US20250237029A1

US20250237029A1 - Erosion control apparatus

Info

Publication number: US20250237029A1
Application number: US18/936,872
Authority: US
Inventors: Seth Wilkinson
Original assignee: Wilkinson Ecological Design Inc
Current assignee: Wilkinson Ecological Design Inc
Priority date: 2018-08-23
Filing date: 2024-11-04
Publication date: 2025-07-24

Abstract

The present invention relates to an erosion control apparatus and methods of using and installing the apparatus. The apparatus is constructed to prevent erosion of soil during typical weather or tidal conditions and adverse weather events. The apparatus can include an anchored marsh installation operative to stabilize a tidal marsh and shoreline.

Description

This application claims priority to U.S. Provisional Application No. 63/547,115 filed Nov. 2, 2923 and is also a continuation-in-part of U.S. patent application Ser. No. 17/982,103, filed Nov. 7, 2022, which is a continuation of U.S. patent application Ser. No. 16/548,422, filed Aug. 22, 2019, which claims the benefit of provisional application No. 62/721,765, filed Aug. 23, 2018, and this application is a continuation-in-part of U.S. patent application Ser. No. 17/866,143 filed on Jul. 15, 2022, which claims the benefit of provisional application No. 63/222,631, filed on Jul. 16, 2021, the entire contents of each of these applications being incorporated herein by reference.

BACKGROUND OF THE INVENTION

Historically, conventional, or “hard engineering” structures have been used to defend against erosion from adjacent water courses or water bodies. While effective, these techniques have proven to have considerable undesirable physical impacts of increasing erosion to adjacent land forms or other “down-stream” natural resources. This is primarily due to the hardness of these structures which reflect and/or transmit the energy contained in waves, currents, and scour from moving water onto the nearby landforms which have not been “hardened” through the installation of structural elements. The reflection of waves, currents, and scour results in increased erosion of adjacent resources such as beaches, tidal areas, subsurface features immersed in water, river courses, lakebeds, and important upland land features which often protect other structures such as homes, roadways, and utilities.
To address damage to adjacent resources, many regulatory agencies, environmental advocacy organizations, and environmental contractors have embraced bioengineering and the “Living Shoreline” approach, which is now a nationally-known campaign by the National Oceanic and Atmospheric Administration (NOAA) in the United States of America. In some US states, state wetland regulations prohibit the use of conventional hard engineering structures to protect structures on properties. In these instances, “soft”, bioengineering measures such as those promoted by the NOAA Living Shoreline program are the only alternatives available for coastal property owners. Unfortunately, bioengineering measures promoted by the Living Shorelines program are not robust or structurally sound enough to defend against erosion in portions of the shoreline which are exposed to higher intensity storms such as oceanfront areas, coastal bays, larger estuaries, larger rivers, and lakes.
Conventional, environmentally friendly bioengineering approaches for stabilizing the base of landforms along exposed shorelines can provide structural integrity at the toe of landforms near the shoreline in order to stabilize these landforms. While these approaches are all somewhat effective at stabilizing exposed landforms, they are generally believed to have much lower success when used along ocean fronting land forms, within larger estuaries, larger rivers, and along the shorelines of larger lakes. It is important to note that an effective and reliable strategy for soft bioengineering methodology presently does not exist for most of the oceanfront, larger estuaries, larger rivers, and along the shorelines of larger lakes. Therefore, the owners of real estate must rely on conventional hard engineering structures, which typically exacerbate shoreline erosion in nearby locations or must rely on substandard soft engineering alternatives which are not robust enough for the given site conditions and level of exposure.

