Method for monitoring sediment deposition effect of river-through lake beach vegetation and sediment collecting device

Abstract

The invention belongs to the technical field of environmental monitoring and governance, and particularly discloses a river-through lake beach vegetation sediment deposition effect monitoring method and a sediment collection device.The method comprises the steps that before the flood period, different sample belts and sample points are arranged at a selected beach along the coastal elevation range, the device is installed, and a vegetation-free area is arranged as a contrast; in the flood period, the silt reaches the river-through lake along with the flood, and the silt intercepted by the vegetation settles to the silt collecting device; and the sediment collected by the sediment collecting device is measured and collected immediately after the flood season ends. The device comprises a connector which is provided with an upper port, a lower port and a plurality of ports which are uniformly distributed along the horizontal direction; the two supporting vertical pipes are connected to the upper end opening and the lower end opening of the connector respectively. The plurality of supporting transverse pipes are respectively connected to ports in the horizontal direction of the connector; the sediment collecting discs are arranged at the ends, away from the connector, of the supporting transverse pipes in a one-to-one correspondence mode. The method is low in cost, and the sediment deposition condition of the whole lake can be accurately evaluated.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental monitoring and governance, and more specifically relates to a monitoring method for sedimentation effects of vegetation on beach of lakes connected to rivers, and also relates to a sediment collection device for sedimentation effects of vegetation on beach of lakes connected to rivers. The invention is suitable for monitoring sedimentation effects of vegetation on beach of lakes connected to rivers in my country. Before the flood season arrives, the sediment collection device is installed in the beach vegetation belt, and a vegetation-free area is set as a control. After the flood season ends, the sediment collected by the sediment collection device is measured and collected. The invention is an effective method for monitoring sedimentation effects of vegetation on beach of lakes connected to rivers with high accuracy, low cost and easy operation. Background Art

[0002] Sedimentation is a distinctive feature of Tongjiang Lakes, which is born with floods. During flood season, a large amount of sediment enters the lake along with the flood. Due to vegetation interception and slowing flow rate, the suspended sediment in the water is deposited on the lake bed, thus forming sedimentation. In lake wetlands, beach vegetation can not only promote the sedimentation of suspended particles in the water body by slowing down the flow and physical interception, but also fix sediments and reduce erosion. The sedimentation effect of beach vegetation is affected by vegetation characteristics such as plant density, basal cover, canopy height, and hydrological characteristics such as flooding duration and flow rate. Moderate sedimentation is very important for shaping wetland microhabitats and maintaining biogeochemical cycles. Severe sedimentation will promote positive succession of wetlands and shorten the life of lakes. Although sedimentation is very important for the functioning of wetland ecosystems, due to the lack of technical means and equipment, there is a lack of monitoring and research on the sedimentation effects of different vegetation types.

[0003] Studies on sediment accumulation in lakes and wetlands show that: (1) From 1956 to 2010, the Dongting Lake area accumulated 5.28 billion tons of sediment, with an average annual accumulation of 0.96 billion tons, or 73.85 million m 3 , with an average annual siltation thickness of about 2.82 cm / a. (2) From 1957 to 2012, the Poyang Lake area accumulated 148 million tons of sediment, with an average annual inflow of 12.6 million tons of sediment, an average annual outflow of 9.91 million tons of sediment (at the lake mouth station), and an average annual siltation of 2.69 million tons. (3) From 1930 to 1974, the accumulated sediment volume of Lake Ontario, Lake Erie, and Lake Huron in the five Great Lakes of the United States was 5069×10 3 t、25787×10 3 t and 4298×10 3t. The sediment transport method is the main means of monitoring the changes in lake erosion and siltation. By measuring the sediment transport rate of rivers entering and leaving the lake, the difference in the amount of sediment entering and leaving the lake is calculated as the amount of erosion and siltation of the lake. This method is mainly based on the determination of the suspended sediment content in key monitoring sections, and lacks consideration of factors such as vegetation type. In addition, even within the same lake wetland, the amount of sediment deposition is highly heterogeneous due to factors such as hydrological conditions, vegetation type, topography and landforms, but current monitoring is only carried out in a few sections, and it is impossible to accurately and comprehensively assess the sediment deposition status of the lake. Therefore, it is urgent to establish a monitoring method and device for the sediment deposition effect of vegetation on the beaches of lakes connected to the river.

