Karst small watershed water and soil loss monitoring system and monitoring method based on nature

Abstract

The invention discloses a karst small watershed water and soil loss monitoring system and method based on nature, the karst small watershed water and soil loss monitoring system comprises a water collecting dam, a water collecting ditch, a monitoring hole, a water level gauge, a triangular weir plate, a grit chamber, a drainage pipe, a filter screen, a flow dividing pool, a flow dividing pipe and a flow collecting pool, the water collecting dam is connected with the water collecting ditch, and the monitoring hole is reserved in the ditch wall of the water collecting ditch; a water level gauge is placed in the monitoring hole, a triangular weir plate is installed at an outlet of the water collecting ditch, the water collecting ditch is communicated with a grit chamber, a water drainage pipe is installed at the bottom of the grit chamber, a filter screen is installed at an inlet of the water drainage pipe, the grit chamber is communicated with a flow dividing tank, and a water drainage pipe and a flow dividing pipe are installed at the bottom and the top of the flow dividing tank respectively. The flow dividing pool is communicated with the flow collecting pool through a flow dividing pipe, and a drainage pipe is mounted at the bottom of the flow collecting pool. The water collecting dam is built at the valley position, runoff and sediment generated under the natural condition of the small karst watershed can be collected, and compared with a traditional water and soil loss monitoring method, the monitoring range is larger, and the water and soil loss condition under the real natural condition can be better reflected; by arranging the monitoring hole, the inaccurate measurement result caused by swinging of the water level gauge due to water flow impact can be avoided; by arranging the grit chamber, most silt can be settled, the amount of silt entering the flow collecting tank is reduced, and the flow dividing pipe is prevented from being blocked; by arranging the flow dividing pool and the flow dividing pipe, only a small part of runoff and sediment enter the water collecting pool, and the too large water collecting pool and the sediment cleaning workload can be avoided.

Description

Technical Field

[0001] The invention relates to the field of soil and water loss monitoring in karst areas, and in particular to a soil and water loss monitoring system and a monitoring method for a small karst watershed based on nature. Background Art

[0002] Karst ecosystems are extremely fragile and highly sensitive to environmental changes. Ecological problems such as soil erosion, desertification, drought and flood disasters frequently occur, leading to backward regional development.

[0003] In recent years, a series of ecological restoration projects have been implemented in karst areas, but the monitoring and evaluation of the benefits after the implementation of the projects is still lagging behind. When monitoring and evaluating the benefits of ecological restoration projects in karst areas, soil erosion is a very important indicator. At present, this field generally monitors soil erosion by setting up runoff plots to simulate natural conditions. The standard runoff plot is 20m long and 5m wide, and generally includes four parts: a retaining wall, a water collection trough, a water pipe and a water measuring pool. The monitoring method is: install a water level meter in the water measuring pool to automatically record the water depth of the water measuring pool during rainfall, and finally convert it into the runoff generated in the runoff plot; after each rainfall generates runoff, first stir the water in the water measuring pool evenly, then collect water samples and filter the sediment, dry and weigh the filtered sediment, and calculate the soil loss of the runoff plot after a single rainfall.

[0004] At present, the defects of this technology are: 1) The runoff area is small, which can only simulate soil erosion under natural conditions, but cannot reflect the soil erosion situation under real natural conditions; 2) The water level meter is generally placed directly on the bottom of the measuring pool, which is easily swayed by the impact of the water flow, resulting in inaccurate measurement results. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a natural karst small watershed soil erosion monitoring system to solve the problems proposed in the above background technology that the runoff area cannot reflect the soil erosion situation under real natural conditions and the monitoring results are inaccurate.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A natural-based soil erosion monitoring system for a karst small watershed comprises a water collecting dam, a water collecting ditch, a monitoring hole, a water level gauge, a triangular weir plate, a grit chamber, a drain pipe, a filter screen, a diversion pool, a diversion pipe, and a collecting pool, wherein the water collecting dam is connected to the water collecting ditch, a monitoring hole is reserved on the wall of the water collecting ditch, a water level gauge is placed in the monitoring hole, a triangular weir plate is installed at the outlet of the water collecting ditch, the water collecting ditch is connected to the grit chamber, a drain pipe is installed at the bottom of the grit chamber, a filter screen is installed at the inlet of the drain pipe, the grit chamber is connected to the diversion pool, a drain pipe and a diversion pipe are installed at the bottom and top of the diversion pool respectively, the diversion pool is connected to the collecting pool through the diversion pipe, and a drain pipe is installed at the bottom of the collecting pool.

[0008] Furthermore, the diameter of the monitoring hole is 1-2 cm larger than the diameter of the water level gauge.

[0009] Furthermore, the triangular weir plate is made of stainless steel plate.

[0010] Furthermore, the drainage pipe and the diversion pipe are made of PVC pipes.