SUMMARY OF THE INVENTION

The present invention addresses the problems of conventional bioengineering installations by providing an erosion control apparatus and methods of installing same. Fiber rolls and fabric encapsulated soil (FES) lifts are combined in anchored configurations together with synthetic mesh netting, to create bioengineered installations with greater durability, greater resistance to storm, sea and water erosion, and corresponding longer useful life, lengthening repair cycles and facilitating the repair process.
In some embodiments, an erosion control apparatus comprises a plurality of fiber rolls, wherein the rolls are arranged relative to a contour of a shoreline; a plurality of anchors coupled to the fiber rolls, the anchors inserted at a depth through the apparatus; a plurality of soil lifts comprising fiber, the soil lifts are connected to the fiber rolls. A mesh can comprise a layer contacting the soil lifts, wherein the anchors pass through the mesh and the soil lifts and optionally enter the soil underneath the apparatus. This operates to distribute the anchoring force across the system. The fiber rolls are situated directly over a plurality of anchors at different levels of the system so that coupling of the system elements causes compression and loading of the anchor system. Thus, the weight of the entire system serves to aid in the retention of the anchor placements.
Further embodiments can utilize a reinforced marsh installation in which a combination of cobblestone, dispersed coir fibers, compost an sediment are encased in a container that can include layers or coir fiber fabric and jute-burlap, for example. The cobblestones can have an average maximum diameter in the range of 8-12 inches that constitute at least 40% of the mixture within the marsh container. One or more marsh containers can be used at a location requiring erosion control and can be used with or without an array of fiber rolls to stabilize a shoreline.
The plurality of fiber rolls can comprise a coir fiber and can be either high density or low density. In an embodiment, the plurality of anchors are duckbill anchors. The anchors can be spaced at intervals across each fiber roll to distribute loading across the structure. Each anchor can include a cable or rod connected to an anchor point surface sized to support an overlying cone of material. In an embodiment, the intervals range from twenty-four inches to thirty inches, for example. In an embodiment, the anchors can be inserted at a depth of at least forty-two inches below a slope or grade of the apparatus and can provide at least three thousand pounds of holding force at each insertion point. The anchors preferably extend at an angle that is orthogonal to the plane of the rolls. However, certain embodiments can be configured such that the anchors extend at an angle that is within 45 degrees of the orthogonal direction, or preferably within 30 degrees of the orthogonal direction from the plane of the rolls.
The soil lifts can comprise at least one layer of coir fabric and may be configured to retain sediment. In some embodiments, the sediment is compacted and can have a depth of at least twelve inches. In some embodiment, the mesh contacting the soil lifts comprises polypropylene, polyethylene, or similar synthetic material. In other embodiments, the mesh comprises coir fiber.
In some embodiments, the apparatus further comprises at least a first trench at a highest end of the apparatus. In further embodiments, the apparatus further comprises a second trench located at a lowest end of the apparatus. Each trench can be backfilled with sand or soil. In some embodiments, the first trench and the second trench are at least six inches wide and at least six inches deep. In some embodiments, each trench is covered with sand or soil.
In some embodiments, the apparatus further comprises plant material on or with at least one fiber roll. The mesh may cover at least one of the fiber rolls. Additional lifts may be added over time to the apparatus by constructing more soil lifts on the top or side of the rolls. In some embodiments, the apparatus further comprises at least one erosion control blanket, which can optionally comprise a biodegradable material.
In some embodiments, a plurality of posts are placed along at least a front roll of the apparatus relative to the shoreline. The lifts may be secured with the posts or stakes.
In some embodiments, a method of installing erosion control apparatus comprises placing a mesh within an excavated site; placing a layer of coir fabric over the mesh; arranging a plurality of fiber rolls relative to a shoreline; connecting a plurality of soil lifts to the fiber rolls, the soil lifts comprising fiber; folding the mesh and the fabric over the soil lifts and the rolls; and inserting a plurality of anchors adjacent or coupled to the fiber rolls, the anchors being inserted at a depth, wherein each of the anchors passes through the mesh, the fabric, and at least one soil lift.
In further embodiments, the anchor system can include rocks, concrete, or other formed components that can be installed prior to placement of the soil lifts and/or fiber rolls. Cables or other coupling rods or elements can be attached to these anchor components by a formed loop in the cable, threaded eyelets or other fixtures suitable to connect the anchors to the rolls. Each anchor point can be attached to one or more fiber rolls. The connecting cables can be attached to the anchor points prior to placement of the soil lifts and fiber rolls. The cables can extend around or extend through slots in the soil lifts.
Generally, the space between the fiber rolls and the anchor points and related anchor surface area has a fill material. This fill material can include soil, rocks, and/or the soil lifts. The fill material is confined by the overlying fiber rolls which combine to load the anchor system. The system components are coupled to the anchoring system to substantially increase the stability of the system during storms and tidal or flooding events.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an erosion control apparatus, according to some embodiments.

FIG. 2 is a side view of an erosion control apparatus including wire baskets, according to some embodiments.

FIG. 3 is a side view of an erosion control apparatus including stakes, according to some embodiments.

FIG. 4 is a close-up side view of a coir fiber roll according to some embodiments.

FIG. 5A depicts a side view of an erosion control apparatus including multiple slope angles, according to some embodiments.

FIG. 5B depicts a side view of a section of an erosion control apparatus and the angular positioning of elements of the apparatus, according to some embodiments

FIG. 6A depicts a side view of an anchor's load according to some embodiments.

FIG. 6B depicts a side view of an anchor's load in an apparatus according to some embodiments.

