Construction method of tidal flat siltation promotion and carbon sequestration repair system based on suaeda salsa-tamarix chinensis synergy

Abstract

The invention discloses a construction method of a tidal flat siltation promotion and carbon sequestration restoration system based on suaeda salsa-tamarix chinensis synergy, and belongs to the technical field of coastal zone ecological restoration and blue carbon sink increasing. Aiming at the technical bottlenecks of unbalanced carbon reservoir structure, insufficient engineering-biological synergy and unsmooth activated carbon conversion in the existing tidal flat restoration, the method constructs a'microtopography-vegetation dam-vegetation 'three-level synergy system based on a near-nature solution (NbS); efficient restoration of a tidal flat ecological system is achieved through the core steps of high-precision surveying and mapping and micro-disturbance terrain finishing, soft energy dissipation unit arrangement, suaeda glauca-tamarix chinensis cooperative vegetation configuration, three-order micro-layer base improvement, engineering-biology cooperative siltation promotion and self-adaptive maintenance. The method has ecological benefits and economic feasibility, is suitable for restoration of mucky tidal flat and estuary degraded wetland in a temperate zone sea area, and provides an efficient and sustainable technical scheme for convergence increase of a blue carbon ecological system and ecological protection of a coastal zone.

Description

Technical Field

[0001] This invention relates to the field of coastal ecological restoration and blue carbon ecosystem enhancement technology, and particularly to a tidal flat ecological restoration method based on near-nature-based solutions (NbS). Specifically, it is a tidal flat restoration method that combines soft engineering, synergistic plant configuration, and mild matrix modification to achieve siltation promotion, carbon sequestration, and biodiversity enhancement. Background Technology

[0002] Current tidal flat ecological restoration projects mainly rely on traditional engineering methods, including large-scale topographic modification and rigid revetment structures. These methods present three main problems: First, they often cause severe biological disturbance. Large-scale engineering activities drastically disrupt the original hydrological connectivity and geomorphological patterns of the tidal flat, hindering the natural succession process of the ecosystem. Second, they are often costly and result in habitat fragmentation. The rigid structures used in large-scale restoration projects are expensive and easily lead to habitat fragmentation, adversely affecting benthic communities. Third, although such measures can stabilize the tidal flat topography in the short term, their ecological benefits are often limited, making it difficult to achieve sustainable systemic restoration and effective enhancement of carbon sequestration functions. While rigid structures can reduce tidal velocity by 40%–50%, they cause a decline in benthic biodiversity and block carbon exchange channels between sediment and plants.

[0003] The three major technical bottlenecks faced by existing technologies in blue carbon remediation: In existing tidal flat remediation practices, the following core technical bottlenecks exist in improving carbon sequestration efficiency and maintaining system stability.

[0004] (1) Defects in carbon pool structure caused by monoculture planting patterns. Current remediation methods mostly rely on monoculture planting patterns, resulting in an imbalance in the vertical distribution of soil carbon pools. Shallow carbon sequestration is easily lost. For example, the annual carbon sequestration of shallow-rooted herbs such as Suaeda salsa is concentrated in the 0-30cm shallow layer, and this part of organic carbon is easily washed away by tides, with an annual loss rate as high as 8%-10%. Deep carbon sequestration is difficult to stabilize. For example, the surface cover of deep-rooted shrubs such as Tamarix chinensis is low, and the shallow carbon storage is limited. This extreme state of "easy loss of shallow carbon sequestration" or "difficult stabilization of deep carbon sequestration" seriously restricts the overall carbon sequestration efficiency.

[0005] (2) Insufficient synergy between engineering and biological measures. In current practice, there is a lack of effective synergy between engineering and biological measures. Hard structures hinder carbon exchange, while pure biological measures, without engineering protection, result in a 60%-70% decrease in vegetation erosion resistance, exacerbating tidal erosion and resuspension release of surface organic carbon. Ultimately, this leads to a serious disconnect between engineering erosion prevention measures and the enhancement of carbon sequestration function.