[0004] After searching the China Patent Network and related paper websites, it was found that there are some reports on wetland vegetation sedimentation monitoring. Li Feng et al. pointed out in "Different roles of three emergent macrophytes in promoting sedimentation in Dongting Lake, China [Aquatic Science, 2016, 78: 159-169]" that the promoting sedimentation effect of Phalaenopsis community is significantly higher than that of Reed community and Short-pointed Sedum community, and the vegetation area is significantly higher than the non-vegetated area, but the study did not propose specific monitoring equipment. Qiao Mingye et al. mentioned in "Reservoir drawdown zone sedimentation collection device" [CN201420227924.0] that a cylinder with upper and lower openings is used as a collection bucket for monitoring, but this method can only allow sediment to enter the collection device from the upper opening of the collection bucket, and changes the hydrodynamic conditions above the sediment, which cannot accurately simulate the sedimentation process under hydrological changes. Lian Xianghua et al. mentioned in "An Ultrasonic Sediment Monitoring Device" [CN202321162446.5] that the method can monitor sediment in real time by emitting and recovering ultrasonic waves, but the sound waves are easily disturbed by the external environment and the cost of ultrasonic equipment is relatively high. The monitoring effect is poor during flood seasons and on beaches with lush vegetation. Therefore, it is particularly urgent to establish a low-cost, stable and accurate method. Summary of the invention

[0005] The purpose of the present invention is to provide a monitoring method for the siltation effect of vegetation on beach in lakes connected to rivers, which is simple to operate, low in cost, and highly stable, and can accurately evaluate the siltation status of the entire lake.

[0006] Another object of the present invention is to provide a sediment collection device used in the aforementioned monitoring method, which has a stable structure, uses common materials, is inexpensive, provides support in four vertical and horizontal directions, and is not easy to tilt; after the collection device is installed before the flood period, no human maintenance is required, and only the accumulated sediment needs to be collected and measured after the flood period, which is convenient for operation and management.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical measures: A monitoring method for the sediment deposition effect of vegetation on the island beach of a lake connected to a river comprises the following steps:

[0008] (1) Monitoring site selection: Select typical areas of vegetation distribution in Tongjiang Lake;

[0009] (2) Monitoring transect setting: Before the flood period, transects were set up parallel to the water surface at the selected sample sites. According to the width of the vegetation belt, one transect was set up at the center line and the upper and lower boundaries of the vegetation belt;

[0010] (3) Monitoring sampling point setting: Multiple monitoring sampling points are evenly set on each sampling strip, and two sampling plots are set at each sampling point. The plant species, density, coverage, and base diameter indicators are investigated and recorded to determine the vegetation characteristics;

[0011] (4) Installation of sediment collection device: Before the flood period, the sediment collection device was fixed in the designated sample plot so that the sediment collection tray was parallel to the ground. For each monitoring sampling point, one of the two sample plots retained plants, while the other sample plot removed the plants around the sediment collection tray as a control for calculating the sedimentation effect of vegetation.

[0012] (5) Sediment accumulation measurement and collection: After the flood period, the sediment accumulated on the sediment collection device was measured and collected using a vernier caliper (accurate to 0.01 mm);

[0013] (6) Calculation of sediment accumulation: The sediment collection device of each sample plot is equipped with multiple sediment collection trays. The amount of sediment accumulated on the multiple sediment collection trays is measured, and the average value is taken as the sediment accumulation amount of the sample plot. The difference between the sediment accumulation of the sample plot with retained vegetation and the sample plot with removed vegetation at each monitoring sample point is calculated, and the sediment accumulation amount of the vegetation at the sample point is obtained by calculating the average sediment accumulation amount of all sample points on the sample strip, that is, the sediment accumulation amount of the sample strip.

[0014] Optionally, the number of monitoring sampling points in step (3) is 4 or 5, and the spacing between the sampling points is 20 to 50 m.

