Mangrove forest ecological island self-growth construction method and artificial island deposition device

Abstract

The invention relates to a self-growth construction method of a biodegradable mangrove forest ecological island based on dynamic regulation and control of tidal energy and an artificial island silting device.The artificial island silting device comprises a bamboo tube gate system, a hemp rope net system, a fixing pile system and a limiting system; the buoyancy difference and the water flow speed change generated by tide rising and falling are utilized, the synergistic effect of accelerating sand-carrying water flow to pass through the environment during tide rising and double sand blocking and siltation promoting during tide falling is achieved, a full-biodegradable material is adopted for constructing a growing siltation body, and bamboo joint holes are matched for regulating buoyancy balance, so that the device is always suspended on the surface layer of the siltation body; the artificial island is formed by continuously depositing and lifting the mud flat elevation, a site is provided for mangrove seedling planting, and the requirement for the time duration of exposing the mangrove forest on the sea day is met. The method and the device have the technical advantages of low construction cost, dynamic self-adaption to tide level change, avoidance of secondary pollution and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of coastal engineering, and relates to the cross technology of tidal energy utilization, artificial siltation for land reclamation and mangrove ecological restoration. Specifically, it is a method for self-growing construction of a mangrove ecological island and an artificial island siltation device. Background Art

[0002] The growth of mangrove seedlings requires that the root systems are exposed above the sea surface for 4 - 6 hours every day. When planting mangroves on tidal flats with a relatively low elevation, it is necessary to build artificial islands to raise the terrain. Traditional construction of mangrove artificial islands mostly uses reinforced concrete dikes or plastic wave breakwaters, which have problems such as high construction costs (cost per meter > 2000 yuan), hindering natural water and sediment exchange, and generating construction waste pollution. In addition, some coastal tidal flats are too low, and mangroves are constantly submerged and cannot survive, which not only affects the survival rate of individual mangroves but also the overall growth requirements of the mangrove forest.

[0003] Existing siltation promotion technologies generally use plastic meshes or fiber bags, which have the defect of non - biodegradable materials; many siltation promotion systems use fixed rock - throwing or concrete piles, which are difficult to adapt to tidal level changes and result in the inability to dynamically adjust the elevation of the silted body. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies existing in the above - mentioned prior art, and provide a method for self - growing construction of a mangrove ecological island and an artificial island siltation device. The present invention and the special device should be able to self - construct an ecological island using tidal kinetic energy on the tidal flat where mangroves are to be planted, meet the requirement that the root systems of mangrove seedlings are exposed above the sea surface for 4 - 6 hours every day, and be applicable to the rapid construction of a biodegradable mangrove ecological island on silty tidal flats.

[0005] In order to achieve the above - mentioned invention purpose, the technical solution provided by the present invention is as follows:

[0006] The present invention first provides a method for self - growing construction of a mangrove ecological island, which specifically includes the following steps:

[0007] S1. Arrange an artificial island siltation device on the tidal flat where mangrove seedlings are to be planted and where the requirement of the mangroves being exposed above the sea surface for 4 - 6 hours every day cannot be met. The artificial island siltation device includes a bamboo tube gate system, a hemp rope net system, a fixed pile system and a limiting system. The fixed pile system includes multiple wooden piles inserted into the tidal flat. The bamboo tube gate system is installed on one side of the fixed pile system. One end of the hemp rope net system is connected to the bamboo tube gate system, and the other end is connected to the fixed pile system. The limiting system is arranged on the fixed pile system to limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system;

[0008] S2. Set the initial elevation of the limiting system through tidal observation data to ensure that the bamboo tube gate system is in a semi - floating state at the mean tide level;

[0009] S3. During the spring tide, start the operation of the artificial island sedimentation device, and utilize the water-sediment separation effect generated by the hemp rope net system to achieve a sedimentation and elevation of 0.5 - 1 cm per day.

