A mangrove planting method considering ship-generated waves

Abstract

The present invention provides a mangrove planting method considering ship-generated waves. The method includes the collection of basic information, the calculation of the wavelength and wave direction of scattered waves and the included angle between the scattered waves and the mangrove vegetation slope, and the determination of the mangrove layout. Existing research shows that ship-generated waves are one of the main reasons for damaging waterways and causing slope collapses. By using the method of the present invention to layout mangroves, the ship-generated waves can be made to undergo a phase mutation when propagating to the mangrove area, thereby reducing the ship-generated waves to protect the slope and endowing it with ecological effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of coastal engineering, and particularly relates to a mangrove planting method considering ship-generated waves, aiming to reduce ship-generated waves to protect the shore slope. Background Art

[0002] Ship-generated waves are generated when a ship moves on the water surface and are distributed in a radial conical shape along the ship's moving direction. These waves include spreading waves and transverse waves, which form a fan-shaped area behind the ship and propagate towards both sides of the shore. Ship-generated waves may cause coastal erosion by continuously impacting the coastline, especially in areas where wave energy is concentrated. The continuous action of the waves will carry away coastal sediment, resulting in the gradual retreat of the coastline.

[0003] Coastal erosion caused by ship-generated waves will damage the beach landscape, reduce the beach width, increase the slope, and coarsen the sediment particle size, affecting the tourism function of the beach and coastal space. It may cause damage to infrastructure such as coastal roads, bridges, and submarine cables, exacerbate port siltation, and damage shore protection projects such as sea dikes and shelter forests. It will also destroy the habitats of marine organisms, such as the spawning grounds of sea turtles, affecting biodiversity and ecosystem balance. The sediment carried by ship-generated waves may deposit near ports and waterways, causing port siltation and affecting shipping and port operations. Due to the long-term action of ship-generated waves, the coastline may retreat or the shore beach may erode, forming erosion scarps or coarsening of beach surface sediments, affecting the beach quality and the stability of the coastline.

[0004] Vegetation shore protection considering ship-generated waves is of great significance for protecting riverbanks and waterway safety. Vegetation shore protection can reduce the energy of ship-generated waves through its root system and stem and leaf structure, reduce the impact and erosion of waves on the coast, and thus protect the stability of the coast. Research shows that the distribution density of vegetation has a significant effect on reducing ship-generated waves, and as the plant density increases, the effect of reducing ship-generated waves gradually increases. In addition, vegetation shore protection also has other ecological functions, such as sewage interception and purification, and protection of biodiversity. In summary, vegetation shore protection can provide double benefits of ecological protection and environmental beautification while considering the impact of ship-generated waves, and is an effective technical means to realize the construction of ecological waterways.

[0005] Therefore, how to achieve the scientific design and optimization of vegetation shore protection is a problem that needs to be solved currently. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a mangrove planting method considering ship-generated waves. Through this method, the layout design of mangroves is completed. When the ship-generated waves encounter the mangrove forest with a rhythmic serrated layout during propagation, the wave path changes suddenly, thereby realizing the effective reflection of the ship-generated waves by the mangrove forest and achieving the purpose of reducing the ship-generated waves. At the same time, through scientific design and optimization, the protection efficiency, stability and environmental adaptability of the vegetation community are significantly improved.

[0007] The purpose of the present invention is achieved by the following technical solutions:

[0008] The present invention provides a mangrove planting method considering ship-generated waves, including the following steps:

[0009] Step 1, collection of basic information:

[0010] First, determine the mangrove planting area to be studied, and then collect the ship information of the ships traveling in the area to be studied and the average plant diameter a of the original mangrove vegetation.

[0011] The ship information includes the ship speed v0 and the Kelvin angle θ0.

[0012] Step 2, calculation of the scattered wave wavelength and the angle between the scattered wave direction and the mangrove vegetation slope:

[0013] Calculate the scattered wave wavelength corresponding to the ship-generated waves generated by the ships traveling in the mangrove planting area to be studied, and the angle between the scattered wave direction corresponding to the ship-generated waves and the slope of the original mangrove vegetation.

