Method and system for evaluating influence of protective engineering on island reef hydrodynamic spatial distribution

Abstract

The invention relates to the technical field of hydrodynamic spatial distribution, and discloses a method and system for evaluating the influence of protective engineering on island hydrodynamic spatial distribution, and the method comprises the steps: obtaining coral parameter data and protective engineering parameter data of a target island region; performing hydrodynamic simulation based on the coral parameter data and the protective engineering parameter data; determining a hydrodynamic factor difference value according to a hydrodynamic simulation result; and generating a composite influence index based on the hydrodynamic factor difference value, and performing protection engineering influence grading. According to the scheme, high-precision simulation of island reef hydrodynamic space distribution can be realized, and a precise collaborative decision basis is provided for engineering optimization and ecological protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrodynamic spatial distribution, and particularly relates to a method and system for evaluating the influence of a protection project on the hydrodynamic spatial distribution of an island reef. Background Technique

[0002] Coral reef ecosystems have the natural functions of reducing wave energy and maintaining geomorphic stability. Protection projects may weaken or enhance these functions by changing the wave-current field structure, thereby affecting the ecological security and resource sustainability of island reefs. Current research mainly focuses on the wave dissipation performance of engineering structures themselves, lacking in-depth analysis of the coupling mechanism of coral reef topography-ecology-hydrodynamics, resulting in contradictions between engineering layouts and ecological protection goals.

[0003] Traditional methods usually adopt simplified constant roughness coefficient and homogenized terrain models, which are difficult to reflect the dynamic influence of complex seabed morphology and biological communities in coral reef areas on hydrodynamics. Traditional hydrodynamic models mostly ignore the changes in friction effects caused by differences in coral types, and only set Manning coefficients based on coral substrate types, unable to accurately characterize the differential blocking effects of branched corals and massive corals; the impact assessment of wave protection projects is often limited to a single project type or fixed wave conditions, lacking systematic analysis of project locations, structural permeability, and multi-wave condition combinations; hydrodynamic impact grading mostly relies on a single parameter threshold, without considering the coupling effects of wave height, flow velocity, and water depth changes, resulting in insufficient spatial resolution of assessment results. These deficiencies make existing methods difficult to meet the requirements of refined design of island reef protection projects, and are likely to cause engineering effects to deviate from expectations or ecological negative effects.

[0004] Therefore, there is an urgent need to develop a method for evaluating the influence of a protection project on the hydrodynamic spatial distribution of an island reef, which can achieve high-precision simulation of the hydrodynamic spatial distribution of the island reef and provide a precise collaborative decision-making basis for engineering optimization and ecological protection. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method for evaluating the influence of a protection project on the hydrodynamic spatial distribution of an island reef, which can achieve high-precision simulation of the hydrodynamic spatial distribution of the island reef and provide a precise collaborative decision-making basis for engineering optimization and ecological protection.

[0006] The present invention provides a method for evaluating the influence of a protection project on the hydrodynamic spatial distribution of an island reef, and the method includes the following steps: S1. Obtain coral parameter data and protection project parameter data of the target island reef area; S2. Conduct hydrodynamic simulation based on the coral parameter data and the protection project parameter data; S3. Determine the difference value of hydrodynamic factors according to the hydrodynamic simulation results; S4. Generate a composite influence index based on the difference values of hydrodynamic factors and conduct a grading of the impact of the protection project.

[0007] Further, in S1, the coral parameter data includes coral type, coral coverage, and coral substrate type; The protection project parameter data includes the height, length, porosity of the protection project, and the location where the protection project is located.

[0008] Further, in S2, the hydrodynamic simulation based on the coral parameter data and the protection project parameter data includes: S21. Determine the dynamic Manning coefficient based on the coral parameter data; S22. Generalize the terrain of the target reef area into a two-dimensional terrain profile function; S23. Modify the two-dimensional terrain profile function according to the dynamic Manning coefficient and the protection project parameter data; S24. Divide the computational grid based on the modified two-dimensional terrain profile function, define the wave boundary conditions, and run the hydrodynamic model to conduct a hydrodynamic simulation.