[0010] S4. After several days of sedimentation and elevation, when the height of the sediment body reaches the elevation required for the growth of mangrove roots, remove the hemp rope net system, and plant mangrove seedlings on the formed mangrove ecological island.

[0011] Furthermore, in the artificial island sedimentation device:

[0012] The bamboo tube gate system is composed of bamboo tubes of moso bamboo to form a horizontal gate body. Vertical through-holes are pre-drilled at both ends of the bamboo tubes, and horizontal through-holes are opened in the center of each bamboo tube segment.

[0013] The hemp rope net system includes a hemp rope net with square holes. The hemp rope net is square with the same length and width. One end of the net body of the hemp rope net is bound to the moso bamboo in the bamboo tube gate system, and the other end is horizontally opened in the direction away from the main wave direction and connected to the fixed pile system.

[0014] The fixed pile system contains four wooden stakes, divided into two groups with two in each group. One group vertically penetrates the vertical through-holes reserved at both ends of the bamboo tubes in the bamboo tube gate system to form a sliding joint; the other group vertically penetrates the outside of the opened hemp rope net, and the wooden stakes are vertically inserted deep into the tidal flat for fixation.

[0015] The limit system is composed of wooden nails nailed into the tops of the wooden stakes. The wooden nails limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Starting from the beach surface, the upward displacement of the bamboo tube gate system ≤ 1.0 m, and the upward displacement of the hemp rope net system in the direction away from the main wave direction ≤ 0.2 m.

[0016] Furthermore, the biodegradation periods of the bamboo tube gate system, the hemp rope net system, the fixed pile system, and the limit system match the artificial island formation period. Among them, the degradation time of moso bamboo is 24 - 36 months, the degradation time of the hemp rope net is 18 - 24 months, and the degradation time of the wooden stakes is 36 - 48 months.

[0017] Furthermore, in S3,

[0018] When the tide rises at the tidal flat location, the tide makes the bamboo tube gate system float, and the hemp rope net at the front end of the fixed pile system floats with the height adjuster, so that the hemp rope net at the front end of the fixed pile system and the hemp rope net at the rear end of the fixed pile system form a maximum opening angle of 30°. At the same time, the holes of the hemp rope net are tightened and opened, and the sea water flows through the hemp rope net, realizing the suspended sediment transport.

[0019] When the tide ebbs at the tidal flat, the bamboo tube gate system at the front end of the fixed pile system drops with the falling tide, and the hemp rope net at the front end of the fixed pile system drops with the bamboo tube gate system, causing the hemp rope net at the front end of the fixed pile system and the hemp rope net at the rear end of the fixed pile system to form a sand-blocking angle. At the same time, the holes of the hemp rope net droop and converge, and the flow velocity of the sea water decays when passing through the mesh holes, prompting the suspended sediment to settle and form a siltation body;

[0020] After the tide on the tidal flat completely ebbs, the bamboo tube gate system clings to the beach surface, and the hemp rope net covers the siltation body, generating surface pressure to prevent the sediment from cracking and flowing away.

[0021] Further, when the bamboo tube gate system is arranged on the tidal flat, the included angle between the length direction of the bamboo tube gate system and the main wave direction of the tide is 75-90°.

[0022] Further, when the tide rises at the tidal flat, the maximum included angle between the hemp rope net and the sea surface is 30°, and when the tide rises at the tidal flat, the included angle between the hemp rope net and the sea surface is not greater than 20°.

[0023] Further, when the fixed pile system is installed, the wooden piles are carbonized, the depth of the wooden piles inserted into the tidal flat is not less than 0.5 m, the height of the wooden piles exposed on the tidal flat is higher than the high tide level of the tidal flat, and the height of the wooden piles exposed on the tidal flat is not less than 1 m.

[0024] Further, in S4, after the thickness of the siltation body increases by 30 cm each time, the position of the limiting system is adjusted to make the bamboo tube gate system in a floating state, and at the same time, the included angle range between the hemp rope net and the beach surface is 0-30°.