[0006] (3) The organic carbon transformation pathway is not smooth. Existing technologies have failed to construct a mechanism for the efficient conversion of active carbon into stable carbon. The decomposition cycle of plant litter generated after remediation is long and the mineralization release rate is high, resulting in a large amount of organic carbon existing in an unstable and easily decomposable form. The lack of a long-term stable humic carbon pool supports the system and limits the carbon sequestration efficiency and sustainability of the system.

[0007] In summary, existing tidal flat restoration technologies have failed to achieve a balanced distribution of organic carbon in the soil profile, lack an engineering-biological synergistic mechanism that simultaneously enhances siltation promotion and carbon sequestration stability, and in particular, have failed to establish an efficient active carbon-stable carbon conversion pathway, ultimately limiting the comprehensive service functions of blue carbon ecosystems. Summary of the Invention

[0008] The purpose of this invention is to provide a tidal flat restoration method based on near-natural solutions (NbS). This method aims to avoid large-scale topographic modification and hard engineering interventions by employing small-scale biodegradable materials and a Tamarix-Suaeda salsa composite community to construct a three-tiered synergistic system of "micro-topography-vegetated dams-vegetation," thereby achieving multiple ecological benefits such as promoting siltation and carbon sequestration, improving soil physicochemical properties, and increasing vegetation cover. It aims to fundamentally solve the bottlenecks in existing technologies, including carbon pool structure imbalance, failure of engineering-biological synergy, and the difficulty in converting active carbon into stable carbon.

[0009] The technical solution of the present invention includes the following steps:

[0010] A method for constructing a tidal flat siltation and carbon sequestration remediation system based on the synergistic effect of Suaeda salsa and Tamarix chinensis includes the following steps:

[0011] (1) High-precision mapping and micro-disturbance terrain correction

[0012] First, the beach surface is mapped with a horizontal accuracy of ±5cm and an elevation accuracy of ±3cm using RTK-GNSS or UAV LiDAR, generating a 1:200 digital topographic map. Based on this, the natural tidal channel network is identified and converted into vector centerlines to ensure that subsequent deployment does not disrupt the original hydrological connectivity. Only locally scoured deep channels (elevation difference > 0.3m and area < 50m²) are addressed. 2 Implement micro-filling and micro-excavation, with a single disturbance area ≤10%, and record the earthwork balance sheet as the basis for acceptance.

[0013] (2) Layout of flexible energy dissipation units

[0014] Along both sides of the tidal channel, in the exposed low-tide zone (0-1.5m horizontally from the channel edge, elevation between -0.2 and 0.1m from the average high tide level), PLA / PCL blended fiber woven bags were laid out. The bags were filled with undisturbed mud, with a trapezoidal cross-section, a top width of 0.5m, a height of 0.3m, a side slope of 1:3, and a center-to-center spacing of 15m (±2m), arranged in a "V" shape or a "staggered strip" pattern. On-site ADV measurements showed that after placement, the peak tidal velocity was reduced by 30-50%, and the bags maintained ≥80% strength within 24 months and were completely degraded within 36 months, requiring no recycling.

[0015] (3) Vegetation synergistic configuration and seed pretreatment

[0016] To achieve balanced carbon enrichment in both the 0-30cm and 30-100cm soil layers, this system constructs a binary composite community of "deep root framework + shallow root pioneer," replacing the traditional single-species model with complementary root functional sites.

[0017] 1) Space Configuration

[0018] Tamarix (deep-rooted framework species): planted in holes, with a spacing of 45cm x 45cm (±5cm), hole diameter 6cm, depth 10cm, one plant per hole, forming a 30-100cm root anchoring layer. Suaeda salsa (shallow-rooted pioneer species): broadcast sowing, seeding rate 15kg / ha. -1 (±2kg), row spacing 30cm, covering 0-30cm of surface layer, quickly forming a surface biofilm.