[0009] Further, in S21, determining the dynamic Manning coefficient based on the coral parameter data includes: S211. Determine the corresponding base Manning coefficient according to the coral substrate type, and weight the coral coverage according to the coral type to generate a spatially distributed Manning coefficient; S212. Obtain the dynamic Manning coefficient by summing the base Manning coefficient and the spatially distributed Manning coefficient.

[0010] Further, in S24, the wave boundary conditions include wave height and period; The results of the hydrodynamic simulation include instantaneous wave height, flow velocity, and water depth.

[0011] Further, in S3, determining the difference value of hydrodynamic factors according to the results of the hydrodynamic simulation includes: S31. Calculate the time-averaged wave height, time-averaged flow velocity, and time-averaged water depth under the conditions with and without the project respectively according to the results of the hydrodynamic simulation; S32. Determine the difference value of hydrodynamic factors according to the time-averaged wave height, time-averaged flow velocity, and time-averaged water depth under the conditions with and without the project.

[0012] Further, in S3, the difference value of hydrodynamic factors includes: wave height attenuation rate, flow velocity change rate, and water depth change rate.

[0013] Further, in S4, generating a composite influence index based on the difference value of hydrodynamic factors and conducting a grading of the impact of the protection project includes: S41. Generate a composite influence index by weighted summation according to the difference value of hydrodynamic factors; S42. Obtain the impact grading of the protective project based on the composite impact index and the preset threshold range.

[0014] The present invention also provides an evaluation system for the impact of a protective project on the spatial distribution of hydrodynamic forces of an island reef, which is used to execute the method for evaluating the impact of a protective project on the spatial distribution of hydrodynamic forces of an island reef according to any one of the above. The system includes the following modules: A data acquisition module, which is used to acquire coral parameter data and protective project parameter data of the target island reef area; A working condition simulation module, which is connected to the data acquisition module and is used to perform hydrodynamic simulation based on the coral parameter data and the protective project parameter data; An impact factor calculation module, which is connected to the working condition simulation module and is used to determine the difference value of hydrodynamic factors according to the hydrodynamic simulation results; An evaluation module, which is connected to the impact factor calculation module and is used to generate a composite impact index based on the difference value of hydrodynamic factors and perform impact grading of the protective project.

[0015] The embodiments of the present invention have the following technical effects: This solution constructs a two-dimensional topographic profile model of the coral reef and improves the hydrodynamic equation by dynamically parameterizing the coral roughness and the characteristics of the wave protection project, and can achieve high-precision simulation of the spatial distribution of hydrodynamic forces of the island reef. First, based on the dynamic Manning coefficient calculation of coral type and coverage, the differential impact of the coral community on the flow resistance can be accurately quantified, overcoming the error caused by the fixed roughness parameter in the traditional method; second, the multi-dimensional combination design of the wave protection project position, structural characteristics and wave conditions in the engineering parameter matrix can systematically reveal the action law of different protection layouts on the wave-current field; finally, through the composite impact index and grading rules of wave height, flow velocity and water depth changes, the disturbance range and degree of the project on the hydrodynamic environment can be identified spatially, providing a quantitative basis for optimizing the engineering layout. Compared with the prior art, this method makes the coupling mechanism between ecological parameters and the hydrodynamic model explicit, realizes the collaborative action analysis of coral reef topographic characteristics, ecological friction effect and protective project structure, and improves the ecological rationality and engineering guiding value of the simulation results. Description of the Drawings

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings without creative efforts.

[0017] Figure 1 It is a flowchart of a method for evaluating the impact of a protective project on the spatial distribution of hydrodynamic forces of an island reef provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the generalized terrain of an island reef provided by an embodiment of the present invention; Figure 3 It is a schematic structural diagram of an evaluation system for the influence of a protection project on the hydrodynamic spatial distribution of an island reef provided by an embodiment of the present invention. Specific embodiments

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope protected by the present invention.

