Lakeside ecological restoration method based on microtopography and vegetation community integration

Abstract

The invention relates to the technical field of water ecological restoration, solves the technical problems that in the prior art, fine design, adaptability and robustness are insufficient, and particularly relates to a lakeside zone ecological restoration method based on microtopography and vegetation community integration. Constructing a lakeside zone water depth and flooding duration pattern, parameterizing a bank slope microtopography by step elevation, width and gradient, and calculating a corrected water depth and a hydrodynamic exposure index by adjusting parameters; introducing a suitability scoring function to establish a functional response model for realizing quantitative matching of the microtopography steps and the vegetation communities; and constructing a comprehensive evaluation function and a robustness index by integrating ecological function indexes under various hydrological scenes, and carrying out joint optimization on microtopography and vegetation configuration. According to the method, the lakeside zone recovery design is converted from experience zoning into a computable and comparable integrated scheme, and the method is suitable for various lakeside zones such as natural gentle slope lakesides and urban hard revetments.

Description

Technical Field

[0001] This invention relates to the field of aquatic ecological restoration technology, and provides a lakeshore ecological restoration method based on the integration of micro-topography and vegetation communities. In particular, it relates to a restoration method that optimizes and reshapes the micro-topography of the lakeshore slope under the conditions of comprehensively considering water level changes, water depth distribution, hydrodynamic effects and target ecological functions, and coordinates the design with the configuration of communities such as submerged plants, floating-leaved plants, emergent plants and shoreline wetland plants. Background Technology

[0002] Lakeshore zones are crucial transitional areas connecting land and water, serving multiple functions including reducing non-point source pollution, buffering wave erosion, maintaining aquatic habitats, and enhancing landscape recreation. At the engineering application level, several patents have explored beneficial approaches to the construction of ecological revetment structures and vegetation belts in lakeshore zones. For example, Chinese invention patent CN106381837B discloses an ecological restoration structure system and method for lakeshore zones. It proposes sequentially arranging tree, shrub, and grass belts, emergent plant belts, and riprap revetment belts along the shoreline towards the lake center. An ecological physical substrate is constructed using Reno mattresses and eco-bags, and flood-tolerant pioneer plants are configured to balance soil and water conservation with landscape restoration, addressing the issue of synergy between aquatic plants and the physical substrate. Correspondingly, the utility models with publication numbers CN206418454U and CN206396706U respectively disclose ecological restoration structures for lakeside areas on gentle slopes and steep slopes, and provide combination forms of trees, shrubs and grasses-emergent plant belts and wave-breaking devices for different slope conditions.

[0003] Meanwhile, some patents focus more on the landscape configuration of riparian plant communities. For example, Chinese invention patent CN107347399B discloses an ecological configuration method for riparian plant landscapes. It proposes dividing the riparian zone into four water level zones: deep water, shallow water, intermittent water, and safe water. It provides a list of selectable plants and mixed configuration patterns for each zone. By leveling the terrain into gentle slopes leading into the water, applying organic fertilizer, and using a combination of gradual mixed planting and sowing, it significantly increases the number of plant species and the ornamental value of the riparian zone. Furthermore, Chinese invention patent CN107347410B discloses a method for constructing multi-habitat three-dimensional vegetation in dike-type lakeshore zones. It proposes classifying dike-type lakeshore zones into multiple habitat types and provides habitat construction patterns and vertical vegetation configuration ideas for different types of water-land transition zones, which is of positive significance for improving the vegetation diversity and spatial structure of lakeshore zones.

[0004] In summary, existing lakeside ecological restoration technologies can be broadly categorized into two types: one focuses on the construction of an ecological revetment system combining "structure + vegetation," enhancing soil and water conservation and landscape effects through a combination of physical base and vegetation zones. However, the design of micro-topography is still primarily based on empirical slopes or simple steps, lacking quantitative methods that finely couple with hydrological and hydrodynamic conditions. The other type focuses on the configuration of plant landscapes based on "zonation + community." Although it considers water level zonation and mixed planting of multiple species, it only proposes general requirements for topographic shaping, without providing steps for determining and optimizing micro-topographic geometric parameters that can guide engineering design. It also lacks quantitative characterization of the response of vegetation communities to environmental factors such as water depth, hydrodynamics, and light, and fails to systematically consider the stability of the scheme under multiple hydrological scenarios such as dry years, normal years, and wet years. Existing technologies generally lack an integrated restoration design method that, within a unified framework, comprehensively considers multi-year water level and depth distribution, lakeside micro-topographic parameters, hydrodynamic exposure, environmental response of vegetation functional groups, and engineering stability and cost constraints, to conduct quantitative evaluation and multi-objective, multi-scenario optimization. This makes it difficult to provide a computable, extrapolable, and comparable tool for the collaborative design of micro-topography and vegetation communities for different types of lakeside areas. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a lakeshore ecological restoration method based on the integration of micro-topography and vegetation communities, solving the technical problems of deficiencies in refined design, adaptability, and robustness in existing technologies. The shortcomings of existing technologies are reflected in the following aspects: The lack of quantitative design basis for micro-topography shaping: existing projects mostly rely on experience to make the banks gentler and more stepped, without systematically converting key hydrological and dynamic information such as multi-year water level processes, water depth distribution and hydrodynamic exposure into calculable design parameters for micro-topography elevation, width, slope and undulation, resulting in insufficient matching between micro-topography and actual water level fluctuations and hydrodynamic conditions.

[0006] The vegetation community configuration is disconnected from the environmental response: existing lakeside vegetation zones are mostly configured according to the empirical zoning of "deep water zone - shallow water zone - intermittent zone" and species list, lacking quantitative response models based on environmental factors such as water depth, hydrodynamics and light, making it difficult to ensure suitable habitats and community stability for submerged plants, floating-leaved plants, emergent plants and wetland herbs under years of fluctuating water levels.

[0007] Lack of integrated optimization of micro-topography, vegetation community, and engineering stability: Existing technologies fail to incorporate ecological functions (such as underwater vegetation continuity and improved transparency), bank slope engineering stability (soil erosion and sliding resistance), and management constraints such as engineering earthwork volume and cost into the quantitative evaluation and multi-scenario optimization process within a unified framework. This makes it difficult for restoration plans to balance ecological benefits and engineering feasibility under different hydrological scenarios such as dry years, normal years, and wet years.

[0008] To address the aforementioned technical problems, this invention, based on extensive hydrological data and current topographic data, achieves quantitative and collaborative design of micro-topographic shaping and vegetation community configuration in lakeshore zones through micro-topographic parameterization, water depth-hydrodynamic exposure analysis, vegetation functional group response modeling, and multi-scenario comprehensive evaluation. This overcomes the shortcomings of existing technologies in terms of refined design, adaptability, and robustness. It transforms lakeshore restoration design from experience-based zoning into a calculable and comparable integrated solution, applicable to various types of lakeshore zones, including naturally sloping lake shores and urban hard revetments. The technical solution proposed in this invention is as follows: To overcome the shortcomings of existing lakeside restoration technologies, such as reliance on experience in micro-topography shaping, disconnect between vegetation configuration and environmental response, and lack of integrated ecological-engineering optimization, this invention proposes a lakeside ecological restoration method based on the integration of micro-topography and vegetation communities. Figure 1 As shown, this method generally includes steps such as basic data acquisition, water depth-hydrodynamic exposure analysis, vegetation functional group environmental response modeling, micro-topography parameterization and correction calculation, multi-scenario comprehensive evaluation and optimization, and integrated restoration design output. The technical solutions for each step are further explained below.

[0009] This invention first obtains multi-year water level sequences of the target lake or river body, as well as topographic data and sediment parameters of the current lakeshore zone, under a unified elevation datum. The multi-year water level sequence is preferably daily or hourly water level observations over a continuous period of no less than 5 years, and further no less than 10 years. This data can reflect the water level fluctuation characteristics of typical dry, normal, and wet years. The topographic data is preferably acquired using methods such as measurement cross-sections, RTK surveying, or UAV lidar, and is discretized into regular grids or cross-section points in the geographic information system. The grid center elevation is denoted as [elevation value missing]. Subsurface parameters, including soil type, natural unit weight, cohesion, and internal friction angle, are used for subsequent slope stability analysis.

[0010] Based on the above, this invention divides the target water body into several shoreline sections along the shoreline direction of the lake. Within each shoreline section, multiple design units are divided along the direction perpendicular to the shoreline at equal or varying elevation intervals. Each design unit is represented by a representative elevation. The slope and horizontal width are used to characterize it.

[0011] Then, the design unit is calculated in time using the following formula. instantaneous water depth ,Right now:

[0012] When the instantaneous water depth At that time, it is considered to be in a state of flooding, when the instantaneous water depth is... It is considered to be exposed or above the water surface at that time.

[0013] Preferably, the water depth is divided into several intervals (e.g., , , , (etc.), statistically analyze the frequency of occurrence in each interval over multiple timescales to construct the water depth frequency distribution of the design unit. .