[0011] A monitoring method based on a natural karst small watershed soil erosion monitoring system comprises the following steps:

[0012] (1) Find suitable valley locations in the ecological restoration project implementation area to build a soil erosion monitoring system. The length and angle of the water collection dam will be determined based on the actual situation on site, with the basic principle of being able to block the runoff from upstream;

[0013] (2) On the topographic map, delineate the catchment area of ​​the water collection dam, i.e., the monitored karst small watershed, and calculate its area S;

[0014] (3) Set the monitoring frequency of the water level meter to once every 15 minutes, then place it at the bottom of the monitoring hole 3, and regularly export the water level data recorded by the water level meter;

[0015] (4) The runoff Q passing through the triangular weir plate is calculated using the following formula (1):

[0016] Q=∑0.014*(h i -Δh) 5 / 2 (1)

[0017] Among them, h i represents the i-th water level data recorded by the water level gauge, in cm; Δh represents the vertical distance from the bottom of the triangular weir plate to the bottom of the sedimentation tank, in cm; the runoff Q is in L / s;

[0018] (5) Whenever the water level in the collecting tank approaches the diversion pipe, open the drain pipe, drain the water in the grit chamber, diversion tank and collecting tank, take out all the sediment in the grit chamber, diversion tank and collecting tank, dry and weigh them, and close the drain pipe for the next monitoring after the sediment is cleaned;

[0019] (6) Calculate the soil erosion modulus A of a small watershed within a hydrological year according to the following formula (2):

[0020] A=(∑W1 i +∑W2 i +∑W3 i *(n-1)) / S (2)

[0021] Among them, W1 i 、W2 i 、W3 i They represent the amount of sediment removed from the sedimentation basin, diversion basin and collection basin for the i-th time in a hydrological year, respectively, in t; n represents the number of diversion pipes; S represents the area of ​​the monitored karst small watershed, in km 2 ; Soil erosion modulus A is in t / (km 2 a).

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] By building a water collection dam at the mountain pass, the runoff and sediment generated under natural conditions in the karst small watershed can be collected. Compared with the traditional soil erosion monitoring method, the monitoring range is larger and can better reflect the soil erosion conditions under real natural conditions; by setting up monitoring holes, the water level meter can be prevented from swinging due to the impact of water flow, resulting in inaccurate measurement results; by setting up a sedimentation tank, most of the sediment can be precipitated, reducing the amount of sediment entering the collecting pool and avoiding blockage of the diversion pipe; by setting up a diversion pool and a diversion pipe, only a small part of the runoff and sediment is allowed to enter the collecting pool, which can avoid excessively large collecting pools and the workload of cleaning up sediment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 yes Figure 1 AA section view;

[0027] Figure 3 yes Figure 1 BB section view;

[0028] Figure 4 yes Figure 1 CC section view;

[0029] In the figure: 1. water collection dam; 2. water collection ditch; 3. monitoring hole; 31. water level gauge; 4. triangular weir plate; 5. sand settling tank; 6. drainage pipe; 61. filter screen; 7. diversion tank; 8. diversion pipe; 9. collecting tank. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] In the drawings, the same reference numerals all refer to the same components.

[0032] In addition, if a detailed description of a known technology is not necessary for illustrating the features of the present invention, it will be omitted. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the drawings, and the words "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0033] Example 1

[0034] like Figure 1 As shown, the present invention provides a natural karst small watershed soil erosion monitoring system, including a water collecting dam 1, a water collecting ditch 2, a monitoring hole 3, a water level gauge 31, a triangular weir plate 4, a grit chamber 5, a drainage pipe 6, a diversion pool 7, a diversion pipe 8, and a water collecting pool 9. The water collecting dam 1 is connected to the water collecting ditch 2, and a monitoring hole 3 is reserved on the wall of the water collecting ditch 2. A water level gauge 31 is placed in the monitoring hole 3. A triangular weir plate 4 is installed at the outlet of the water collecting ditch 2. The water collecting ditch 2 is connected to the grit chamber 5. A drainage pipe 6 is installed at the bottom of the grit chamber 5. A filter screen 61 is installed at the inlet of the drainage pipe 6. The grit chamber 5 is connected to the diversion pool 7. The drainage pipe 6 and the diversion pipe 8 are installed at the bottom and top of the diversion pool 7 respectively. The diversion pool 7 is connected to the water collecting pool 9 through the diversion pipe 8, and the drainage pipe 6 is installed at the bottom of the water collecting pool 9.

[0035] Furthermore, the diameter of the monitoring hole 3 is 1-2 cm larger than the diameter of the water level gauge 31 , the triangular weir plate 4 is made of a stainless steel plate, and the drainage pipe 6 and the diversion pipe 8 are made of a PVC pipe.

