Method for ecological restoration of river channel based on construction of ecological island

Abstract

The invention discloses a river channel ecological restoration method based on construction of an ecological island, and the method comprises the following steps: S1, bank protection pile foundation construction: after the bank protection pile foundation is completed, ecological island planting piles are constructed; s2, pile foundation construction of ecological island planting piles is conducted according to the construction drawing; s3, pile foundation construction of ecological island planting piles is completed through piling equipment; s4, steel pipe piles are installed around the ecological island planting piles, and then earthwork backfilling is conducted in the ecological island planting piles; the construction of the ecological island is completed; s5, after the ecological island is constructed, plants in the island are planted, and construction of the ecological island is completed; s6, river dredging and water quality adjustment are conducted, and river bottom sludge is cleaned through a pontoon; and S7, ecological soft enclosure construction is carried out, water quality adjustment treatment is carried out through an ecological soft enclosure, and river ecological restoration is completed. According to the method, by building the ecological island and arranging the ecological soft enclosure, the pollution load of the water body is rapidly reduced, a healthy aquatic ecological sequence is rebuilt, and the water body remediation speed is increased.

Description

Technical Field

[0001] This invention belongs to the field of ecological restoration technology, and in particular relates to a method for river ecological restoration based on the construction of ecological islands. Background Technology

[0002] With the acceleration of global urbanization and the rapid development of industry and agriculture, large amounts of inadequately treated industrial wastewater, domestic sewage, and agricultural non-point source pollutants are discharged into natural water bodies, leading to serious water environment problems in many lakes, rivers, and reservoirs. Among these problems, eutrophication is one of the most common and prominent. Excessive nitrogen, phosphorus, and other nutrients in water bodies promote the abnormal proliferation of algae, forming algal blooms, consuming dissolved oxygen, leading to water quality deterioration, decreased water transparency, degradation of the structure and function of aquatic ecosystems, and even the production of algal toxins, seriously threatening drinking water safety, the survival of aquatic organisms, and the landscape and recreational functions.

[0003] Traditional water remediation technologies primarily rely on physical methods (such as sediment dredging, artificial aeration, and mechanical algae removal) and chemical methods (such as the addition of algaecides and phosphorus-locking agents). While these methods can achieve some short-term results, they often only address the symptoms and not the root cause, and have limitations such as high operating costs, the potential for secondary pollution, and disruption of the original ecological balance. For example, sediment dredging is a massive undertaking that may disturb and release pollutants from the sediment; the use of chemical agents may be toxic to non-target organisms and pose long-term ecological risks. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for river ecological restoration based on the construction of ecological islands. The method of this invention rapidly reduces the water pollution load, reshapes a healthy aquatic ecological sequence, and improves the speed of water body restoration by constructing ecological islands and setting up ecological soft barriers.

[0005] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows: A method for river ecological restoration based on the construction of ecological islands, the method specifically includes the following steps: S1, Revetment pile foundation construction: Install revetment pile foundations on both sides of the river according to the trend of the river. After the revetment pile foundations are completed, carry out the construction of ecological island planting piles. S2, According to the construction drawings, the pile foundation construction is carried out by deploying the pile driving equipment on the lake or river to carry out the pile foundation construction of the ecological island planting piles by floating the pile driving equipment. S3, before piling construction, the on-site measurement control baseline and baseline points are checked, and the piling construction baseline is laid out; the piling equipment is used to complete the pile foundation construction of multiple ecological island planting piles; S4. Backfilling of the ecological island: After the construction of the ecological island planting piles is completed, steel pipe piles are installed around the ecological island planting piles, and geotextile is laid inside the steel pipe piles to prevent river water from entering the ecological island planting piles; then backfilling is carried out into the ecological island planting piles; the construction of the ecological island is completed. S5. After the construction of the ecological island is completed, plants will be planted on the island to complete the construction of the ecological island. S6, River dredging and water quality regulation, which involves cleaning the riverbed silt from upstream to downstream using floating vessels, following the direction of river flow. S7, ecological soft enclosure construction, uses ecological soft enclosures to divide and segment the river area for water quality regulation and treatment, and completes the ecological restoration of the river.

[0006] Furthermore, when the revetment pile foundations are constructed along both banks of the river, the revetment pile foundations on both banks of the river are constructed in an alternating manner.

[0007] Furthermore, when driving the planting piles for the ecological island, the pile position deviation is less than or equal to D / 6-D / 4, and the pile verticality tolerance is less than 1%. The pile verticality is controlled by cross-checking with a total station and a theodolite, and the pile elevation is controlled by a level.