[0014] Furthermore, the present invention utilizes sequential scanning of water depth time series. Identify continuous flooding periods and continuous exposure time period The distribution of flood duration and the distribution of exposure duration .

[0015] Furthermore, these two distributions can be used to limit the upper limit of flood tolerance for submerged plants, as well as to evaluate the adaptability of emergent and wetland plants to alternating wet and dry conditions, thus expanding the traditional single water level zone division into a description of flooding-emergence rhythm over time.

[0016] To simultaneously characterize the hydrodynamic environment, this invention introduces the hydrodynamic exposure index. Preferably, the following formula or its equivalent form can be used, namely: in, To act on the design unit under multi-year wind field and open conditions Representative significant wave height, For design unit Average water depth over many years For design unit Representative bank slope. Significant wave height. The hydrodynamic exposure index can be estimated using a simplified wave extrapolation formula based on wind direction frequency, wind path length, and water depth. The higher the value, the stronger the wave energy and flow velocity shear, and the more significant the erosion of the bank slope and vegetation.

[0017] Preferably, in scenarios requiring detailed characterization, the hydrodynamic exposure index can also be used. Break it down by season or flood season / non-flood season to reflect seasonal disturbance differences.

[0018] To achieve a precise match between vegetation community configuration and actual environmental conditions, this invention introduces candidate vegetation functional groups – environmental response modeling. The candidate vegetation functional groups include at least one or more of the following: submerged plant functional groups, floating-leaved plant functional groups, emergent plant functional groups, and riparian wetland herbaceous functional groups. Each candidate vegetation functional group… It may contain one or more representative species.

[0019] Preferably, through transect surveys and water and flow control experiments in the lakeside zone, at a series of water depths... With hydrodynamic exposure index Determining the functional groups of each candidate vegetation under certain conditions Survival rate, canopy cover, or aboveground biomass were measured, and these observations were normalized into a fitness score. The preferred value range is .

[0020] Preferably, logistic regression or generalized linear models are used to fit the environmental response curves of each candidate vegetation functional group. This invention specifically provides a suitability scoring function in the following form: in, For the first Candidate vegetation functional groups at water depth Hydrodynamic Exposure Index Suitability score under conditions These are parameters obtained by fitting measured data. For example... Figure 3 and Figure 4 As shown, different candidate vegetation functional groups at different water depths The suitability curves for different directions show different peak positions and widths. Submerged plants have the highest suitability score R value in the medium water depth range, emergent plants reach their peak in the shallow water area, and wetland herbs have high suitability in the range close to the normal water level.

[0021] Preferably, when the suitability score When the depth exceeds a certain threshold (e.g., 0.6 or 0.7), the corresponding water depth-hydrodynamic combination... This area is considered a preferred habitat for this functional group and is suitable for intensive planting; when the suitability score is... Areas below a low threshold (e.g., 0.3) can be considered unsuitable and are generally not selected in community configuration.

[0022] Furthermore, to more accurately reflect the light requirements of submerged plants, this invention introduces a vertical light attenuation constraint. The water depth is estimated using the following relationship. The light intensity at that location, i.e.: in, The intensity of light on the water surface. The total optical attenuation coefficient is... The water is deep.

[0023] Preferably, the target planting water depth for submerged plants is specified. Light intensity at the location Not lower than the light compensation point of the candidate vegetation functional group ,Right now: For water depth-topography combinations that do not meet the above conditions This invention calculates the suitability score. A penalty factor is introduced to force the suitability score to be lowered or recorded as 0, thereby avoiding false suitability zones where the water depth is suitable but the lighting is insufficient.

[0024] By modeling the environmental response under the combined effects of water depth, hydrodynamics, and illumination, this invention can quantitatively identify the optimal growth zone and acceptable habitat range for each functional group in the lakeside space, providing precise ecological constraints for subsequent micro-topography design and community combination.

[0025] To transform micro-topography from conceptual gentle slopes / steps into optimizable design variables, this invention explicitly parameterizes the micro-topography of the lakeside zone. Preferably, the first... The micro-topography of each design unit is represented by a design parameter vector, i.e., a micro-topography parameter vector. for: in, For the first The target elevation of the stepped or gentle slope section. For the corresponding horizontal width, To correspond to the slope, The micro-topography level within the unit is usually taken as 3 to 5 levels according to the water level variation and design requirements.

[0026] Preferably, the elevation of some target areas can also be adjusted based on existing roads, embankment crest elevations, and land use boundaries. Introduce engineering constraints that are either "fixed and immutable" or "limited and adjustable." For example... Figure 2 As shown, in a typical cross-section, the first The micro-topography of the first design unit is obtained through the first Target elevation of stepped or gentle slope sections Horizontal width and slope The parameters are used to describe the micro-topography, forming a micro-topography parameter vector. .

[0027] Preferably, given a micro-topography parameter vector Subsequently, the present invention recalculates the typical water level at each step. Corrected water depth under the conditions ,Right now:

[0028] This leads to the updating of the water depth frequency distribution and flooding duration distribution at each level of the steps, and the correction of the hydrodynamic exposure index based on the updated average water depth and local slope. The corrected hydrodynamic exposure index was obtained. This process allows for the quantitative assessment of the impact of micro-topographical adjustments, such as "raising or lowering the step elevation" and "slowing down or steepening the slope," on the water depth-hydrodynamic environment, thus achieving the coupling between topography, hydrology, and dynamics.

[0029] After determining the topographic, hydrological, and dynamic conditions, this invention considers each level of terrace as a potential vegetation zone, and adjusts the water depth at each level accordingly. and corrected hydrodynamic index Substitute vegetation functional groups In the suitability scoring function, different vegetation functional groups are calculated. Suitability score This leads to the formation of a step-functional group-suitability matrix.

[0030] Preferably, 2 to 3 vegetation functional groups with high suitability scores and strong functional complementarity on the terrace can be selected. Community combination design is carried out to form a gradual structure of submerged-floating-emergent-wetland in the vertical direction, and to form repeatable micro-topography-community modules in the coastal direction.

[0031] In terms of engineering safety, this invention calculates the slope safety factor based on step slope, soil shear strength, and hydrodynamic exposure index, using conventional slope stability analysis methods. In general form, it can be expressed as: in, For anti-slip force or anti-slip moment, This refers to the sliding force or sliding torque.

[0032] Furthermore, the safety factor for the bank slope is specified. (Slope safety threshold) Choose 1.3 or 1.5), and require the slope to meet this condition in both high-water years and high-wind-wave scenarios.

[0033] Furthermore, this invention calculates the volume of earthwork per unit shoreline by comparing the elevation of the original terrain with that of the target micro-topography, combined with soil density. This provides a basis for subsequent economic evaluation and construction organization.

[0034] Based on the coupling between topography, hydrology, and dynamics, this invention constructs a comprehensive evaluation system that simultaneously considers ecological function, engineering stability, and engineering quantity, and introduces robustness indicators under multiple hydrological scenarios to achieve integrated optimization of micro-topographic parameters and vegetation community configuration.

[0035] Furthermore, the present invention preferably selects a dry year scenario. Changshui Nian Scene Scenes of the Flood Year To construct a representative water level process for each scenario. Then, the water depth-hydrodynamic conditions and vegetation suitability of each design scheme under this scenario were recalculated using the aforementioned method. For any candidate scheme (Including a set of micro-topography parameter vectors) (and corresponding candidate vegetation functional group configurations), this invention in scenario The following is a calculation of the comprehensive evaluation function, namely: in, For the context Submarine vegetation continuity index, It is a functional diversity index. Potential indicators for improving transparency For the bank slope safety factor, This refers to the volume of earthwork. Let the weighting coefficients satisfy: Preferably, for the bank slope safety factor and earthwork volume indicators In this case, 0-1 normalization needs to be performed first before participating in the comprehensive evaluation function. The calculation of the comprehensive evaluation function is therefore necessary. This is uniformly written as a weighted combination of normalized indicators, i.e.:

[0036] in, ; Normalized value of the slope safety factor (e.g.) (or interval normalization); , is the normalized value of the earthwork volume index.

[0037] Furthermore, each design unit Length along the shoreline Summing yields the effective length for the continuous formation of underwater vegetation belts. ,Right now:

[0038] in, Design unit collection; For design unit In the context The availability criterion is as follows:

[0039] In the formula, This represents the proportion of this condition occurring during the growing season or throughout the year (flooding frequency / water depth frequency). The lowest frequency threshold (e.g., 0.5 or 0.6); For this unit in the scenario Average fitness (or average during the growing season); This is the suitability threshold (e.g., 0.7, corresponding to the optimal suitability zone). For design unit In time instantaneous water depth ; Indicates the target water depth zone for submerged plants, such as 0.3–0.8m; Define the underwater vegetation continuity index for:

[0040] in, This refers to the shoreline length (or shoreline segment length). Clearly... , is a dimensionless quantity.

[0041] Design Unit The area is .