[0015] Optionally, two adjacent 100 cm×100 cm sample plots are set for each sample point in step (3).

[0016] Optionally, the step of cutting off the plants around the sediment collection tray in step (4) is cutting off the plants within 30 cm around the sediment collection tray.

[0017] Optionally, the sediment collection device in step (6) is provided with four sediment collection trays, each of which is a circular tray with a diameter of 20 cm.

[0018] Accordingly, the present invention also claims protection for a sediment collection device used in the aforementioned method, comprising:

[0019] A connector having two upper and lower ports and a plurality of ports evenly distributed in the horizontal direction, for connecting the supporting horizontal pipe and the supporting vertical pipe;

[0020] Two supporting vertical pipes, respectively connected to the upper and lower ports of the connector, for fixing the sediment collection device to the sample site;

[0021] A plurality of supporting transverse pipes, respectively connected to the ports in the horizontal direction of the connector, for providing connection and support for the sediment collection tray;

[0022] A plurality of sediment collecting plates, which are respectively arranged at the ends of the plurality of supporting transverse tubes away from the connector in a one-to-one correspondence, and are used to collect the accumulated sediment;

[0023] A waterproof tape measure is arranged on the support vertical pipe above the connector and is used to observe the water level and the height of the silt deposits.

[0024] Preferably, the connector has four ports evenly distributed in the horizontal direction, and each of the ports is connected to a supporting transverse tube.

[0025] Preferably, the sediment collection tray contacts the upper end of the supporting transverse tube through an M6*16mm plastic gasket to keep the sediment collection tray horizontal, and the sediment collection tray is connected to the supporting transverse tube through M6*50mm screws, M6*12mm plastic gaskets and M6 nuts.

[0026] Preferably, the waterproof tape is fixed to the section of the support vertical pipe located above the connector by means of a waterproof adhesive tape.

[0027] Preferably, the supporting cross tube is connected to a port reserved on the connector via M6*40mm screws.

[0028] The present invention establishes a monitoring method and sediment collection device for the sediment deposition effect of vegetation on the islands and beaches of lakes connected to rivers, which is simple to operate, low in cost and high in accuracy. Compared with the prior art, it has the following advantages and beneficial effects:

[0029] (1) The effects of vegetation and site hydrological conditions can be accurately distinguished: by setting a non-vegetated control, the siltation-promoting effect of vegetation can be determined; by setting sample plots at different elevations, the effect of water level elevation on siltation in lakes connected to rivers can be determined. Therefore, compared with existing methods, the method and device established by the present invention have high accuracy.

[0030] (2) Low cost and easy operation and management: The present invention has a stable structure, low price, and common experimental materials. The cost of each device is about 50 yuan. The present invention provides support in four directions, both vertically and horizontally, so that the collection device can maintain a stable structure under the impact of water flow and is not easy to tilt. The sediment collection plate is set as a circular plate, which is evenly stressed, not easy to damage, and easy to transport. After the collection device is installed before the flood period, no human maintenance is required. Only after the flood period, the silt accumulation needs to be collected and measured, which is easy to operate and manage.

[0031] (3) The siltation condition of the entire lake can be accurately assessed: The siltation of lakes connected to the river has strong heterogeneity, and monitoring of a few points is difficult to reflect the siltation condition of the entire lake. The present invention is less restricted by terrain and the device is simple to install, and multiple monitoring locations can be set up throughout the lake. The present invention sets multiple sample strips at each monitoring location, and each sample strip sets multiple sample plots, and the collection device of each sample plot has 4 collection plates, each of which is a circular disc with a diameter of 20 cm. Each collection plate is kept parallel to the ground, and the underlying surface is evenly stressed. The accuracy of the monitoring data is ensured by multi-level repetition, and the siltation condition of the lake can be accurately assessed.

