Mangrove tree planting method considering ship traveling waves

Abstract

The invention provides a mangrove planting method considering ship traveling waves. The mangrove planting method includes the steps of collecting basic information, calculating the included angle between the wave length and direction of scattered waves and a mangrove vegetation bank slope, and determining the layout of mangroves. Existing researches show that ship waves are one of the main reasons for destroying channels and causing bank slope collapse and damage, and when the mangroves are laid out through the method, the ship waves can be spread to the mangrove forest area to generate phase mutation, so that the ship waves are reduced to protect the bank slope, and the bank slope has the ecological effect.

Description

Technical Field

[0001] The invention belongs to the technical field of coastal engineering, and in particular relates to a mangrove planting method taking ship-borne waves into consideration, aiming at reducing ship-borne waves to protect shore slopes. Background Art

[0002] Ship waves are generated by ships traveling on the water and are distributed in a radial cone along the direction of the ship. These waves include diffusion waves and transverse waves, which form a fan-shaped area behind the ship and propagate to the shore on both sides. Ship waves can cause coastline erosion by continuously impacting the coastline, especially in areas where wave energy is concentrated. The continuous action of waves will carry away coastal sediment, causing the coastline to gradually retreat.

[0003] Coastal erosion caused by ship waves can lead to the destruction of beach landscapes, reduction of beach width, increase of slope, and coarsening of sediment particle size, affecting the tourism function of the beach and coastal space. It may cause damage to coastal infrastructure such as roads, bridges, and submarine cables, aggravate port siltation, and destroy shore protection projects such as seawalls and shelterbelts. It will also destroy the habitats of marine organisms, such as the spawning grounds of turtles, and affect biodiversity and ecosystem balance. The sediment carried by ship waves may be deposited near ports and waterways, causing port siltation and affecting shipping and port operations. Due to the long-term action of ship waves, the coastline may retreat or the beach may be eroded, forming erosion scarps or coarsening of beach surface sediments, affecting beach quality and the stability of the coastline.

[0004] Vegetation revetments that take ship waves into consideration are of great significance for protecting riverbanks and waterways. Vegetation revetments can reduce the energy of ship waves through their root systems and stem and leaf structures, reduce the impact and erosion of waves on the coast, and thus protect the stability of the coast. Studies have shown that the distribution density of vegetation has a significant effect on reducing ship waves, and as the density of plants increases, the effect of reducing ship waves gradually increases. In addition, vegetation revetments also have other ecological functions, such as intercepting and purifying pollution and protecting biodiversity. In summary, while considering the impact of ship waves, vegetation revetments can also provide the dual benefits of ecological protection and environmental beautification, and are an effective technical means to achieve the construction of ecological waterways.

[0005] Therefore, how to achieve scientific design and optimization of vegetation revetment is a problem that needs to be solved at present. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a mangrove planting method that takes ship waves into consideration. The layout design of mangroves is completed by this method. When the ship waves encounter the mangroves with a rhythmic zigzag layout during propagation, the wave path is suddenly emitted, thereby realizing the effective reflection of the ship waves by the mangroves, thereby achieving the purpose of reducing the ship waves. At the same time, through scientific design and optimization, the protective efficiency, stability and environmental adaptability of the vegetation community are significantly improved.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] The present invention provides a mangrove planting method taking ship waves into consideration, comprising the following steps:

[0009] Step 1, collection of basic information:

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

[0011] The ship information includes ship speed v 0 and Kelvin angle θ 0 ;

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

[0013] Calculate the scattered wave wavelength corresponding to the ship wave generated by the ship in the mangrove planting area to be studied, and the angle between the scattered wave direction corresponding to the ship wave and the original mangrove vegetation slope;

[0014] Specifically include:

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

[0016]

[0017] Among them, π is the circumference of a circle, g is the acceleration due to gravity, and v is the velocity of the circle. 0 is the ship speed, θ 0 for Kelvin Point;

[0018] S22, the angle θ between the scattered wave direction and the mangrove vegetation slope is determined by the ship's line and the slope angle θ 1 , Kelvin angle θ 0 Joint decision, all three are met:

[0019]

[0020] Step 3, determination of mangrove layout:

[0021] 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;

[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 vegetation composition, ε 1 The diffraction secondary.

