Hydrological process regulation-based degraded wetland near-natural recovery method and system

Abstract

The invention discloses a degraded wetland near-natural restoration method and system based on hydrological process regulation and control, relates to the technical field of wetland ecological restoration, and provides the following scheme: the method comprises the following steps: S1, investigating and accurately diagnosing the current situation of a degraded wetland; s2, constructing and implementing a hydrological process dynamic regulation and control system; s3, implementing collaborative remediation measures; s4, performing dynamic monitoring and feedback optimization; and S5, later maintenance and long-term maintenance. According to the method, hydrological process systematic regulation and control are taken as a core, a near-natural restoration concept is fused, wetland multi-element collaborative restoration is realized, regulation and control accuracy is guaranteed through a dynamic monitoring closed-loop mechanism, manual excessive intervention in the whole process is reduced, the problems that traditional natural restoration is low in efficiency and poor in manual restoration stability are solved, and the artificial restoration efficiency is improved. And the restored wetland forms a sustainable near-natural ecological system, so that the restoration effect and the long-term effect of the degraded wetland are greatly improved, and the method is suitable for wetland restoration scenes with different types and different degradation degrees.

Description

Technical Field

[0001] This invention relates to the field of wetland ecological restoration technology, and in particular to a method and system for near-natural restoration of degraded wetlands based on hydrological process regulation. Background Technology

[0002] Wetlands, as important ecosystems on Earth, have irreplaceable ecological functions such as water conservation, water purification, flood control, and biodiversity maintenance. They are a core component of ecologically fragile zones. In recent years, due to human activities (such as water diversion, reclamation, and sewage discharge) and natural factors, the global wetland area has continued to shrink. Disruption of hydrological processes has become the core driving factor for wetland degradation. Currently, degraded wetland restoration technologies are mainly divided into two categories: natural restoration and artificial restoration. Natural restoration relies on the wetland's own self-regulation ability and does not require human intervention. However, the restoration cycle is long and the efficiency is low. It is not suitable for moderately and severely degraded wetlands. Artificial restoration often adopts rigid engineering measures (such as artificial dam construction, hardened revetments, and planting of alien species). Although it can change the hydrological conditions of wetlands in the short term, excessive human intervention damages the natural attributes of wetlands. This can easily lead to poor stability and weak self-sustaining capacity of the restored wetland ecosystem, making it difficult to form a sustainable near-natural ecosystem. Furthermore, there are problems such as uncertain restoration effects and the risk of secondary degradation. While some existing wetland restoration methods involve hydrological regulation, they often focus on adjusting single hydrological parameters (such as water level and flow rate), failing to achieve systematic regulation of hydrological processes. Furthermore, they do not fully consider the natural succession patterns of wetlands, and cannot simultaneously address the synergistic restoration of hydrological restoration with vegetation, substrate, and biological communities. Moreover, existing restoration systems lack precise monitoring and dynamic regulation mechanisms, making it difficult to adjust regulation strategies in real time according to the degree of wetland degradation and the restoration process, resulting in poor restoration effects and resource waste. Therefore, developing a near-natural restoration method and system that can achieve systematic regulation of hydrological processes, align with the natural attributes of wetlands, and dynamically adapt to the restoration process is crucial for solving the current challenges of degraded wetland restoration. Summary of the Invention

[0003] The present invention proposes a method and system for near-natural restoration of degraded wetlands based on hydrological process regulation, which solves the above-mentioned shortcomings of the prior art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method and system for near-natural restoration of degraded wetlands based on hydrological process regulation includes the following steps: S1. Survey and precise diagnosis of degraded wetlands: Conduct a comprehensive survey of degraded wetlands to identify wetland types (floodplains, coastal mudflats, marshes, etc.), the extent of degradation, and the degree of degradation; S2. Construction and Implementation of Dynamic Regulation System for Hydrological Processes: Based on the wetland degradation diagnosis results and combined with the natural hydrological rhythm of the wetland, a three-in-one dynamic regulation system for hydrological processes, namely "connectivity restoration + water level regulation + water purification", is constructed. S3. Implementation of Collaborative Restoration Measures: Based on the regulation of hydrological processes, collaborative restoration measures are implemented. Relying on the wetland's own restoration capacity and supplemented by appropriate artificial guidance, the coordinated restoration of "hydrology-vegetation-soil-biology" is achieved, avoiding the limitations of single-element restoration and further consolidating the water purification effect. S4. Dynamic monitoring and feedback optimization: Establish a full-cycle dynamic monitoring system, set up monitoring stations in the core area, buffer zone and surrounding areas of the wetland, and monitor hydrological indicators (water level, flow rate, water quality), vegetation indicators (coverage, biomass, community structure), soil indicators (organic matter, salinity, pollutant content) and biological indicators (species number, habitat distribution) in real time. S5. Post-restoration maintenance and long-term maintenance: After the wetland restoration is implemented, long-term post-restoration maintenance will be carried out to reduce human intervention and rely on the self-repair capacity of the wetland's own ecosystem to achieve long-term stable maintenance. The focus will be on consolidating the water purification effect and ensuring the long-term application effect of water purification technology.