[0036] The method for monitoring soil and water loss in a karst small watershed under natural conditions according to the present invention comprises the following steps:

[0037] (1) Find a suitable valley location in the ecological restoration project implementation area to build a soil erosion monitoring system. The length and angle of the water collection dam 1 will be determined based on the actual situation on site, with the basic principle of being able to block the runoff from upstream;

[0038] (2) On the topographic map, delineate the catchment area of ​​dam 1, i.e., the monitored karst small watershed, and calculate its area S;

[0039] (3) The monitoring frequency of the water level meter 31 is set to once / 15 minutes, and then placed at the bottom of the monitoring hole 3, and the water level data recorded by the water level meter 31 is regularly exported;

[0040] (4) The runoff Q passing through the triangular weir plate 4 is calculated by the following formula (1):

[0041] Q=∑0.014*(h i -Δh) 5 / 2 (1)

[0042] Among them, h i represents the i-th water level data recorded by the water level meter 31, in cm; Δh represents the vertical distance from the bottom of the triangular weir plate 4 to the bottom of the sand settling tank 5, in cm; the runoff Q is in L / s;

[0043] (5) Whenever the water level in the collecting tank 9 approaches the diversion pipe 8, open the drain pipe 6 to drain the water in the grit chamber 5, the diversion tank 7 and the collecting tank 9, take out all the sediment in the grit chamber 5, the diversion tank 7 and the collecting tank 9, dry them and weigh them, and after cleaning the sediment, close the drain pipe 6 for the next monitoring;

[0044] (6) Calculate the soil erosion modulus A of a small watershed within a hydrological year according to the following formula (2):

[0045] A=(∑W1 i +∑W2 i +∑W3 i *(n-1)) / S (2)

[0046] Among them, W1 i 、W2 i 、W3 i They represent the amount of sediment removed from the sedimentation tank 5, the diversion tank 7 and the collection tank 9 for the i-th time in a hydrological year, in t; n represents the number of diversion pipes 8; S represents the area of ​​the monitored karst small watershed, in km 2 ; Soil erosion modulus A is in t / (km 2 a).

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A natural-based soil erosion monitoring system for a karst small watershed, comprising a water collecting dam 1, a water collecting ditch 2, a monitoring hole 3, a water level gauge 31, a triangular weir plate 4, a grit chamber 5, a drainage pipe 6, a diversion pool 7, a diversion pipe 8, and a water collecting pool 9, wherein the water collecting dam 1 is connected to the water collecting ditch 2, a monitoring hole 3 is reserved on the wall of the water collecting ditch 2, a water level gauge 31 is placed in the monitoring hole 3, a triangular weir plate 4 is installed at the outlet of the water collecting ditch 2, the water collecting ditch 2 is connected to the grit chamber 5, a drainage pipe 6 is installed at the bottom of the grit chamber 5, a filter screen 61 is installed at the inlet of the drainage pipe 6, the grit chamber 5 is connected to the diversion pool 7, a drainage pipe 6 and a diversion pipe 8 are installed at the bottom and top of the diversion pool 7 respectively, the diversion pool 7 is connected to the water collecting pool 9 through the diversion pipe 8, and a drainage pipe 6 is installed at the bottom of the water collecting pool 9.

2. A natural karst small watershed soil erosion monitoring system according to claim 1, characterized in that: The diameter of the monitoring hole 3 is 1-2 cm larger than the diameter of the water level gauge 31 .

3. The natural karst small watershed soil erosion monitoring system according to claim 1 is characterized in that: The triangular weir plate 4 is made of stainless steel plate.

4. The natural karst small watershed soil erosion monitoring system according to claim 1 is characterized in that: The drainage pipe 6 and the diversion pipe 8 are made of PVC pipes.

5. A monitoring method for a natural karst small watershed soil erosion monitoring system as claimed in any one of claims 1 to 4, characterized in that: The steps include: (1) Find a suitable valley location in the ecological restoration project implementation area to build a soil erosion monitoring system. The length and angle of the water collection dam 1 will be determined based on the actual situation on site, with the basic principle of being able to block the runoff from upstream; (2) On the topographic map, delineate the catchment area of ​​dam 1, i.e., the monitored karst small watershed, and calculate its area S; (3) The monitoring frequency of the water level meter 31 is set to once / 15 minutes, and then placed at the bottom of the monitoring hole 3, and the water level data recorded by the water level meter 31 is regularly exported; (4) The runoff Q passing through the triangular weir plate 4 is calculated by the following formula (1): Q=∑0.014*(h i -Δh) 5 / 2 (1) Among them, h i represents the i-th water level data recorded by the water level meter 31, in cm; Δh represents the vertical distance from the bottom of the triangular weir plate 4 to the bottom of the sand settling tank 5, in cm; the runoff Q is in L / s; (5) Whenever the water level in the collecting tank 9 approaches the diversion pipe 8, open the drain pipe 6 to drain the water in the grit chamber 5, the diversion tank 7 and the collecting tank 9, take out all the sediment in the grit chamber 5, the diversion tank 7 and the collecting tank 9, dry them and weigh them, and after cleaning the sediment, close the drain pipe 6 for the next monitoring; (6) Calculate the soil erosion modulus A of a small watershed within a hydrological year according to the following formula (2): A=(∑W1 i +∑W2 i +∑W3 i *(n-1)) / S (2) Among them, W1 i 、W2 i 、W3 i They represent the amount of sediment removed from the sedimentation tank 5, the diversion tank 7 and the collection tank 9 for the i-th time in a hydrological year, in t; n represents the number of diversion pipes 8; S represents the area of ​​the monitored karst small watershed, in km 2 ; Soil erosion modulus A is in t / (km 2 a).

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