[0019] 2) Seed pretreatment (Suaeda salsa)

[0020] Seawater dormancy breaking: Soak in 5‰ seawater for 18 hours (12-24 hours range) to break seed coat dormancy;

[0021] Hormone-induced germination: Soaking seeds in 0.4% gibberellin solution for 7 hours (6-8 hours range) resulted in a germination rate ≥70%;

[0022] Shoot coating: After being removed from the water, it is mixed with peat moss and water-retaining agent at a volume ratio of 1:3 to form 3mm shooting coating, which can achieve no drifting during aerial seeding and no agglomeration during hill seeding.

[0023] (4) Improvement of the “three-layer microlayer” substrate

[0024] To improve the survival rate of transplanted plants and simultaneously enhance the soil's water retention, fertilizer retention, and carbon sequestration functions, this method adopts a "three-stage micro-layer" lightweight improvement strategy, avoiding large-scale soil replacement or chemical input.

[0025] 1) Straw-Biochar Reverse Filter Microlayer

[0026] A 4cm±1cm thick layer of straw segments (5-8cm in length) is laid at the bottom of the planting hole and mixed with 3% (w / w) biochar powder. This layer forms a pore water retention zone of ≥12h, which promotes the conversion of activated carbon into humus and intercepts leached salts. The annual reduction of total salt content in the 0-20cm layer is ≥20%.

[0027] 2) Biodegradable fiber covering layer

[0028] The surface density of the filter layer is 50 g m³. -2 A natural or biodegradable fiber web with a pore size of 3mm; the "micro-arch" effect of the mesh reduces evaporation by 15% and provides lateral anchoring points for the root system; the strength retention rate is ≥80% within 3 months; it is completely degraded within 24 months and does not require recycling.

[0029] 3) Salinity-slow-release drip irrigation layer

[0030] Within 3-7 days after transplanting, strip drip irrigation is carried out using fresh water with a salinity of ≤2‰ or slightly saline water, with a daily irrigation volume of 7mm±2mm. The irrigation water seeps down along the preferential channels of the mesh to form a 0-10cm low-salt moist front, which significantly improves the seedling survival rate and irrigation water utilization rate.

[0031] (5) Engineering-biological synergistic sludge-promoting mechanism

[0032] The system achieves simultaneous instantaneous energy dissipation and continuous siltation through a three-level coupling of "micro-topography-vegetated dam-vegetation", solving the pain points of traditional "hard dams do not increase carbon and purely biological dams are not resistant to erosion".

[0033] 1) Engineering-biological synchronous energy dissipation

[0034] The soft dam (PLA / PCL bag) reduces the peak flow velocity by 30-50%, providing a 0.3m high micro-platform for planting and preventing seedlings from being directly pulled up by the peak shear. The dam body has a degradation cycle of 24-36 months, and the strength decay curve overlaps with the root shear growth curve for ≥60% of the time, ensuring a seamless transition from "weak dam to strong roots".

[0035] 2) Complementary root function sites promote siltation

[0036] The deep roots (30-100cm) of Tamarix provide ≥4.8kPa of root-soil composite shear strength, controlling ditch wall collapse; the shallow roots (0-3cm) of Suaeda salsa + surface biofilm increase the near-bed surface settlement efficiency by 25%, with an annual elevation of 3-4cm.

[0037] (6) Adaptive maintenance and self-sustaining strategies

[0038] Establish a closed loop of "data triggering - threshold response - material self-degradation" to achieve zero human disturbance after 3 years:

[0039] 1) Data-driven decision making

[0040] Drone multispectral NDVI + visible light AI recognition, once a month;

[0041] Triggering conditions: NDVI < 0.25 and two consecutive monitoring areas > 5m² 2 Or, the percentage of bare spots is greater than 10%.

[0042] 2) Graded replanting

[0043] Years 1-2: Replant once each in spring and autumn, with a replanting density equal to 100% of the designed density;

[0044] From the third year onwards: only sparse replanting is done on patches with NDVI < 0.35, with the density reduced to 30-50%, and the workload reduced by 70%.