[0005] Furthermore, the S1 focuses on monitoring the following core indicators: (1) Hydrological indicators: including annual precipitation, runoff, groundwater level, seasonal fluctuation range of water level, and hydrological connectivity; (2) Water indicators: Focus on monitoring pH value, dissolved oxygen (DO), chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5), ammonia nitrogen (NH3-N), total nitrogen (TN), total phosphorus (TP), and heavy metal content (such as cadmium, lead, mercury, etc.) to clarify the type and degree of water pollution and provide accurate data for subsequent water purification and regulation. (3) Vegetation indicators: The transect method was used to conduct vegetation surveys. 3-5 transects were set up, and 3 quadrats were randomly set up in each transect. The vegetation species, cover, biomass and density were recorded. The vegetation degradation level (mild, moderate and severe) was classified. Local dominant species (such as sedge, small-leaved sedge, mangrove, etc.) were identified first. The relationship between vegetation degradation and water pollution was analyzed. (4) Soil indicators: soil texture, water content, organic matter content, salinity (especially coastal wetlands), heavy metal content (if pollution exists), and analyze the coupling relationship between soil pollution and water pollution; (5) Biological indicators: species, number, and habitat distribution of birds, amphibians, aquatic organisms, etc., and analyze the relationship between biodiversity decline and water pollution and hydrological disturbance; Based on the survey results and combined with the wetland degradation classification standards, the core causes of wetland degradation were accurately diagnosed (such as insufficient hydrological connectivity, abnormal water level fluctuations, water pollution, and soil salinization). The focus was on clarifying the types and degrees of water pollution and their correlation with other degradation factors, providing a basis for subsequent hydrological regulation, water purification, and coordinated restoration. The degradation classification referenced existing technologies and was optimized in conjunction with hydrological and water body indicators: Mild degradation (basically normal hydrological rhythm, water body meeting or exceeding Class IV surface water standards, vegetation cover 60%–90%, and basically intact soil function); Moderate degradation (disordered hydrological rhythm, water body meeting Class V surface water standards, vegetation cover 30%–60%, and mild soil salinization or impoverishment); Severe degradation (disrupted hydrological connectivity, water body worse than Class V surface water standards, vegetation cover below 30%, severe soil salinization or pollution, and significant decline in biodiversity). The formula for calculating the Wetland Degradation Index (WDI) is as follows: ; in, This is a comprehensive wetland degradation index, with a value range of [0,1]. The closer the value is to 1, the more severe the degradation. Assign weights to each indicator, satisfying The core impact factor in this application is hydrology ( ), water bodies ( ),vegetation( ),soil( ),biology( ); Hydrological degradation index, ; The water pollution index is determined by using a single-factor evaluation method, taking the largest single-factor pollution index among nitrogen and phosphorus, heavy metals, and COD. The vegetation degradation index, ; The soil degradation index, If it is a saline-alkali wetland, replace with ; It is a biological degradation index. .

[0006] Furthermore, the specific measures of the dynamic control system for hydrological processes in S2 are as follows: S21. Hydrological connectivity restoration: For wetlands with disrupted hydrological connectivity, adopt near-natural engineering measures to construct ecological ditches and connecting corridors, demolish unreasonable dikes or set up ecological gates, restore the natural connectivity between the wetland and the surrounding water system (rivers, lakes, etc.), avoid the obstruction of hydrological connectivity by artificial facilities, preserve the original micro-topography of the wetland, enhance the naturalness and stability of hydrological connectivity, promote water circulation, and create favorable conditions for water purification.

[0007] S22. Dynamic Water Level Control: Based on wetland type, degradation level, and seasonal changes, set appropriate water level thresholds (including maximum water level, minimum water level, and fluctuation range). Employ a combination of ecological water replenishment and drainage control to achieve dynamic water level adaptation. For example, during the rainy season, drainage is achieved through ecological gates to prevent wetland flooding. During the dry season, ecological water replenishment (prioritizing natural precipitation and surrounding clean surface water, supplemented by reclaimed water) is used to maintain the minimum water level and ensure the survival needs of vegetation and aquatic organisms. For floodplain wetlands, the natural flood pulse rhythm is simulated to periodically and moderately raise the water level, promoting wetland nutrient cycling, water body renewal, and vegetation renewal. For coastal tidal flat wetlands, water level fluctuations are controlled in conjunction with tidal rhythms to achieve alkali leaching and desalination, improving the soil and water environment. At the same time, water level monitoring sensors are installed to provide real-time feedback of water level data and dynamically adjust control measures.

[0008] S23. Water Purification and Control: For wetlands with water pollution, near-natural purification technologies are employed. Ecological purification units are set up at wetland entrances, connecting corridors, and core areas to reduce the use of artificial chemical purifiers. Through natural processes such as plant absorption, microbial degradation, and soil adsorption, nitrogen, phosphorus, and heavy metal pollutants in the water are removed, improving water quality and providing a favorable hydrological environment for wetland ecosystem restoration. This achieves precise removal of water pollutants, as detailed below: ①Inlet purification unit: Set up aquatic plant community such as reeds, cattails, and calamus to create a vegetation buffer zone, intercept the silt and pollutants brought in by surface runoff, and initially purify the water body; ② Intermediate purification unit: A microbial purification bed is set up and inoculated with degrading microorganisms (such as nitrifying bacteria, denitrifying bacteria, and heavy metal degrading bacteria). Combined with the soil infiltration zone, pollutants such as nitrogen, phosphorus, and heavy metals in the water are removed through microbial degradation and soil adsorption. ③ Core purification unit: Cultivate submerged plants (such as goldfish algae and foxtail algae) and floating plants (such as water lilies and duckweed) in the core area of ​​the wetland to further absorb nutrients and pollutants in the water, improve water quality, and provide a habitat for aquatic organisms, so as to achieve the coordinated promotion of water purification and ecological restoration. The formula for calculating the nitrogen and phosphorus purification efficiency (P) of water is as follows: ; The purification efficiency of nitrogen (total nitrogen / ammonia nitrogen) / phosphorus (total phosphorus) in water bodies is given. A negative result indicates the enrichment of pollutants in the water body. The target pollutant concentration (mg / L) and water flow rate (m³ / s) at the wetland inlet. The target pollutant concentration (mg / L) and water flow rate (m³ / s) at the wetland outlet. The pollutant concentration (mg / L) and inflow rate (m³ / s) at the i-th non-point source pollution input point around the wetland. This refers to the number of non-point source pollution input points around the wetland.