[0008] Furthermore, the specific process of driving the planting piles on the ecological island is as follows: the planting piles are transported to the floating operation vessel on the water by crane; before construction, a theodolite is set up about 25m away from the construction pile position on the center line of the pile row, and the verticality of the pile is observed with the center line as the angle to ensure verticality and avoid the center position of the pile row from exceeding the axis position; another theodolite is set up at a position where the first theodolite and the pile position form an angle of about 90° to check the verticality deviation; the first planting pile is lifted and inserted into the pile position that has been arranged underground, first inserted into the soil 30-50cm, and after the insertion is stable, the theodolite is used to perform vertical correction until the verticality of the pile meets the specifications before the pile is driven into the ground to complete the construction of the planting piles.

[0009] Furthermore, the construction of the ecological island planting piles is specifically as follows: according to the construction drawings, a closed area is formed by using ecological island planting piles. After the ecological island planting piles are installed, soil is filled into the ecological island planting piles to build an island. Steel pipe piles are installed around the ecological island planting piles. A double-layer impermeable geomembrane is laid between the steel pipe piles and the ecological island planting piles, and the soil is filled and compacted. Soil is then filled and compacted between the steel pipe piles and the ecological island planting piles to prevent river water from entering the ecological island planting piles. The ecological island well is used for strong drainage. A vertical well is dug in the middle of the ecological island to allow the river water in the ecological island to collect into the well. The river water in the well is then pumped out to complete the drainage of the ecological island. Finally, the well is filled in to complete the construction of the ecological island.

[0010] Furthermore, the ecological island includes an emergent area and a submerged area. One side of the emergent area is connected to the riverbank, and the other side is the submerged area. The boundary between the emergent and submerged areas is separated by planting stakes. Coconut fiber vegetation mats are laid in the emergent area. The thickness of the coconut fiber vegetation mats is 5.8-25mm. The coconut fiber vegetation mats extend 20cm around the perimeter and are buried in the soil, and are fixed with 60cm bamboo nails every 1m. Emergent plants are planted in the emergent area, and submerged plants are planted in the submerged area.

[0011] Furthermore, the coconut fiber vegetation blanket comprises coconut fiber and PP mesh, with a coconut fiber to PP mesh ratio of 4:1.

[0012] Furthermore, the ecological soft enclosure includes a first fixed steel pipe, a second fixed steel pipe, a support pipe, diagonal braces, and a soft enclosure. Support pipes are respectively provided at both ends of the second fixed pipe, and the support pipes are vertically connected to the second fixed tank. The first fixed pipe is installed on the support pipe below the second fixed pipe. The first fixed pipe is vertically arranged with the second fixed tank. The soft enclosure is provided on the first fixed pipe, and multiple hooks are provided on the first fixed pipe. The first fixed pipe is connected to the soft enclosure through the hooks.

[0013] Furthermore, the upper end of the soft enclosure is connected and fixed to the first fixed pipe, and the lower end of the soft enclosure is provided with a corrugated pipe, which is arranged parallel to the first fixed pipe and filled with sand; a diagonal brace is provided between adjacent first fixed pipes, which is connected and fixed to the first fixed pipe, the depth of the diagonal brace in the soil is greater than 3m, and the angle between the diagonal brace and the support pipe is 30°.

[0014] Based on the above technical solutions, the method for river ecological restoration based on constructing ecological islands, as proposed in this invention patent, has achieved the following technical advantages through practical application: 1. The present invention discloses a method for river ecological restoration based on the construction of ecological islands. By constructing ecological islands and setting up ecological soft barriers, the method can quickly reduce the pollution load on water bodies, reshape a healthy aquatic ecological sequence, and improve the speed of water body restoration. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of an ecological island in the method for river ecological restoration based on the construction of ecological islands according to the present invention.

[0016] Figure 2 This is a front view of the soft enclosure in a method for river ecological restoration based on the construction of ecological islands according to the present invention.

[0017] Figure 3 This is a side view of the soft enclosure in a method for river ecological restoration based on the construction of ecological islands according to the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided with reference to the accompanying drawings. The invention is described using specific examples shown. However, it should be understood that these descriptions are merely exemplary. This description is intended not to limit the scope of the invention. Furthermore, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the invention.