[0014] Specifically, it includes:

[0015] S21. The scattered wave wavelength l corresponding to the ship-generated waves generated by the ships traveling in the mangrove planting area satisfies:

[0016]

[0017] where π is the circumference ratio, g is the acceleration due to gravity, v0 is the ship speed, and θ0 is the Kelvin angle;

[0018] S22. The angle θ between the scattered wave direction and the mangrove vegetation slope is jointly determined by the ship's travel line, the slope angle θ1, and the Kelvin angle θ0, and the three satisfy:

[0019]

[0020] Step 3, determination of the mangrove layout:

[0021] According to the scattered wave wavelength l calculated in Step 2, the angle θ between the scattered wave direction and the mangrove vegetation slope, and the average plant diameter a of the mangrove vegetation determined in Step 1, calculate the size parameters of the mangrove layout.

[0022] Among them, the size parameter d of the mangrove layout, the angle θ between the scattered wave direction and the mangrove vegetation slope, and the scattered wave wavelength l corresponding to the ship waves generated by ships traveling in the mangrove planting area satisfy:

[0023]

[0024] Among them, the size parameter d of the mangrove layout represents the length of each identical unit of the vegetation composition, and ε1 is the diffraction order.

[0025] Furthermore, in step 1, the ship information and the average plant diameter a of the mangrove vegetation are determined by methods including on-site sampling and investigation, and must satisfy: a<d.

[0026] Furthermore, in step 3, the layout of mangroves in the area to be studied includes a rhythmic sawtooth triangle or a trapezoid.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] Mangroves are an important marine ecosystem with significant wave attenuation capabilities. They can serve as a barrier for coastal organisms and effectively reduce the damage to the coastline caused by ship waves. First of all, the mangroves laid out by this method can effectively reduce wave energy and reduce wave erosion of the coastline through the interaction between their roots, stems, and leaves and waves. Moreover, the mangroves laid out by this method serve as natural wave-breaking forest belts, which can resist the impact of waves, reduce the damage to coastal structures by waves, and improve the stability of the coastline. This provides habitats and breeding grounds for many marine organisms, helping to protect and increase biodiversity. It can also promote the interception of organic matter and phosphorus, reducing the risk of their escape to the offshore environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0030] Figure 1 This is a schematic flow chart of a mangrove planting method taking ship-borne waves into consideration according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of vegetation layout provided by an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the energy dissipation effect of mangroves arranged in consideration of ship waves provided in an embodiment of the present invention;

[0033] Figure 4 A schematic diagram of the energy dissipation effect of rhythmic semicircular distribution of mangroves provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example

[0036] like Figure 1 As shown, this embodiment provides a mangrove planting method considering ship waves, comprising the following steps:

[0037] Step 1: Collection of basic information:

[0038] First, the mangrove planting area to be studied is determined, and then the information of ships sailing in the area to be studied and the average plant diameter a of the original mangrove vegetation are collected by consulting historical data and / or field investigation.

[0039] The ship information includes the ship speed v0 and the Kelvin angle θ0.

[0040] This embodiment assumes that the ship speed v0=5 m / s, the Kelvin angle θ0=19.467°, and the average plant diameter a=10 cm in the mangrove planting area to be studied.

[0041] Step 2: Calculation of the angle between the scattered wave wavelength and the scattered wave direction and the mangrove vegetation slope:

[0042] The wavelength of scattered waves corresponding to the ship waves generated by the ships traveling in the mangrove planting area to be studied, as well as the angle between the scattered wave direction corresponding to the ship waves and the original mangrove vegetation slope are calculated.

[0043] Specifically include:

[0044] S21. The scattered wave wavelength l corresponding to the ship wave generated by ships traveling in the mangrove planting area satisfies:

[0045]

[0046] Among them, π is pi, g is the acceleration due to gravity, v0 is the ship speed, and θ0 is the Kelvin angle.

[0047] S22, the angle θ between the scattered wave direction and the mangrove vegetation slope is determined by the ship's line, the slope angle θ1, and the Kelvin angle θ0. In this embodiment, it is assumed that the slope angle θ1 is 0, and the above three conditions are satisfied:

[0048]

[0049] Step 3, determination of mangrove layout:

[0050] Calculate the size parameters of the mangrove layout based on the scattered wave wavelength \(l\) calculated in step 2, the angle \(\theta\) between the scattered wave direction and the mangrove vegetation slope, and the average stem diameter \(a\) of the mangrove vegetation determined in step 1.

[0051] Assume that the mangrove layout method in the proposed planting area is a rhythmic trapezoid; the size parameter \(d\) of the mangrove layout is such that each triangle or arc formed by the vegetation has the same unit length.