[0009] Further, step S3 includes the following steps: S31. Near-natural vegetation restoration: Prioritize the selection of native dominant wetland species (such as *Caragana korshinskii* and *Spathiphyllum nitidum* in floodplain wetlands, and mangroves and reeds in coastal wetlands), and prioritize plant species that are pollution-resistant and have water purification functions. Use a combination of direct seeding and seedling transplanting. Adjust planting density and planting area according to the degradation level—for mildly degraded wetlands, natural restoration should be the main approach, with replanting only in sparsely vegetated areas; for moderately and severely degraded wetlands, increase replanting appropriately, but avoid high-density artificial planting to preserve space for natural vegetation growth. At the same time, remove non-target invasive species (such as Asteraceae weeds and *Spartina alterniflora*) to reduce the impact of human intervention on the natural evolution of the vegetation community. In addition, combine hydrological regulation and water purification to ensure the water conditions and clean water environment required for vegetation growth, promote the natural succession of the vegetation community, and further enhance the vegetation's ability to purify water. S32. In-situ Soil Improvement: For wetlands with impoverished, salinized, or polluted soil, near-natural improvement methods are adopted to avoid excessive chemical improvement, linking with water purification effects and reducing the secondary impact of soil pollution on water bodies. For impoverished soil areas, well-rotted organic fertilizers and humus (such as medium-granular humic acid urea) are applied to increase soil organic matter content. For salinized soils (especially coastal mudflats), leaching and desalination measures are combined with water level control, along with the planting of salt-tolerant and pollution-resistant plants (such as reeds and tamarisk) to improve soil structure through plant roots, reduce soil salinity, and minimize the impact of soil salt on water bodies. For polluted soils, microbial remediation technology is used, inoculating degrading microorganisms to achieve in-situ degradation of soil pollutants, improve soil fertility and ecological functions, and prevent soil pollutants from migrating to water bodies. The formula for calculating the Soil Salinization Improvement Index (SEI) is as follows: ; SEI represents the soil salinization improvement effect index, with a value range of [0, 100%]. The higher the value, the better the improvement effect. SEI ≥ 80% indicates that the improvement has been achieved. The patent uses the salinity (‰) / pH value of the soil before improvement. The salinity is used for coastal wetlands, while the pH value can be used for inland saline-alkali wetlands. The ratio of soil salinity (‰) to pH value after improvement at time t; The critical value of soil salinity (‰) / pH value suitable for native dominant species in wetlands (suitable salinity for mangroves is ≤1.5‰).

[0010] S33. Habitat Creation: Combining hydrological regulation, water purification, and vegetation restoration, create diverse habitats for organisms, such as shallow water areas, mudflats, shrublands, and herbaceous communities, to provide places for birds, amphibians, and aquatic organisms to forage, inhabit, and reproduce. Establish ecological buffer zones around wetlands to reduce interference from human activities (such as aquaculture, grazing, and sewage discharge), prohibit excessive harvesting, and set a grazing ban period of at least 2 years to protect biodiversity, promote the restoration of the integrity of wetland ecosystems, and further enhance water purification capacity through the metabolic activity of biological communities.

[0011] Furthermore, the real-time monitoring in S4 includes the following core indicators: (1) Water indicators: pH value, dissolved oxygen, chemical oxygen demand, five-day biochemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus, heavy metal content, to monitor the water purification effect in real time, and the monitoring data is used to evaluate the application effectiveness of water purification technology. (2) Hydrological indicators: water level, flow rate, hydrological connectivity, and monitoring of the effectiveness of hydrological regulation; (3) Vegetation indicators: cover, biomass, community structure, to monitor vegetation restoration and vegetation purification effects; (4) Soil indicators: organic matter, salinity, pollutant content, monitoring the soil improvement effect and its impact on water bodies; (5) Biological indicators: species numbers, habitat distribution, and monitoring of the effectiveness of biodiversity restoration; The monitoring frequency is once a month. During the rainy season, the critical period of vegetation growth (such as May to August), and the critical period of water purification, the monitoring frequency is appropriately increased (once every 15 days) to ensure timely capture of water changes and other dynamic indicators. The monitoring data is retained for subsequent effect evaluation. Establish a linkage feedback mechanism between monitoring data and control measures, as well as water purification measures. Input monitoring data into the control model and compare it with the preset restoration targets (such as vegetation coverage ≥80%, water reaching Class III surface water standards, and groundwater level stabilizing within a suitable range). Analyze the reasons for deviations, focusing on deviations in water indicators, and optimize the operating parameters of the water purification unit (such as microbial inoculation amount and vegetation replanting density). At the same time, optimize hydrological control parameters (such as water replenishment amount, water level fluctuation range, and connectivity) and collaborative restoration measures (such as replanting density and soil improvement methods) to achieve the closed-loop requirement of "monitoring-optimization-improvement".