[0019] Example 1, such as Figure 1-3 As shown, a method for river ecological restoration based on the construction of ecological islands is presented. The method specifically includes the following steps: S1, Revetment pile foundation construction: Install revetment pile foundations on both sides of the river according to the trend of the river. After the revetment pile foundations are completed, carry out the construction of ecological island planting piles 11. S2, According to the construction drawings, the pile foundation construction is carried out by deploying the pile driving equipment on the lake or river to carry out the pile foundation construction of the ecological island planting pile 11 through floating boats. S3, before the piling construction, the on-site measurement control baseline and baseline points are checked, and the piling construction baseline is laid out; the piling equipment is used to complete the pile foundation construction of multiple ecological island planting piles 11; S4. Backfilling of the ecological island: After the construction of the ecological island planting piles 11 is completed, steel pipe piles are installed around the ecological island planting piles 11, and geotextile is laid inside the steel pipe piles to prevent river water from entering the ecological island planting piles 11; then backfilling is carried out into the ecological island planting piles 11; the construction of the ecological island is completed. S5. After the construction of the ecological island is completed, plants will be planted on the island to complete the construction of the ecological island. S6, River dredging and water quality regulation, which involves cleaning the riverbed silt from upstream to downstream using floating vessels, following the direction of river flow. S7, ecological soft enclosure construction, uses ecological soft enclosures to divide and segment the river area for water quality regulation and treatment, and completes the ecological restoration of the river.

[0020] When the revetment pile foundations are constructed along both banks of the river, the revetment pile foundations on both banks of the river are constructed in an alternating manner.

[0021] When the ecological island planting piles 11 are driven, the pile position deviation of the ecological island planting piles 11 shall be less than or equal to D / 6-D / 4, and the pile position verticality tolerance shall be less than 1%. The pile verticality shall be controlled by cross-checking with a total station and a theodolite, and the pile elevation shall be controlled by a level.

[0022] The specific process for driving the planting piles 11 on the ecological island is as follows: The planting piles are transported to the floating operation vessel on the water by crane; before construction, a theodolite is set up about 25m away from the construction pile position on the center line of the pile row, and the verticality of the pile is observed with the center line as the angle to ensure verticality and avoid the center position of the pile row from exceeding the axis position; another theodolite is set up at a position where the first theodolite and the pile position form an angle of about 90° to check the verticality deviation; the first planting pile is lifted and inserted into the pile position that has been arranged underground, first inserted into the soil 30-50cm, and after the insertion is stable, the theodolite is used to perform vertical correction until the verticality of the pile meets the specifications before the pile is driven into the ground to complete the construction of the planting pile.

[0023] The construction of the ecological island planting piles 11 is as follows: According to the construction drawings, a closed area is formed by the ecological island planting piles 11. After the ecological island planting piles 11 are installed, soil is filled into the ecological island planting piles 11 to build an island. Steel pipe piles are installed around the ecological island planting piles 11. A double-layer impermeable geomembrane is laid between the steel pipe piles and the ecological island planting piles 11 and the soil is filled and compacted. Soil is then filled and compacted between the steel pipe piles and the ecological island planting piles 11 to block river water from entering the ecological island planting piles 11. The ecological island well is used for drainage. A vertical well is dug in the middle of the ecological island to allow the river water in the ecological island to collect into the well. The river water in the well is then pumped out to complete the drainage of the ecological island. The well is then filled in to complete the construction of the ecological island.

[0024] The ecological island includes an emergent zone 1 and a submerged zone 2. One side of the emergent zone 1 is connected to the riverbank, and the other side is the submerged zone 2. The boundary between the emergent zone 1 and the submerged zone 2 is separated by planting stakes. Coconut fiber vegetation mat 3 is laid in the emergent zone 1. The thickness of the coconut fiber vegetation mat 3 is 5.8-25mm. The coconut fiber vegetation mat 3 extends 20cm around its perimeter and is buried in the soil, and is fixed with 60cm bamboo nails every 1m. Emergent plants are planted in the emergent zone 1, and submerged plants are planted in the submerged zone 2.

[0025] The coconut fiber vegetation mat 3 includes coconut fiber and PP mesh, with a ratio of coconut fiber to PP mesh of 4:1.

[0026] The ecological soft enclosure 8 includes a first fixed steel pipe 51, a second fixed steel pipe 52, a support pipe 4, a diagonal brace 6, and a soft enclosure 8. The second fixed pipe is provided with support pipes 4 at both ends. The support pipes 4 are vertically connected to the second fixed tank. The first fixed pipe is installed on the support pipe 4 below the second fixed pipe. The first fixed pipe is vertically arranged with the second fixed tank. The soft enclosure 8 is provided on the first fixed pipe. Multiple hooks are provided on the first fixed pipe. The first fixed pipe is connected to the soft enclosure 8 through the hooks.

[0027] The upper end of the flexible enclosure 8 is connected and fixed to the first fixed pipe, and the lower end of the flexible enclosure 8 is provided with a corrugated pipe 7, which is arranged parallel to the first fixed pipe and filled with sand. A diagonal brace 6 is provided between adjacent first fixed pipes, and the diagonal brace 6 is connected and fixed to the first fixed pipe. The insertion depth of the diagonal brace 6 is greater than 3m, and the angle between the diagonal brace 6 and the support pipe 4 is 30°. By filling the corrugated pipe 7 with sand, the flexible enclosure 8 will not sway excessively due to water flow, and the water within the flexible enclosure 8 will not interact with each other, facilitating water regulation within the flexible enclosure 8.