[0042] Furthermore, this invention obtains each vegetation functional group using a suitability criterion or a suitability-weighted area. In the context The predicted configuration area (or coastal zone area) is as follows. ,Right now: Threshold method:

[0043] Weighted method (smoother):

[0044] make ,but:

[0045] in, It is a collection of vegetation functional groups. , is a dimensionless quantity.

[0046] In this invention, the transparency enhancement potential index This is a normalized composite index for improving water transparency potential, reflecting the combined contribution of submerged plant cover, emergent plant wave-cutting, and sediment disturbance suppression to improving water transparency. This index does not require direct prediction of absolute Secchi depth values, but rather is used for relative evaluation and optimization among candidate solutions (a common multi-index decision-making approach in engineering design).

[0047] Through hydrodynamic exposure index Calculation scenario Spatial average value ,Right now:

[0048] in, For the context Lower design unit The hydrodynamic exposure index.

[0049] Spatial average Perform 0-1 normalization, that is:

[0050] in, This is the normalized spatial average. It represents the minimum / maximum value under the set of possible candidate solutions (or design variable boundaries), and can be updated iteratively during implementation.

[0051] Meanwhile, let the coverage rate itself be a dimensionless quantity of 0–1, that is:

[0052] in, This indicates the predicted coverage rate or proportion of submerged plants. This indicates the predicted coverage rate or proportion of emergent plants.

[0053] The transparency improvement potential indicator is defined as follows:

[0054] in, .

[0055] This definition ensures It is a dimensionless quantity and consistent with the mechanism of transparency improvement, namely: the higher the submerged cover, the more complete the emergent zone, and the lower the average disturbance, the greater the potential for transparency improvement. Those skilled in the art can calculate it directly based on this.

[0056] Preferably, the present invention assigns higher weights to ecological and stability indicators and incorporates earthwork volume indicators in a negative form, so as to reflect the principle of saving as much engineering work as possible while meeting ecological and safety requirements.

[0057] Based on this, the present invention defines a scenario robustness index. A preferred form is: That is, the minimum value of the comprehensive evaluation function under the three scenarios is taken to ensure that the scheme still has an acceptable comprehensive performance under the most unfavorable scenario.

[0058] Another form is the weighted average, namely: in, Assign weights to each scenario, satisfying This invention allows for flexible setting of scenario weights based on the management department's level of attention to different hydrological years. .

[0059] Furthermore, under the premise of satisfying the constraints, this invention aims to maximize the scenario robustness index. With the goal of [targeting], candidate micro-topography and vegetation community combinations were analyzed. For joint optimization, the constraint conditions are expressed as follows: Preferably, simulated annealing, genetic algorithms, or other heuristic optimization methods are used, with the existing terrain and existing community as the initial scheme, and the micro-topography parameter vector is optimized. Limited-amplitude perturbation, stepwise screening, and acceptance-rejection discrimination are applied to the combination of vegetation functional groups to iteratively update candidate solutions. The scenario robustness index is then evaluated over several iterations. When the improvement is less than the preset threshold, it is considered to have converged, thus obtaining a lakeside ecological restoration scheme with strong cross-year landscape adaptability.

[0060] Furthermore, iterative search or heuristic combinatorial optimization methods include: Using the existing terrain as the initial scheme, the micro-topography parameter vector is... Limited-amplitude disturbances were carried out in combination with vegetation functional groups; Calculate the comprehensive evaluation function and scenario robustness index of the scheme after disturbance under various hydrological scenarios; The perturbation scheme is accepted when its scenario robustness index improves and the constraints are met; otherwise, it is rejected or accepted with a low probability, in order to escape local optima. Repeat the iteration until the improvement of the scenario robustness index is lower than the preset threshold in several consecutive iterations, and output a converged integrated recovery design scheme.

[0061] After optimization, this invention transforms the calculation results into design outcomes that can be directly applied to engineering, including but not limited to: micro-topographic parameters such as target elevation, slope, and step width for each shoreline and design unit; functional group combinations and planting densities of submerged plants, floating-leaved plants, emergent plants, and wetland herbs in different water depth zones; and standardized micro-topographic-community combination modules that can be repeatedly deployed in planar and longitudinal cross-sections.

[0062] Preferably, the present invention divides the shoreline into several implementation zones according to the optimization results, and selects 1 to 2 typical micro-topography-community combination modules for repeated laying in each zone, so as to ensure the continuity of the overall ecological function while taking into account the standardization of construction and local adaptability.

[0063] Furthermore, based on the lakeside ecological restoration scheme, this invention outputs the micro-topographic longitudinal and transverse section layout of each shoreline section, the target elevation and slope parameters of each design unit, the vegetation community combination and planting density, and divides the implementation into zones according to shoreline sections and water depth gradients, which are used to guide the engineering shaping and vegetation restoration construction of the lakeside zone.

[0064] Furthermore, the present invention also includes repeatedly arranging several micro-topography-vegetation combination modules along the shoreline of the lakeside zone at the design unit scale, each micro-topography-vegetation combination module comprising at least: A gently sloping deep-water platform located in a year-round deep-water area, used for planting submerged plants; A mid-water terrace located in a seasonally flooded area, used for planting floating-leaved plants and emergent plants; Shallow water steps or gentle slopes along the shore in areas of intermittent flooding or flooding are used for planting wetland herbs and shrubs; The steps and gentle slopes at all levels are connected by continuous slope surfaces. Their elevation and width are set according to the ecological restoration scheme of the lakeside zone under various hydrological scenarios, so that the continuity of the underwater vegetation zone and the overall stability of the bank slope structure can be maintained under low water, normal water and high water conditions.

[0065] Furthermore, the calculation and visualization process of this invention can be realized through a geographic information system platform or dedicated design software. However, the core of this invention lies in proposing an integrated and coupled design framework of "multi-year water level – water depth distribution – micro-topographic parameters – hydrodynamic exposure – vegetation functional group response – bank slope stability – engineering quantity", which elevates the micro-topographic shaping and vegetation community configuration of the lakeside zone from an empirical method to a quantifiable and optimizable engineering design technical solution.

[0066] By employing the above technical solution, the present invention provides a method for ecological restoration of lakeside areas based on the integration of micro-topography and vegetation communities, which has at least the following beneficial effects: 1. This invention explicitly transforms multi-year water level processes, water depth distribution, and hydrodynamic exposure into micro-topographic parameter vectors. By parametrically modeling and calculating and correcting elevation, width, slope, and number of steps, the water depth-hydrodynamic conditions corresponding to each step can be quantitatively derived, avoiding the existing method of selecting gentle slopes and steps based solely on experience.

[0067] 2. This invention constructs a suitability response function of candidate vegetation functional groups to water depth, hydrodynamics, and light intensity, and compares it with the water depth adjusted by micro-topography. Hydrodynamic Exposure Index By matching conditions step by step, quantitative selection and spatial combination of submerged, floating-leaved, emergent, and wetland vegetation zones can be achieved, making the community configuration process calculable, comparable, and optimizable, thereby improving the environmental adaptability and long-term stability of the restored community.

[0068] 3. This invention incorporates indicators such as underwater vegetation continuity, functional diversity, transparency enhancement potential, bank slope stability safety factor, and earthwork volume into a unified model to construct a comprehensive evaluation function under multiple hydrological scenarios. and robustness indicators With this goal in mind, we will jointly optimize the micro-topography and vegetation configuration to achieve a holistic balance between ecological function and engineering safety, as well as the amount of engineering work under different scenarios such as dry years, normal years and wet years. This is something that existing lakeside restoration technologies do not have. Attached Figure Description

[0069] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of the lakeside ecological restoration method in this invention; Figure 2 This is a schematic diagram of the design unit for the parametric expression of micro-topography in this invention, showing the correspondence between parameters such as step elevation, step width, and slope and micro-topography parameter vectors; Figure 3 This is a suitability-water depth response curve for the submerged, emergent, and wetland functional groups in this invention; Figure 4 This is a schematic diagram illustrating the light attenuation constraints of the submerged, emergent, and wetland functional groups in this invention. Figure 5 This is a schematic diagram comparing the current cross-section of a typical shallow lake gentle slope section in Embodiment 1 of the present invention with the cross-section of the designed micro-topography-vegetation zone configuration. Figure 6 This is a schematic diagram comparing the comprehensive evaluation values ​​and scenario robustness indicators of the scheme before and after optimization under multiple scenarios of dry year, normal water year and wet year in Embodiment 2 of the present invention. Figure 7 This is a typical cross-sectional schematic diagram of the ecological step structure and vegetation community configuration of the urban hard revetment section in Embodiment 3 of the present invention. Detailed Implementation

[0070] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding of how the present application uses technical means to solve technical problems and achieve technical effects, and to facilitate its implementation.

[0071] Example 1: Integrated restoration design of micro-topography and vegetation community in a typical shallow lake with gentle slope.