[0032] (4) The present invention provides a monitoring method and sediment collection device for the vegetation sedimentation effect of islands and beaches in Tongjiang lakes. By monitoring the sediment sedimentation effect at different altitudes and vegetation conditions, the sediment carried by the flood is intercepted by vegetation, topography, flooding duration and other factors, resulting in differences in the sediment collected by the sediment collection plate under different conditions. By monitoring sediment sedimentation at different altitudes of typical islands and beaches in Tongjiang lakes, the current situation of lack of information on sediment sedimentation in Tongjiang lakes can be solved. The sediment sedimentation effect of islands and beaches with different vegetation types can also be monitored. By calculating the difference in the amount of sediment sedimentation treated by retaining vegetation and cutting off vegetation, the influence of vegetation on the sediment sedimentation effect of islands and beaches in Tongjiang lakes can be clarified. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the structure of the sediment collection device provided by the present invention;

[0034] Figure 2 A schematic diagram of a connector of the sediment collection device provided by the present invention;

[0035] Figure 3 A schematic diagram of a sediment collection plate of the sediment collection device provided by the present invention.

[0036] In the figure, 1. Waterproof tape, 2. Connector, 3. Support horizontal pipe, 301. M6*40mm screws, 4. Sediment collection plate, 401. M6*50mm screws, 402. M6*16mm plastic gasket, 403. M6*16mm plastic gasket, 404. M6 nut, 5. Support vertical pipe. DETAILED DESCRIPTION

[0037] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings.

[0038] Example 1

[0039] A method for monitoring the sediment deposition effect of vegetation on islands and beaches of lakes connected to rivers, comprising the following steps:

[0040] (1) Selection of monitoring sites: Select typical areas of vegetation distribution in Tongjiang Lake.

[0041] (2) Setting up monitoring sample strips: Before the flood period, sample strips are set up in the selected sample plots parallel to the water surface. Depending on the width of the vegetation belt, one sample strip is set up in the center line and at the upper and lower boundaries of the vegetation belt.

[0042] (3) Monitoring sampling point setting: 4 or 5 monitoring sampling points are evenly set on each sampling strip, with a spacing of 20 to 50 m between sampling points. Two adjacent 100 cm × 100 cm sample plots are set at each sampling point, and indicators such as plant species, height, density, coverage, and base diameter are investigated and recorded to determine vegetation characteristics.

[0043] (4) Installation of sediment collection device: Before the flood period, the sediment collection device was fixed in the designated sample plot so that the sediment collection tray was parallel to the ground. For each monitoring point, one sample plot retained the plants, and the other sample plot removed the plants 30 cm around the sediment collection tray as a control for calculating the sedimentation effect of vegetation.

[0044] (5) Measurement and collection of sediment deposition: After the flood period, a vernier caliper (accurate to 0.01 mm) was used to measure and collect the sediment deposited on the sediment collection device.

[0045] (6) Calculation of sediment accumulation: Each sample plot is equipped with four sediment collection trays. The sediment accumulation on the four sediment collection trays is measured and the average value is taken as the sediment accumulation of the sample plot. The sediment accumulation of the vegetation-retained sample plot and the vegetation-removed sample plot at each monitoring sample point is calculated, and the difference is the sediment accumulation of the vegetation at the sample point. The average sediment accumulation of all sample points on the sample strip is calculated to obtain the sediment accumulation at the sample strip.

[0046] Example 2

[0047] A sediment collection device used in the monitoring method described in Example 1 is as follows: Figures 1 to 3As shown, it is composed of a waterproof tape 1, a connector 2, a supporting transverse tube 3, an M6*40mm screw 301, a sediment collection plate 4, an M6*50mm screw 401, an M6*16mm plastic gasket 402, an M6*12mm plastic gasket 403, an M6 nut 404, and a supporting vertical tube 5. The connector 2 has two upper and lower ports and four ports evenly distributed in the horizontal direction. The ports of the connector 2 in the two vertical directions are respectively connected to the two supporting vertical tubes 5, and the four ports in the horizontal direction are respectively connected to the four supporting transverse tubes 3. The supporting vertical tubes 5 are fastened to the connector by manpower. 2 are connected, the waterproof tape 1 is fixed to the supporting vertical pipe 5 located above the connector 2 by the waterproof tape, the supporting horizontal pipe 3 is connected to the port reserved on the connector 2 by the M6*40mm screw 301, and a sediment collecting tray 4 is arranged on the supporting horizontal pipe 3. The sediment collecting tray is a circular disk with a diameter of 20cm. The sediment collecting tray 4 contacts with the upper end of the supporting horizontal pipe 3 by the M6*16mm plastic gasket 402 to keep the sediment collecting tray 4 horizontal, and the sediment collecting tray 4 is connected to the supporting horizontal pipe 3 by the M6*50mm screw 401, the M6*12mm plastic gasket 403 and the M6 ​​nut 404.

