Coastline defender

Abstract

An artificial seaweed comprising: a seaweed blade; a holdfast for anchoring the seaweed blade to a bottom of a body of water; at least one stipe that couples the seaweed blade to the holdfast; wherein the holdfast comprises a length of chain having links.

Description

RELATED APPLICATIONS

[0001] The present application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application 63 / 435,816 filed on Dec. 29, 2022, the disclosures of which are incorporated herein by reference.FIELD

[0002] Embodiments of the disclosure relate to methods and systems for protecting coastlines against erosion.BACKGROUND

[0003] Coastal erosion is the loss of landmass from shorelines and resultant landward recession of coastlines due to the action of ocean currents and winds on the coastlines. Shoreline damage and rate of erosion are exacerbated by activities of the increasing global human populations. The populations have generated structural changes on land masses bordering coastlines, pollution that has damaged flora and fauna that inhabit coastal regions, and global warming that has already led to rising sea levels and increased deposition of energy from sea and weather patterns on and near to shorelines.SUMMARY

[0004] An aspect of an embodiment of the disclosure relates to providing an artificial seaweed, a plurality of which may be deployed to form an artificial seaweed meadow on a seabed along a coastal region to ameliorate deleterious effects of waves and ocean currents that interact with the coastal region.

[0005] In an embodiment each individual seaweed comprises an artificial blade connected to a holdfast by a stipe. The blade is formed from a suitable polymer so that it has a specific gravity less than that of water and is buoyant and characterized by a pliability similar to that of a natural seagrass or seaweed. The holdfast operates to anchor the blade to the seabed and has a shape and weight so that the blade may be anchored to the seabed simply by dropping the artificial seaweed into the water above a region of the seabed where it is to be deployed. The holdfast may be formed as a length of chain comprising a plurality of relatively heavy links formed from an environment friendly material. Optionally, the links are formed from a black iron. The seaweed stipe may be integrally formed with the blade, optionally from the same material as the blade. Alternatively the stipe may be formed separately from the blade and after being formed joined to the blade. A length of an artificial seaweed is advantageously sufficiently less than a depth of water in which the seaweed is deployed so that the seaweed does not interfere with expected normal human activity along the coastline.

[0006] An aspect of an embodiment relates to a method of configuring deployment of a plurality of artificial seaweeds to form a meadow on a seabed bordering a coastline in which the individual artificial seaweeds are positioned and / or dimensioned to advantageously moderate current flows in water bordering the coastline. In an embodiment the method comprises acquiring a time resolved mapping of currents in the water and configuring positions and dimensions of individual seaweeds in the meadow responsive to the mapping to moderate relatively strong currents in the water. A suitable finite element algorithm is optionally used to determine positions and / or dimensions of the seaweeds in the meadow.

[0007] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE FIGURES

[0008] Non-limiting examples of embodiments of the disclosure are described below with reference to figures attached hereto that are listed following this paragraph. Identical features that appear in more than one figure are generally labeled with a same label in all the figures in which they appear. A label labeling an icon representing a given feature in a figure of an embodiment of the disclosure may be used to reference the given feature. Dimensions of features shown in the figures are chosen for convenience and clarity of presentation and are not necessarily shown to scale

[0009] FIG. 1 schematically shows an artificial seaweed in accordance with an embodiment of the disclosure; and

[0010] FIG. 2 schematically shows a plurality of artificial seaweeds deployed to form a meadow along a coastline, in accordance with an embodiment of the disclosure;DETAILED DESCRIPTION

[0011] In the discussion, unless otherwise stated, adjectives such as “substantially” and “about” modifying a condition or relationship characteristic of a feature or features of an embodiment of the disclosure, are understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment in an application for which it is intended. Wherever a general term in the disclosure is illustrated by reference to an example instance or a list of example instances, the instance or instances referred to, are by way of non-limiting example instances of the general term, and the general term is not intended to be limited to the specific example instance or instances referred to. The phrase “in an embodiment”, whether or not associated with a permissive, such as “may”, “optionally”, or “by way of example”, is used to introduce for consideration an example, but not necessarily required, configuration of possible embodiments of the disclosure. Each of the verbs, “comprise”“include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb. Unless otherwise indicated, the word “or” in the description and claims is considered to be the inclusive “or” rather than the exclusive or, and indicates at least one of, or any combination of more than one of items it conjoins.

[0012] FIG. 1 schematically shows an artificial seaweed 20, in accordance with an embodiment of the disclosure. Seaweed 20 comprises a blade 22 coupled to a holdfast 26 by a stipe 24. Blade 22 is formed from a material such as a flexible polymer so that when subject to forces generated by currents along a coastline in which seaweed 20 is deployed, the blade mimics motion of natural seaweed subjected to similar currents. Stipe 24 is, optionally as schematically shown in FIG. 1, integrally formed with blade 22. Alternatively, stipe 24 may be formed separately from blade 22 and joined to the blade after formation. For example, stipe 24 may be separately made from a same polymer as blade 22 and joined to the blade by bonding, acoustic welding, by stitching, or linking. In accordance with an embodiment, holdfast 26 comprises a length of chain 28 having links 27. Stipe 24 may be attached to at least one link 27 by looping an end 25 of the stipe around the link and sealing the end to the stipe. The chain configuration of holdfast 26 advantageously functions to anchor seaweed 20 in place on coastline soil to which the seaweed is deployed because under the action of coastline water currents links 27 tend to burrow into soft and / or sandy soil that typically characterizes coastline terrain.