[0072] This embodiment uses a 200-meter-long section of a naturally sloping bank on the east shore of a typical shallow lake as an example. Figure 5 The image shows a typical cross-section of the current state and the designed section of the shoreline. Behind this section are low-lying farmland and rural roads, while the front edge is an open lake. The current shoreline slope is relatively gentle, but it has been eroded by wind and waves over a long period of time, forming a single slope. The underwater vegetation zone is fragmented, and the emergent vegetation zone has receded, with only scattered patches of reeds and cattails remaining in some areas.

[0073] First, water level monitoring data for the lake over the past 10 years was obtained, and a representative "normal water year" was selected as the design hydrological scenario. Using the local elevation datum as 0, the monthly average water level elevation for this representative year was calculated. The water levels for January to December are as follows: 8.90m, 8.92m, 8.95m, 9.00m, 9.05m, 9.10m, 9.15m, 9.12m, 9.05m, 9.00m, 8.95m, and 8.90m, respectively. It can be seen that the lake level fluctuates by approximately 0.25m throughout the year, with a relatively high water level from April to October, and lower water levels from January to March and November to December, consistent with the seasonal water level characteristics of a shallow lake in a typical eastern monsoon climate.

[0074] Regarding the cross-sectional topography, longitudinal and transverse cross-sectional measurements were conducted in the middle of this bank section, resulting in a typical cross-sectional elevation distribution: starting from the inner shoulder of the road on the bank crest, the horizontal distance from the bank crest... Current elevations at positions 0m, 5m, 15m, 25m, and 35m. The elevations are 9.60m, 9.20m, 8.90m, 8.60m, and 8.30m, respectively. It can be seen that the shoreline slopes gently towards the water from the land side, with the elevation gradually decreasing from 8.90m to 8.30m within the 15–35m range, corresponding to an average slope of approximately 0.6 / 20 ≈ 1:33. The lakeshore substrate is mainly composed of silty clay with a natural unit weight of approximately 18 kN / m³. 3With a cohesion of approximately 12 kPa and an internal friction angle of approximately 18°, it meets the stability requirements of conventional gentle slope revetments.

[0075] Under current conditions, the 15–35m range is defined as the main lakeshore zone. Based on the aforementioned water level data, the time series of water depth at different representative elevations are calculated. Taking elevation 8.60m as an example, representing the deep-water nearshore zone, its average water depth for each month is... The water depth is approximately 0.30m, 0.32m, 0.35m, 0.40m, 0.45m, 0.50m, 0.55m, 0.52m, 0.45m, 0.40m, 0.35m, and 0.30m respectively from January to December. The area is flooded year-round, with an average water depth of approximately: This can be approximated as 0.41m. Taking an elevation of 8.90m as an example (the current location on the gentle central slope), the average water depth from January to December is 0, 0.02, 0.05, 0.10, 0.15, 0.20, 0.25, 0.22, 0.15, 0.10, 0.05, and 0m. From February to November, the area is flooded, with a flooding frequency of approximately 10 / 12 ≈ 83%, and an average water depth of: Approximately 0.11m. Taking an elevation of 9.05m as an example (the shallow water edge zone near the normal water level), the water level is only slightly higher than this elevation for three months from June to August, corresponding to water depths of approximately 0.05m, 0.10m, and 0.07m, respectively. During the remaining months, the water is exposed. The annual average water depth is approximately: The flooding frequency is approximately 3 / 12 = 25%. The above calculation results indicate that the lower part of the current bank slope is always flooded, suitable for submerged plants but has a steep slope and is greatly disturbed by waves; the middle part is shallow water for most of the time, which has some potential for emergent plants but lacks stable steps; the upper part is only flooded for a short period during the high-water season, which is not conducive to the formation of a continuous wetland plant zone, resulting in a discontinuous distribution of the overall vegetation zone.

[0076] Regarding vegetation functional groups, this embodiment selects three typical functional groups: submerged plant functional group (denoted as...). Represented by Elodea-Vallisneria communities), emergent plant functional groups ( (represented by cattails and reeds), functional group of riparian wetland herbs ( (Represented by sedges and grass-based wetland weed communities). Based on existing survey data and indoor water control experiments in this lake area, the water depth requirements for each functional group are given. and hydrodynamic exposure index The suitable range and optimal interval for submerged plant functional groups. It exhibits high dominance in water depths of 0.3–1.2 m and under moderate wave conditions, but its coverage decreases significantly in water depths below 0.2 m or above 1.5 m; emergent plant functional groups It performs well in water depths of 0–0.5m, especially between 0.1–0.3m, which is beneficial for root stability and facilitates the formation of dense vegetation by allowing the above-ground parts to emerge above the water surface; wetland herbaceous functional group The optimal location is within 0.2m above and below the normal water level, requiring relatively high soil moisture content but not prolonged deep submersion. The suitability response function obtained by fitting measured data is as follows: When suitability score Time is considered the optimal zone. Considered an appropriate area This is considered an inappropriate area.

[0077] In this embodiment, since the shoreline is a relatively leeward shore, the representative significant wave height is... Approximately 0.20–0.30 m, hydrodynamic exposure index The overall level is relatively low. Hydrodynamic factors are mainly reflected in the suppression of submerged plants in the outermost deep water area. The specific parameters will not be elaborated in this embodiment.

[0078] Having grasped the aforementioned hydrological-topographic and vegetation response relationships, this embodiment, based on the method of the present invention, conducts an integrated micro-topographic-vegetation design for the gentle slope section. The goal is to construct a continuous underwater submerged plant zone, a stable emergent plant zone, and a wetland herbaceous zone of a certain width within a 200m shoreline. Considering the existing topography and construction feasibility, this embodiment designs a three-zone integrated micro-topographic terrace along a representative cross-section: the outermost is a submerged plant terrace, selected at an elevation of 8.60m, with a width of 10m along the shoreline; the middle is an emergent plant terrace, selected at an elevation of 8.90m, with a width of 7m; and the wetland herbaceous terrace, selected at an elevation of 9.05m, with a width of 5m, naturally transitioning towards the landward side to the shoreline top elevation of 9.60m without significant alteration. The terraces are connected by short slopes of approximately 1:3, forming a micro-topographic combination of wide, gentle terraces and short slope transitions against an overall gentle slope background of approximately 1:33.

[0079] Based on the above-mentioned step elevation and water level sequence, the flooding status of each step in the representative year was calculated. For the submerged plant step (8.60m), it was flooded for all 12 months of the year, with an average water depth of approximately 0.41m, a minimum monthly average water depth of approximately 0.30m, and a maximum of approximately 0.55m, completely submerged. This area is ideal for development, with a 100% flooding frequency, allowing for the formation of a stable continuous zone of submerged vegetation. For the emergent vegetation terrace (8.90m), it is in a shallow flooded state from February to November, with a water depth between 0.02 and 0.25m, and from April to September, the water depth is generally within the range of 0.10 to 0.22m, which meets the requirements. The optimal range for this vegetation zone, with short periods of exposure in January and December promoting root aeration and renewal, and an annual flooding frequency of approximately 83%, allows for the stable formation of emergent vegetation zones such as cattails and reeds. For the 9.05m wetland herbaceous terraces, only shallow flooding of 0.05–0.10m occurs during the high-water season from June to August, with the rest of the time the vegetation is exposed, maintaining high soil moisture content without prolonged waterlogging, making it ideal for wetland environments. Community establishment.

[0080] From a spatial perspective, the redesigned cross-section provides a relatively constant water depth zone of approximately 10m for submerged plant terraces within a water depth range of 0.3–0.8m, a significant increase compared to the current connected suitable water depth zone width of less than 5–6m. Within a water depth range of 0–0.3m, emergent plant terraces provide a dedicated width of approximately 7m, avoiding the problems of excessively steep soil, exposed roots, and susceptibility to erosion found in the current system. Within a range of ±0.2m near the normal water level, wetland herbaceous terraces provide a width of approximately 5m to construct a dense shoreline herbaceous belt, improving the shoreline landscape and preventing localized collapse caused by pedestrian trampling. The underwater vegetation continuity index proposed in this invention... Roughly estimated, using a continuous bandwidth of 0.3–0.8m water depth as an indicator, the current underwater vegetation continuity index of the cross-section... The value is approximately 0.3–0.4, and can be increased to around 0.8 after design, indicating a significant improvement in the continuity and integrity of the underwater vegetation zone.

[0081] Regarding earthwork and stability, this embodiment optimizes the earthwork volume in the 15–35m section of the cross-section by cutting and filling balance. By appropriately adjusting the step width and slope toe position, the submerged steps are mainly slope-cut, while the emergent and wet steps take into account a small amount of fill. The final calculated net earthwork volume of this section is controlled at approximately 0.10–0.15m. 3 Within a reasonable range of 200m shoreline, the overall slope stability safety factor, calculated using the simplified slice method, is no less than 1.5, meeting the safety requirements for lake embankments. Considering a 200m shoreline range, the total earthwork volume for this scheme is approximately 20–30m³. 3 The earthwork requirements are significantly lower than those of traditional large-scale slope protection or high-standard ecological retaining wall solutions.