FIG. 6C depicts a side view of an anchor's load in an apparatus with reinforced anchoring elements according to some embodiments.

FIG. 6D depicts a side view of an anchor's load in an apparatus including concrete according to some embodiments.

FIGS. 7A and 7B are side views of coir fiber rolls covered in sand according to some embodiments.

FIG. 8 is a side view of marsh pillows or containers according to some embodiments.

FIG. 9 is a side view of stakes utilized in an erosion control apparatus according to some embodiments.

FIGS. 10A, 10B, 10C, and 10D are a top view, side view, perspective view, and a front view of an assembled apparatus according to some embodiments.

FIG. 11A depicts a method of installing an erosion control apparatus, according to some embodiments.

FIG. 11B depicts a method of inserting anchors to secure fiber rolls and soil lifts according to some embodiments.

FIG. 12A is a side view of an inserted anchor according to some embodiments.

FIG. 12B is a side view of an inserted anchor according to some embodiments.

FIG. 13 is a side view of an anchoring system inserted relative to soil saturation according to some embodiments.

FIG. 14A is a side view of an anchoring system including reinforcement elements according to some embodiments.

FIG. 14B is a side view of an anchoring system including concrete according to some embodiments.

FIGS. 15A and 15B are side views of an anchoring system including helical anchors according to some embodiments.

FIG. 16A is a side view of a shared anchor cable system according to some embodiments.

FIG. 16B is a side view of a shared anchor cable system including a connecting cable according to some embodiments.

FIG. 17 is side view of an erosion control apparatus including helical anchors, according to some embodiments.

FIG. 18 is a side view of an inserted helical anchor according to some embodiments.

FIG. 19 is a side view of an erosion control apparatus including one fiber roll, according to some embodiments.

FIGS. 20A, 20B, 20C, 20D, 20E, and 20F are side views depicting the installation of a whip cable in an erosion control apparatus according to some embodiments.

FIG. 21 is a side view of an erosion control apparatus including a reinforced salt marsh pillow according to some embodiments.

FIG. 22 is a side view of a reinforced salt marsh pillow according to some embodiments.

FIG. 23 is a cross-sectional view of a marsh stabilization installation for an existing marsh in accordance with preferred devices and methods described herein.

FIG. 24 is an enlarged sectional view of the shellfish retention system for restoration of shellfish populations in shoreline/marsh stabilizing structures.

FIG. 25 is a further enlarged sectional view of a further shellfish restoration installation. illustrates a system for installing and/or repairing a fiber roll array system having at least partial anchoring using one or more helical anchors.

FIG. 26 is a side view of an installed fiber roll anchor anchored to the slope of a shoreline with a plurality of helical anchors.

FIG. 27 is an expanded view of a cable connected to the top ends of helical anchor shafts to harness the anchors to the fiber roll array in accordance with preferred embodiments.