[0013] By way of numerical example, seaweed blade 22 may comprise a sleeve made from a thin sheet of flexible material filled with a low density filler. Optionally, the sleeve is formed from PVC (Polyvinyl Chloride) sheet compliant with the internationally recognized standard for Environmental Management Systems (EMS) ISO 14001 and / or the standard for Energy Management Systems (EnMS) ISO 50001 issued by the international Organization for Standardization (ISO). In an embodiment the sheet is similar to PVC sheet used in lining drinking water reservoirs. The filler material may be a crosslinked, closed cell polyethylene foam having a density of about 25 kg / m3 and about 400 kg / m3. The filled sleeve may have a width “W” and thickness “T” indicated in FIG. 1 equal respectively to about 15 cm (centimeters) and 5 mm (millimeters). Assuming that seaweed 20 is to be deployed in water 10 to 15 m (meters) deep seaweed 20 may have a length “L” measured from holdfast 26 equal to about 8-13 m. Holdfast 26 may be made from black iron links 27 having an oval shape characterized by internal major and minor axes equal respectively to about 15 cm and 8 cm and have a weight of about 2 kg (kilograms). A number of iron links in holdfast 26 is determined so that the weight of the holdfast is sufficient to counter buoyancy of blade 22 and maintain the seaweed securely anchored to a seabed in which it is deployed when subjected to forces generated by expected currents in the water column overlying the seabed.

[0014] Whereas in FIG. 1 a single seaweed blade 22 is coupled to holdfast 26, in an embodiment a plurality of seaweed blades, such as seaweed blades 22, may be coupled to a same holdfast to form a compound seaweed. For example, a plurality of optionally six seaweed blades 22 may be coupled to a same holdfast comprising an extended length of chain having links such as links 27. A compound seaweed in accordance with an embodiment may facilitate simultaneous deployment of a plurality of seaweeds.

[0015] It is noted that seaweed 20 shown in FIG. 1 shows a seaweed 20 comprising a blade 22 that is dimensionally and apparently structurally internally uniform. However, a seaweed in accordance with an embodiment is not limited to seaweeds having uniform blades and may be non-uniform. A seaweed in accordance with an embodiment may have a blade 22 in which thickness T or width W is not uniform but a function of location along the blade so that flexibility and / or elasticity of the blade may be tailored to provide desired properties of the blade and its interaction with currents. Or a seaweed blade in accordance with an embodiment may be formed having blind or through holes that operate to affect flexibility and / or elasticity of the blade and interaction of the seaweed with nearshore or offshore water in which it is deployed. Optionally, a seaweed may have a blade for which material from which the blade is made is a function of location in the blade. For example, density or type of the blade material may be a function of location along the width of the blade and / or distance along the blade from the blade holdfast to provide desired blade buoyancy and / or mechanical characteristics, such as pliability and / or elasticity, as a function of location in the blade.

[0016] It is further noted that a seaweed, in accordance with an embodiment may be produced to exhibit different attributes-hue, saturation, and / or lightness-of color. A seaweed may have a blade for which a color attribute changes with location in the blade. For example, hue, saturation and / or lightness of the blade may be a function of distance from a holdfast of the blade, optionally to mimic a change in color exhibited by natural seaweed as a function of depth below a surface of water in which the seaweed is deployed. Or seaweeds in accordance with an embodiment may be colored for use to visually identify different regions of nearshore waters in which they are deployed, for example to indicate regions of nearshore water prohibited to presence of people for reasons of safety or environmental protection.

[0017] In an embodiment a plurality of artificial seaweeds 20 are arrayed to form a meadow of seaweeds to protect a coastline from erosion by currents in a body of water along the coastline. FIG. 2 schematically shows a meadow 40 of artificial seaweed 20 deployed in water 101 and anchored to a coastal sea bottom 102 along a portion of a coastline 100 bordering water 101 along a shoreline 103 to protect the coastline against erosion in accordance with an embodiment of the disclosure. In meadow 40 seaweeds 20 are optionally configured in a regular array of substantially parallel, equally spaced rows 41, in which seaweeds 20 in a given row 41 are equally spaced. Rows 41 may be substantially perpendicular to a component of flow of currents in water 101 substantially perpendicular to shoreline 103. Optionally, as shown in FIG. 2 seaweeds 20 in a same row 41 are deployed as compound seaweed and are coupled to and share a same extended holdfast 26.