[0082] In terms of vegetation configuration, this embodiment arranges submerged plants such as Elodea nuttallii and Vallisneria natans on the submerged steps, with a planting width of 8–10m and a planting density of 6–8 plants / m². 2Cattails and reeds are planted on the water-emerging terraces, with some sweet flag mixed in appropriately on the inner and outer sides to enhance landscape diversity. The average planting density is 3–4 plants / m². 2 On the wetland herbaceous terraces, sow sedges, thrushes, and other wetland grasses, and plant a small amount of calamus and iris to create a herbaceous belt dominated by native species. Based on the suitability function... According to the estimation results, the three vegetation belts designed will be in the optimal or suitable areas of their respective functional groups for most of the representative year, and it is expected that a relatively stable three-level shoreline community structure of "submerged-emergent-wetland" can be formed within 2-3 growing seasons.

[0083] In summary, this embodiment fully demonstrates the entire process of how the method of the present invention starts from multi-year water level and cross-sectional topographic data, and through water depth-flooding duration analysis, vegetation functional group environmental response determination, and micro-topographic step parameterized design and correction calculation, ultimately forming an integrated restoration scheme for lakeside micro-topography and community with clear elevation, width and vegetation configuration. This proves the feasibility and effectiveness of the technical solution of the present invention in actual engineering scenarios.

[0084] Example 2: Optimized design of integrated restoration scheme for micro-topography and vegetation community under multiple hydrological scenarios.

[0085] This embodiment, based on a 200m gentle slope section on the east bank of the same shallow lake, introduces three representative hydrological scenarios: dry year, normal water year, and wet year. It performs multi-scenario comprehensive evaluation and robust optimization of micro-topographic step parameters and vegetation community configuration, further demonstrating the adaptive design capability of the method under "the same bank section, different year conditions." Without changing the basic data and construction conditions in Embodiment 1, this embodiment focuses on demonstrating the calculation process of the multi-scenario comprehensive evaluation function and scenario robustness indices, as well as the quantitative comparison of the comprehensive performance of the optimized scheme under each scenario.

[0086] In terms of constructing the hydrological scenario, the monthly average water level sequence of the "normal water year" selected in Example 1 is still used as the benchmark, that is, the average water level elevation from January to December. The average monthly water levels for the following years are 8.90m, 8.92m, 8.95m, 9.00m, 9.05m, 9.10m, 9.15m, 9.12m, 9.05m, 9.00m, 8.95m, and 8.90m, respectively. Analysis of water level data from the past 10 years shows that typical dry years are generally 0.10–0.20m lower than normal throughout the year, with a more pronounced lower level during winter and spring; typical wet years are generally higher, with water levels slightly higher than normal during the summer and autumn high-water periods. For simplicity, this example uses the average monthly water level for dry years, while ensuring reasonableness. Assuming an overall decrease of 0.15m from the normal water level year, the average monthly water level during the high water year is... Approximately assuming an overall elevation increase of 0.15m, we have: This yields the monthly average water levels for dry and wet years: 8.75m, 8.77m, 8.80m, 8.85m, 8.90m, 8.95m, 9.00m, 8.97m, 8.90m, 8.85m, 8.80m, and 8.75m for January to December in dry years; and 9.05m, 9.07m, 9.10m, 9.15m, 9.20m, 9.25m, 9.30m, 9.27m, 9.20m, 9.15m, 9.10m, and 9.05m for January to December in wet years. This setting aligns with the empirical pattern of a 0.1–0.2m overall shift in water level between dry and wet years in actual shallow lakes, facilitating consistent comparison in calculations.

[0087] The integrated micro-topography-vegetation scheme obtained in Example 1 can be considered as the initial scheme or Scheme A. In this scheme, a typical cross-section is designed with three functional steps: a submerged plant step with an elevation of 8.60m and a horizontal width of approximately 10m; an emergent plant step with an elevation of 8.90m and a horizontal width of approximately 7m; and a wetland herbaceous step with an elevation of 9.05m and a horizontal width of approximately 5m. These steps are repeated within a 200m radius along the bank, forming a three-tiered community structure of "submerged-emergent-wetland". To analyze the performance of this scheme under different hydrological scenarios, this example calculates the ecological-engineering performance of Scheme A under three scenarios: dry year, normal water year, and wet year, according to the index system and comprehensive evaluation function given in the invention.

[0088] Taking a submerged terrace as an example, in a normal flood year, the terrace elevation of Scheme A is 8.60m, and the average water depth from January to December is 0.30m, 0.32m, 0.35m, 0.40m, 0.45m, 0.50m, 0.55m, 0.52m, 0.45m, 0.40m, 0.35m, and 0.30m respectively, with an annual average water depth of approximately 0.41m, falling within the submerged plant functional group. Within the optimal water depth range of 0.3–1.0 m, the expected suitability score is... The water level ranges from 0.75 to 0.90, with an annual average of approximately 0.83. In dry years, due to an overall water level drop of 0.15m, the average water depth on the submerged terrace from January to December becomes 0.15–0.40m, with an annual average of approximately 0.26m. Specifically, the water depth from January to March and November to December is only 0.15–0.20m, close to... The suitable lower limit indicates that submerged communities remain in a "critically shallow" state for a considerable period, resulting in decreased resistance to cold and disturbance. Under high-water conditions, the water depth range of the submerged steps rises to 0.45–0.70 m, averaging approximately 0.56 m annually, still within the acceptable range. The optimal range is as follows. It is evident that Scheme A is more favorable for the submerged zone in normal and wet years, but in dry years, the shallowest edge section has a shallower water depth, and the continuity of the underwater zone is significantly weakened. Analysis of emergent and wet terraces shows that in dry years, emergent terraces are exposed for many months, only submerged by shallow water of 0.05–0.10 m from May to August; conversely, in wet years, wet terraces are submerged by 0.10–0.20 m of water during the summer and autumn water levels, increasing the risk of waterlogging to wet herbaceous communities. Therefore, the same scheme exhibits an uneven distribution of ecosystem width and stability under the three scenarios.

[0089] Regarding the calculation of comprehensive indicators, this embodiment adopts the evaluation system and weight settings given in the invention. For ease of explanation, the underwater vegetation continuity index is used... Functional diversity index Transparency Improvement Potential Index Normalized value of bank slope stability safety factor and the normalized value of earthwork volume per unit shoreline Represented by 0–1 indicators, and weighted accordingly. The comprehensive evaluation function is taken as: in Indicates the hydrological scenario (dry year L, normal year N, or wet year H). This indicates a specific design scheme. A negative sign for the earthwork volume indicates that, all other things being equal, the design with the smaller earthwork volume is preferred.

[0090] In this embodiment, the length of the continuous submerged zone within a 200m radius along the shore, where the water depth is between 0.3 and 0.8m and the submerged plant suitability is higher than 0.7, is defined as the continuous length of the submerged zone. With 200m as the target length Calculate the underwater vegetation continuity index Calculations showed that the underwater vegetation continuity index of Scheme A under dry, normal, and wet year scenarios was [data missing]. The values ​​were approximately 0.55, 0.80, and 0.70, respectively. In dry years, due to lower water levels, parts of the submerged zone were exposed or compressed, resulting in a significant decrease in continuity. In normal water years, the continuity was best, approaching design conditions. In wet years, due to overall increased water depth and a slight shift of the suitable area towards the shore, the continuity was slightly lower than in normal water years. Functional Diversity Index Maintaining a value of approximately 0.70–0.75 across the three scenarios reflects that the three functional groups—submerged, emergent, and wetland—can maintain a certain combination under each scenario; transparency has the potential to improve. The water level is slightly lower in dry years than in normal years, mainly due to the shrinkage of the submerged zone and a reduced ability to weaken bottom sediment disturbance; the safety factor for bank slope stability is also lower. After normalization, the value remained between 0.88 and 0.90 under all scenarios, indicating a good earthwork volume index diameter. Approximately 0.42 (based on a maximum allowable earthwork volume of 1.0 for a specific project). Therefore, the comprehensive evaluation values ​​of Scheme A under the three scenarios are as follows: Dry Year Changshui Nian Flood Year According to the scenario robustness definition in this invention, that is: It can be seen that the robustness index of scheme A is... Its shortcomings mainly stem from the situation of dry years.

[0091] Based on this, this embodiment uses the elevation and width of the micro-topographic steps as adjustable design variables to perform robust optimization of Scheme A across multiple scenarios. While ensuring that the conditions of the riverbank road and the land use on the landside remain unchanged, adjustments to the elevations of the submerged steps, emergent steps, and wetland steps are permitted. and horizontal width The optimization objective is to ensure that the safety factor for bank slope stability is not less than 1.5 and the net earthwork volume per unit shoreline does not exceed 1.5m. 3 Maximize robustness index under the condition of / m Preferably, this embodiment uses a simplified simulated annealing algorithm for searching, taking solution A from embodiment 1 as the initial solution, and within a certain range... and A limited-amplitude perturbation is performed, and after each perturbation, the water depth-hydrodynamic conditions and ecological-engineering evaluation indicators under the three scenarios are recalculated, thereby updating the data. and In several consecutive iterations The improvement stops when it falls below the set threshold, resulting in optimization scheme B.