[0019] An embodiment of the present invention provides an evaluation method for the influence of a protection project on the hydrodynamic spatial distribution of an island reef, Figure 1 It is a flowchart of an evaluation method for the influence of a protection project on the hydrodynamic spatial distribution of an island reef provided by an embodiment of the present invention. Refer to Figure 1 and the method includes the following steps: S1. Obtain coral parameter data and protection project parameter data for the target island reef area.

[0020] In some embodiments, the coral parameter data includes coral type, coral coverage, and coral substrate type; the protection project parameter data includes the height, length, porosity of the protection project, and the position parameter of the location where the protection project is located.

[0021] Among them, the coral type includes branched corals (such as Acropora) and massive corals (such as Brain coral); the coral coverage refers to the proportion of the coral-covered area to the total area of the surveyed area; the coral substrate type includes reef rock, sandy or detrital bottom beds, etc., which are used to determine the bed Manning coefficient. The height of the protection project determines the overtopping height of the wave, the length of the protection project is the extension length of the protection project along the reef flat, which affects the wave dissipation range, and the porosity, for example, the porosity of a solid structure (such as a concrete dyke) is 0, and the porosity of a permeable structure (such as an ecological reef) is 0.2 - 0.5; the position parameter of the location where the protection project is located refers to the distance of the protection project from the reef edge.

[0022] S2. Conduct hydrodynamic simulation based on the coral parameter data and the protection project parameter data.

[0023] In some embodiments, step S2 includes the following sub-steps: S21. Determine the dynamic Manning coefficient based on the coral parameter data.

[0024] S211. Determine the corresponding bed Manning coefficient according to the coral substrate type, and weight the coral coverage according to the coral type to generate a spatially distributed Manning coefficient.

[0025] S212. Obtain the dynamic Manning coefficient by summing the base Manning coefficient and the spatially distributed Manning coefficient.

[0026] Specifically, the formula for the dynamic Manning coefficient is as follows: ; where n represents the dynamic Manning coefficient, n base represents the base Manning coefficient, i.e., the roughness of the reef flat without coral coverage, and the parameter can be calibrated through experiments. For example, for reef rock, it is taken as 0.03, and for sandy, it is taken as 0.02. K coral represents the coral type. Exemplarily, for branched coral, it can be taken as 0.04 (high friction), and for massive coral, it can be taken as 0.02 (low friction). C cover represents the coral coverage, and the value range is 0 - 1.

[0027] S22. Generalize the topography of the target reef area into a two-dimensional topographic profile function.

[0028] Figure 2 is a schematic diagram of the generalized topography of the reef provided by an embodiment of the present invention. Refer to Figure 2 , and generalize the reef topography into a two-dimensional model of reef flat - lagoon - breach. The two-dimensional topographic profile function is as follows: ; where z(x, y) represents the bed elevation at the position (x, y), which varies with the coordinate x. z 0 represents the initial elevation of the reef edge, γ represents the reef flat slope, δ represents the breach area slope, z lagoon represents the bed elevation of the lagoon area, x 1 represents the boundary position between the lagoon area and the breach area, x 礁坪区 represents the x - coordinate range of the reef flat area, x 潟湖区 represents the x - coordinate range of the lagoon area, x 裂口区 represents the x - coordinate range of the breach, which is determined by the measured topography.

[0029] S23. Modify the two-dimensional topographic profile function according to the dynamic Manning coefficient and the protection engineering parameter data.

[0030] Specifically, at the position parameter D of the protection engineering location, stack the height of the protection engineering, that is, on the basis of z(x, y) with x = D, stack the height of the protection engineering according to the length of the protection engineering to obtain the modified two-dimensional topographic profile function.

[0031] S24. Divide the computational grid based on the modified two-dimensional topographic profile function, define the wave boundary conditions, and run the hydrodynamic model for hydrodynamic simulation.