[0028] Combining ecological soft barriers with ecological island technology can achieve synergistic effects. Ecological soft barriers provide a "protective shield" for the restoration of plant communities and surrounding aquatic vegetation on the ecological island, while the ecological island acts as a powerful "purification engine," rapidly reducing water pollution load and reshaping a healthy aquatic ecosystem. This combination of technologies is particularly suitable for the ecological restoration of eutrophic lakes, urban landscape water bodies, drinking water source pretreatment areas, and slow-flowing sections of polluted rivers, and is an effective means to achieve the dual goals of water purification and ecological landscape enhancement.

[0029] Example 2: The main construction tasks of the water-based operation of the present invention are pile foundation construction, earthwork backfilling and shaping, and greening planting.

[0030] Due to the large amount of silt and mud in the lake area over the years, the riverbed soil lacks stability, and the newly backfilled soil loses its plasticity after being soaked in water. Therefore, the construction of the ecological island requires the prior construction of structural pile foundations. The pile foundation construction will begin with the construction of piles along the revetment. After the revetment pile foundations are completed, the construction of the ecological island and the piles for planting emergent plants will proceed, and finally, the construction of the pile foundations for planting plants within the lake will be carried out.

[0031] 1. Pile foundation construction arrangement The pile foundation is constructed according to the design drawings. The pile foundation construction is carried out in lakes or rivers using floating boats equipped with pile driving equipment, and the corresponding equipment is used according to the construction requirements. 2. Earthwork backfilling and shaping The earthwork will be carried out by taking soil from the nearby riverbank, with construction proceeding simultaneously on land and water. On land, excavators and dump trucks will be used for construction; on water, dredging vessels and barges will be used for shaping the bottom sediment.

[0032] After the foundation piles for the protective island are completed, long-arm excavators will be used to fill soil on both sides of the island from both the water and the land. The backfill soil will be homogeneous clay or silty clay, and will be compacted in layers. The soil level will be adjusted according to the moisture content of the backfill soil during construction. After the artificial island takes shape, the slope will be manually trimmed. Next, the ditches between adjacent islands will be constructed, proceeding from high to low.

[0033] 1. Construction of ecological islands ①Preparations before island construction After the construction team arrived on site, they first conducted surveying and setting out, marking the location of the highest point in the center of the island. Earthwork was carried out using both land-based and water-based excavators. Dump trucks were used in conjunction with long-arm excavators on land, while barges were used in conjunction with water-based excavators. The excavated earth was unloaded near the island's construction site.

[0034] ②Island construction and reclamation Construct a temporary access road from the land to the island, following the shortest distance between the ecological island and the revetment. After the island is basically formed, the remaining soil from the access road will be removed to construct ditches between the islands and other islands. During construction, excavators will push the earthwork towards the center of the river according to the surveyed and laid-out lines. The construction of the temporary access road requires layered compaction. Aquatic excavators will assist in shaping the outer slope of the ecological island along the river, gradually moving it towards the center of the river as construction progresses. The backfill soil will be evenly distributed to ensure the island piles are evenly stressed and stable.

[0035] ③ Construction and shaping of inter-island ditches Centered on the construction of the main island, earthwork gradually spread outwards to the surrounding areas, with each layer compacted. Finally, manual labor combined with machinery was used to construct the slope and gullies of the ecological island. During construction, the terrain was laid out in layers, and measurements were taken and verified after completion to ensure that the island's shape was aesthetically pleasing and natural.

[0036] To ensure the compactness of the newly filled soil within the ecological island and to guarantee the survival rate of large trees: ① After the construction of the ecological island wooden piles is completed, steel pipe piles with a diameter of 50mm and a length of 4m are arranged at 10cm intervals around the perimeter of the wooden piles. The top elevation of the piles is driven to 3.5m, and 450g / m² steel pipes are laid on the inner side of the piles. 2 After double-layer impermeable geomembrane is applied, the soil is backfilled and compacted to prevent river water from entering and ensure a dry planting environment for the newly planted seedlings. Once the plants have recovered, taken root, and survived, the upper steel pipe enclosure is manually removed. ② A 2m long φ300 pipe well is installed on the island to forcefully drain water and accelerate soil stabilization and compaction. ③ When planting trees, the root ball of large trees is enlarged, and large supporting timbers are added around the large trees. After a period of recovery, the survival of the plants is ensured.