[0045] 3) Material self-degradation and long-term stability

[0046] The dam body and fiber mesh completely degrade within 24-36 months, with a C / N ratio of 25:1 in the degraded debris, which can be directly included in the soil carbon pool; continuous monitoring for 3 years meets the standards (coverage ≥60%, deposition rate ≥5 mm / a). -1 Erosion amount ≤3mm a -1 This means that the system has entered a self-sustaining state and manual intervention has ceased.

[0047] The beneficial effects of this invention are as follows:

[0048] Compared with existing technologies, the present invention adopts a near-natural solution (NbS) to construct a tidal flat restoration system, which has the following significant advantages: (1) Hydrological and topographic protection. Topographic disturbance is significantly reduced, the original tidal channel network is completely preserved, and the water-sediment connectivity is not damaged. The system continuously reduces the peak flow velocity of the high tide by more than 45% through the dual energy dissipation of the platform slope and the ridge-shaped vegetation dam; (2) Structural stability and erosion resistance. The biodegradable soft energy dissipation structure and the biodam work together to improve the stability of the beach surface and reduce the amount of gully wall erosion; (3) Siltation and soil stabilization and salinity regulation: The beach surface is silted up year by year, and each vegetation dam can raise the beach surface by more than 3cm per year. At the same time, the annual reduction of total salt content in the 0-20cm soil layer can reach more than 20%, which effectively alleviates the problem of tidal flat salinization; (4) Vegetation synergy and high survival rate. The straw filter layer combined with the biodegradable fiber network significantly improves the soil water retention capacity during the planting period, so that the initial survival rate of tamarisk reaches a high level, which is significantly better than the untreated control. The complex community achieved a balanced distribution of organic carbon in the soil profile. Attached Figure Description

[0049] This invention constructs a synergistic siltation and restoration system for tidal flats using a unified process of "surveying, design, construction, monitoring, and adaptive management." The core of this system architecture lies in the five-level synergy of micro-topography adaptation, soft energy dissipation structures, synergistic vegetation configuration, substrate improvement and planting, and adaptive maintenance, aiming to achieve efficient siltation promotion, carbon sequestration, and enhanced ecosystem stability.

[0050] Figures 1 to 3 The key technical aspects and architecture of the system construction method of this invention are demonstrated.

[0051] Figure 1 This diagram illustrates the five-level collaborative architecture of the present invention.

[0052] The diagram visually illustrates the entire repair process from the initial high-precision mapping (1) to the final self-sustaining state of the system, as well as the logical relationships and synergistic effects between each stage, highlighting the integrated and ecological repair concept of this invention.

[0053] Figure 2 This image shows a cross-sectional view of the tidal flat restoration system of the present invention.

[0054] The figure details the layered design of the system structure in the vertical direction, including the soft energy dissipation dam (PLA / PCL) at the top and the "three-layer micro-layer" composite substrate at the bottom (straw-biochar reverse filter micro-layer, biodegradable fiber mesh covering layer, etc.), highlighting the key roles of structural engineering protection, substrate improvement and planting, and salinity regulation.

[0055] Figure 3 This diagram illustrates the adaptive maintenance NDVI decision-making process of the present invention.

[0056] This flowchart details how the system utilizes multispectral NDVI monitoring data from drones, combined with preset thresholds, to intelligently trigger maintenance measures such as replanting, thereby achieving low-cost, self-sustaining management of the restoration system. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the construction method of the "tidal flat alkali grass-tamarisk synergistic siltation and restoration system" will now be fully described in conjunction with the accompanying drawings.

[0058] A method for constructing a tidal flat siltation and carbon sequestration remediation system based on the synergistic effect of Suaeda salsa and Tamarix chinensis includes the following steps:

[0059] 1. Construction Preparation

[0060] Equipment: 0.8m 3 Amphibious excavators, RTK-GNSS, handheld hole diggers, and straw crushers.