[0025] The present invention also relates to a mangrove artificial island siltation device, which includes a bamboo tube gate system, a hemp rope net system, a fixed pile system and a limiting system. The fixed pile system includes multiple wooden piles inserted into the tidal flat. The bamboo tube gate system is installed on one side of the fixed pile system. One end of the hemp rope net system is connected to the bamboo tube gate system, and the other end is connected to the fixed pile system. The limiting system is arranged on the fixed pile system to limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system; the bamboo tube gate system floats on the tide when the tide reaches the tidal flat.

[0026] Further, the bamboo tube gate system is composed of bamboo tubes of bamboo to form a horizontal gate body. Vertical through holes are pre-drilled at both ends of the bamboo tubes, and horizontal through holes are opened in the center of each bamboo tube segment;

[0027] The hemp rope net system includes a hemp rope net with square holes. The hemp rope net is square with the same length and width. One end of the net body of the hemp rope net is bound to the bamboo in the bamboo tube gate system, and the other end is horizontally opened in the direction away from the main wave direction and connected to the fixed pile system;

[0028] The fixed pile system comprises four wooden piles, two in a group, and a total of two groups. One group vertically penetrates the vertical through holes reserved at both ends of the bamboo tube in the bamboo tube gate system to form a sliding joint; the other group vertically penetrates the outside of the opened hemp rope net, and the wooden piles are vertically inserted into the depth of the tidal flat for fixing;

[0029] The limiting system is composed of wooden nails nailed into the top of the wooden piles, which limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Calculated from the beach surface, the upward displacement of the bamboo tube gate system is ≤1.0m, and the upward displacement of the hemp rope net system facing away from the main wave direction is ≤0.2m.

[0030] Based on the above technical solution, the self-growth construction method of mangrove ecological island and the artificial island siltation device of the present invention have achieved the following technical advantages through practical application:

[0031] 1. The method for constructing a mangrove ecological island by self-growth of the present invention uses a special artificial island siltation device, which includes a bamboo tube gate system, a hemp rope net system, a fixed pile system and a limit system. A dynamic filtering structure is formed by a liftable bamboo tube gate made of bamboo (diameter 15cm×1.5m) and a 10×10cm pore size hemp rope net. The buoyancy difference and water flow velocity changes caused by tidal fluctuations are utilized to achieve the synergistic effect of accelerating the passage of sand-carrying water during high tide and double sand blocking and siltation promotion during low tide.

[0032] 2. During the formation of the mangrove ecological island of the present invention, the bamboo tube gate system adopts a double adjustment mechanism of bamboo node holes. Each bamboo tube segment is provided with a horizontal through hole to allow seawater to flow in, which not only controls the buoyancy of the bamboo tube and keeps the bamboo tube suspended about 10 cm below the water surface, but also forms local turbulence to enhance fine particle flocculation.

[0033] 3. During the formation of the mangrove ecological island of the present invention, the hemp rope net siltation promoting system forms a dynamic filtering structure. When the tide is high, the mesh is open, which does not affect the transportation of suspended sand; when the tide is low, the mesh is closed to block the seawater and promote the sedimentation of suspended sand. The porosity of the hemp rope net changes nonlinearly with the tide level (80% at high tide → 40% at low tide). The buoyancy balance is regulated by the holes in the bamboo nodes, so that the device is always suspended on the surface layer of the silt body, and the siltation of the beach is continuously raised to form an ecological artificial island. After the mangrove seedlings are planted on the ecological artificial island, the mangrove roots can be guaranteed to be exposed to the sea surface for a long time.

[0034] 4. The mangrove artificial island siltation device of the present invention innovatively uses fully biodegradable materials to construct a growable siltation body, and the degradation period of the device (2-3 years) is precisely matched with the artificial island forming period (24-30 months). The bamboo tube gate, hemp rope net, fixed piles and limiters are all eco-friendly and degradable materials, which can be completely degraded to avoid pollution to the ocean.