[0037] The average elevation of the lake bottom in the current design planting area is between 0.8m and 1.20m, while the elevation of the submerged plant bottom mud of the design planting piles is 1.70m, a difference of 0.5 to 0.9m. The amount of bottom mud backfill is large. Therefore, the bottom mud needs to be transferred from other lakes and ponds in the surrounding area to backfill to the design elevation.

[0038] Tree species planted include pond cypress and dawn redwood, while ground cover is planted with pennywort.

[0039] 3. Planting of aquatic vegetation Construction was carried out using a floating work platform while the water was submerged. Aquatic plants were planted once the water depth reached the design level. When planting aquatic plants, they were secured to the bottom of the water by binding them with aquatic plants and sinking them to the bottom. Submerged plants were planted in designated areas according to the diagram and in sequence to prevent trampling, damage, and omissions during construction.

[0040] Pile driving construction method 1. The precast piles are transported by crane to the floating vessel for water operations.

[0041] 2. Moving the piling vessel and positioning the pile driver: The piling vessel is rowed to the construction site, anchored, and the piling machine is positioned.

[0042] 3. Positioning and Control: Pile Alignment and Verticality Calibration. The key to pile alignment is ensuring the pile layout is on the positioning centerline. Before construction, a theodolite is set up approximately 25m away from the pile location on the pile centerline. Using the centerline as the angle of observation, the verticality of the pile and the center position of the guide trench are monitored to ensure verticality and prevent the pile center from exceeding the axis. Additionally, another theodolite is set up at approximately a 90° angle to the pile location to check for verticality deviation. The first pile section is lifted and inserted into the pre-arranged underground pile location, initially 30-50cm into the soil. After stabilization, the theodolite is used for simultaneous vertical correction until the pile's verticality meets the specifications (vertical correction should not be performed after the pile has been driven 3m into the soil; if deviation occurs, it should be pulled out and re-inserted).

[0043] The elevation of the pile top is monitored using a level instrument during pile driving, with an allowable error controlled within ±5mm.

[0044] 4. Pile Installation: Before installing the pile, the surveyor uses a weight to measure the water depth and reports the water level and depth to the pile-laying team leader. When the torsion angle, verticality, and pile position all meet the requirements, the pile-laying team leader directs the lowering of the main hook to install the pile. During installation, the surveying team and the pile-laying team monitor the pile position and verticality, taking measures to ensure that the pile position and verticality meet the requirements based on the actual situation. When installing piles on a slope, the pile tip is generally moved a certain distance forward towards the bank slope before installation, allowing the pile to slide down the slope. Once the pile stops sliding, the verticality is adjusted.

[0045] 5. A hammer pad (made of hardwood) should be installed at the top of the pile, and a pile pad with appropriate elasticity should be installed at the top of the pile. The pile pad should be of uniform thickness and its dimensions should be as similar as possible to the cross-section of the pile top.

[0046] 6. Replacement Hammer and Pressure Hammer: After the pile body stabilizes under its own weight, the pile position is re-measured. Once confirmed to meet requirements, the main hoisting hook is released, and the pile foreman directs the lowering of the replacement hammer. When approaching the pile top, the work is paused to observe whether the pile top and the replacement hammer are aligned. If there is a deviation, the boat or a variable-amplitude pile frame should be moved to align them before lowering the replacement hammer. During pressure hammer operation, the pile foreman closely monitors changes in the pile position, the surveyor re-measures the pile position, and adjustments are made before continuing pressure hammering.

[0047] 7. Pile Driving: After the pile has stabilized, adjust the vibratory hammer so that the auger is parallel to the pile body, ensuring that the center lines of the pile, hammer, and other components are on the same axis. The surveyor re-measures the pile position to confirm its accuracy. After approval by the site technician, the pile driving foreman directs the hammering. During hammering, attention should be paid to issues such as pile slippage, pile head breakage, whether the pile penetration has reached the hammer's operating limit, and wave surges. All original data should be recorded. The surveyor should observe the entire hammering process and report any deviations to the site technician immediately.

[0048] 8. Stopping and restarting the hammer: The pile driving is mainly controlled by the elevation, and the penetration is used as a check. The penetration check is based on the design requirements.

[0049] Floating dredging operation After conducting a construction survey, and based on the specific conditions of the river, our department decided to adopt floating dredging, which involves placing the excavating machinery on a floating pontoon, i.e., a construction platform on the water, and using the pontoon to carry out excavation and dredging work on the water surface.