[0061] Materials: 1200 tamarisk cuttings (55-65cm tall, diameter at ground level ≥0.6cm), 15kg of Suaeda salsa seeds, 400m of hemp fiber netting 2 (2m width, 0.8cm mesh), 0.8m of rice straw 3 0.4m of reed stalks 3 (Crushed on-site to 5-8cm pieces).

[0062] 2. Micro-topography layout and land preparation

[0063] Elevation control. A 5m×5m grid was laid out using RTK-GNSS, and the overall slope of the repair platform was set to 0.4% (i.e., a height difference of 2cm every 5m).

[0064] Tidal ditch excavation. Lines were drawn on both sides of the centerline to determine the ditch bottom width (0.8m), depth (0.4m), and slope ratio (1:3). The excavated tidal flat soil was piled on the outer edge of the ditch for later reuse in the construction of vegetation dams.

[0065] 3. Construction of Vegetated Dams (Soft Energy Dissipation Structures)

[0066] This step corresponds to the construction of the soft energy dissipation structure in this invention.

[0067] (1) Dam site layout. On the inner side of the tidal ditch, 0.3m from the toe of the slope, drive wooden stakes every 1.5m to mark the center line of the vegetation dam.

[0068] (2) Subgrade treatment (reverse filter micro-layer). A 5cm thick layer of straw (rice straw to reed straw volume ratio 2:1) is laid in the strip area (0.6m wide) of the dam foundation and lightly pressed into the ground.

[0069] (3) Bag placement and filling: Place the PLA / PCL blended fiber woven bag above the base bed, and use the cleared beach soil to backfill in layers (15cm per layer) to maintain the porosity of the beach soil at about 45%.

[0070] (4) Structural forming and shaping: A slope plate is used for calibration to form a trapezoidal ridge with a top width of 0.5m (50cm) and a height of 0.3m (30cm). The surface of the bag is manually tamped down to about 2cm to form a slightly rough surface, which is beneficial for the bonding of the hemp fiber web.

[0071] 4. Planting of tamarisk and dam mulching

[0072] (1) Mark the lines on the top of the dam. Arrange the rows with a spacing of 45cm and the plants with a spacing of 45cm. Use a hand-held hole-drilling tool (Φ6cm×10cm deep) to press vertically down to 2cm above the straw layer. The root and stem junction of the cuttings should be 4cm below the dam surface. Complete 120 plants / dam on the same day.

[0073] (2) Dam Covering. Lay hemp fiber netting in the direction of water flow, with an overlap of 10cm, and fix U-shaped bamboo sticks (20cm long) every 0.5m; cut "+" shapes at the corresponding positions of the mesh to bring out the tamarisk stems without breakage.

[0074] 5. Sowing of Suaeda salsa in saline-alkali soil.

[0075] On the morning of the second day after the spring tide (when the water content of the beach is 35%), manual row sowing was carried out with a row spacing of 30cm and a sowing rate of 15kg ha. -1 The platform between the dams and the back slope are fully covered, and the soil is lightly raked and covered with 0.5cm of soil.

[0076] 6. Initial maintenance

[0077] Water each plant thoroughly with fresh water (salinity ≤2‰) before 17:00 on the day of planting, using 1.5L per plant; re-water on the 3rd and 7th days (automatically cancelled during high tide). Check the integrity of the netting and dam body after each low tide, and repair any damage within 2 hours.

[0078] 7. Monitoring and Acceptance

[0079] (1) Monitoring Requirements This remediation system requires systematic monitoring of hydrodynamics, erosion, vegetation, and soil environment to guide management and verify functionality. Velocity measurements must be performed using three sets of propeller current meters at key locations such as the dam crest, between dams, and in the center of the gully. Erosion control effectiveness requires long-term observation of 10 fixed profiles. Vegetation indicators primarily involve statistical analysis of the initial survival rate of *Tamarix chinensis* (30 days) and the seedling density of *Suaeda salsa*. Simultaneously, the monitoring depth for soil improvement effectiveness is 0-20 cm, focusing on tracking the changing trends of total salt content and organic matter content.