[0035] 5. Experimental results show that the self-growing construction method of the mangrove ecological island and the artificial island siltation device of the present invention have achieved rapid siltation of the artificial island, with the siltation efficiency increased by more than 40% compared with the traditional technology (the measured average monthly siltation thickness reaches 20 cm), the construction cost reduced by about 75%, the structural integrity rate > 95% under typhoon conditions, and the natural stability coefficient of the artificial island still remaining above 0.85 after the materials are completely degraded. Description of the Drawings

[0036] Figure 1 It is a schematic flow chart of a self-growing construction method of a mangrove ecological island of the present invention.

[0037] Figure 2 It is a three-dimensional installation view of the artificial island siltation device used in the self-growing construction method of a mangrove ecological island of the present invention.

[0038] Figure 3 It is a usage state diagram of the fixed pile system and the hemp rope net system during high tide on the tidal flat in the self-growing construction method of a mangrove ecological island and the artificial island siltation device of the present invention.

[0039] Figure 4 It is a usage state diagram of the fixed pile system and the hemp rope net system during low tide on the tidal flat in the self-growing construction method of a mangrove ecological island and the artificial island siltation device of the present invention. Detailed Embodiments

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described below through specific examples shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following descriptions, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0041] Example 1

[0042] As Figure 1 shown, this example belongs to a self-growing construction method of a mangrove ecological island, and the method specifically includes the following steps:

[0043] S1. Arrange an artificial island siltation device on the tidal flat where mangrove seedlings are to be planted and where the mangroves cannot be exposed to the sea surface for 4 - 6 hours per day. The artificial island siltation device includes a bamboo tube gate system 1, a hemp rope net system 2, a fixed pile system 3, and a limit system 4. The fixed pile system 3 includes multiple wooden piles inserted into the tidal flat. The bamboo tube gate system 1 is installed on one side of the fixed pile system 3. One end of the hemp rope net system 2 is connected to the bamboo tube gate system 1, and the other end is connected to the fixed pile system 3. The limit system 4 is arranged on the fixed pile system 3 to limit the vertical sliding height of the bamboo tube gate system 1 and the hemp rope net system 2;

[0044] S2. Set the initial elevation of the limit system 4 through tidal observation data to ensure that the bamboo tube gate system 1 is in a semi-floating state at the mean tide level;

[0045] S3. Start the operation of the artificial island sedimentation device during the spring tide, and utilize the water-sand separation effect generated by the hemp rope net system 2 to achieve a sedimentation and elevation of 0.5 - 1 cm per day;

[0046] S4. After days of sedimentation and elevation, when the height of the sediment body reaches the elevation required for the growth of mangrove roots, remove the hemp rope net system 2. The sediment body forms a special ecological artificial island, and plant mangrove seedlings on the formed mangrove ecological island to meet the requirement that the mangroves are exposed to the sea surface for 4 - 6 hours per day, providing a good growth environment for the subsequent growth of mangroves.

[0047] In the artificial island sedimentation device:

[0048] The bamboo tube gate system 1 is composed of bamboo tubes of moso bamboo to form a horizontal gate body. Vertical through-holes are pre-drilled at both ends of the bamboo tubes, and horizontal through-holes are opened in the center of each bamboo tube segment; when the bamboo tube gate system 1 is arranged on the tidal flat, the included angle between the length direction of the bamboo tube gate system 1 and the direction of the main tidal wave is 75 - 90°.

[0049] The hemp rope net system 2 includes a hemp rope net with square holes. The hemp rope net is square with the same length and width. One end of the net body of the hemp rope net is bound to the bamboo in the bamboo tube gate system, and the other end is horizontally opened in the direction away from the main wave direction and connected to the fixed pile system;

[0050] The fixed pile system 3 includes four wooden piles, divided into two groups with two in each group. One group vertically penetrates the vertical through-holes reserved at both ends of the bamboo tubes in the bamboo tube gate system to form a sliding joint; the other group vertically penetrates the outside of the opened hemp rope net, and the wooden piles are vertically inserted deep into the tidal flat for fixation;

[0051] The limit system 4 is composed of wooden nails nailed to the top of the wooden piles. The wooden nails limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Starting from the beach surface, the upward displacement of the bamboo tube gate system ≤ 1.0 m, and the upward displacement of the hemp rope net system in the direction away from the main wave direction ≤ 0.2 m.

