Evaluation method for coastal vegetation bank protection efficiency

Abstract

The invention relates to a coastal vegetation revetment efficiency evaluation method, which comprises the following steps: S1, on the basis of field measurement or remote sensing data, collecting meteorological and hydrological elements and topographic and geomorphic data of a target coast; s2, quantifying key characteristic parameters of vegetation, wherein the key characteristic parameters comprise a planting scheme, a vegetation diameter, a height and a form; s3, constructing a tidal water power-vegetation coupling model, analyzing an interaction mechanism of a tidal current field and vegetation, and quantitatively evaluating the vegetation bank protection efficiency from the aspect of tidal current flow velocity weakening amplitude; s4, establishing a wave-vegetation coupling model, simulating a vegetation wave dissipation and energy consumption process, and quantitatively evaluating the vegetation bank protection efficiency from the aspect of wave reduction amplitude; and S5, integrally constructing a hydrodynamic force-wave-sediment-vegetation coupling numerical model, and quantitatively evaluating the vegetation bank protection efficiency from the aspect of bank slope form change.

Description

Technical Field

[0001] The invention relates to a method for evaluating the effectiveness of coastal vegetation bank protection, which belongs to the fields of environmental engineering and marine engineering. Background Art

[0002] As a frontier zone for land-sea interaction, coastal zones face increasing risks of erosion and degradation amidst global climate change and intensified human activities. While traditional hard revetment systems (such as seawalls and breakwaters) can provide short-term protection, they also pose drawbacks such as damage to coastal ecosystems, increased shoreline rigidity, and high operation and maintenance costs. In recent years, ecological revetment technologies based on natural solutions have garnered widespread attention. Coastal vegetation revetments, through processes such as slowing down currents and dissipating waves and promoting sedimentation, demonstrate significant advantages in synergizing ecological benefits with protective effectiveness.

[0003] However, current vegetation revetment projects face some challenges in practice, especially in the scheme design stage of coastal vegetation revetment projects. The lack of a scientific pre-assessment method system makes it difficult to quantify and accurately predict the slope protection effectiveness of vegetation planting schemes. This problem affects the early evaluation and optimization of project effects. To address this challenge, the patent of this invention is based on numerical simulation technology. By constructing a tidal hydrodynamic-wave-sediment-vegetation coupling model, it comprehensively evaluates the bank protection effectiveness of vegetation planting schemes from three dimensions: tidal flow velocity weakening, wave height attenuation, and slope morphology changes. Through this multi-dimensional evaluation system, a more scientific and accurate technical support is provided for the effect prediction of ecological revetment projects. Summary of the Invention

[0004] This patent provides a method for evaluating the effectiveness of coastal vegetation bank protection. By constructing a tidal hydrodynamic-wave-sediment-vegetation coupling model, it realizes a multi-dimensional analysis of the energy dissipation mechanism and sediment redistribution process in the process of vegetation bank protection, and realizes a systematic evaluation of the coastal protection effectiveness of vegetation planting schemes, providing technical support for the effect prediction of ecological bank protection projects.

[0005] To achieve the above-mentioned purpose of the invention patent, the present invention patent provides a method for evaluating the effectiveness of coastal vegetation bank protection, including the following steps:

[0006] Collect meteorological and hydrological elements and topographic data of the target coast based on on-site measurements or remote sensing data; the meteorological and hydrological elements include wind field characteristics, tidal dynamics, wave parameters, and sediment characteristics;

[0007] S2: Quantify key characteristic parameters of vegetation, including planting scheme, vegetation diameter, height and morphology; the planting scheme includes plant species, planting density and planting width.

[0008] S3: Construct a tidal hydrodynamic-vegetation coupling model to analyze the interaction mechanism between tidal currents and vegetation, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of the magnitude of tidal velocity reduction.

[0009] S4: Establish a wave-vegetation coupling model to simulate the wave-dissipation energy consumption process of vegetation, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude.

[0010] S5: An integrated hydrodynamic-wave-sediment-vegetation coupled numerical model is constructed to quantitatively evaluate the effectiveness of vegetation bank protection from the perspective of bank slope morphology changes.

[0011] Furthermore, step S3 constructs a tidal hydrodynamic-vegetation coupling model to analyze the interaction mechanism between the tidal field and vegetation, and quantitatively evaluates the effectiveness of vegetation bank protection in terms of the magnitude of tidal velocity reduction. The steps are as follows:

[0012] S31, constructing a tidal hydrodynamic model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0013] S32, the effect of vegetation is introduced into the tidal hydrodynamic model to construct a tidal hydrodynamic-vegetation model, in which the specific expression of the vegetation drag force is given by the following formula.

[0014]

[0015] Where ρ0 is the density of seawater at room temperature; C dv is the tidal drag coefficient of vegetation; b v is the stem diameter of vegetation; h v is the vegetation height; N v is the planting density of vegetation; u(x,y,t) is the tidal velocity.

[0016] S33, run the model to obtain the results.