[0080] (2) Acceptance requirements

[0081] The system's acceptance criteria are based on the actual functional effects achieved and the verification of its advantages.

[0082] The peak tidal velocity can be reduced by about 45%, effectively reducing hydrodynamic erosion; in the initial stage of operation, the average erosion depth of the ditch wall can be controlled within 3mm (significantly better than the control area); the survival rate of tamarisk can be stabilized at over 70%; and the seedling density of Suaeda salsa can reach 100 plants / m². 2 The above methods enable high-density planting. Soil improvement: The total salt content in the 0-20cm soil layer can be effectively reduced by more than 3g / kg, while the organic matter content increases.

[0083] 8. Post-management

[0084] Replant missing plants in March of the second year; once the hemp netting has completely degraded (autumn of the second year), it does not need to be recycled; from the third year onwards, harvest the above-ground parts of Suaeda salsa every November to remove 2.3 tons of salt. -1 .

[0085] Monitoring has been conducted for three consecutive years and the standards have been met (coverage ≥ 60%, deposition rate ≥ 5 mm a). -1 Erosion amount ≤3mm a -1 This means that the system has entered a self-sustaining state and manual intervention has ceased.

[0086] Through the above steps, the integrated system of "micro-topography-vegetated dam-vegetation" can be constructed within 90 days, realizing multiple functions such as rapid consolidation of beach surface, erosion prevention of gully walls, desalination of salinity and blue carbon sequestration.

[0087] In summary, the technical advantages of this invention are summarized as follows.

[0088] (1) Vertical carbon pool balanced carbon enrichment

[0089] The complementary functional niches between deep and shallow roots ensure that the coefficient of variation of carbon increment in the 0-30cm and 30-100cm soil layers is ≤15%, and the annual carbon sequestration is ≥6tC ha. -1 It breaks through the bottleneck of "shallow layer is easily lost and deep layer is difficult to stabilize" and can be included in CCER transactions in real time.

[0090] (2) Dual synchronous energy dissipation

[0091] The platform's gentle slope (0.4%) and the ridge-shaped vegetation dam (12°) continuously reduced the peak tidal velocity by ≥45%, decreasing the instantaneous shear force from 0.48 kN / m² to 0.26 kN / m². -2 The erosion of the trench wall is ≤3mm a -1 The shore will be stabilized within the year.

[0092] (3) Locally sourced materials with zero external transportation

[0093] The original soil from the ditch wall was mixed with 15% reed stalks and used directly to build the dam. There was no need to purchase soil or discard waste, which reduced the project cost by ≥30% and carbon emissions by 20%.

[0094] (4) Desalination meets the standards during the season

[0095] The combination of straw-biochar reverse filtration microlayer and drip irrigation moistening layer reduces the total salt content in the 0-20cm layer by ≥24% annually, reaching a salinity suitable for plant growth within 90 days, thus solving the bottleneck of salinization.

[0096] (5) Rapidly promotes positive succession of sedimentation

[0097] A single-bar rises the beach surface by 3-4 cm annually, and the sedimentation rate increases from 1 mm / year. -1 Increased to ≥5mm a -1 Positive succession will be achieved within the year.

[0098] (6) High survival rate and self-sustaining

[0099] The combination of a filter layer and a fiber mesh ensures water retention, resulting in an initial survival rate of ≥90% for Tamarix chinensis (compared to 60% for the control group). After 3 years, NDVI-triggered replanting decreases by 70%, and the material is almost completely degraded within 36 months, allowing the system to enter a self-sustaining state with low human intervention.

[0100] (7) Cost-benefit analysis

[0101] The design of this "Tidal Flat Suaeda salsa-Tamarix spp. Synergistic Siltation and Restoration System" aims to achieve a balance between high efficiency and low cost, and its economic model has outstanding advantages.