[0052] The bamboo tube gate system 1, the hemp rope net system 2, the fixed pile system 3, and the limit system 4 are all made of eco-friendly degradable materials. The biodegradation periods of these materials match the formation period of the artificial island. Among them, the degradation time of moso bamboo is 24 - 36 months, the degradation time of the hemp rope net is 18 - 24 months, and the degradation time of the wooden piles is 36 - 48 months, which can be completely degraded to avoid pollution to the ocean.

[0053] In S3, when the tide is rising at the tidal flat location, the tide causes the bamboo tube gate system 1 to float, and the hemp rope net at the front end of the fixed pile system 3 floats along with the limit system 4, causing the hemp rope net at the front end of the fixed pile system 3 and the hemp rope net at the rear end of the fixed pile system 3 to form a maximum opening angle of 30°. At the same time, the holes in the hemp rope net are stretched and opened, and the seawater carrying sediment quickly rushes onto the shore from below the bamboo tube gate and through the holes in the hemp rope net, realizing suspended sediment transport;

[0054] When the tide is ebbing at the tidal flat location, the bamboo tube gate system 1 at the front end of the fixed pile system 3 drops with the ebbing tide, and the hemp rope net at the front end of the fixed pile system 3 drops along with the bamboo tube gate system 1, causing the hemp rope net at the front end of the fixed pile system 3 and the hemp rope net at the rear end of the fixed pile system 3 to form a sand-blocking angle. At the same time, the holes in the hemp rope net droop and close up, and the flow velocity of the seawater decreases when passing through the mesh holes, promoting the settlement of suspended sediment to form a siltation body; during the ebbing tide, as the bamboo tube gate system 1 drops and the hemp rope net droops and closes up close to the beach surface, the seawater carrying sediment is hindered and decelerated when passing through the hemp rope net, promoting gravitational settlement to produce a water-sediment separation phenomenon, and the seawater flows back from above the bamboo tube gate, and the sediment is jointly blocked by the hemp rope net and the bamboo tube gate and quickly sinks and accumulates. At the same time, after the seawater flow velocity is reduced, erosion damage to the already accumulated sediment pile can be reduced.

[0055] When the tide on the tidal flat has completely ebbed, the bamboo tube gate system 1 is close to the beach surface, and the hemp rope net covers the upper surface of the siltation body, generating surface pressure to prevent the sediment from cracking and flowing away. By covering the sediment pile that forms the siltation body with the dropping hemp rope net, the crack resistance of the sediment pile can be improved, and the wind resistance of the sediment pile can also be enhanced. Through the above, the bamboo tube gate and the hemp rope net always remain above the sediment pile relying on the buoyancy of the tide, and the sediment pile can continuously accumulate and rise to form an artificial island, ensuring the growth needs of the mangroves to be submerged and exposed to the sea every day.

[0056] When the tide is rising at the tidal flat location, the maximum opening angle between the hemp rope net and the sea surface is 30°. When the tide is rising at the tidal flat location, the opening angle between the hemp rope net and the sea surface is not greater than 20°.

[0057] When the fixed pile system 3 is installed, the wooden piles are carbonized, the depth of the wooden piles inserted into the tidal flat is not less than 0.5 m, the height of the wooden piles exposed on the tidal flat is higher than the high tide level of the tidal flat, and the height of the wooden piles exposed on the tidal flat is not less than 1 m.

[0058] In S4, after the thickness of the siltation body increases by 30 cm each time, the position of the limit system 4 is adjusted to make the bamboo tube gate system in a floating state, and at the same time, the inclination angle range between the hemp rope net and the beach surface is 0 - 30°.