[0018] The spacings in a meadow such as meadow 40 may be determined responsive to a spatiotemporal mapping of water currents in water 101 and an algorithm that determines spacings that are best adapted to moderate erosion of coastline 100 due to flow patterns in water 101. And it is noted that whereas meadow 40 shown in FIG. 2 comprises a spatially substantially regular array of seaweeds 20, embodiments of the disclosure are not limited to meadows having regular arrays of artificial seaweed. A meadow for example may comprise seaweeds 20 distributed in spatially irregular arrays. For example, a seaweed meadow in accordance with an embodiment may comprise dense clusters of seaweeds 20 at locations in water along a coastline that has been determined to evidence unusually strong currents and sparse clusters of seaweeds where current flows are determined to be moderate. Or density of seaweeds 20 as a function of distance from a shore of a coastline may increase inversely with distance from the shore to improve absorption of energy is rising waves.

[0019] Whereas FIG. 2 schematically shows seaweeds 20 deployed along a coastline region that does not harbor natural seaweeds to protect the coastline against damage, seaweeds 20 may be deployed in an area of coastline that does harbor natural seaweeds to enhance the protective activity of the natural seaweeds. The positioning of the seaweeds 20 may be determined responsive to a model of the density and protective activity of the natural seaweed already growing along the coastline.

[0020] It is noted that the construction of an artificial seaweed in accordance with an embodiment of the disclosure similar to seaweed 20 allows relatively easy redeployment of deployed seaweeds 20 as water current patterns change with the seasons and / or to adjust positions of the seaweeds in a meadow to improve their protective functioning.

[0021] By way of a numerical example, assuming components of currents in water 101 are relatively uniform and have an average flow velocity in calm weather of about 2 m / s and a stormy weather velocity that may reach about 10 m / s perpendicular to shoreline 103, each row 41 may comprise seaweeds 20 equally spaced apart by about three times the width of the seaweed blades 22. A distance between rows may be equal to between about ⅔ and ¾ of a length of the seaweed blades In an embodiment rows 20 are equally spaced apart by about six times the widths of the seaweeds.

[0022] Descriptions of embodiments of the invention in the present application are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments utilize only some of the features or possible combinations of the features. Variations of embodiments of the invention that are described, and embodiments of the invention comprising different combinations of features noted in the described embodiments, will occur to persons of the art. The scope of the invention is limited only by the claims.

Claims

1. An artificial seaweed comprising:a seaweed blade;a holdfast comprising a length of chain having links for anchoring the seaweed blade to a bottom of a body of water; andat least one stipe that couples directly to the seaweed blade and directly to the holdfast chain.

2. The artificial seaweed in accordance with claim 1 wherein the blade comprises a sleeve formed from thin sheet of flexible material filled with a suitable filler.

3. The artificial seaweed in accordance with claim 2 wherein the thin sheet of flexible material is compliant with the ISO 14001 standard and / or the ISO 50001 standard issued by the international Organization for Standardization (ISO).

4. The artificial seaweed in accordance with claim 2 wherein the thin sheet comprises a PVC (Polyvinyl Chloride) sheet.

5. The artificial seaweed in accordance with claim 2 wherein the thickness of the sheet is between 0.5 mm and 3 mm.

6. The artificial seaweed in accordance with claim 2 wherein the filler material has a density between 25 kg / m3 and 400 kg / m3.

7. The artificial seaweed in accordance with claim 2 wherein the filler material comprises a crosslinked, closed cell polyethylene foam.

8. The artificial seaweed in accordance with claim 1 wherein the blade has a width of about 15 cm.

9. The artificial seaweed in accordance with claim 1 wherein the blade has a thickness of about 5 cm.

10. The artificial seaweed in accordance with claim 1 wherein the blade is dimensionally uniform.

11. The artificial seaweed in accordance with claim 1 wherein the blade is dimensionally non-uniform.

12. The artificial seaweed in accordance with claim 11 wherein the thickness and / or the width of the blade varies with location on the blade.

13. The artificial seaweed in accordance with claim 12 wherein the blade is formed having blind or through holes.

14. The artificial seaweed in accordance with claim 1 wherein the blade is structurally uniform.

15. The artificial seaweed in accordance with claim 1 wherein the blade is structurally non-uniform.

16. The artificial seaweed in accordance with claim 15 wherein density of material from which the blade is formed varies with location on the blade.

17. The artificial seaweed in accordance with claim 15 wherein pliability and / or elasticity of the blade varies with location on the blade.

18. The artificial seaweed in accordance with claim 1 wherein at least one or any combination of more than one of hue, saturation and / or lightness of the surface of the blade varies with location on the surface.

19. The artificial seaweed in accordance with claim 1 wherein the links of the holdfast are formed from black iron.

20. (canceled)21.-24. (canceled)25. A seaweed meadow comprising a plurality of seaweeds in accordance with claim 1.26.-29. (canceled)30. The seaweed meadow in accordance with claim 25 wherein the positions and / or dimensions of the seaweeds in the meadow are determined based on a finite element algorithm and a model of a littoral environment in which the meadow is deployed.

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