[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 4A 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 v 0 and Kelvin angle θ 0 .

[0040] In this example, it is assumed that the ship speed v in the mangrove planting area to be studied 0 =5m / s, Kelvin angle θ 0 =19.467°, the average plant diameter of mangrove vegetation is a=10cm.

[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 the circumference of a circle, g is the acceleration due to gravity, and v is the velocity of the circle. 0 is the ship speed, θ 0 Kelvin Point.

[0047] S22, the angle θ between the scattered wave direction and the mangrove vegetation slope is determined by the ship's line and the slope angle θ 1 , Kelvin angle θ 0 In this embodiment, it is assumed that the bank slope angle θ 1 is 0, the above three conditions are satisfied:

[0048]

[0049] Step 3, determination of mangrove layout:

[0050] The size parameters of the mangrove layout are calculated based on 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.

[0051] It is assumed that the layout of mangroves in the proposed planting area is a rhythmic trapezoid; the size parameter d of the mangrove layout means that each triangle or arc composed of vegetation has the same unit length.

[0052] 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:

[0053]

[0054] Among them, ε 1 is the diffraction order, which is taken as 1 here.

[0055] Through this embodiment, Figure 2 As shown, a mangrove layout under a mangrove planting method considering ship waves is shown. According to this embodiment, Figure 3 A schematic diagram of the energy dissipation effect of mangroves arranged considering ship waves is given. Figure 4 A schematic diagram of the energy dissipation effect of mangroves with rhythmic semicircular distribution is given.

[0056] It can be seen that the mangrove layout considering ship waves can more effectively reduce ship waves by scientifically analyzing the interaction between ship waves and mangrove vegetation, optimizing the geometric parameters and layout of mangrove vegetation, thereby reducing the huge wave energy carried by ship waves, causing serious erosion of the coastline, and improving the stability of the coastline and the defense against natural disasters. However, the traditional method may ignore the propagation characteristics of ship waves, resulting in poor effect of mangrove vegetation layout on reducing ship waves.

[0057] This application not only enhances the stability of mangrove vegetation itself, resists the impact of ship waves, and reduces the cost of repair caused by mangrove damage, but also effectively improves the survival rate of mangroves and protects their healthy growth. In addition, the mangrove coastal zone laid out by the method described in this application can significantly reduce the direct impact of ship waves on the coastline, thereby improving the stability of the bank slope.

[0058] It should be noted here that all data in the embodiments of the present application are derived from historical statistical data of hydrological stations near the area to be studied. There are no specific values ​​and no 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 wavelength and wave direction mentioned in the article, as well as the wavelength range and wave direction range are all obtained through local hydrological stations or actual measurements. Therefore, there are no specific values ​​and no specific ranges in the article.

[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 scheme, a person skilled in the art should understand that the technical solution of the present invention (such as the use of various formulas, the sequence of steps, etc.) can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A mangrove planting method taking ship waves into consideration, characterized in that: The method comprises the following steps: Step 1, collection of basic information: First, determine the mangrove planting area to be studied, and then collect information on ships traveling in the area to be studied and the average plant diameter a of the original mangrove vegetation; The ship information includes ship speed v0 and Kelvin angle θ0; Step 2: Calculation of the angle between the scattered wave wavelength and the scattered wave direction and the mangrove vegetation slope: Calculate the scattered wave wavelength corresponding to the ship wave generated by the ship in the mangrove planting area to be studied, and the angle between the scattered wave direction corresponding to the ship wave and the original mangrove vegetation slope; Specifically include: S21. The scattered wave wavelength l corresponding to the ship wave generated by ships traveling in the mangrove planting area satisfies: Among them, π is 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 determined by the ship's line, the slope angle θ1, and the Kelvin angle θ0, which meet the following conditions: Step 3, determination of 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 waves generated by ships traveling in the mangrove planting area satisfy: 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.

2. The mangrove planting method considering ship waves according to claim 1, characterized in that: 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.

3. The mangrove planting method considering ship waves according to claim 1, characterized in that: In step 3, the layout of mangroves in the area to be studied includes rhythmic sawtooth triangles or trapezoids.

Images