FIG. 28 is an expanded view of the fiber roll anchoring system described herein

FIGS. 29A and 29B show a process sequence for repairing a fiber roll array having one or more helical anchors.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various embodiments of the disclosed devices and methods, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, the use of the term “including”, as well as other forms, such as “includes” and “included”, is not limiting. Any range described herein will be understood to include the endpoints and all values between the endpoints.
Prior to this disclosure, there has not been a reliable and robust bioengineering method of stabilizing an exposed landform in locations of higher erosion risk, such as oceanfront, estuarine, riverfront, lakefront, and other features of land bordering a body of water.
The present disclosure incorporates the benefits of mass and weight of sediment-filled lifts and the benefits of fiber rolls to prevent sediment from liquefying and flowing through the fabric in storm or flooding events. The present disclosure also relies on anchoring the fiber rolls with the use of earth anchors. The earth anchors can include different structures such as helical-style anchors and duckbill-style anchors, provided they can be positioned below grade and provide superior holding power. In some embodiments, the earth anchors are produced by A. B. Chance Company located in Centralia, Missouri. In some embodiments, the anchors are rock anchors such as those produced by MilSpec® Anchors located in Alexander City, Alabama. In an embodiment, earth anchors provide a minimum of 3,000 pounds of holding force at each anchor point. In an embodiment, each element of the disclosed apparatus provides a minimum of 3,000 pounds of holding force. Anchor points are installed at intervals of approximately twenty-four to thirty inches along an edge of each fiber roll. In some embodiments, anchor points are installed at intervals of approximately twenty-four to ninety-six inches along an edge of each fiber roll. In an embodiment, the anchor points are installed every thirty inches from along the top and bottom edge of each fiber roll.
Prior to this disclosure, property owners were faced with choosing between substandard, soft bioengineering techniques which require frequent repairs or fail during storm conditions. Such conditions increase the forces of moving water on the bioengineering components or conventional engineering approaches which tend to reflect storm energy and exacerbate erosion damage to adjacent or down-stream natural resources. Neither conventional engineering approaches or prior bioengineering techniques were well-matched for sea level rise. Conventional engineering measures for erosion control do not support plants and often cannot be expanded in a modular technique without major foundational reconstruction. While fiber rolls and similar bioengineering methods provide good support for the root systems of plants, the inability to hold the fiber rolls in place during a storm event undermines the ability for plants to become established as the plants are damaged every time the array becomes dislodged. Successful bioengineering relies extensively on the integrity of the plant root systems for long-term performance.
The present disclosure not only provides substantially more structural integrity than any other bioengineering method for shoreline protection, but due to its superior structural integrity and ability to support plant growth, the important role plants play in all bioengineering designs is enhanced and secured on a substantially longer timeframe. The disclosed apparatus are also readily expandable, making it possible to increase the number of lifts over time by simply constructing more lifts on the top or sides of the array without making any other structural changes to the array or damaging the supporting bioengineering materials and plants. In some instances, more than one apparatus can be installed at the same site vertically, horizontally, or a combination thereof. Conversely, conventional engineering methods such as sea walls often require substantial increases in their foundation or embedment below grade before their height can be increased. The expandability of the present disclosure makes it a preferred alternative in marine environments undergoing sea level rise.
The disclosed apparatus, in some embodiments, is installed in a site above ground water in the surrounding soil. In other embodiments, the lowest section of the disclosed apparatus is inserted no more than one foot into ground water.
FIG. 1 is a side view of an erosion control apparatus, according to some embodiments. The apparatus 100 comprises at least one coir fiber roll 110. The coir fiber rolls 110 may be either high density or low density. For one example, 20″ diameter by 10′ long, high density fiber rolls are measured at a nine pound per cubic foot density, comprised of a mattress of inner coir fibers encased in a UV stabilized synthetic polypropylene mesh. Alternatively, the high density fiber rolls are comprised of a mattress of inner coir fibers encased in a 100% biodegradable coir rope mesh. In a further example, 20″ diameter by 20′ long, low density fiber rolls are measured at a seven pound per cubic foot density, comprised of a mattress of inner coir fibers encased in a UV stabilized synthetic polypropylene mesh. In some embodiments, some or all of the low density fiber rolls are 20″ diameter by 10′ long.
The coir fiber rolls 110 are arranged along a shoreline, riverbank, lakefront, or other waterfront. The soil behind the coir fiber rolls 110, relative to the shoreline, riverbank, lakefront, or other waterfront, may be graded. In some embodiments, the soil is graded at a slope angle in a range of 0 to 45 degrees (1:1 slope). In an embodiment, the soil is graded at a slope angle in a range of 20 to 50 degrees. In a further embodiment, the soil is graded at a slope angle no greater than 33 degrees (2:1 slope). The slope angle may be 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 degrees, or any angle in between. In some embodiments, the soil of the apparatus 100 can include varying slope angles throughout the apparatus 100. The coir fiber rolls are described in greater detail below with respect to FIG. 4 . Varying slope angles are described in greater detail below with respect to FIGS. 5A and 5B.