[0032] Among them, the wave boundary conditions include wave height H and period T.

[0033] The results of hydrodynamic simulation include the instantaneous wave height H s (x, y, t), flow velocity u(x, y, t), and water depth h(x, y, t); where (x, y) represents the spatial position coordinates and t represents time.

[0034] Exemplarily, based on the parameters shown in Table 1 as inputs, the porosity of the protection project (affecting water permeability) can be defined and the dynamic Manning coefficient can be input, and the coral bottom shear stress term in the momentum equation (i.e., τ b (the calculation formula), and the hydrodynamic model can be run for hydrodynamic simulation. In the table, L represents the reef flat length and W represents the atoll perimeter.

[0035] where τ b The calculation formula is as follows: ; where τ b represents the coral bottom shear stress, ρ represents the seawater density, g represents the acceleration due to gravity, n represents the dynamic Manning coefficient, u represents the flow velocity, and h represents the water depth.

[0036] Table 1 Simulation condition table

[0037] In addition, on this basis, a set of simulation results without a protection project also needs to be simulated.

[0038] S3. Determine the difference value of hydrodynamic factors according to the hydrodynamic simulation results.

[0039] S31. Calculate the time-averaged wave height, time-averaged flow velocity, and time-averaged water depth in the cases with and without the project respectively according to the hydrodynamic simulation results.

[0040] In some embodiments, the calculation formula of the time-averaged wave height H avg is as follows: ; The calculation formula of the time-averaged flow velocity U avg is as follows: ; The calculation formula of the time-averaged water depth h avg is as follows: .

[0041] where H avg (x, y) represents the time-averaged wave height at the spatial position coordinates (x, y), U avg (x, y) represents the time-averaged flow velocity at the spatial position coordinates (x, y), and h avg(x, y) represents the time-averaged water depth at the spatial position coordinates (x, y).

[0042] S32. Determine the difference value of hydrodynamic factors based on the time-averaged wave height, time-averaged flow velocity, and time-averaged water depth in the cases with and without the project.

[0043] In some embodiments, the difference value of hydrodynamic factors includes: wave height attenuation rate, flow velocity change rate, and water depth change rate.

[0044] The calculation formula for the wave height attenuation rate is as follows: ; where ΔH(x, y) represents the wave height attenuation rate at the spatial position coordinates (x, y), and H avg,1 (x, y) represents the time-averaged wave height in the case with the project at the spatial position coordinates (x, y), and H avg,0 (x, y) represents the time-averaged wave height in the case without the project at the spatial position coordinates (x, y); The calculation formula for the flow velocity change rate is as follows: ; where Δu(x, y) represents the wave height attenuation rate at the spatial position coordinates (x, y), and U avg,1 (x, y) represents the time-averaged flow velocity in the case with the project at the spatial position coordinates (x, y), and U avg,0 (x, y) represents the time-averaged flow velocity in the case without the project at the spatial position coordinates (x, y); The calculation formula for the water depth change rate is as follows: ; where Δh(x, y) represents the wave height attenuation rate at the spatial position coordinates (x, y), and h avg,1 (x, y) represents the time-averaged water depth in the case with the project at the spatial position coordinates (x, y), and h avg,0 (x, y) represents the time-averaged water depth in the case without the project at the spatial position coordinates (x, y).

[0045] S4. Generate a composite influence index based on the difference value of hydrodynamic factors and conduct a grading of the influence of the protection project.

[0046] In some embodiments, step S4 includes the following sub-steps: S41. Generate a composite influence index by weighted summation according to the difference value of hydrodynamic factors.

[0047] In some embodiments, the calculation formula for the composite influence index is as follows: ; Among them, I(x, y) represents the composite influence index at the spatial position coordinates (x, y), which is used to comprehensively reflect the degree of hydrodynamic disturbance, w 1 、w 2 、w 3 represent weight coefficients, and w 1 +w 2 +w 3 = 1, and it can be set according to methods such as the expert experience method. Exemplarily, it can be set to 0.5, 0.3, 0.2.