[0012] Furthermore, the specific measures in S5 include the following steps: S51. Regularly clean up invasive species and fallen leaves to avoid clogging hydrological corridors and water purification units, and ensure normal water circulation and water purification functions. S52. Prohibit illegal fishing, aquaculture, grazing, and sewage discharge activities that damage wetlands, and prevent further pollution of water bodies; A comprehensive assessment of wetland restoration effectiveness is conducted annually, focusing on water purification, hydrological regulation, and ecological restoration. Based on the assessment results, fine-tuning of regulation measures and water purification plans is performed to ensure the continued stability of the wetland ecosystem and achieve self-circulation, self-purification, and evolution in a near-natural state.

[0013] A near-natural restoration system for degraded wetlands based on hydrological process regulation, applicable to any of the above-mentioned near-natural restoration methods for degraded wetlands based on hydrological process regulation, comprising a current status investigation and diagnosis module, a hydrological process regulation module, a collaborative restoration module, a dynamic monitoring and feedback module, and a post-construction maintenance and assessment module; The current situation investigation and diagnosis module includes: Data acquisition unit: Composed of various sensors (water level sensor, water quality sensor, soil sensor, vegetation cover sensor), drones, and quadrat survey tools, it is used to collect core indicators of wetland hydrology, vegetation, soil and organisms. Among them, drones are used for large-scale surveys of vegetation cover and habitat distribution, quadrat survey tools are used for precise measurement of vegetation biomass and density, and sensors transmit data to the data processing center in real time. Diagnostic Analysis Unit: Based on the collected data, analyze the degree of wetland degradation and the core causes of degradation. Combined with the preset degradation level standards, generate a diagnostic report, clarify the key directions of hydrological regulation and collaborative restoration, and provide data support for subsequent modules.

[0014] Furthermore, the hydrological process control module includes: Connectivity restoration unit: including ecological ditches, connecting corridors, and ecological gates, used to restore the natural connectivity between the wetland and the surrounding water system. The ecological gates dynamically adjust their opening and closing status according to hydrological data to ensure connectivity while avoiding abnormal water level fluctuations. Water level control unit: includes an ecological water replenishment device, a drainage device, a water level monitoring sensor, and a control controller. The ecological water replenishment device is connected to a natural water source or a reclaimed water source, the drainage device is connected to an ecological ditch, and the control controller automatically controls the operation of the water replenishment and drainage devices based on the water level monitoring data to achieve dynamic water level control that conforms to the natural hydrological rhythm of the wetland. Water purification unit: including aquatic plant purification community, microbial purification bed, and soil infiltration zone, set at wetland entrance, connecting corridor, and core area, removes water pollutants and improves water quality through natural purification process without the need for artificial addition of chemical purification agents.

[0015] Furthermore, the collaborative repair module includes: Vegetation restoration unit: includes seed cultivation device, seedling transplanting tool, and invasive species removal tool, used for the cultivation and replanting of local dominant species, as well as the removal of non-target invasive species, and adjusting the replanting density and area according to the degradation level and vegetation monitoring data; Soil improvement unit: includes an organic fertilizer application device and a microbial inoculation device, used for in-situ soil improvement. Based on soil monitoring data, organic fertilizer is applied precisely and degrading microorganisms are inoculated to avoid excessive chemical improvement. The biological habitat creation unit includes micro-topography shaping tools and buffer zone setting devices, which are used to create diverse biological habitats, set up ecological buffer zones, reduce human activity interference, and protect biodiversity.

[0016] Furthermore, the dynamic monitoring and feedback module includes: Monitoring Unit: Composed of various sensors, drones, and a human survey team, it realizes real-time monitoring of hydrological, vegetation, soil, and biological indicators throughout the entire cycle, and transmits the data to the data processing unit in real time. Data processing unit: Organizes and analyzes monitoring data, compares it with preset recovery targets, identifies data deviations, and generates monitoring reports; Feedback control unit: Based on monitoring reports, automatically or manually optimize the operating parameters of the hydrological control module and the collaborative restoration module to achieve closed-loop operation of "monitoring-analysis-feedback-optimization" and ensure that the restoration process meets the needs of wetland ecology; The post-maintenance and evaluation module includes: Maintenance units: used for later invasive species cleanup, clearing of dead branches and fallen leaves, and control of human activities, reducing human intervention and relying on the wetland's own restoration capabilities to achieve long-term maintenance; Assessment Unit: Conduct a comprehensive assessment of wetland restoration effectiveness annually, combine monitoring data with restoration targets, generate an assessment report, and provide a basis for optimizing subsequent maintenance and control measures.