[0048] In the present invention, the main function of the waterproof tape 1 is to observe the water level and the height of the accumulated silt; the main function of the connector 2 is to connect the supporting transverse tube 3 and the supporting vertical tube 5; the main function of the supporting transverse tube 3 is to provide connection and support for the silt collecting plate 4; the main function of the M6*40mm screw 301 is to fix the supporting transverse tube 3 on the connector 2 through the port reserved in the horizontal direction of the connector 2; the main function of the silt collecting plate 4 is to collect the accumulated silt; the main function of the M6*16mm plastic gasket 402 is to adjust the angle of the silt collecting plate 4 to keep it as horizontal as possible; the main function of the M6*12mm plastic gasket 403 and the M6 ​​nut 404 is to fix the silt collecting plate 4 to the supporting transverse tube 3; the main function of the supporting vertical tube 5 is to fix the silt collecting device to the sample site.

[0049] The detailed monitoring process of the present invention is: before the flood period, different sample strips and sample points are set along the altitude at the selected beach, and a sediment collection device is installed. The two supporting vertical pipes are fastened to the two directions of the vertical surface of the connector by manpower, and the four sediment collection plates are fixed to the supporting horizontal pipe by screws, nuts, and plastic gaskets. The four supporting horizontal pipes are fixed to the four directions of the horizontal surface of the connector by screws. The waterproof tape is fixed to the supporting vertical pipe above the device by waterproof tape. A hole is dug vertically downward in the center of each sample plot, and the supporting vertical pipe under the device is vertically placed and fixed, and the surface of the sediment collection plate is filled with adjacent soil so that the height after burial is consistent with the height near the center of the sample plot, which is the initial height value. During the flood period, the sediment arrives at the Tongjiang Lake with the flood, and the sediment intercepted by the vegetation settles on the sediment collection plate. After the flood period, immediately go to the monitoring sample point to measure and collect the silt on the sediment collection plate.

[0050] Example 3

[0051] Below, the applicant will further explain the method of the present invention in detail in conjunction with an example of monitoring the silt deposition effect on vegetation on a lake beach connected to a river constructed in Shengjin Lake National Nature Reserve in Chizhou City, Anhui Province. The purpose is to enable those skilled in the art to have a more detailed understanding and recognition of the method of the present invention. The following embodiments should not be understood as limiting the scope of protection requested by the present invention to any extent.

[0052] A method for monitoring the sediment deposition effect of vegetation on islands and beaches of lakes connected to rivers, comprising the following steps:

[0053] (1) Selection of monitoring sites: Three typical beaches with natural distribution of sedge vegetation were selected for monitoring: Shengjin Lake Dazhou, Yang'etou and Qixingdun. The height of the sedge community is 50-80cm, and the density is 1000-1600 plants / m 2 .

[0054] (2) Monitoring sample strip setting: Before the flood period, monitoring was carried out on the beaches of Shengjin Lake Dazhou, Yang'etou and Qixingdun. Three sample strips (high water level, middle water level and low water level) were evenly set up along the altitude and parallel to the water surface, with an interval of 40-50m between the sample strips. There were 9 sample strips in total.

[0055] (3) Monitoring sample point setting: 5 sample points were evenly set on each sampling strip of Dazhou, Yang'etou and Qixingdun. The interval between sample points was 50m. Two monitoring plots were set at each sample point (one with retained plants and the other with removed plants), for a total of 45 sample points and 90 plots. The amount of sediment deposition in vegetation was calculated by removing plants as a control treatment. Plant surveys were conducted on the plots and indicators such as plant species, height, coverage, density, and base diameter were recorded to determine the vegetation characteristics at the sample points.

