate position of the obstacle edge. Subtracting the fixed adjustment amount s from K is to fine-tune the sampling ruler depth, eliminate false obstructions caused by slightly deeper or shallower depths, and ensure that the actual obstacle edge is locked. If the rotation angle and deflection torque change continuously within N consecutive intervals, it indicates that the sampling ruler has not contacted the obstacle. Continue to perform the rotation action and maintain the linear detection in the depth calibration state. The continuous change in rotation angle refers to the angle in the tilt angle rotation action continuously decreasing towards the initial sampling line; The continuous change of the deflection torque refers to the fact that the deflection torque fluctuates non-constantly within the resistance threshold range corresponding to the current target medium, without unidirectional continuous increase or decrease. The continuous decrease in the rotation angle indicates that the sampling ruler is not rigidly blocked and can move normally towards the original sampling point; the continuous fluctuation in the deflection torque indicates that the sampling ruler is always in the same target medium layer and has not contacted any obstacles or touched the bottom. At this time, continuing to rotate can further reduce the horizontal deviation from the original sampling point. If the rotation angle continues to change within N consecutive intervals and the end point of the sampling ruler returns to the initial sampling line, it means that the obstacle has been completely bypassed and the horizontal deviation between the corrected sampling point and the original sampling point is within a reasonable range. The rotation action needs to be stopped immediately, and the current preliminary corrected sampling point is the final corrected sampling point. The initial sampling line is the vertical sampling path of the original preset sampling point. When the end of the sampling ruler returns to this line, it means that the horizontal position of the initial correction point has enabled the sampling ruler to bypass the obstacle and return to the extension line of the original sampling path. The horizontal deviation is within a reasonable range. At this time, stop rotating to lock the final correction point and ensure that subsequent sampling can avoid obstacles while reflecting the medium condition of the original preset point to the greatest extent. Based on the eutrophication indicators obtained from the acquired media data, ecological restoration operations for the aquatic body are performed. The specific steps are as follows: The eutrophication index in the media data is classified into lightly polluted, moderately polluted, and heavily polluted. The specific operation is as follows: Base samples were collected from uncontaminated areas of the target water body, and the background levels of total nitrogen and total phosphorus in the samples were measured and denoted as TN0 and TP0, respectively. Based on the critical nutrient concentration for algal blooms in the target water body, calibrated grading thresholds were set: the threshold values ​​for mild and moderate algal blooms were TN1 = TN0 + TN0. min TP1 = TP0 + TP min The threshold between moderate and severe cases is TN2 = TN0 + TN max TP2 = TP0 + TP max ; among which, TN min TN max These are the lower and upper limits of total nitrogen, i.e., TN. min <TN max TPmin TP max These are the lower and upper limits of total phosphorus, i.e., TP. min <TP max All four indicators mentioned above need to be dynamically adjusted according to the background value of the target water body; Obtain the actual measured values ​​of TN and TP in the medium data: if TN < TN1 and TP < TP1, it is judged as light pollution; if TN1 ≤ TN < TN2 and TP1 ≤ TP < TP2, it is judged as moderate pollution; if TN ≥ TN2 and TP ≥ TP2, it is judged as heavy pollution. Different strategies are implemented for different levels of pollution, including: If the pollution is mild, oxygenation equipment should be installed in key water flow areas (such as inlets and the central lake area). The oxygenation equipment includes an aerator, an aeration boat, and a fountain; At this time, TN and TP are only slightly higher than the background value of the target water body, and no large-scale algal bloom has occurred. The core problem of the water body is insufficient dissolved oxygen, which leads to low activity of aerobic microorganisms and inability to efficiently decompose the small amount of organic nutrients in the water body, resulting in slight accumulation of nutrients. Key circulation areas such as the inlet and the central lake area are the core nodes for water exchange and nutrient diffusion. Deploying oxygenation equipment in these areas can achieve directional and efficient diffusion of dissolved oxygen. If the pollution level is moderate, continue planting submerged plants on the basis of oxygenation treatment for mild pollution. The submerged plants include Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum; At this point, TN and TP have accumulated to a certain scale. Microorganisms activated by oxygenation can only decompose organic nutrients, but cannot remove inorganic nutrients in the water or nutrients adsorbed in the sediment. This can easily lead to a situation where the decomposition rate cannot keep up with the nutrient release rate. In contrast, Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum are native submerged plants that are adapted to the growth characteristics of freshwater areas. Their roots can directly absorb TN and TP from the water and sediment and continuously release oxygen through photosynthesis. If the pollution is severe, on the basis of moderate pollution, an environmentally friendly bottom sediment dredging equipment is used to remove the polluted bottom sediment in layers: first remove the top 5-10cm of floating mud (the layer where eutrophic substances are concentrated), and then gently disturb the bottom 10-20cm of polluted bottom sediment to promote the release of nutrients in the bottom sediment for absorption by plants. At this point, TN and TP levels are significantly exceeded, and the nutrient content in the surface sludge can be several times that of the water body. Furthermore, it will continue to release nutrients into the water body. Relying solely on oxygenation and submerged plants cannot cut off this core source of pollution. Since the surface 5-10cm sludge is the area where eutrophic substances are most concentrated, direct removal can quickly and significantly reduce the total nutrient reserves in the bottom sediment. At the same time, only slight disturbance rather than complete removal of the polluted bottom sediment in the bottom 10-20cm is done to protect the indigenous microbial community and aquatic organism habitat in the bottom sediment. Disturbance can release a small amount of nutrients adsorbed in the bottom sediment, which can be quickly absorbed by the planted submerged plants. After dredging, timely replenishment of an appropriate amount of clean river sand is necessary to maintain the stability of the water body bottom and prevent the destruction of aquatic organism habitats.