[0017] Compared with existing technologies, the beneficial effects of this invention are: 1. This invention abandons the single hydrological parameter adjustment mode and constructs a three-in-one dynamic regulation system of "connectivity restoration + water level regulation + water purification". It combines wetland natural hydrology and tidal rhythm to implement regulation, adopts near-natural engineering measures, preserves the original micro-topography, avoids excessive artificial intervention and damage to the natural attributes of wetlands, and solves the problem of poor stability of traditional artificial restoration. 2. Based on hydrological regulation, this invention achieves the coordinated restoration of hydrology, vegetation, soil and organisms. The vegetation restoration prioritizes local purification species, and the soil is improved in situ using near-natural methods. At the same time, diverse habitats are created to avoid the limitations of single-element restoration and to form a positive interaction among the various elements of the ecosystem, thus consolidating the effects of water purification and ecological restoration. 3. This invention establishes a full-cycle, multi-regional monitoring system, which conducts graded and frequency monitoring of core indicators such as hydrology, water bodies, and vegetation, and builds a closed-loop mechanism of "monitoring-analysis-feedback-optimization". It can adjust the control and restoration parameters in real time according to the restoration process, solve the problems of rigidity and poor effect of traditional technical restoration strategies, and improve resource utilization efficiency. 4. This invention reduces the use of chemical reagents and rigid engineering throughout the process, and the later maintenance is mainly based on light intervention. It relies on the wetland's own restoration ability to achieve long-term maintenance, while controlling human destructive activities to prevent secondary pollution and degradation. This allows the restored wetland to form a near-natural ecosystem with self-circulation and self-purification, and has a long-term self-sustaining ability. In summary, this invention takes the systematic regulation of hydrological processes as its core, integrates the concept of near-natural restoration, and achieves the coordinated restoration of multiple elements of wetlands. It ensures the accuracy of regulation through a dynamic monitoring closed-loop mechanism and reduces excessive human intervention throughout the process. This not only solves the pain points of low efficiency of traditional natural restoration and poor stability of artificial restoration, but also allows the restored wetlands to form a sustainable near-natural ecosystem, greatly improving the effectiveness and long-term sustainability of degraded wetland restoration. It is applicable to wetland restoration scenarios of different types and different degrees of degradation. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the method and system steps for near-natural restoration of degraded wetlands based on hydrological process regulation, as proposed in this invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Example 1 Reference Figure 1 Near-natural restoration of degraded floodplain wetlands This embodiment addresses the degraded Caragana-Smallleaf Herbaceous Grass wetland in the western floodplain of the Songnen Plain. Due to upstream water conservancy projects causing damming, the wetland has experienced reduced runoff and decreased hydrological connectivity. Furthermore, it is affected by agricultural non-point source pollution from surrounding areas, resulting in excessive nitrogen and phosphorus levels in the water (ammonia nitrogen 1.8 mg / L, total phosphorus 0.25 mg / L, water quality classified as Class V surface water). Vegetation cover has decreased to 40% (moderate degradation), the soil is slightly impoverished, and biodiversity has declined. The restoration method and system of this invention are employed, with the specific steps as follows: 1. Current Status Survey and Precise Diagnosis: Four transects were established, with three 1.5m × 1.5m quadrats in each transect. The survey found that the coverage of *Caragana korshinskii* was 25%, *Cyclocarya paliurus* was 15%, and other weeds accounted for 60%. The groundwater level was 0.8m lower than the natural state, with seasonal fluctuations of less than 0.5m. The soil organic matter content was 1.2%, indicating slight infertility. The number of bird species was 30% lower than the natural state. Water quality indicators: pH 7.8, dissolved oxygen 5.2mg / L, ammonia nitrogen 1.8mg / L, total phosphorus 0.25mg / L, chemical oxygen demand 35mg / L. The water quality was classified as Class V surface water, with slight nitrogen and phosphorus pollution. The core causes of degradation were diagnosed as insufficient hydrological connectivity, low groundwater levels, abnormal water level fluctuations, and nitrogen and phosphorus pollution in the water, leading to the degradation of the Caragana microphylla-Smallleaf sedge vegetation.

[0022] 2. Dynamic regulation of hydrological processes: ① Connectivity restoration: Construct two ecological ditches (2m wide and 1m deep) to connect the wetland with the surrounding rivers, and set up one ecological gate to restore hydrological connectivity, promote water circulation, and create conditions for water purification; ② Water level regulation: Set an appropriate water level threshold (0.3-0.8m), drain water through ecological gates during the rainy season to avoid waterlogging, and use clean surface water from the surrounding area for ecological water replenishment during the dry season to maintain stable groundwater levels. Simulate the pulse rhythm of natural floods and raise the water level to 0.8m in July each year for 15 days to promote vegetation and water body renewal. ③ Water purification: A reed purification community (50m long and 10m wide) is set up at the entrance of the wetland to intercept sediment and nitrogen and phosphorus pollutants brought by agricultural non-point source pollution. A microbial purification bed is set up in the middle area, inoculated with nitrifying bacteria and denitrifying bacteria, and combined with soil infiltration strips to degrade ammonia nitrogen and total phosphorus in the water. Submerged plants such as goldfish algae and foxtail algae are planted in the core area to further absorb nutrients in the water and achieve graded purification.

[0023] 3. Collaborative remediation measures (joint water purification): ①Vegetation restoration: Replant local sedge and small-leaved sedge seedlings, and at the same time replant reeds, cattails and other vegetation with water purification functions. The replanting density is 50 plants / m². Remove non-target Asteraceae weeds to enhance the vegetation's ability to purify water. ② Soil improvement: Apply medium-particle humic acid urea (total nitrogen ≥46%, humic acid ≥2200mg / kg) at a rate of 90kg / ha. Broadcast before rain in early May each year to increase soil organic matter content and reduce the impact of soil nitrogen and phosphorus loss on water bodies. ③ Habitat creation: Improve wetland micro-topography, create shallow water areas (0.3-0.5m deep) and tidal flats, set up a 100m ecological buffer zone, prohibit grazing and cutting, set a 2-year grazing ban period, protect biodiversity, and further improve water purification through biological community metabolism.