[0017] S34. Compare the model results with and without vegetation planting to quantitatively evaluate the effectiveness of vegetation bank protection in terms of the degree of tidal velocity reduction.

[0018] Furthermore, step S4 constructs a wave-vegetation coupling model to simulate the energy consumption of vegetation in reducing waves and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude.

[0019] S41, constructing a wave model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0020] S42, introduce the effect of vegetation into the model and construct a wave-vegetation model, in which the dissipation term S caused by vegetation is veg , is given by:.

[0021]

[0022] Where g is the acceleration due to gravity, C Dw is the drag coefficient of vegetation, b v is the stem diameter of the plant, N v is the vegetation density, h is the water depth, is the mean wave number, is the average frequency, E tot is the total wave energy per unit area, and E(f,θ) is the function relationship between energy density, frequency f and wave direction θ. where h v is the vegetation height.

[0023] S43, run the model to obtain the results.

[0024] S44, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude.

[0025] Furthermore, step S5 constructs a multi-field coupled numerical model of hydrodynamics, waves, sediments, and vegetation to quantitatively evaluate the effectiveness of vegetation bank protection from the perspective of slope morphology changes. The steps are as follows:

[0026] S51, constructing a sediment model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0027] S52, coupling the sediment model with the tidal hydrodynamic-vegetation coupling model and the wave-vegetation model in steps S3 and S4, and integrating and constructing a hydrodynamic-wave-sediment-vegetation coupling numerical model.

[0028] S53, run the model to obtain the results.

[0029] S54, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of changes in slope morphology.

[0030] Compared with the existing technology, the beneficial effects achieved by the patent of this invention are:

[0031] This patent provides a method for evaluating the effectiveness of coastal vegetation bank protection. By constructing a tidal hydrodynamic-wave-sediment-vegetation coupling model, it realizes a multi-dimensional analysis of the energy dissipation mechanism and sediment redistribution process in the process of vegetation bank protection, and realizes a systematic evaluation of the coastal protection effectiveness of vegetation planting schemes, providing technical support for the effect prediction of ecological bank protection projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flowchart of the steps of a method for evaluating the effectiveness of coastal vegetation revetment;

[0033] Figure 2 This is a comparison of tidal flow velocities at a monitoring point on the target coast in specific embodiment 1 of the present invention with and without vegetation planted during certain time periods.

[0034] Figure 3 This is a comparison of wave heights at a monitoring point on the target coast in specific embodiment 1 of the present invention, with and without vegetation planted during certain time periods.

[0035] Figure 4 The present invention provides a comparison of the changes in the slope morphology of a target coastline with and without vegetation planting during the implementation period of the specific embodiment 1 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below by way of specific example 1. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that these equivalent forms also fall within the scope defined by the appended claims.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0038] Reference Figure 1 This embodiment 1 provides a flowchart of a method for evaluating the effectiveness of coastal vegetation revetment. By simulating a target coastline as the research object and constructing a tidal hydrodynamic-wave-sediment-vegetation coupling model, the technical feasibility of the method for evaluating the effectiveness of coastal vegetation revetment is systematically verified. The technical solution of the present invention is further explained, and specifically includes the following steps:

[0039] S1: Based on on-site measurements or remote sensing data, collect meteorological and hydrological elements (wind field characteristics, tidal dynamics, wave parameters, sediment characteristics) and topographic and geomorphological data of the target coast.

[0040] S2: Quantify key characteristic parameters of vegetation, including planting scheme (plant species, planting density, planting width), vegetation diameter, height and morphology. The vegetation parameters of Example 1 are shown in Table 1.

[0041] Table 1

[0042]

[0043] S3: Construct a tidal hydrodynamic-vegetation coupling model to analyze the interaction mechanism between tidal currents and vegetation, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of the magnitude of tidal velocity reduction. Follow the steps below:

[0044] S31, constructing a tidal hydrodynamic model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0045] S32, the effect of vegetation is introduced into the tidal hydrodynamic model to construct a tidal hydrodynamic-vegetation model, in which the specific expression of the vegetation drag force is given by the following formula.

[0046]

[0047] Where ρ0 is the density of seawater at room temperature; C dv is the tidal drag coefficient of vegetation; b v is the stem diameter of vegetation; h v is the vegetation height; N v is the planting density of vegetation; u(x,y,t) is the tidal velocity.

[0048] S33, run the model to obtain the results.

[0049] Figure 2 This is a comparison of tidal flow rates at a monitoring point on the target coast in specific embodiment 1 of the present invention, with and without vegetation planted during certain time periods. It can be seen that under the current planting scheme, the presence of vegetation reduces the tidal flow rate by about 60%.

[0050] S4: Construct a wave-vegetation coupling model to simulate the energy consumption of vegetation in reducing waves and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude. Follow the steps below:

[0051] S41, constructing a wave model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0052] S42, introduce the effect of vegetation into the model and construct a wave-vegetation model, in which the dissipation term S caused by vegetation is veg , is given by:.