[0050] The construction sequence follows the direction of the river, proceeding from top to bottom. The specific construction steps are as follows: (1) Mechanical preparation: The floating platform will be constructed using a three-phase floating platform, with the intermediate floating platform having dimensions of [missing information]. (Length, Width, Height), weighing 28 tons, with the following dimensions for the floating hulls on both sides: (Length, width, height) (The floating hull is connected as one unit), one long-arm excavator, and one regular excavator. First, the floating hull is placed in sections into the river channel, connected as a whole, and then fixed to the riverbank. After the riverbank wall is demolished, a straight ramp is built to the floating hull. One long-arm excavator and one regular excavator are then loaded onto the floating hull along the temporary dock. When the excavators are loading the floating hull, a crane or excavator is needed to assist in ensuring the stability of the floating hull and to prevent it from capsizing due to stress on one side.

[0051] (2) The dredging of the river shall be carried out in the order from upstream to downstream, and from the center to the sides.

[0052] (3) During the dredging operation of the floating vessel, two excavators are placed at both ends of the floating vessel. The ordinary excavator is used to fix the floating vessel and assist the floating vessel in moving and traveling during the dredging operation, while the long-arm excavator is used for the dredging operation.

[0053] (4) First, the silt in the middle of the river channel is dredged. The current width of the river channel in my section is between 35 and 50 meters. During construction, the excavator cannot dredge the silt in the middle of the river channel to the riverbank in one go. Therefore, the silt in the middle of the river channel needs to be transported to both sides of the river channel in 2 to 3 times. Then the floating boat moves to the edge of the river channel and directly dredges the silt to the riverbank.

[0054] (5) Since dredging is carried out in water, the silt has a high water content and is prone to causing pollution to roads and the surrounding environment during transportation. Therefore, the silt needs to be dried after being dug to the riverbank before it can be transported out.

[0055] (6) Since the elevation of the river embankment cannot be clearly detected during the dredging process, a small boat and a set of probes are required. After the dredging is completed in a certain area, the inspection personnel will immediately use the probes to check the dredging depth to avoid areas that are missed or not dug deep enough.

[0056] Ecological soft enclosure Before construction begins, thorough preparations must be made for the construction area, including clearing the riverbed and surrounding debris, and defining the construction boundaries to ensure that there are no obstacles around the construction area.

[0057] ② Install and fix the steel pipe support According to the design requirements, a 6-meter-long galvanized steel pipe with a wall thickness of 3.5 and a diameter of 50 was driven into the riverbed. The spacing between the steel pipes was 2.8 meters, and the burial depth had to be greater than 3 meters to ensure the stability and safety of the embankment support.

[0058] ③ Install flexible enclosure materials Select suitable flexible enclosure materials and cut and install them according to the size and shape of the construction area. During installation, ensure a tight seal between the enclosure material and the steel pipe piles to guarantee the isolation effect. Use 50mm diameter corrugated pipes filled with sand for counterweighting at the bottom, with a counterweight requirement of at least 1.8kg / m.

[0059] ④ Fixed enclosure Materials were transported on site using floating vessels, and galvanized steel pipes were installed using floating vessels in conjunction with excavators. On-site construction and layout were carried out according to the design drawings. After the layout was completed, the steel pipe pile driving was carried out on the water. The enclosure was installed using a floating platform.

[0060] The enclosure material is fixed to the steel pipe with clips. When fixing, first pull the enclosure flat and straight, and then use clips to lock it at both ends. Observe that the smoothness of the enclosure meets the design requirements before locking it in place.

[0061] Aquatic plant cultivation Aquatic plants have significant environmental and ecological functions. By utilizing aquatic plants suitable for the corresponding river water environment and their symbiotic microenvironment, aquatic plant community suitable for the characteristics of the water body can be constructed, which can effectively reduce the concentration of suspended solids, improve water transparency and dissolved oxygen, provide a good living environment for other organisms, and improve the biodiversity of aquatic ecosystems.

[0062] (1) The submerged plant construction area mainly planted with dwarf Vallisneria, whorled Hydrilla verticillata, Potamogeton malaise, Myriophyllum spicatum, Mimosa pudica, and Potamogeton bamboo.

[0063] (2) Emergent plants are mainly planted in the aquatic plant construction area, including reeds, cattails, pickerelweed, reed shoots and water lilies.

[0064] Cultivation of submerged plants Submerged plants provide aquatic animals with more habitats and shelters, increase dissolved oxygen in the water, purify the water, and expand the effective living space for aquatic animals. Furthermore, the tender parts of submerged plants can be consumed by aquatic animals, thus improving the entire aquatic ecosystem. There are several methods for cultivating submerged plants: (1) Fork planting method A bamboo or wooden pole with a fork at one end is typically used as a tool. During the operation, workers from a boat use the fork to hold the stem of the plant and thrust it into the water. This method is suitable for clump-forming submerged plants, such as *Hydrilla verticillata* and *Myriophyllum spicatum*, or for planting multiple single plants, such as bundling 5 to 6 plants of *Vallisneria natans* or *Potamogeton malaise* together before planting. Applicable to: water systems with soft bottom mud greater than 10cm and water depths of 0.5 to 2.0m or even deeper (for water depths less than 0.5m, workers can plant directly. Beyond 0.5m, where hands are not long enough, tools are needed).