[0024] 4. Dynamic monitoring and feedback optimization (enhanced water quality monitoring): Three monitoring stations are set up in the core area of ​​the wetland to monitor water level, water quality (with ammonia nitrogen, total phosphorus, and chemical oxygen demand) and vegetation cover monthly. Vegetation biomass and water quality indicators are monitored every 15 days. Based on the monitoring data, the amount of water replenishment and the fluctuation range of water level are adjusted. When weeds rebound, they are removed in time. When water quality indicators deviate, microorganisms are added to optimize the vegetation purification community and ensure the water purification effect.

[0025] 5. Post-maintenance and care: Regularly remove dead branches, fallen leaves and invasive weeds to avoid clogging hydrological corridors and water purification units. Assess the restoration effect annually, focusing on the effectiveness of water purification, and fine-tune water replenishment parameters and water purification plans. Results: One year after restoration, the wetland's hydrological connectivity returned to normal, the groundwater level stabilized at 0.3-0.8m, water quality indicators met the Class III surface water standard, ammonia nitrogen content decreased to below 0.5mg / L, total phosphorus content decreased to below 0.1mg / L, and chemical oxygen demand decreased to below 20mg / L, demonstrating significant water purification effects. The coverage of *Caragana korshinskii* increased to 55%, *Cyclocarya paliurus* coverage increased to 25%, total vegetation coverage reached 80%, biomass increased 3.5 times, population density increased 4.8 times, bird species recovered to 90% of their natural state, and the wetland ecosystem achieved self-sustaining operation. The restoration effect was significantly better than existing vegetation-oriented restoration technologies and traditional hydrological regulation technologies.

[0026] Example 2 Near-natural restoration of degraded coastal wetlands (focusing on seawater intrusion and heavy metal pollution control). This embodiment focuses on degraded coastal wetlands in eastern my country. Due to reclamation and development and seawater intrusion, these wetlands have suffered from disrupted hydrological connectivity, soil salinization (salt content 3.5‰), and heavy metal pollution from seawater intrusion (cadmium content 0.12mg / L, lead content 0.35mg / L). The vegetation is dominated by Spartina alterniflora (an invasive species), and the local mangrove vegetation has degraded (coverage less than 20%, severely degraded), resulting in a reduction in aquatic species. The restoration method and system of this invention incorporates heavy metal pollution purification technology, and the specific steps are as follows: 1. Current Status Survey and Precise Diagnosis: Through drone and quadrat surveys, the extent of wetland degradation was identified as 500 mu, mangrove coverage was 18%, and Spartina alterniflora coverage was 65%. The soil salinity is 3.5‰, the groundwater level is 0.2m, hydrological connectivity is disrupted, and seawater intrusion is severe. The number of aquatic species has decreased by 50% compared to their natural state; Water quality indicators: pH value 8.2, dissolved oxygen 4.8 mg / L, cadmium content 0.12 mg / L, lead content 0.35 mg / L, salinity 3.2‰. The water quality is worse than Class V surface water, and there are problems with heavy metal pollution and excessive salinity. The core causes of degradation are: disruption of hydrological connectivity, seawater intrusion leading to soil salinization and heavy metal pollution in the water, and invasive species crowding out the living space of local vegetation.

[0027] 2. Dynamic regulation of hydrological processes (integrated with water purification technology): ① Connectivity restoration: Remove unreasonable reclamation dikes and build three ecological connectivity corridors to connect wetlands and the sea, restore tidal connectivity, promote the exchange of seawater and freshwater, and reduce water salinity and heavy metal concentration; ② Water level regulation: Combined with tidal rhythm, regulate the fluctuation range of water level (0.2-1.0m). During high tide, seawater is introduced appropriately through ecological gates, and excess seawater is discharged during low tide to achieve alkali washing and desalination, reduce soil and water salinity, and replenish fresh water during the dry season to further reduce soil salinization and water salinity. ③ Water purification: Set up microbial purification beds (inoculated with heavy metal degrading bacteria) and reed infiltration belts to degrade heavy metal pollutants such as cadmium and lead in the water and adsorb salt in the water; replant mangroves, reeds and other salt-tolerant and heavy metal-tolerant vegetation in the core area to absorb heavy metals through plant roots and achieve near-natural purification of heavy metal pollution.

[0028] 3. Collaborative remediation measures (joint water purification): ①Vegetation restoration: Remove Spartina alterniflora and replant local mangrove seedlings (Paulownia tomentosa, Kandelia candel), while replanting reeds, tamarisk and other salt-tolerant, heavy metal-tolerant and water-purifying plants with water purification functions. The replanting density is 30 plants / m² to improve vegetation coverage and heavy metal purification capacity. ② Soil improvement: In conjunction with water level leaching and desalination, apply zeolite conditioner to reduce soil salinity and heavy metal content, inoculate with salt-tolerant and heavy metal-tolerant microorganisms to improve soil fertility, reduce the migration of heavy metals from the soil to water bodies, and consolidate the water purification effect. ③ Habitat creation: Create diverse habitats such as shallow water areas, mudflats, and mangrove shrublands, set up ecological buffer zones, prohibit illegal fishing and aquaculture, protect biodiversity, and further degrade heavy metal pollutants through biological community metabolism.

[0029] 4. Dynamic monitoring and feedback optimization (enhanced water quality monitoring): Five monitoring stations are set up to monitor soil salinity, water level, mangrove cover, and aquatic species in real time. The focus is on monitoring key indicators such as the content of heavy metals such as cadmium and lead in the water and salinity. Based on the monitoring data, the tidal connection time and freshwater replenishment amount are adjusted, recurring Spartina alterniflora is removed in a timely manner, heavy metal degrading bacteria are added, and the water purification plan is optimized.