[0048] S42. Obtain the impact grading of the protective project according to the composite influence index and the preset threshold interval.

[0049] In some embodiments, the preset threshold Jiutong can be determined by methods such as calibrating the ecological-hydrodynamic response data of historical engineering cases, allocating expert experience weights, and coupling analysis of physical mechanisms. For example, based on the measured data of existing protective engineering cases (such as the correlation between wave height attenuation, flow velocity change, water depth disturbance and coral coverage change), the distribution range of the composite influence index I(x, y) is statistically analyzed, and the 75% quantile of the distribution of the composite influence index corresponding to the significant decrease in coral coverage or the damage to geomorphic stability is used as the lower threshold of the high-impact area. Exemplarily, it is assumed that the lower threshold of the high-impact area is set to 0.25, and the upper threshold of the low-impact area is set to 0.15.

[0050] Obtain the impact grading of the protective project based on the above preset threshold and the composite influence index: ; Among them, Level(x, y) represents the impact grading of the protective project at the position (x, y). The high-impact area means that the protective project has significantly changed the local hydrodynamic conditions, resulting in the change range of wave height, flow velocity or water depth exceeding the natural recovery threshold of the ecosystem or the critical value of geomorphic stability. Such areas may have problems such as the failure of coral larvae attachment, abnormal sediment transport or aggravated seabed erosion, and it is necessary to optimize the engineering layout or implement ecological restoration measures preferentially; the medium-impact area means that the degree of hydrodynamic disturbance is controllable, but it has had an observable impact on coral growth, benthic habitat or sediment balance. Such areas need to monitor the correlation changes between hydrodynamic parameters and ecological indicators for a long time to prevent secondary environmental risks caused by the accumulation of disturbances; the low-impact area means that the hydrodynamic changes are within the natural fluctuation range and have not significantly interfered with the functions of the coral reef ecosystem and geomorphic processes. Such areas can be regarded as the safe areas for engineering layout, but sensitive habitats (such as coral-dense areas) still need to be avoided during construction.

[0051] This solution constructs a two-dimensional coral reef terrain profile model and improves the hydrodynamic equation by dynamically parameterizing the coral roughness coefficient and the characteristics of the wave protection project, enabling high-precision simulation of the hydrodynamic spatial distribution of island reefs. First, based on the dynamic calculation of the Manning coefficient for coral types and coverage, the differential impact of coral communities on water flow resistance can be accurately quantified, overcoming the errors caused by fixed roughness parameters in traditional methods. Second, the multi-dimensional combination design of the wave protection project location, structural characteristics, and wave conditions in the engineering parameter matrix can systematically reveal the action laws of different protection layouts on the wave-current field. Finally, through the composite impact index and classification rules for changes in wave height, flow velocity, and water depth, the disturbance range and degree of the project on the hydrodynamic environment can be identified spatially, providing a quantitative basis for optimizing the engineering layout. Compared with the existing technology, this method makes the coupling mechanism between ecological parameters and the hydrodynamic model explicit, realizes the collaborative action analysis of coral reef terrain characteristics, ecological friction effects, and protection engineering structures, and improves the ecological rationality and engineering guiding value of the simulation results.

[0052] An embodiment of the present invention provides a system for evaluating the impact of a protection project on the hydrodynamic spatial distribution of an island reef, which is used to execute the method for evaluating the impact of a protection project on the hydrodynamic spatial distribution of an island reef described in the above embodiment. Figure 3 It is a schematic structural diagram of a system for evaluating the impact of a protection project on the hydrodynamic spatial distribution of an island reef provided by an embodiment of the present invention. Refer to Figure 3 , the system includes the following modules: A data acquisition module, which is used to acquire coral parameter data and protection project parameter data of the target island reef area. A working condition simulation module, connected to the data acquisition module, which is used to perform hydrodynamic simulation based on the coral parameter data and the protection project parameter data. An impact factor calculation module, connected to the working condition simulation module, which is used to determine the difference value of hydrodynamic factors according to the hydrodynamic simulation results. An evaluation module, connected to the impact factor calculation module, which is used to generate a composite impact index based on the difference value of hydrodynamic factors and perform classification of the impact of the protection project.