[0065] (2) Throwing method Direct throwing method: Plants such as floating-leaf pondweed, bamboo-leaf pondweed, and whorled-leaf hydrangea can be thrown directly into the water. This method is suitable for still water bodies but not for flowing water bodies. After several days, these plants will naturally sink to the bottom, take root, and sprout new shoots.

[0066] Wrapping with non-woven fabric: Wrap the planting soil and plant roots with non-woven fabric and throw it into the water. The plant will initially grow using the planting soil inside the wrapping. This method is suitable for aquatic systems with mortar-lined bottoms or no soft bottom mud, for single submerged plants, and for submerged plants propagated by cuttings due to a shortage of seedlings, such as Hydrilla verticillata, Myriophyllum spicatum, and Potamogeton crispus. It does not have requirements on water depth.

[0067] (3) Other methods Container seedling cultivation: If the water in the planting area is not transparent enough or if immediate results are desired after planting, submerged plants can be first planted in nutrient pots to cultivate taller plants before planting. Other methods include suspended bag cultivation and submerged bag cultivation.

[0068] (4) Vegetation arrangement for the restoration of submerged plants The submerged plant landscape effect of *Hydrilla verticillata*, *Vallisneria natans*, and *Myriophyllum spicatum* is shown in the figure: 3.10.2 Cultivation of Emergent Plants Emergent plants are mostly perennial herbaceous plants with numerous varieties. Their growing season is from March to November, with the peak growth period concentrated from April to September. They have a strong sprouting ability, so transplanting can be done from March to November. When planting, emergent plants should be buried 3-7 cm deep, ensuring the plant is stable and the roots are fully in the soil. Planting too deep will hinder sprouting and affect the survival rate. The suitable water depth for planting emergent plants is 3-5 cm. To promote new plant growth, a water management method of alternating wet and dry periods is often used, i.e., watering and allowing the soil to dry naturally before watering again. As new plants sprout and grow, the water level should be gradually increased, with 10-15 cm being most suitable during the vigorous growth period. The initial maintenance water level is around 5-10 cm, and once the plant recovers, a normal maintenance water level of 20-30 cm can be maintained. For pest and disease control, the main pest during the growth period of emergent plants is aphids, which are concentrated in the rainy and humid season. They mainly damage the tender buds and leaves of emergent plants. A foliar spray of 45% dimethoate emulsion at a dilution of 500-800 times can be used to control them.

[0069] 1. Select suitable varieties: Choose aquatic plant varieties that are suitable for the local climate and water conditions to ensure that they can grow well.

[0070] 2. Substrate selection: A suitable substrate is required, such as soil or mixture suitable for the growth of aquatic plants.

[0071] 3. Planting: Gently bury the roots of the aquatic plant in the substrate soil, and then gently press to stabilize the plant.

[0072] 4. Prevent pollution: Regularly inspect and maintain water quality to ensure that the water source is not polluted by external water bodies and to prevent water containing chemical substances from seeping into the water body and damaging plant growth.

[0073] 5. Regular maintenance: Regularly prune and clean aquatic plants, remove dead leaves and excessive weeds, and prevent excessive algae growth to ensure the shape and growth of aquatic plants.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it; although the present invention has been described in detail with reference to preferred embodiments, the scope of the invention is not limited to this. Those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solution claimed in the present invention.

Claims

1. A method for river ecological restoration based on constructing an ecological island, characterized in that, The method specifically comprises the following steps: S1, bank protection pile construction, installing the bank protection pile along the trend of the river, after the bank protection pile is completed, the ecological island planting pile construction is performed; S2, according to the construction drawing, the pile foundation construction is performed through the floating ship to arrange the pile foundation equipment at the lake or the river to perform the pile foundation construction of the ecological island planting pile; S3, before the pile driving construction, the measurement control baseline and the baseline point are reviewed, and the pile driving construction baseline is laid out; the pile foundation construction of multiple ecological island planting piles is completed through the pile driving equipment; S4, ecological island earthwork backfilling, after the pile foundation construction of the ecological island planting pile is completed, the steel pipe pile is installed around the ecological island planting pile, and the geotextile is laid on the inner side of the steel pipe pile to prevent the river water from entering the ecological island planting pile; the earthwork is backfilled into the ecological island planting pile; and the ecological island is constructed; S5, after the ecological island construction is completed, the plant in the island is planted to complete the construction of the ecological island; S6, river dredging and water quality regulation, according to the river flow direction, the river bottom silt is cleaned from the upstream to the downstream through the floating ship; S7, ecological soft enclosure construction, the river area is separated and blocked through the ecological soft enclosure for water quality regulation treatment, and the river ecological restoration is completed.