[0092] After several iterations, the optimized scheme B obtained in this embodiment has the following micro-topographic parameters on a typical cross-section: the elevation of the submerged step is slightly lowered to 8.55m and the width is increased to approximately 11m; the elevation of the emergent step is slightly lowered to 8.88m and the width is slightly narrowed to approximately 6.5m; the elevation of the wetland step is slightly lowered to 9.02m and the width is approximately 4.5m, while the elevations of the remaining landside slopes and shore tops remain unchanged. The purpose of lowering the submerged step by 0.05m is to increase the water depth of the outer edge section under the dry year scenario, so that the submerged zone can maintain a certain width even in the dry year; the emergent and wetland steps are slightly lowered and their widths are slightly adjusted to mitigate excessive inundation in the wet year, while also taking into account the emergent-wetland transition zone under normal water year conditions.

[0093] Recalculating the water depth under the scenarios of dry years, normal years, and wet years using the optimized parameters above reveals that: under the dry year scenario, the average water depth on the submerged step from January to December increases from 0.15–0.40m in the original scheme to approximately 0.20–0.45m, and the annual average increases from 0.26m to approximately 0.31m, which is within the range of... The shoreline width within the suitable water depth range increased significantly, and the length of the continuous submerged zone increased from approximately 110m to approximately 144m, corresponding to an underwater vegetation continuity index. The value was increased from 0.55 to approximately 0.72; under the scenario of normal water years, the water depth range of the submerged step was adjusted from 0.30–0.55m to approximately 0.35–0.60m, still completely within the range of normal water years. In the optimal zone, the continuity has been slightly improved, but the improvement is limited. Under the scenario of a wet year, the water depth range of the submerged step is adjusted from 0.45–0.70m to about 0.50–0.75m. Although it is slightly deeper, it is still within the suitable range of 0.3–1.2m. In addition, the elevation of the inner emergent step is slightly lowered, so that some water areas that are too deep to allow emergent plants to emerge are transformed into areas suitable for emergent plants, resulting in a smoother water depth gradient.

[0094] Analysis of emergent and wetland terraces shows that in dry years, the emergent terraces, due to a slight decrease in elevation, experience a prolonged shallow water period of 0.02–0.12 m from May to September, allowing emergent plants to maintain growth through root contact with groundwater even during the lowest water levels. Wetland terraces remain generally shallowly moist in dry years, without prolonged deep submersion. In wet years, the water depth of emergent terraces is concentrated between 0.17–0.32 m, while that of wetland terraces is concentrated between 0.03–0.18 m. This alleviates the situation in Scheme A, where wetland terraces experience prolonged submersion of 0.10–0.20 m, thus reducing the risk of waterlogging-induced mortality for wetland herbs. Considering all three scenarios, the optimized terrace elevation and width achieve a better balance between preventing the drying up of the submerged zone in dry years, mitigating over-inundation of the wetland zone in wet years, and maintaining stability across all three zones in normal water years.

[0095] In terms of index calculation, the underwater vegetation continuity index of optimization scheme B under three scenarios... The functional diversity index is approximately 0.72 in dry years, 0.78 in normal years, and 0.77 in wet years. Compared to Scheme A's 0.55, 0.80, and 0.70, this significantly improves performance in dry and wet years while maintaining a slightly higher level in normal years. Because the three functional groups of submerged, emergent, and wetland are more balanced in different water depth zones, the transparency potential index reaches approximately 0.76–0.78 in all three scenarios, higher than the 0.70–0.75 in Scheme A; The water level increased from approximately 0.50 to approximately 0.63 in dry years, from approximately 0.72 to approximately 0.75 in normal years, and from approximately 0.76 to approximately 0.79 in wet years, reflecting the combined effect of a more continuous submerged zone and a more significant weakening effect of the emergent zone on waves. Because the optimized scheme moderately reduced and widened the slope, the earthwork volume per unit shoreline increased slightly. The linearly normalized values ​​obtained in this embodiment are... The normalized safety factor increased from 0.42 to approximately 0.54, but remained below the preset allowable upper limit; after recalculation, the slope stability was adjusted. The values ​​remain between 0.86 and 0.88 in all three scenarios, slightly lower than 0.88–0.90 in Scheme A, but higher than the minimum safety requirements.

[0096] Substituting the above indicators into the comprehensive evaluation function, we can obtain the comprehensive evaluation values ​​of optimized scheme B under the three scenarios, such as... Figure 6 Approximately: dry year Changshui Nian Flood Year Compared with Scheme A , , The comparison shows that the optimized scheme only slightly decreases the overall evaluation value by 0.009 under the normal water year scenario, while it increases by approximately 0.076 under the dry year scenario and by approximately 0.019 under the wet year scenario. According to the definition of scenario robustness index, then:

[0097] Robustness indicators of Plan A Robustness indicators of Option B The improvement was approximately 14%, indicating that, without significantly increasing the earthwork volume and maintaining the required slope safety factor, multi-scenario comprehensive evaluation and parameter optimization can significantly improve the overall robustness of the lakeshore restoration scheme under different hydrological years.

[0098] This embodiment demonstrates that the integrated restoration design method for lakeside micro-topography and vegetation communities proposed in this invention can not only provide a reasonable micro-topography-vegetation configuration scheme under a single representative year scenario, but also optimize and compare the schemes under multiple hydrological scenarios such as dry years, normal water years, and wet years through comprehensive evaluation functions and scenario robustness indicators. This makes the final design more adaptable and robust to interannual water level changes while ensuring ecological benefits and engineering safety, thus further highlighting the technical advantages of this invention over existing empirical design methods.

[0099] Example 3: Integrated restoration design of micro-topography and vegetation community of lake hard revetment section under engineering constraints.

[0100] This embodiment selects a 150m long section of hard revetment on the north bank of a landscape lake in the same watershed to illustrate how, under strict constraints such as the inability to remove existing vertical or steep-slope concrete revetments, limited land use on the land side, and restricted waterside expansion width, the method of this invention can be applied to achieve an integrated restoration design of the lakeshore micro-topography and vegetation community. Figure 7 As shown, the existing revetment consists of a road on top and a vertical or steep-slope concrete panel structure, with the natural lakebed on the outer side of the slope toe. This embodiment adds ecological steps at its leading edge. The land side of this section is adjacent to a main urban road and sidewalk. The revetment is a masonry block structure with cast-in-place concrete panels. Below the slope toe is the natural lakebed, and in front is an open water surface, navigable year-round by small sightseeing boats. Management requires that the original main revetment structure not be demolished, and large-scale excavation on the land side is prohibited. The horizontal distance between the outer edge of the waterside ecological structure and the original revetment toe should not exceed 3.0m to avoid affecting navigation and winter icebreaking operations. Therefore, the micro-topographical modification in this embodiment can only be achieved by adding narrow ecological steps and planting strips on the outer side of the original revetment toe.

[0101] According to operational data provided by the city's water resources department, the water level of the scenic lake is regulated by a control gate, resulting in relatively small fluctuations throughout the year. Using the local elevation datum of 0.00m as the reference surface, a representative year from the past five years was selected as the design hydrological year, and its monthly average water level elevation was... The approximate values ​​are: January 10.00m, February 10.02m, March 10.05m, April 10.08m, May 10.10m, June 10.12m, July 10.15m, August 10.13m, September 10.10m, October 10.07m, November 10.05m, and December 10.02m. The annual fluctuation range is approximately 0.15m, which is basically in a controlled operating state of "high-level small fluctuations". Cross-sectional measurements of the target revetment show that the elevation of the pedestrian walkway on the backwater side is approximately 10.80m, and the top elevation of the revetment is 10.60m. From 10.60m to 9.60m, there is a sloping section with cast-in-place concrete panels laid on masonry blocks, with a slope ratio of approximately 1:1.5 and an elevation at the toe of the slope of approximately 9.60m. Within 3–4m beyond the toe of the slope is the natural lakebed, with a gentler underwater slope, gradually decreasing from 9.60m to approximately 9.20m. Based on a representative annual average water level of 10.10m, the original revetment in the 10.10–9.60m section is a nearly vertical hard interface above and below the water level, while in the 9.60–9.20m section, there is a natural bedbed with a water depth of approximately 0.5–0.9m. Because the upper part is a steep slope with hard revetment and there is only a narrow deep water zone on the water side, there is almost no shallow water beach with a depth of 0–0.3m. As a result, submerged plants only form sparse patches in front of the local slope foot, while emergent and wetland vegetation are almost non-existent. This is a typical problem of vertical revetment and lack of ecological zone in urban lakes.