[0052] The size parameter \(d\) of the mangrove layout, the angle \(\theta\) between the scattered wave direction and the mangrove vegetation slope, and the scattered wave wavelength \(l\) corresponding to the ship-generated waves in the mangrove planting area satisfy:

[0053]

[0054] where \(\varepsilon_1\) is the diffraction secondary, and here it is taken as 1.

[0055] Through this embodiment, as Figure 2 shown, a mangrove forest layout under a mangrove planting method considering ship-generated waves is demonstrated. According to this embodiment, Figure 3 a schematic diagram of the energy dissipation effect of the mangrove forest layout considering ship-generated waves is given, Figure 4 and a schematic diagram of the energy dissipation effect of the mangrove forest with a rhythmic semi-circular distribution is given.

[0056] It can be seen that the mangrove forest layout considering ship-generated waves can more effectively reduce ship-generated waves by scientifically analyzing the interaction between ship-generated waves and mangrove vegetation, optimizing the geometric parameters and layout methods of mangrove vegetation, thereby reducing the huge wave energy carried by ship-generated waves, preventing serious erosion of the shoreline, and improving the stability of the shoreline and the ability to defend against natural disasters. The traditional method may lead to poor results in reducing ship-generated waves due to ignoring the propagation characteristics of ship-generated waves.

[0057] By considering the mangrove vegetation layout considering ship-generated waves in this application, not only can the stability of the mangrove vegetation itself be enhanced, the impact of ship-generated waves be resisted, and the restoration cost caused by mangrove damage be reduced, but also the survival rate of mangroves can be effectively improved to protect their healthy growth. In addition, the mangrove forest coast belt laid out by the method described in this application can significantly reduce the direct impact of ship-generated waves on the shoreline, thereby improving the slope stability.

[0058] It should be noted here that all the data in the embodiments of this application come from the historical statistical data of the hydrological station near the area to be studied. There are no specific values or specific ranges. This method is general, that is, it is applicable to the geometric layout design of this type of vegetation under any sea conditions. Therefore, the wavelengths and wave directions mentioned in the text, as well as the wavelength ranges and wave direction ranges, are obtained through local hydrological stations or actual measurements. Therefore, there are no specific values or specific ranges in the text.

[0059] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred arrangement, those of ordinary skill in the art should understand that the technical solution of the present invention (such as the application of various formulas, the sequence of steps, etc.) can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for mangrove planting considering ship-generated waves, characterized in that, The method includes the following steps: Step 1, collection of basic information: First, determine the mangrove planting area to be studied, and then collect the ship information of the ships traveling in the area to be studied and the average plant diameter a of the original mangrove vegetation; The ship information includes the ship speed v0 and the Kelvin angle θ0; Step 2, calculation of the scattered wave wavelength and the angle between the scattered wave direction and the mangrove vegetation slope: Calculate the scattered wave wavelength corresponding to the ship-generated ship wave in the mangrove planting area to be studied, and the angle between the scattered wave direction corresponding to the ship wave and the slope of the original mangrove vegetation; Specifically, it includes: S21. The scattered wave wavelength l corresponding to the ship wave generated by the ship traveling in the mangrove planting area satisfies: where π is the pi, g is the acceleration due to gravity, v0 is the ship speed, and θ0 is the Kelvin angle; S22. The angle θ between the scattered wave direction and the mangrove vegetation slope is jointly determined by the ship track, the slope angle θ1, and the Kelvin angle θ0, and the three satisfy: Step 3, determination of the mangrove layout: Calculate the size parameters of the mangrove layout according to the scattered wave wavelength l, the angle θ between the scattered wave direction and the mangrove vegetation slope calculated in Step 2, and the average plant diameter a of the mangrove vegetation determined in Step 1; Among them, the size parameter d of the mangrove layout, the angle θ between the scattered wave direction and the mangrove vegetation slope, and the scattered wave wavelength l corresponding to the ship wave generated by the ship traveling in the mangrove planting area satisfy: Among them, the size parameter d of the mangrove layout represents each identical unit length composed of vegetation, and ε1 is the diffraction secondary.

2. The mangrove planting method considering ship traveling waves according to claim 1, wherein, In Step 1, the ship information and the average plant diameter a of the mangrove vegetation are determined by means including on-site sampling and investigation, and it is required that: a < d.

3. The mangrove tree fixing method considering ship traveling waves according to claim 1, characterized in that, In Step 3, the mangrove layout method of the area to be studied includes a rhythmic zigzag triangle or trapezoid.

Images