[0056] (4) Installation of sediment collection device: Two adjacent 100cm×100cm sample plots are set at each sampling point, one retains the original plants and minimizes human interference; the other removes the plants within 30cm around each sediment collection plate as a blank control for the sampling point to determine the impact of vegetation on sediment deposition. A pit with a diameter of 5cm and a depth of 60cm is dug vertically downward in the center of each monitoring sample plot, and the support vertical pipe 5 under the device is placed vertically and fixed, and the surface of the sediment collection plate 4 is filled with adjacent soil so that its buried height is consistent with the height near the center position, which is the initial height value.

[0057] (5) Measurement and collection of sediment accumulation: Immediately after the flood period, go to the sediment collection device at the monitoring sampling point, use a vernier caliper and waterproof tape 1 to measure the height of the sediment accumulation on the sediment collection tray, take photos and record, collect the sediment accumulation on the sediment collection tray, put it in a plastic ziplock bag and bring it back to the laboratory.

[0058] (6) Calculation of sediment accumulation. The amount of sediment accumulated on the four sediment collection plates on each sediment collection device was measured, and the average value was the sediment accumulation at the sample point. The sediment accumulation of the vegetation at the sample point was obtained by calculating the difference between the sediment accumulation of the vegetation-retaining sample plot and the vegetation-removing sample plot at each sample point. There were 5 monitoring sample points on Dazhou, Yang'etou and Qixingdun. The average sediment accumulation of the sample points on each sample strip was calculated to obtain the sediment accumulation of each sample strip.

[0059] Table 1. Sedimentation effect of vegetation on Dazhou, Yang'etou and Qixingdun beaches in Shengjinhu National Nature Reserve, Chizhou City, Anhui Province

[0060]

[0061] As can be seen from Table 1, due to the interception of water flow and the blocking of sediment by vegetation, the sediment deposition under different vegetation types is different. The sediment deposition in the vegetation-retained areas of the three beaches of Shengjin Lake is 0.3-0.7 mm, and the sediment deposition in the vegetation-removed areas is 0.3-0.8 mm. By calculating the difference between the sediment deposition in the vegetation-retained and vegetation-removed areas, the sediment deposition effect of the vegetation on the beaches is 0.007±0.288 mm. Vegetation has a silting-promoting effect on the sediment deposition process of the beaches, but due to different topography, flooding duration and other factors, the sediment deposition is different at different altitudes. The sedimentation in low altitude areas is 0.4-0.8mm, and the sedimentation effect of vegetation is 0.125±0.344mm. The sedimentation in medium altitude areas is 0.4-0.7mm, and the sedimentation effect of vegetation is 0.083±0.254mm. The sedimentation in high altitude areas is 0.3-0.6mm, and the sedimentation effect of vegetation is 0.029±0.189mm. The data accuracy of the present invention is high. The amount of sedimentation can be measured with a vernier caliper, which can be accurate to 0.01mm. In addition, the present invention is simple to install and low in price. Multiple monitoring sample points can be set in the target lake, and the sedimentation status of the entire lake can be accurately evaluated.

[0062] Example 4

[0063] The sediment collection device used in the monitoring method described in Example 3 has the following dimensions: the connector 2 is a 32mm diameter six-way PVC connector; the supporting horizontal pipe 3 and the supporting vertical pipe 5 are both 32mm diameter, 3.6mm thickness, and 50cm length PVC pipes; the sediment collection plate 4 is an acrylic disc with a diameter of 20cm and a thickness of 2mm. The remaining parts, connection relationships, and usage methods are the same as those in Example 2.

[0064] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person skilled in the art within the technical sub-scope disclosed in the present invention should be included in the protection scope of the invention. Therefore, the protection scope of the present invention should be based on the scope of the claims.