[0102] In selecting vegetation functional groups, considering urban landscape requirements, this embodiment divides the target functional groups into submerged plant functional groups while taking into account both aesthetics and ecological function. (Represented by Hydrilla verticillata and Elodea nuttallii), functional group of ornamental emergent aquatic plants (Represented by yellow iris, variegated reed, and small cattail), as well as the functional group of riparian wetland herbs. (Represented by irises along the water's edge, sedges, and dwarf grasses in wetland turfgrass). Based on existing experimental and literature data from management units, the approximate water depth preferences of the three functional groups can be summarized as follows: The suitable water depth is about 0.4–1.0m. Below 0.3m, the light is too strong and it is easy to cause the large-scale reproduction of attached algae and the floating and dying during the high temperature period in summer. Above 1.2m, the growth is poor due to insufficient light. The suitable water depth is about 0.1–0.3m, requiring the root base to be in shallow water or saturated soil for a long time, and the stems and leaves to rise above the water surface to form a dense zone; The optimal conditions for growth are within a high water-bearing zone of ±0.1–0.2 m near the normal water level. Growth can be maintained under short-term submergence conditions, but it cannot tolerate long-term submergence at depths exceeding 0.3 m. Since this lake is an urban regulating lake, wind and wave conditions are relatively weak, with a representative effective wave height of approximately 0.15–0.25 m. The overall hydrodynamic exposure index is not high. In this embodiment, the suitability of each functional group is mainly controlled by water depth and flooding frequency, with wave factors considered only as secondary disturbances.

[0103] Under strict engineering constraints, this embodiment employs the parametric micro-topography design method of the present invention to control feasible additional micro-topography within a range of 0–2.5m from the waterside of the original revetment slope toe. Considering the site conditions and the navigation clearance for ships, this embodiment designs two levels of ecological steps on the outer side of the original revetment slope toe using reinforced concrete cantilever slabs and steel piles: an underwater step serving submerged plants and a shallow water step serving emergent plants. Simultaneously, a narrow wetland flower trough is set on the waterside of the revetment top to simulate a wetland zone. The submerged plant terraces are designed with a top elevation of 9.50m, extending continuously for 150m along the bank, with a horizontal width of 2.0m (extending 2.0m outward from the original slope toe). The terraces are covered with approximately 0.40m of soil, using a lightweight substrate mixed with river sand to reduce weight. The emergent plant terraces are designed with a top elevation of 9.85m and a horizontal width of 1.0m, connected to the upper revetment panel via stepped supports. Their surface is also covered with approximately 0.40m of soil and equipped with overflow holes to connect with the water below. A 0.80m wide and 0.30m deep strip-shaped flower trough, at an elevation of approximately 10.55m, is located along the inner edge of the revetment top, maintaining a wetland herbaceous zone through rainwater and drip irrigation. It is no longer used as a micro-topographic step in water depth calculation, but it supplements the shoreline vegetation layer in the overall community structure.

[0104] Based on the aforementioned micro-topographic parameters, the water depth conditions of the two-stage water-side steps were calculated in a representative year according to the method of this invention. The elevation of the submerged step is 9.50 m, and the monthly average water depth is... Substituting the values ​​into the aforementioned representative annual water levels, we obtain the average water depths for January to December as approximately 0.50m, 0.52m, 0.55m, 0.58m, 0.60m, 0.62m, 0.65m, 0.63m, 0.60m, 0.57m, 0.55m, and 0.52m, respectively. The annual average water depth is: The maximum depth is approximately 0.65m, and the minimum depth is approximately 0.50m, with an annual water depth variation of about 0.15m, consistently remaining within the target range of 0.4–1.0m. The relatively mild fluctuations make it suitable for constructing a continuous submerged vegetation zone. The emergent terrace elevation is 9.85m, and the average monthly water depth is... Therefore, the average water depth from January to December is approximately 0.15m, 0.17m, 0.20m, 0.23m, 0.25m, 0.27m, 0.30m, 0.28m, 0.25m, 0.22m, 0.20m, and 0.17m, respectively. The annual average water depth is: The water depth varies from 0.15 to 0.30 meters throughout the year, almost entirely falling within the emergent plant functional group. Within the optimal range, the water level ensures long-term root immersion without creating high water levels that would be detrimental to the functionality of the urban shoreline. Because the lake's water level is controlled, extreme low water levels generally do not fall below 9.95m. Even during short-term regulation or maintenance periods, the submerged steps maintain a water depth of at least 0.30–0.35m, and the emergent steps do not completely dry up. This is crucial for maintaining stable shoreline vegetation in urban landscape lakes.

[0105] Under the aforementioned hydrological and micro-topographical conditions, the vegetation functional group suitability response model proposed in this invention can be used to quantitatively estimate the suitability of vegetation functional groups on different terraces. and The suitability level. Since the hydrodynamic exposure is relatively weak in this embodiment, it can be considered under simplified conditions... Located in the low to medium exposure range, its contribution to the fitness function is relatively small, mainly determined by water depth. Decision. Taking submerged steps as an example, substituting the values ​​within the water depth range of 0.50–0.65m. response function Based on empirically fitted parameters, the suitability value for most months of the year is around 0.80–0.90, with an annual average of around 0.85; the emergent step is within a water depth range of 0.15–0.30m. response function The average annual suitability is approximately 0.82. Considering the 150m length along the shoreline and the continuous layout of the two steps, the length of the "continuous usable strip" provided in this embodiment is basically equal to the shoreline length. If 150m is taken as the target length... The continuous length of the submerged zone Reaching depths of 140–150m (with slight interruptions in the location of local inlet and outlet water facilities), corresponding to an underwater vegetation continuity index. It is far higher than the state before the transformation, which was almost zero.

[0106] In terms of engineering quantity and stability, the submerged step is 2.0m wide and the emergent step is 1.0m wide, with a planting substrate thickness of approximately 0.40m for both, and a planting substrate density of approximately 1.6 t / m³. 3 Converted, the filling volume per unit shoreline length is approximately The total filling volume corresponding to a 150m shoreline is approximately 180m³. 3 This is a medium-scale additional structural engineering project. Since the two-tiered steps are anchored to the existing revetment panels and foundations using steel piles and cantilever slabs, the original slope's stress conditions are not altered. The additional bending moment generated by their self-weight on the revetment structure can be controlled within the original design safety reserve during design calculations. It only has a minor covering effect on the underwater natural slope and will not induce deep-seated sliding damage. Through simplified structural analysis and slope stability verification, under normal operating water conditions, the ecological steps and planting loads in this embodiment reduce the safety factor of the original revetment structure from approximately 1.80 to approximately 1.65, still higher than the standard requirement of 1.50. Considering the combined effects of high summer water levels and wave action, the safety factor is no less than approximately 1.55, meeting the long-term operational safety requirements of urban lake shores.

[0107] In terms of vegetation configuration, this embodiment employs a combination of pre-cultivated block-shaped grass mats and on-site planting on submerged terraces to lay submerged plants such as *Hydrilla verticillata* and *Elodea nuttallii*. The initial planting coverage is controlled at 50–60%, and it is expected that 70–80% continuous underwater vegetation coverage can be formed by the end of the first growing season. On emergent terraces, *Iris tectorum* and *Typha orientalis* are the main plants, supplemented by a small amount of *Arundinaria variegata* and other ornamental emergent plants, using a combination of clump planting and strip planting, with an initial planting density of approximately 4 plants / m². 2 The wetland flower troughs on the top of the revetment will be planted with water-side irises, dwarf sedges, and water-tolerant turfgrass to form a continuous green belt along the shore. Based on the aforementioned water depth-environment response analysis, it is expected that within 2-3 years, this hard revetment section can be transformed from its current state of "exposed concrete panels + a small amount of underwater algae" to a three-layer vegetation structure of "a continuous submerged zone in the lower layer + an emergent zone in the middle layer + an upper wetland herbaceous zone". This will significantly improve the ecological function and landscape quality of the urban lake shore without changing the original main structure of the revetment or significantly increasing earthwork.

[0108] This embodiment demonstrates that even under conditions of rigid revetment for urban lakes where the revetment structure cannot be demolished, the landside cannot be excavated, and waterside expansion is strictly limited, the method proposed in this invention can still achieve integrated local micro-topography reconstruction and community rebuilding by optimizing the design of parameters such as the elevation and width of the additional steps under strict constraints. This allows the water depth-flooding process to match the environmental response of the vegetation functional group, achieving integrated local micro-topography reconstruction and community rebuilding. Compared with the traditional approach of simply hanging pots on concrete panels or planting in partial blocks, the technical solution in this embodiment utilizes water depth-water level data and a functional group suitability model, enabling the micro-topography-vegetation combination within a limited width to have higher hydrological adaptability and spatial continuity.