[0030] 5. Post-construction maintenance: Regularly inspect and remove invasive species, and maintain the normal operation of the water purification unit; annually assess the growth status of mangroves, the degree of soil salinization, and the effectiveness of water purification (with a focus on assessing the effect of heavy metal removal), and optimize control measures and water purification plans.

[0031] Results: Two years after restoration, the hydrological connectivity of the wetland was restored, the soil salinity dropped to 1.2‰, and the water quality was significantly improved. Water quality indicators: cadmium content decreased to below 0.01 mg / L, lead content decreased to below 0.05 mg / L, salinity decreased to below 1.0‰, water quality reached the Class IV standard for surface water, heavy metal pollution was effectively controlled, mangrove coverage increased to 65%, local vegetation communities were restored, Spartina alterniflora was effectively controlled, aquatic species were restored to 85% of their natural state, and bird habitat function was restored.

[0032] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for near-natural restoration of degraded wetlands based on hydrological process regulation, characterized in that, Includes the following steps: S1. Survey and precise diagnosis of degraded wetlands: Conduct a comprehensive survey of degraded wetlands to clarify the wetland type, degradation range, and degree of degradation; S2. Construction and Implementation of Dynamic Regulation System for Hydrological Processes: Based on the wetland degradation diagnosis results and combined with the natural hydrological rhythm of the wetland, a three-in-one dynamic regulation system for hydrological processes, namely "connectivity restoration + water level regulation + water purification", is constructed. S3. Implementation of Collaborative Restoration Measures: Based on the regulation of hydrological processes, collaborative restoration measures are implemented, relying on the wetland's own restoration capacity and supplemented by appropriate artificial guidance, to achieve the coordinated restoration of "hydrology-vegetation-soil-biology". S4. Dynamic monitoring and feedback optimization: Establish a full-cycle dynamic monitoring system, set up monitoring stations in the core area, buffer zone and surrounding areas of the wetland, and monitor hydrological indicators, vegetation indicators, soil indicators and biological indicators in real time. S5. Post-restoration maintenance and long-term maintenance: After the wetland restoration is implemented, long-term post-restoration maintenance should be carried out to reduce human intervention.

2. The method for near-natural restoration of degraded wetlands based on hydrological process regulation according to claim 1, characterized in that, The S1 system focuses on monitoring the following key indicators: (1) Hydrological indicators: including annual precipitation, runoff, groundwater level, seasonal fluctuation range of water level, and hydrological connectivity; (2) Water indicators: Focus on monitoring pH value, dissolved oxygen, chemical oxygen demand, five-day biochemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus and heavy metal content to clarify the type and degree of water pollution and provide accurate data for subsequent water purification and regulation; (3) Vegetation indicators: The vegetation survey was conducted using the transect-transect method. Three to five transects were set up, and three quadrats were randomly set up in each transect. The vegetation species, cover, biomass and density were recorded, the vegetation degradation level was classified, local dominant species were identified first, and the correlation between vegetation degradation and water pollution was analyzed. (4) Soil indicators: soil texture, water content, organic matter content, salinity, heavy metal content, and analysis of the coupling relationship between soil pollution and water pollution; (5) Biological indicators: species, number, and habitat distribution of birds, amphibians and aquatic organisms, and analysis of the relationship between biodiversity loss and water pollution and hydrological disturbance.

3. The method for near-natural restoration of degraded wetlands based on hydrological process regulation according to claim 1, characterized in that, The specific measures of the dynamic control system for hydrological processes in S2 are as follows: S21. Hydrological Connectivity Restoration: For wetlands with disrupted hydrological connectivity, near-natural engineering measures are adopted to construct ecological ditches and connecting corridors, remove unreasonable dams or set up ecological gates, restore the natural connectivity between the wetland and the surrounding water system, avoid artificial facilities from blocking hydrological connectivity, preserve the original micro-topography of the wetland, enhance the naturalness and stability of hydrological connectivity, promote water circulation, and create favorable conditions for water purification. S22. Dynamic water level control: Based on wetland type, degradation level and seasonal changes, set appropriate water level thresholds and adopt a combination of ecological water replenishment and drainage control to achieve dynamic water level adaptation. S23. Water Purification and Regulation: For wetlands with water pollution, near-natural purification technology is adopted. Ecological purification units are set up at wetland entrances, connecting corridors, and core areas to reduce the use of artificial chemical purifiers. Through natural processes such as plant absorption, microbial degradation, and soil adsorption, nitrogen, phosphorus, and heavy metal pollutants in the water are removed, improving water quality and providing a good hydrological environment for the restoration of the wetland ecosystem, thus achieving precise removal of water pollutants.

4. The method for near-natural restoration of degraded wetlands based on hydrological process regulation according to claim 1, characterized in that, S3 includes the following steps: S31. Near-natural vegetation restoration: Prioritize the selection of native dominant species in wetlands, and prioritize plant varieties that are pollution-resistant and have water purification functions. Use a combination of direct seeding and seedling transplanting. Adjust planting density and planting area according to the degradation level—for mildly degraded wetlands, natural restoration is the main approach, with replanting only in sparsely vegetated areas; for moderately and severely degraded wetlands, increase replanting appropriately, but avoid high-density artificial planting to preserve space for natural vegetation growth. At the same time, remove non-target invasive species to reduce the impact of human intervention on the natural evolution of vegetation communities. In addition, combine hydrological regulation and water purification to ensure the water conditions and clean water environment required for vegetation growth, promote the natural succession of vegetation communities, and further enhance the vegetation's ability to purify water. S32. In-situ soil improvement: For wetlands with poor soil, salinization, and pollution, near-natural improvement methods are adopted to avoid excessive chemical improvement, link with water purification effects, and reduce the secondary impact of soil pollution on water bodies. S33. Habitat creation: Combining hydrological regulation, water purification and vegetation restoration, create diverse habitats for birds, amphibians and aquatic organisms to forage, inhabit and reproduce.