[0053] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics, characterized in that: The method comprises the following steps: S1. Obtain coral parameter data and protection engineering parameter data of the target island and reef area; S2. Performing hydrodynamic simulation based on the coral parameter data and the protective engineering parameter data; S3, determining a hydrodynamic factor difference value according to the hydrodynamic simulation result; S4. Generate a composite impact index based on the difference value of the hydrodynamic factors and perform a classification of the impact of protective projects.

2. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 1 is characterized in that: In S1, the coral parameter data includes coral type, coral coverage and coral bottom type; The protection project parameter data includes the height, length, porosity and location of the protection project.

3. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 2 is characterized in that: In S2, performing hydrodynamic simulation based on the coral parameter data and the protective engineering parameter data includes: S21, determining a dynamic Manning coefficient based on the coral parameter data; S22, generalizing the topography of the target island and reef area into a two-dimensional topographic profile function; S23, correcting the two-dimensional terrain profile function according to the dynamic Manning coefficient and the protective engineering parameter data; S24. Divide the computational grid based on the modified two-dimensional terrain profile function, define the wave boundary conditions and run the hydrodynamic model to perform hydrodynamic simulation.

4. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 3 is characterized in that: In S21, determining the dynamic Manning coefficient based on the coral parameter data includes: S211, determining a corresponding base Manning coefficient according to the coral substrate type, weighting the coral coverage according to the coral type, and generating a spatially distributed Manning coefficient; S212. Obtain the dynamic Manning coefficient by summing the base Manning coefficient and the spatially distributed Manning coefficient.

5. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 3 is characterized in that: In S24, the wave boundary conditions include wave height and period; The results of the hydrodynamic simulation include instantaneous wave height, flow velocity and water depth.

6. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 5 is characterized in that: In S3, determining the difference value of the hydrodynamic factor according to the hydrodynamic simulation result includes: S31, calculating the time-averaged wave height, time-averaged flow velocity and time-averaged water depth under the conditions with and without the project according to the hydrodynamic simulation results; S32. Determine the difference in hydrodynamic factors based on the time-averaged wave height, time-averaged flow velocity and time-averaged water depth with and without the project.

7. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 1 is characterized in that: In S3, the hydrodynamic factor difference values ​​include: wave height attenuation rate, flow velocity change rate and water depth change rate.

8. The method for evaluating the impact of protective engineering on the spatial distribution of island and reef hydrodynamics according to claim 7 is characterized in that: In S4, generating a composite impact index based on the difference value of the hydrodynamic factor and performing a protective engineering impact classification includes: S41, generating a composite impact index according to the weighted sum of the hydrodynamic factor difference values; S42. Obtaining the protection project impact classification according to the composite impact index and the preset threshold range.

9. A system for evaluating the impact of protective engineering on the spatial distribution of hydrodynamic forces of islands and reefs, used to implement the method for evaluating the impact of protective engineering on the spatial distribution of hydrodynamic forces of islands and reefs as described in any one of claims 1 to 8, characterized in that: The system includes the following modules: Data acquisition module, used to obtain coral parameter data and protection engineering parameter data of target island and reef areas; A working condition simulation module, connected to the data acquisition module, for performing a hydrodynamic simulation based on the coral parameter data and the protective engineering parameter data; An influence factor calculation module, connected to the working condition simulation module, for determining a hydrodynamic factor difference value according to the hydrodynamic simulation result; An evaluation module is connected to the impact factor calculation module and is used to generate a composite impact index based on the difference value of the hydrodynamic factors and to perform a protective engineering impact classification.

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