[0109] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0110] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are substantially similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0111] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A lake shore zone ecological restoration method based on the integration of micro-topography and vegetation community, characterized in that, The method comprises the following steps: S1, obtaining the basic data of the target water body under the same elevation reference, and dividing the target water body into several shore sections containing multiple design units along the shoreline direction of the lake shore; S2, constructing the water depth time series of each design unit on a multi-year scale according to the basic data, and calculating the hydrodynamic exposure index for representing the wave energy and flow velocity shear intensity of each design unit; S3, obtaining the survival rate, coverage or aboveground biomass data of the candidate vegetation functional group under different water depths and hydrodynamic exposure indexes, and fitting the data to obtain the environmental response curve of each candidate vegetation functional group, and obtaining the suitability score function under the given water depth-hydrodynamic combination; S4, parameterizing the microtopography of each design unit to form a microtopography parameter vector, and calculating the corrected water depth and corrected hydrodynamic exposure index of each design unit under the typical water level condition after applying the microtopography; S5, predicting the vegetation suitability, expected coverage and community continuity of each design unit under the corrected water depth and corrected hydrodynamic exposure index based on the suitability score function, and constructing a functional response model for realizing the quantitative matching of microtopography steps and vegetation community by combining the ecological function index; S6, calculating the comprehensive evaluation function under multiple hydrological scenarios based on the functional response model and defining the scenario robustness index, and obtaining the lake shore ecological restoration scheme of microtopography and vegetation community integration through iterative search or heuristic combinatorial optimization method.

2. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, The basic data includes multi-year water level sequence of the target water body and topographic data and bottom material parameters of the present situation of the lake shore; The multi-year water level sequence includes daily or hourly water level observation values for no less than 5 consecutive years to reflect the water level fluctuation characteristics of typical dry years, normal years and wet years; The terrain data includes measurement section, RTK measurement or unmanned aerial vehicle laser radar acquisition, and is discretized as regular grid or section point in a geographic information system, and the grid center elevation is recorded as ; The bottom material parameters include soil type, natural unit weight, cohesion and internal friction angle for slope stability analysis.

3. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, In step S2, the specific process comprises the following steps: In each shore section, multiple design units are divided along the vertical shore line direction with equal or variable elevation intervals, and each design unit is characterized by representative elevation , slope and horizontal width. Time step Calculate the instantaneous water depth of each design unit Construct the water depth time series , and count the instantaneous water depth in the whole year The frequency of falling into the preset interval forms the water depth frequency distribution ; Sequentially scanned water depth time series , identifying successive flooding time periods and successive emergence time periods , forming a flooding duration distribution for limiting the flooding tolerance upper limit of submerged plants or evaluating the adaptation of emergent and helophytic plants to dry-wet alternation and emergence duration distribution ; Based on the time series of water depth The water power exposure index is calculated to represent the relative hydrodynamic intensity that each design unit is subjected to, based on the average value of the time series of water depth That is: ； wherein is the water power exposure index of the design unit , is the representative significant wave height acting on the design unit under the multi-year wind field and open sea conditions, is the average water depth of the design unit over the years, is the representative slope of the bank slope of the design unit .

4. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, In step S3, the specific process comprises the following steps: establishing candidate vegetation functional groups, at least including one or more of a submerged plant functional group, a floating leaf plant functional group, an emergent plant functional group and a riparian wetland herbaceous functional group, each candidate vegetation functional group containing one or more representative species; Through transect surveys or water and flow control experiments along the lakeshore, at a series of water depths... With hydrodynamic exposure index Determining the functional groups of each vegetation under certain conditions Survival rate, canopy cover, or aboveground biomass were measured, and these observations were normalized into a fitness score. The range of values ​​is ; The environmental response curves of each candidate vegetation functional group are fitted using logistic regression or generalized linear models, and an environmental response curve is established to represent the candidate vegetation functional group in a given water depth-water dynamic combination The fitness score function of the lower fitness, namely: ； wherein, is the first candidate vegetation functional group is assigned a suitability score under conditions of water depth , hydrodynamic exposure index , and are parameters fitted from monitoring or experimental data. Suitability score Water depth - hydrodynamic combination above a preset threshold As a vegetation functional group Preferred planting condition interval, i.e.: When the suitability score Corresponding water depth - hydrodynamic combination for values greater than the threshold of 0.6 or 0.7 Preferred habitat interval for the functional group of vegetation Suitable for focused planting; When the suitability score Below threshold 0.3, considered unsuitable area, not selected in colony configuration.

5. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, In step S4, the specific process comprises the following steps: The micro-terrain of each design unit is represented by a design parameter vector, i.e. a micro-terrain parameter vector is: ； wherein, is the number of steps or ramp segments, is the target elevation of the step or ramp segment, is the corresponding horizontal width, is the corresponding slope, is the number of microterrain classes within the design unit, i.e. the number of steps. The modified water depth of each step after micro-topography reconstruction is calculated by geometric relationship under typical water level conditions i.e.: ； wherein is time corresponding water level observation value; updating the water depth frequency distribution and the duration of inundation distribution for each level of step, and correcting the hydrodynamic exposure index based on the updated average water depth and local slope , obtaining the modified hydrodynamic exposure index for the vegetation functional group suitability prediction .

6. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, The ecological function index in the functional response model at least includes: Ecological indicators: including an underwater vegetation continuity index along a water depth gradient , a vegetation functional type diversity index , and an expected transparency improvement index ; Engineering indicators include bank stability factor of safety , slope stability factor of safety, and scour resistance to extreme flood scenarios; Management index: including unit shoreline length earthwork , unit function to promote the corresponding project cost and post-maintenance workload score.

7. The method for ecological restoration of the riparian zone according to claim 6, characterized by the fact that, In step S5, the specific process comprises the following steps: The various levels of steps corresponding to the micro-topography within the design unit are considered as potential vegetation zones, and the water depth will be adjusted at each level of the steps. and corrected hydrodynamic index Substitute into the suitability scoring function to calculate different vegetation functional groups. Suitability score This forms a step-functional group-suitability matrix; Select 2-3 vegetation functional groups with high score of suitability on the step and strong functional complementarity Carry out community combination design to form submerged-float leaf-emersed-wetland gradual structure in vertical direction; Based on the slope gradient, soil shear strength and hydrodynamic exposure index, the bank safety factor is calculated by using the conventional slope stability analysis method and the bank safety factor is defined as the bank safety threshold i.e. ； wherein, is the anti-sliding force or anti-sliding torque, is the sliding force or sliding torque; Comparing the original terrain with the target micro-terrain elevation, combined with soil density calculation of unit shoreline earthwork ; The functional response model for realizing the quantitative matching of microtopography steps and vegetation community is constructed, that is: ； wherein are weight coefficients, and satisfy .

8. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, In step S6, the specific process comprises the following steps: At least three representative hydrological scenarios are selected, which are dry year scenario , normal year scenario , and wet year scenario , and weights are assigned to each scenario ; For any candidate microtopography and vegetation community combination , the integrated evaluation function of each scenario is calculated , the calculation formula of the integrated evaluation function is: ； wherein, is the scenario is the underwater vegetation continuity index, is the functional diversity index, is the transparency improvement potential indicator, is the bank slope safety factor, is the earthwork volume indicator, is the weight coefficient; According to the comprehensive evaluation function Defining the scenario robustness index including the minimum or weighted average of the comprehensive evaluation function under the water intake scenarios, expressed as: ； Or ； wherein are the weights for each scenario, satisfying ; Under the premise of constraints, maximize the scenario robustness index For the target, the candidate micro-topography and vegetation community combination is optimized by iterative search or heuristic combinatorial optimization method The integrated lake shore zone ecological restoration scheme of micro-topography and vegetation community is obtained by joint optimization. The expression of the constraint condition is: ； wherein, is a bank slope safety threshold, is a earthwork volume index threshold.

9. The method for ecological restoration of the riparian zone according to claim 1, characterized in that, Between step S5 and step S6, the following steps are also included: Based on the vertical light attenuation coefficient and the surface light intensity, the light intensity at different water depths is estimated , the expression is: ； wherein, is the water surface light intensity, is the total light attenuation coefficient, is the water depth; The specified planting depth for submerged plants is [not specified]. Light intensity at the location Not lower than the light compensation point of the candidate vegetation functional group ,Right now: ； For water depth-topography combinations not meeting the above conditions are considered as not suitable for planting submerged plants under transparency conditions and a penalty factor is introduced in the calculation of the suitability score forcing the suitability score to be forced down or to be zero.

10. The method of ecological restoration of the riparian zone according to claim 1, characterized in that, It also includes repeating the layout of several microtopography-vegetation combination modules along the shoreline direction of the lake shore with design units as the scale, each microtopography-vegetation combination module at least includes: A gentle slope deep water platform located in the perennial deep water level interval for planting submerged plants; A middle water step located in the seasonal flooding interval for planting floating leaf plants and emergent plants; A shallow water step or shore slope located in the intermittent flooding or shore edge flooding area for planting wetland herbs and shrubs; The elevation and width of each step and slope are set according to the lake shore ecological restoration scheme of multiple hydrological scenarios, so that the continuity of underwater vegetation zone and the overall stability of shore slope structure can be maintained in dry years, normal years and wet years.

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