[0023] Some of the data in the above formulas are numerical calculations with dimensions removed, and the contents not described in detail in this specification are all prior art known to those skilled in the art.

[0024] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A method for ecological restoration of eutrophic water bodies based on aquatic plants, characterized in that, include: S1. Obtain the current water body plane information, draw the sampling point coordinate distribution map, and collect the sampling device depth torque data in real time. Calculate the depth torque difference between adjacent time points in time sequence to form a complete depth torque difference sequence, and synchronously record the drive end angle deflection corresponding to each time point. S2. Determine the initial and final points of the media boundary based on the depth-torque difference sequence, correct the sampling points preset by the sampling device, record the corresponding data of the media obtained through the corrected sampling points, classify the eutrophication indicators in the obtained media data, and perform water body ecological restoration operations.

2. The method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 1, characterized in that, The specific rules for determining the initial point of the medium boundary are as follows: Set a comparison threshold and a number of consecutive judgments N. If there are N consecutive torque differences in the depth torque difference sequence that are not within the comparison threshold and the difference in the angle deflection of the drive end at adjacent times is not 0, then extract the first difference that is not within the comparison threshold, obtain the depth torque data that is used as the minuend when calculating the difference, record the angle deflection of the drive end corresponding to the depth torque data, and record it as the initial point of the medium boundary.

3. The method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 1, characterized in that, The specific steps for determining the endpoint of the medium boundary are as follows: Set a fixed deflection increment, deflection growth value and data sampling frequency, synchronously collect the angle deflection, depth torque and tilt angle deflection of the drive end, and initialize the deflection counter and the maximum deflection number threshold. The deflection growth value = real-time length of the sampling ruler × sin(fixed deflection increment). The tilt angle deflection action is executed according to a fixed deflection increment to generate a continuous deflection sequence. After each deflection is completed, the angle is kept stable for a preset time, and the drive end angle deflection and depth torque at the corresponding deflection angle are recorded. If the angle deflection at the drive end increases continuously and the difference between adjacent increases is less than or equal to the deflection growth value, and the corresponding depth torque continuously meets the preset threshold, then it is determined to be bottoming out. At this time, the angle deflection at the drive end when the deflection action is not performed is extracted as the media boundary endpoint.

4. The method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 3, characterized in that, If the angle deflection at the drive end increases continuously and the difference between adjacent increases is greater than the deflection growth value, then calculate the difference between the adjacent increase difference and the deflection growth value and the corresponding adjacent growth coefficient, obtain the uncorrected drive end angle deflection L and the total deflection angle α corresponding to the maximum growth coefficient, substitute them into the formulas K=L×cosα and A=L×sinα to calculate the corrected drive end angle deflection K and the corrected length A, and take K as the end point of the medium boundary.