[0059] Embodiment 2

[0060] As Figures 2 - 4As shown in the figure, this embodiment is a siltation device for a mangrove artificial island. The artificial island siltation device includes a bamboo tube gate system 1, a hemp rope net system 2, a fixed pile system 3, and a limit system 4. The fixed pile system 3 includes multiple wooden piles inserted into the tidal flat. The bamboo tube gate system 1 is installed on one side of the fixed pile system 3. One end of the hemp rope net system 2 is connected to the bamboo tube gate system 1, and the other end is connected to the fixed pile system 3. The limit system 4 is arranged on the fixed pile system 3 to limit the vertical sliding height of the bamboo tube gate system 1 and the hemp rope net system 2. When the tide reaches the tidal flat, the bamboo tube gate system 1 floats on the tide.

[0061] Furthermore, the bamboo tube gate system 1 is composed of bamboo tubes of moso bamboo to form a horizontal gate body. Vertical through holes are pre-drilled at both ends of the bamboo tubes, and horizontal through holes are opened in the center of each bamboo tube segment.

[0062] The hemp rope net system 2 includes a hemp rope net with square holes. The hemp rope net is square with the same length and width. One end of the net body of the hemp rope net is bound to the moso bamboo in the bamboo tube gate system, and the other end is horizontally opened in the direction away from the main wave direction and connected to the fixed pile system.

[0063] The fixed pile system 3 includes four wooden piles, divided into two groups with two in each group. One group vertically penetrates the vertical through holes reserved at both ends of the bamboo tubes in the bamboo tube gate system to form a sliding joint. The other group vertically penetrates the outside of the opened hemp rope net, and the wooden piles are vertically inserted deep into the tidal flat for fixation.

[0064] The limit system 4 is composed of wooden nails nailed into the top of the wooden piles. The wooden nails limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Starting from the beach surface, the upward displacement of the bamboo tube gate system ≤ 1.0 m, and the upward displacement of the hemp rope net system in the direction away from the main wave direction ≤ 0.2 m.

[0065] The artificial island siltation device of the present invention is provided with a bamboo tube gate system 1, a hemp rope net system 2, a fixed pile system 3 and a limit system 4. During the flood tide, the bamboo tube gate floats upward, and the hemp rope net leaves the beach surface and stretches and unfolds. Sea water carries sediment and quickly rushes onto the shore from below the bamboo tube gate and through the holes of the hemp rope net; during the ebb tide, the bamboo tube gate descends, and the hemp rope net droops and closes close to the beach surface. When the sea water carries sediment through the hemp rope net, it is blocked and decelerated, promoting gravitational sedimentation to produce the phenomenon of water-sediment separation. The sea water flows back from above the bamboo tube gate, and the sediment is jointly blocked by the hemp rope net and the bamboo tube gate and quickly sinks and accumulates; at the same time, after the sea water flow rate is reduced, the erosion damage to the already accumulated sediment pile can be reduced; after the complete ebb tide, the hemp rope net covers the surface of the already accumulated sediment pile, improving the crack resistance of the sediment pile and enhancing the wind resistance of the sediment pile; the bamboo tube gate and the hemp rope net always stay above the sediment pile relying on the buoyancy of the tide, and the sediment pile can continuously accumulate and rise to form an artificial island, ensuring the growth needs of mangroves to be submerged and exposed to the sea surface every day; the bamboo tube gate, the hemp rope net, the fixed pile and the limiter are all environmentally friendly degradable materials and can be completely degraded to avoid polluting the ocean.