5. The method for near-natural restoration of degraded wetlands based on hydrological process regulation according to claim 1, characterized in that, The real-time monitoring in S4 includes the following core indicators: (1) Water indicators: pH value, dissolved oxygen, chemical oxygen demand, five-day biochemical oxygen demand, ammonia nitrogen, total nitrogen, total phosphorus, heavy metal content, to monitor the water purification effect in real time, and the monitoring data is used to evaluate the application effectiveness of water purification technology. (2) Hydrological indicators: water level, flow rate, hydrological connectivity, and monitoring of the effectiveness of hydrological regulation; (3) Vegetation indicators: cover, biomass, community structure, to monitor vegetation restoration and vegetation purification effects; (4) Soil indicators: organic matter, salinity, pollutant content, monitoring the soil improvement effect and its impact on water bodies; (5) Biological indicators: species number, habitat distribution, and monitoring of the effect of biodiversity restoration.

6. The method for near-natural restoration of degraded wetlands based on hydrological process regulation according to claim 1, characterized in that, The specific measures in S5 include the following steps: S51. Regularly clean up invasive species and fallen leaves to avoid clogging hydrological corridors and water purification units, and ensure normal water circulation and water purification functions. S52. Illegal fishing, aquaculture, grazing, and sewage discharge are prohibited to prevent human activities that damage wetlands and to prevent further pollution of water bodies.

7. A near-natural restoration system for degraded wetlands based on hydrological process regulation, applicable to the near-natural restoration method for degraded wetlands based on hydrological process regulation described in any one of claims 1-6, characterized in that, It includes modules for current status investigation and diagnosis, hydrological process regulation, collaborative restoration, dynamic monitoring and feedback, and post-construction maintenance and assessment. The current situation investigation and diagnosis module includes: Data acquisition unit: used to collect core indicator data of wetland hydrology, vegetation, soil and biology; Diagnostic Analysis Unit: Based on the collected data, analyze the degree of wetland degradation and the core causes of degradation. Combined with the preset degradation level standards, generate a diagnostic report, clarify the key directions of hydrological regulation and collaborative restoration, and provide data support for subsequent modules.

8. A near-natural restoration system for degraded wetlands based on hydrological process regulation according to claim 7, characterized in that, The hydrological process control module includes: Connectivity restoration unit: including ecological ditches, connecting corridors, and ecological gates, used to restore the natural connectivity between the wetland and the surrounding water system. The ecological gates dynamically adjust their opening and closing status according to hydrological data to ensure connectivity while avoiding abnormal water level fluctuations. Water level control unit: includes an ecological water replenishment device, a drainage device, a water level monitoring sensor, and a control controller. The ecological water replenishment device is connected to a natural water source or a reclaimed water source, the drainage device is connected to an ecological ditch, and the control controller automatically controls the operation of the water replenishment and drainage devices based on the water level monitoring data to achieve dynamic water level control that conforms to the natural hydrological rhythm of the wetland. Water purification unit: including aquatic plant purification community, microbial purification bed, and soil infiltration zone, set at wetland entrance, connecting corridor, and core area, removes water pollutants and improves water quality through natural purification process without the need for artificial addition of chemical purification agents.

9. A near-natural restoration system for degraded wetlands based on hydrological process regulation according to claim 7, characterized in that, The collaborative repair module includes: Vegetation restoration unit: used for the cultivation and replanting of local dominant species, as well as the removal of non-target invasive species. The replanting density and area are adjusted according to the degradation level and vegetation monitoring data. Soil amendment unit: Used for in-situ soil improvement, it precisely applies organic fertilizer and inoculates degrading microorganisms based on soil monitoring data, avoiding excessive chemical amendment; Habitat creation units: These are used to create diverse habitats for organisms, establish ecological buffer zones, reduce human disturbance, and protect biodiversity.

10. A near-natural restoration system for degraded wetlands based on hydrological process regulation according to claim 7, characterized in that, The dynamic monitoring and feedback module includes: Monitoring unit: Enables real-time monitoring of hydrological, vegetation, soil, and biological indicators throughout the entire lifecycle, with data transmitted to the data processing unit in real time; Data processing unit: Organizes and analyzes monitoring data, compares it with preset recovery targets, identifies data deviations, and generates monitoring reports; Feedback control unit: Based on monitoring reports, automatically or manually optimize the operating parameters of the hydrological control module and the collaborative restoration module to achieve closed-loop operation of "monitoring-analysis-feedback-optimization" and ensure that the restoration process meets the needs of wetland ecology; The post-maintenance and evaluation module includes: Maintenance units: used for later invasive species cleanup, clearing of dead branches and fallen leaves, and control of human activities, reducing human intervention and relying on the wetland's own restoration capabilities to achieve long-term maintenance; Assessment Unit: Conduct a comprehensive assessment of wetland restoration effectiveness annually, combine monitoring data with restoration targets, generate an assessment report, and provide a basis for optimizing subsequent maintenance and control measures.

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