2. The method for river ecological restoration based on the construction of ecological islands according to claim 1, characterized in that, When the bank protection pile is constructed along the two banks of the river, the bank protection piles on the two banks of the river are staggered.

3. The method for river ecological restoration based on the construction of ecological islands according to claim 1, characterized in that, When the ecological island planting pile is driven, the pile position deviation of the ecological island planting pile is less than or equal to D / 6-D / 4, and the pile position verticality tolerance is less than 1%; the pile driving verticality is cross-checked and controlled through the total station and the theodolite, and the leveling instrument controls the pile driving elevation.

4. The method for river ecological restoration based on the construction of ecological islands according to claim 3, characterized in that, The ecological island planting pile driving specifically comprises the following steps: the planting pile is transported to the water operation floating ship through the crane; before the construction, a theodolite is arranged on the pile arrangement center line at a distance of about 25m from the construction pile position, the center line is used as the angle observation direction, the verticality of the pile is observed, the verticality is ensured, and the pile arrangement center position is prevented from exceeding the axis position; another theodolite is arranged at a position forming about 90° with the first theodolite and the pile position to check the verticality deviation; the first planting pile is hoisted and inserted into the arranged pile position in the ground, and is inserted into the soil by 30-50cm, the verticality is corrected using the theodolite after the insertion is stable, the pile is driven after the verticality of the pile meets the specification requirements, and the construction of the planting pile is completed.

5. The method for river ecological restoration based on the construction of ecological islands according to claim 1, characterized in that, The ecological island planting pile construction body specifically comprises the following steps: an enclosed area is formed by the ecological island planting pile according to the construction drawing, after the installation of the ecological island planting pile is completed, the island is built by filling the soil into the ecological island planting pile, the steel pipe pile is installed around the ecological island planting pile, the double-layer anti-seepage geomembrane is laid between the steel pipe pile and the ecological island planting pile and is filled and rammed, the soil is filled and rammed between the steel pipe pile and the ecological island planting pile, the river water is prevented from entering the ecological island planting pile, the ecological island pipe well is strongly drained, the vertical pipe well is dug in the middle of the ecological island, the river water in the ecological island is collected into the pipe well, the river water in the pipe well is pumped out to complete the drainage of the ecological island, the pipe well is filled and buried, and the ecological island is constructed.

6. The method for river ecological restoration based on the construction of ecological islands according to claim 5, characterized in that, The ecological island comprises a emergent zone and a submerged zone, the emergent zone is connected with the river bank on one side, the submerged zone is on the other side of the emergent zone, a partition is arranged between the emergent zone and the submerged zone, the emergent zone is separated from the submerged zone by planting piles, a coconut fiber vegetation mat is laid in the emergent zone, the thickness of the coconut fiber vegetation mat is 5.8-25mm, the coconut fiber vegetation mat extends 20cm into the soil around the coconut fiber vegetation mat, and is fixed by 60cm bamboo nails every 1m; emergent plants are planted in the emergent zone, and submerged plants are planted in the submerged zone.

7. The method for river ecological restoration based on the construction of ecological islands according to claim 6, characterized in that, The coconut fiber vegetation mat comprises coconut fibers and PP nets, and the ratio of the coconut fibers to the PP nets is 4:

1. 8.The method of claim 1, wherein, The ecological soft enclosure comprises a first fixed steel pipe, a second fixed steel pipe, a support pipe, an inclined brace and a soft enclosure, the second fixed pipe is provided with the support pipe at both ends, the support pipe is connected with the second fixed pipe perpendicularly, the first fixed pipe is installed on the support pipe below the second fixed pipe, the first fixed pipe is arranged perpendicularly to the second fixed pipe, the soft enclosure is arranged on the first fixed pipe, a plurality of hooks are arranged on the first fixed pipe, and the first fixed pipe is connected with the soft enclosure through the hooks.

9. The method for river ecological restoration based on the construction of ecological islands according to claim 8, characterized in that, The upper end of the soft enclosure is connected with the first fixed pipe, the lower end of the soft enclosure is provided with a corrugated pipe, the corrugated pipe is arranged parallel to the first fixed pipe, and the corrugated pipe is filled with sand; the inclined brace is arranged between adjacent first fixed pipes, the inclined brace is connected with the first fixed pipe, and the depth of the inclined brace in the soil is greater than 3m; and the angle between the inclined brace and the support pipe is 30°.

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