[0066] The present invention utilizes the buoyancy difference and the change of water flow velocity generated by the ebb and flow of the tide to achieve the synergistic effect of accelerating the flow of sediment-carrying water during the flood tide and double sediment blocking and silt promoting during the ebb tide. It innovatively uses fully biodegradable materials to construct a growable siltation body, and cooperates with the bamboo joint holes to regulate the buoyancy balance, so that the device always floats on the surface layer of the siltation body, realizing the continuous siltation and elevation of the beach elevation, and facilitating the early formation of an ecological artificial island, that is, the bamboo tube gate and the hemp rope net always stay above the sediment pile relying on the buoyancy of the tide, and the sediment pile can continuously accumulate and rise to form an artificial island, ensuring the growth needs of mangroves to be submerged and exposed to the sea surface every day. The device of the present invention has technical advantages such as low construction cost, dynamic adaptive change of the tide level, and avoidance of secondary pollution.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A method for constructing a mangrove ecological island by self-growth, characterized in that: The method specifically comprises the following steps: S1, arranging a special artificial island silting device on the tidal flat where mangrove seedlings are to be planted and the mangroves cannot be exposed to the sea surface for 4-6 hours a day, the artificial island silting device comprising a bamboo tube gate system, a hemp rope net system, a fixed pile system and a limit system, the fixed pile system comprising a plurality of wooden piles to be inserted into the tidal flat, the bamboo tube gate system being installed on one side of the fixed pile system, one end of the hemp rope net system being connected to the bamboo tube gate system and the other end being connected to the fixed pile system, the limit system being arranged on the fixed pile system to limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system; S2, setting the initial elevation of the limit system through tidal observation data to ensure that the bamboo tube gate system is in a semi-floating state at the average tide level; S3, during the spring high tide, the artificial island siltation device is started to operate, and the water-sand separation effect produced by the hemp rope net system is used to achieve an average daily siltation lift of 0.5 to 1 cm; S4, after many days of siltation and lifting, when the height of the silt body reaches the elevation required for the growth of mangrove roots, the hemp rope net system is removed and mangrove seedlings are planted on the mangrove ecological island formed.

2. The method for self-growth construction of a mangrove ecological island according to claim 1, characterized in that: In the artificial island siltation device: The bamboo tube gate system (1) is composed of a bamboo tube of moso bamboo to form a horizontal gate body, both ends of the bamboo tube are pre-drilled with vertical through holes, and the center of each bamboo tube segment is opened with a horizontal through hole; The hemp rope net system (2) comprises a hemp rope net with square holes, the hemp rope net is in a square shape with the same length and width, one end of the hemp rope net is bound to the bamboo in the bamboo tube gate system, and the other end is horizontally spread out facing away from the main wave direction and connected to the fixed pile system; The fixed pile system (3) comprises four wooden piles, two in a group, and a total of two groups, one group vertically penetrates through the vertical through holes reserved at both ends of the bamboo tube in the bamboo tube gate system to form a sliding joint; the other group vertically penetrates through the outside of the opened hemp rope net, and the wooden piles are vertically inserted into the depth of the tidal flat for fixing; The limiting system (4) is composed of wooden nails nailed into the top of the wooden piles, which limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Calculated from the beach surface, the upward displacement of the bamboo tube gate system is ≤1.0m, and the upward displacement of the hemp rope net system facing away from the main wave direction is ≤0.2m.

3. The method for self-growth construction of a mangrove ecological island according to claim 2, characterized in that: The biodegradation period of the bamboo gate system (1), the hemp rope net system (2), the fixed pile system (3) and the limit system (4) matches the artificial island forming period, wherein the degradation time of the bamboo is 24-36 months, the degradation time of the hemp rope net is 18-24 months, and the degradation time of the wooden pile is 36-48 months.

4. The method for self-growth construction of a mangrove ecological island according to claim 2, characterized in that: In S3, When the tide rises at the tidal flat, the tide causes the bamboo tube gate system (1) to float up, and the hemp rope net at the front end of the fixed pile system (3) floats up along with the bamboo tube gate system (1), so that the hemp rope net at the front end of the fixed pile system (3) and the hemp rope net at the rear end of the fixed pile system (3) form a maximum opening angle of 30 degrees, and at the same time, the holes of the hemp rope net are stretched and opened, and seawater flows through the hemp rope net, thereby realizing the transport of suspended sand; When the tide recedes at the tidal flat, the bamboo gate system (1) at the front end of the fixed pile system (3) falls with the tide, and the hemp rope net at the front end of the fixed pile system (3) falls with the bamboo gate system (1), so that the hemp rope net at the front end of the fixed pile system (3) and the hemp rope net at the rear end of the fixed pile system (3) form a sand blocking angle, and at the same time, the holes of the hemp rope net sag and shrink, and the flow velocity of seawater decreases when passing through the mesh holes, which promotes the sedimentation of suspended sand to form a siltation body; When the tide on the tidal flat completely recedes, the bamboo sluice system (1) is close to the beach surface, and the hemp rope net is covered on the silt body, generating surface pressure to prevent the silt from drying up and flowing away.