[0102] 1) Advantages in investment and operating costs

[0103] The system effectively avoids purchasing soil and waste by using locally sourced materials (such as beach soil and reed stalks), saving approximately 30% of engineering material costs (about 45,000 yuan per hectare) compared to traditional soil-purchasing solutions. -1 The total one-time investment was reduced to approximately 10,500 yuan. -1 .

[0104] Operating costs are extremely low; maintenance becomes negligible after 3 years once it becomes self-sustaining; and the total operating cost over 30 years is only approximately 0.9 million yuan per day. -1 .

[0105] 2) Output and return on investment

[0106] Annual net carbon sequestration is approximately 6 t C·ha -1 (22.0t CO2·ha -1 The annual carbon sequestration revenue is 1320 yuan / ha, and the carbon sequestration revenue will contribute approximately 40,000 yuan·ha over a 30-year period. -1 (Based on the current price of 60 yuan / tCO2), a stable cash flow is formed.

[0107] Compared to traditional rigid revetments, it saves approximately 90,000 yuan in maintenance costs. -1 (Including two reinforcements within 30 years), which constitutes a significant economic benefit.

[0108] The static payback period is approximately 4 years; the net present value over 30 years reaches 80,000 yuan. -1 With an internal rate of return of approximately 15%, it demonstrates significant economic sustainability.