[0053]

[0054] Where g is the acceleration due to gravity, C Dw is the drag coefficient of vegetation, b v is the stem diameter of the plant, N v is the vegetation density, h is the water depth, is the mean wave number, is the average frequency, E tot is the total wave energy per unit area, and E(f,θ) is the function relationship between energy density, frequency f and wave direction θ. where h v is the vegetation height.

[0055] S43, run the model to obtain the results.

[0056] S44, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude.

[0057] Figure 3 This is a comparison of wave heights at a monitoring point on the target coast in specific embodiment 1 of the present invention, with and without vegetation planted during certain time periods. It can be seen that under the current planting scheme, the presence of vegetation reduces the significant wave height by approximately 64%.

[0058] S5: Integrate and construct a hydrodynamic-wave-sediment-vegetation coupled numerical model to quantitatively evaluate the effectiveness of vegetation bank protection from the perspective of slope morphology changes. Follow the steps below:

[0059] S51, constructing a sediment model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions.

[0060] S52, coupling the sediment model with the tidal hydrodynamic-vegetation coupling model and the wave-vegetation model in steps S3 and S4, and integrating and constructing a hydrodynamic-wave-sediment-vegetation coupling numerical model.

[0061] S53, run the model to obtain the results.

[0062] S54, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of changes in slope morphology.

[0063] Figure 4 This figure compares the changes in bank slope morphology with and without vegetation planting during the implementation period of Specific Example 1 of the present invention. It can be seen that under the current planting scheme, the bank slope morphology remains unchanged, and the maximum erosion of the bank slope decreases by 97% compared to the absence of vegetation.

[0064] In summary, this patented method, based on numerical simulation technology and by constructing a tidal hydrodynamic-wave-sediment-vegetation coupling model, can accurately evaluate the revetment effectiveness of vegetation planting schemes from three dimensions: tidal velocity reduction, wave height attenuation, and bank slope morphology changes. This provides more scientific and accurate technical support for predicting the effectiveness of ecological revetment projects.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for evaluating the effectiveness of coastal vegetation revetment, characterized in that The following steps are involved: S1: Collect meteorological and hydrological elements and topographic data of the target coast based on on-site measurements or remote sensing data; the meteorological and hydrological elements include wind field characteristics, tidal dynamics, wave parameters, and sediment characteristics; S2: Quantify key characteristic parameters of vegetation, including planting scheme, vegetation diameter, height and morphology; the planting scheme includes plant species, planting density and planting width; S3: Construct a tidal hydrodynamic-vegetation coupling model to analyze the interaction mechanism between tidal currents and vegetation, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of the magnitude of tidal velocity reduction; S4: Establish a wave-vegetation coupling model to simulate the wave-dissipation energy consumption process of vegetation, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude; S5: An integrated hydrodynamic-wave-sediment-vegetation coupled numerical model is constructed to quantitatively evaluate the effectiveness of vegetation bank protection from the perspective of slope morphology changes.

2. The method for evaluating the effectiveness of coastal vegetation revetment according to claim 1, characterized in that: Step S3 is specifically as follows: S31, constructing a tidal hydrodynamic model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions; S32, introducing the effect of vegetation into the tidal hydrodynamic model to construct a tidal hydrodynamic-vegetation model, wherein the tidal hydrodynamic-vegetation model includes a vegetation drag force variable, and its specific expression is given by formula (1); Where ρ0 is the density of seawater at room temperature; C dv is the tidal drag coefficient of vegetation; b v is the stem diameter of vegetation; h v is the vegetation height; N v is the planting density of vegetation; u(x,y,t) is the tidal velocity; S33, run the model to obtain the results; S34. Compare the model results with and without vegetation planting to quantitatively evaluate the effectiveness of vegetation bank protection in terms of the degree of tidal flow velocity reduction.

3. The method for evaluating the effectiveness of coastal vegetation revetment according to claim 1, characterized in that: Step S4 is specifically as follows: S41, constructing a wave model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions; S42, introducing the effect of vegetation into the model to construct a wave-vegetation model, wherein the wave-vegetation model includes the dissipation term S caused by vegetation. veg , given by formula (2): Where g is the acceleration due to gravity, C Dw is the drag coefficient of vegetation, b v is the stem diameter of the plant, N v is the vegetation density, h is the water depth, is the mean wave number, is the average frequency, E tot is the total wave energy per unit area, and E(f,θ) is the energy density as a function of frequency f and wave direction θ; where h v is the vegetation height; S43, run the model to obtain the results; S44, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of wave reduction amplitude.

4. The method for evaluating the effectiveness of coastal vegetation revetment according to claim 1, characterized in that: Step S5 is specifically as follows: S51, constructing a sediment model, including drawing a grid, setting terrain, setting model parameters, and setting model boundary conditions; S52, coupling the sediment model with the tidal hydrodynamic-vegetation coupling model and the wave-vegetation model in steps S3 and S4, and integrating and constructing a hydrodynamic-wave-sediment-vegetation coupling numerical model; S53, run the model to obtain the results; S54, compare the model results with and without vegetation planting, and quantitatively evaluate the effectiveness of vegetation bank protection in terms of changes in slope morphology.

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