Claims

1. A method for monitoring the sediment deposition effect of vegetation on islands and beaches of lakes connected to rivers, characterized in that: The following steps are involved: (1) Monitoring site selection: Select typical areas of vegetation distribution in Tongjiang Lake; (2) Monitoring transect setting: Before the flood period, transects were set up parallel to the water surface at the selected sample sites. According to the width of the vegetation belt, one transect was set up at the center line and the upper and lower boundaries of the vegetation belt; (3) Monitoring sampling point setting: Multiple monitoring sampling points are evenly set on each sampling strip, and two sampling plots are set at each sampling point. The plant species, density, coverage, and base diameter indicators are investigated and recorded to determine the vegetation characteristics; (4) Installation of sediment collection device: Before the flood period, the sediment collection device was fixed in the designated sample plot so that the sediment collection tray was parallel to the ground. For each monitoring sampling point, one of the two sample plots retained plants, while the other sample plot removed the plants around the sediment collection tray as a control for calculating the sedimentation effect of vegetation. (5) Sediment accumulation measurement and collection: After the flood period, the sediment accumulated on the sediment collection device was measured and collected using a vernier caliper; (6) Calculation of sediment accumulation: The sediment collection device of each monitoring plot is equipped with multiple sediment collection trays. The amount of sediment accumulated on the multiple sediment collection trays is measured, and the average value is taken as the sediment accumulation amount of the plot. The difference between the sediment accumulation of the plot with retained vegetation and the plot with removed vegetation at each monitoring sample point is calculated, and the sediment accumulation amount of the vegetation at the sample point is obtained. The average sediment accumulation amount of all the sample points on the sample strip is calculated to obtain the sediment accumulation amount of the sample strip.

2. The method for monitoring the sediment deposition effect of vegetation on the islands and beaches of lakes connected to rivers according to claim 1 is characterized in that: The number of monitoring sampling points in step (3) is 4 or 5, and the spacing between the sampling points is 20 to 50 m.

3. The method for monitoring the sediment deposition effect of vegetation on the islands and beaches of lakes connected to rivers according to claim 1, characterized in that: In step (3), two adjacent 100 cm × 100 cm sample plots are set at each sample point.

4. The method for monitoring the sediment deposition effect of vegetation on the islands and beaches of lakes connected to rivers according to claim 1 is characterized in that: The step (4) of cutting off the plants around the sediment collection tray is to cut off the plants within 30 cm around the sediment collection tray.

5. The method for monitoring the sediment deposition effect of vegetation on the islands and beaches of lakes connected to rivers according to claim 1, characterized in that: The sediment collection device in step (6) is provided with four sediment collection trays, each of which is a circular tray with a diameter of 20 cm.

6. A sediment collection device used in the method according to any one of claims 1 to 5, characterized in that: include: A connector having two upper and lower ports and a plurality of ports evenly distributed in the horizontal direction, for connecting the supporting horizontal pipe and the supporting vertical pipe; Two supporting vertical pipes, respectively connected to the upper and lower ports of the connector, for fixing the sediment collection device to the sample site; A plurality of supporting transverse pipes, respectively connected to the ports in the horizontal direction of the connector, for providing connection and support for the sediment collection tray; A plurality of sediment collecting plates, which are respectively arranged at the ends of the plurality of supporting transverse tubes away from the connector in a one-to-one correspondence, and are used to collect the accumulated sediment; A waterproof tape measure is arranged on the support vertical pipe above the connector and is used to observe the water level and the height of the silt deposits.

7. The sediment collection device according to claim 6, characterized in that: The connector has four ports evenly distributed in the horizontal direction, and each of the ports is connected to a supporting horizontal pipe.

8. The sediment collection device according to claim 6, characterized in that: The sediment collection tray is in contact with the upper end of the supporting transverse tube through an M6*16mm plastic gasket to keep the sediment collection tray level, and the sediment collection tray is connected to the supporting transverse tube through an M6*50mm screw, an M6*12mm plastic gasket, and an M6 nut.

9. The sediment collection device according to claim 6, characterized in that: The waterproof tape is fixed to the support vertical pipe above the connector by waterproof adhesive tape.

10. The sediment collection device according to claim 6, characterized in that: The supporting cross pipe is connected to the reserved port on the connector through M6*40mm screws.

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