[0109] Adaptation Notes

[0110] This invention is applicable to silty tidal flats and estuaries in temperate seas, and is especially suitable for degraded coastal wetlands with salinity of 10–25‰. Exceeding this limit will result in reduced benefits or a shift to a high-cost model.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a Suaeda- Tamarix synergistic tidal flat siltation-promoting carbon sequestration restoration system, characterized in that, The system includes the following steps: (1) High-precision mapping and micro-disturbance topographic modification First, use RTK-GNSS or unmanned aerial vehicle LiDAR to map the beach surface with a precision of ±5 cm in plane and ±3 cm in elevation, and generate a 1:200 digital topographic map. According to this, identify the natural network of tidal ditches and convert it to a vector center line to ensure that subsequent layout does not damage the original hydrological connectivity. Only implement micro-filling and micro-digging in local scouring deep channels, with a single disturbance area of ≤10%, and record the earthwork balance table as the basis for acceptance; (2) Soft energy dissipation unit layout Along the both sides of the tidal ditch, the exposed belt during ebb tide is arranged in a "herringbone" or "banded staggered" manner; Through on-site ADV measurement, the peak flow velocity is reduced by 30-50% after layout, and the strength retention rate of the bag is ≥80% within 24 months, and it is completely degraded within 36 months without the need for recycling; (3) Vegetation collaborative configuration and seed pretreatment To achieve "double reservoir equalization carbon increase" in 0-30 cm and 30-100 cm soil layers, the system constructs a "deep root framework + shallow root pioneer" dual composite community to replace the traditional single species model by complementary root function sites. 1) Spatial configuration Tamarix chinensis deep-rooted frame planting, hole planting, plant spacing 45cm×45cm, hole diameter 6cm, depth 10cm, one plant per hole, forming a 30-100cm root anchoring layer; Suaeda salsa shallow-rooted pioneer seeding, broadcast sowing, seeding rate 15kg ha -1 With a row spacing of 30cm, it covers a surface layer of 0-30cm and quickly forms a biofilm on the ground. 2) Seed pretreatment - Suaeda salsa Seawater breaking dormancy: soak in 5‰ seawater for 12-24 hours to break seed coat dormancy; Hormone promotes germination: soak in 0.4% gibberellin solution for 6-8 hours, with a germination rate of ≥70%; Marum coat: after being taken out, mix with peat and water-retaining agent at a volume ratio of 1:3 to make 3mm marum coat, realizing no drift in aerial seeding and no aggregation in hole seeding; (4) "Three-step micro-layer" base improvement To improve the survival rate of planting and simultaneously improve the soil water-retaining, fertilizer-retaining and carbon-fixing functions, the "three-step micro-layer" light improvement strategy is adopted to avoid large-scale guest soil or chemical investment. 1) Straw-biochar inverse filtration micro-layer Lay 4cm±1cm thick straw section at the bottom of the planting hole, with a length of 5-8cm, and mix with 3%(w / w) biochar powder; this layer forms a ≥12h pore water retention zone, promoting the conversion of active carbon to humus, while intercepting leached salt, with a 0-20cm total salt content annual decrease of ≥20%; 2) Biodegradable fiber cover layer Infiltration layer surface coverage density 50 g m -2 Natural or biodegradable fiber mesh with 3 mm pore size; mesh "micro-arch" effect reduces evaporation by 15% and provides lateral anchoring points for root systems, strength retention ≥ 80% for 3 months, complete degradation in 24 months without the need for recovery; 3) Salinity release drip irrigation layer Within 3-7 days after planting, use salt content ≤2‰ fresh water or desalination slightly salty water for strip drip irrigation, with a daily irrigation water volume of 7mm±2mm; the irrigation water infiltrates along the net hole preferential channel, forming a 0-10cm low-salt wet front, significantly improving seedling survival rate and irrigation water use efficiency; (5) Engineering-biological synergistic siltation mechanism The system realizes instantaneous energy dissipation and continuous siltation promotion simultaneously through three-level coupling of "micro-topography-vegetation dam-vegetation"; 1) Engineering-biological synchronous energy dissipation Soft dam (PLA / PCL bag) reduces peak flow velocity by 30-50%, providing a 0.3m high micro-platform for planting, avoiding direct uprooting of seedlings by peak shear; the dam degradation period is 24-36 months, and the strength decay curve overlaps with the root shear resistance growth curve for ≥60% of the time, ensuring "weak dam and strong root" seamless transition; 2) Root function site complementary siltation promotion Tamarix deep roots 30-100cm, providing ≥4.8kPa root-soil combined shear strength to control ditch wall collapse; Suaeda salsa shallow roots 0-3cm, forming a surface biological membrane, increasing near-bed surface sedimentation efficiency by 25%, lifting 3-4cm per year; (6) Adaptive maintenance and self-sustaining strategy Establish a "data trigger-threshold response-material self-degradation" closed loop: 1) Data-driven decision making Unmanned aerial vehicle multispectral NDVI + visible light AI recognition, once a month; Trigger condition: NDVI < 0.25 and area of consecutive 2 times monitoring > 5m 2 or the bare spot rate > 10%; 2) Grading reseeding 1st-2nd year: each spring and autumn, reseeding density = 100% of design density; From the 3rd year: only for NDVI <0.35 patch sparse reseeding, density reduced to 30-50%, workload decreased by 70%; 3) Material self-degradation and long-term stability Dam body, fiber mesh 24-36 months complete degradation, degradation debris C / N ratio 25:1, can be directly included in the soil carbon pool; Continuous 3 years of monitoring meet the standards, data qualified into self-sustaining state, stop artificial intervention.

2. The method according to claim 1, wherein the method is characterized in that, In step (2), the ebb bare zone on both sides of the tidal creek, 0-1.5m from the edge of the horizontal distance, elevation between the average high tide high tide-0.2~0.1m, PLA / PCL blended fiber woven bag is laid out; The bag is filled with undisturbed beach mud, the trapezoidal cross section is 0.5m wide at the top, 0.3m high, and the slope is 1:3, with a center-to-center distance of 15±2m.

3. The method according to claim 1, wherein the method is characterized in that, The monitoring is conducted for 3 consecutive years, the coverage is ≥60%, and the deposition rate is ≥5mm a -1 The erosion amount is ≤3mm a -1 That is, it is determined to enter a self-sustaining state, and artificial intervention is stopped.

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