5. The method for self-growth construction of a mangrove ecological island according to claim 2, characterized in that: When the bamboo tube sluice system (1) is arranged on a tidal flat, the angle between the length direction of the bamboo tube sluice system (1) and the main wave direction of the tide is 75-90°.

6. The method for self-growth construction of a mangrove ecological island according to claim 2, characterized in that: When the tide is high at the tidal flat, the maximum angle between the hemp rope net and the sea surface is 30°. When the tide is high at the tidal flat, the angle between the hemp rope net and the sea surface is no more than 20°.

7. The method for constructing a mangrove ecological island based on the dynamic regulation of tidal energy according to claim 2 is characterized in that: When the fixed pile system is installed, the wood piles are carbonized, the depth of the wood piles inserted into the tidal flat is not less than 0.5m, the height of the wood piles exposed on the tidal flat is higher than the height of the high tide of the tidal flat, and the height of the wood piles exposed on the tidal flat is not less than 1m.

8. The method for constructing a mangrove ecological island based on the self-growth of tidal energy dynamic regulation according to claim 2 is characterized in that: In S4, after the thickness of the sediment body increases by 30 cm, the position of the limit system (4) is adjusted to make the bamboo tube gate system float, and at the same time, the inclination angle between the hemp rope net and the beach surface ranges from 0 to 30 degrees.

9. A mangrove artificial island siltation device, characterized in that: The artificial island siltation device comprises a bamboo tube gate system (1), a hemp rope net system (2), a fixed pile system (3) and a limit system (4); the fixed pile system (3) comprises a plurality of wooden piles inserted into the tidal flat; the bamboo tube gate system (1) is installed on one side of the fixed pile system (3); one end of the hemp rope net system (2) is connected to the bamboo tube gate system (1) and the other end is connected to the fixed pile system (3); the limit system (4) is arranged on the fixed pile system (3) to limit the vertical sliding height of the bamboo tube gate system (1) and the hemp rope net system (2); the bamboo tube gate system (1) floats on the tide when the tide reaches the tidal flat.

10. The mangrove artificial island siltation device according to claim 9, characterized in that: The bamboo tube gate system (1) is composed of a bamboo tube of moso bamboo to form a horizontal gate body, both ends of the bamboo tube are pre-drilled with vertical through holes, and the center of each bamboo tube segment is opened with a horizontal through hole; The hemp rope net system (2) comprises a hemp rope net with square holes, the hemp rope net is in a square shape with the same length and width, one end of the hemp rope net is bound to the bamboo in the bamboo tube gate system, and the other end is horizontally spread out facing away from the main wave direction and connected to the fixed pile system; The fixed pile system (3) comprises four wooden piles, two in a group, and a total of two groups, one group vertically penetrates through the vertical through holes reserved at both ends of the bamboo tube in the bamboo tube gate system to form a sliding joint; the other group vertically penetrates through the outside of the opened hemp rope net, and the wooden piles are vertically inserted into the depth of the tidal flat for fixing; The limiting system (4) is composed of wooden nails nailed into the top of the wooden piles, which limit the vertical sliding height of the bamboo tube gate system and the hemp rope net system. Calculated from the beach surface, the upward displacement of the bamboo tube gate system is ≤1.0m, and the upward displacement of the hemp rope net system facing away from the main wave direction is ≤0.2m.

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