5. A method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 4, characterized in that, The specific steps to obtain the adjacent growth coefficients are as follows: Obtain the driving end angle deflection recorded during the deflection of the sampling ruler, and calculate the difference between two adjacent driving end angle deflections, i.e., the adjacent increase difference. For each adjacent increase difference, subtract the corresponding deflection growth value to obtain the comparison sequence q, and calculate the i-th adjacent growth coefficient = (q i+1 -q i ) / q i ; The real-time length of the sampling ruler when calculating the corresponding deflection growth value refers to the length of the sampling ruler before a single deflection action occurs.

6. The method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 1, characterized in that, The specific steps for correcting the sampling points preset by the sampling device are as follows: Using the preset sampling point as the origin, the effective direction of the sampling ruler around the obstacle is taken as the horizontal lateral movement direction, and the correction length A calculated at the end of the medium boundary is taken as the fixed lateral movement length. The horizontal lateral movement operation is performed, and the end of the lateral movement is the preliminary correction sampling point. Obtain the correction drive end angle deflection information K corresponding to the media boundary endpoint, control the operation of the drive end of the sampling device, and make the actual depth of the sampling ruler completely consistent with K. Initiate the tilt angle rotation action, collect the deflection torque during the rotation process in real time, and calculate the drive end angle deflection = rotation angle × deflection growth value coefficient, and update the drive end angle in real time. If the rotation angle remains constant but the deflection torque continues to increase within N consecutive intervals, stop the rotation immediately, record the current total rotation angle and end point position, subtract the fixed adjustment amount s from the correction drive end angle deflection K and re-enter it, restart the rotation action until the torque no longer continues to increase, and locate the accurate position of the obstacle edge. If the rotation angle and deflection torque change continuously over N consecutive intervals, the rotation action continues. If the rotation angle continues to change within N consecutive intervals and the end point of the sampling ruler returns to the initial sampling line, then the rotation action should be stopped immediately, and the current preliminary correction sampling point is the final correction sampling point.

7. A method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 6, characterized in that, The continuous change in the rotation angle refers to the angle during the tilting rotation action continuously decreasing towards the initial sampling line; the continuous change in the deflection torque refers to the deflection torque fluctuating non-constantly within the resistance threshold range corresponding to the current target medium, without unidirectional continuous increase or decrease.

8. The method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 1, characterized in that, The specific steps for classifying eutrophication indicators in the acquired media data are as follows: Base samples were collected from uncontaminated areas of the target water body, and the background levels of total nitrogen and total phosphorus in the samples were measured and denoted as TN0 and TP0, respectively. Based on the critical nutrient concentration for algal blooms in the target water body, calibrated grading thresholds were set: the threshold values ​​for mild and moderate algal blooms were TN1 = TN0 + TN0. min TP1 = TP0 + TP min The threshold between moderate and severe cases is TN2 = TN0 + TN max TP2 = TP0 + TP max ; Among them, TN min TN max These are the lower and upper limits of total nitrogen, i.e., TN. min <TN max TP min TP max These are the lower and upper limits of total phosphorus, i.e., TP. min <TP max ; Obtain the actual measured values ​​of TN and TP in the medium data: if TN < TN1 and TP < TP1, it is judged as light pollution; if TN1 ≤ TN < TN2 and TP1 ≤ TP < TP2, it is judged as moderate pollution; if TN ≥ TN2 and TP ≥ TP2, it is judged as heavy pollution.

9. A method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 8, characterized in that, If the pollution is mild, oxygenation equipment will be installed in key water flow areas; if the pollution is moderate, submerged plants will be planted in addition to the oxygenation treatment for mild pollution; if the pollution is severe, environmentally friendly bottom sediment dredging equipment will be used to remove the polluted bottom sediment in layers in addition to the treatment for moderate pollution.

10. A method for ecological restoration of eutrophic water bodies based on aquatic plants according to claim 9, characterized in that, The oxygenation equipment includes an aerator, an aeration boat, and a fountain; the submerged plants include Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum.

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