The coir fiber rolls 110 are anchored with the use of anchors 120. The anchors 120 may be referred to as “earth anchors” and may be helical-style anchors, duckbill-style anchors, or any other type of anchor that can be driven below grade. The anchors 120 are inserted at a specified depth into the soil lifts 130 or the soil underneath the apparatus 100. In some embodiments, the anchors 120 are inserted adjacent to the plurality of the coir fiber rolls 110. In an embodiment, each anchor 120 provides a minimum of three thousand pounds of holding force. The distribution of anchors is described with more detail with respect to FIGS. 6A-6D.
In an embodiment, the anchors 120 are installed across a face of the coir fiber rolls 110. In some embodiments, the anchors 120 are inserted adjacent to the coir fiber rolls 110 to secure the coir fiber rolls 110. In some embodiments, the anchors 120 are inserted adjacent to multiple coir fiber rolls 110. The anchoring system of the apparatus 100 further comprises ¼″ galvanized aircraft cable 116 and zinc-coated copper crimps. The crimps are used to form a loop in the cable 116. Cables 116 are attached to each earth anchor 120 by forming a loop with a crimp. One cable 116 may be joined to another cable 116 by securing two loops together. These cables 116 form a network of cables 116 which harness the coir fiber rolls 110 and all tie back to the individual anchors 120 to create a high degree of integrity. The anchors 120 are placed to a depth of at least 42″ below finished slope grade into naturally or artificially compacted soil using a hardened steel driving rod. Deeper anchor placements can be used with greater slope angles or more exposed formations.
The apparatus 100 further comprises a plurality of fiber encased soil lifts 130. The soil lifts 130 can comprise two layers of seven hundred-gram (or heavier) woven coir fabric encased by high tenacity polypropylene or polyethylene synthetic mesh 140 that is resistant to ripping. The soil lifts 130 are configured to retain sediment and allow the sediment to naturally compact within the soil lift 130. All sediment in each soil lift 130 preferably has a consistent depth of approximately 12″, but the depth of each soil lift 130 can vary across the apparatus 100. The sediment in each soil lift 130 can be compacted using a portable plate compactor at 6″ soil depth intervals.
In some embodiments, each soil lift 130 in an apparatus 100 is of uniform length. In some embodiments, the length of each soil lift 130 is four feet. In some embodiments, the length of each soil lift 130 is eight feet. In some embodiments, the top soil lift 130 has a length of eight feet and each other soil lift 130 has a length of four feet. In some embodiments, each soil lift 130 has a length of about three to three and a half feet.
The soil lifts 130 are connected to the coir fiber rolls 110. Additional soil lifts 130 can be added to the apparatus 100 over time by constructing the additional soil lifts 130 onto the top of the coir fiber rolls 110, for example. The completed series of coir fiber rolls and soil lifts may be referred to as a protection array, configured to protect a shoreline. In some embodiments, the coir fiber rolls 110 are incorporated into, or encapsulated within, the soil lifts 130.
In some embodiments, the soil lifts 130 can optionally be coupled to one another by fasteners or coupling elements 108 such as stakes, hog rings, or clips. As an example, hog rings may be inserted through two adjacent soil lifts 130 and subsequently bent with pliers, or other manipulation means, to bend the hog rings into a circular shape to couple the adjacent soil lifts 130. In some embodiments, the fasteners or coupling elements 108 are stainless steel. In some embodiments, rope is weaved through the surface of adjacent soil lifts 130 to couple the soil lifts 130. The fasteners or coupling elements 108 serve to mechanically couple the soil lifts 130 together.
The synthetic mesh 140 is incorporated as an outward layer of fabric used for developing fabric encased soil lifts. In some embodiments, the mesh 140 comprises raschel polypropylene knotless netting, 3 mm high tenacity (rip resistant), 1½″ mesh opening, with enhanced UV stabilization. In other embodiments, the mesh 140 comprises polyethylene. In other embodiments, the mesh 140 comprises 100% biodegradable coir fabric. In some embodiments, the mesh opening can range from ½″ to 7″. In an embodiment, the mesh 140 covers the coir fiber rolls 110 that are not filled with plant material 170. In a preferred embodiment, the netting is not photo-degradable. The earth anchors 120 pass through the mesh 140 and soil lifts 130 into the soil beneath. In some embodiments, the synthetic mesh 140 can be substituted with a layer of coir fabric.
After installation of the mesh 140, the coir fiber rolls 110 covered by the mesh 140 are at least partially covered by sand 150. In an embodiment, the first six coir fiber rolls 110 relative to the shoreline, riverbank, lakefront, or other waterfront are at least partially covered by the mesh 140 and sand 150. The number of coir fiber rolls 110 covered by the mesh 140 and sand 150 may be adjusted based on the conditions of the site of the apparatus 100. The inclusion of sand 150 is described in more detail below with respect to FIGS. 7A and 7B.
A plurality of posts 160 may be placed at intervals along at least the front coir fiber roll 110 of the apparatus 100 relative to the shoreline, riverbank, lakefront, or other waterfront. The posts 160 provide additional support for the apparatus 100. In an embodiment, the posts 160 may be 4″ by 4″ or 6″ by 6″, and spaced at 5 foot intervals along the first coir fiber roll 110. In some embodiments, the apparatus 100 does not include posts 160.
In some embodiments, coir fiber rolls 110 not covered by the mesh 140 are filled with plant material 170. In other embodiments, at least one of the coir fiber rolls 110 covered by the mesh 140 or incorporated into the soil lifts 130 are filled with the plant material 170. The plant material 170 may be any vegetation with suitable roots for securing the apparatus 100 from eroding. In an embodiment, the plant material 170 is American beachgrass. In other embodiments, the plant material 170 may be any native plantings appropriate to the site conditions, which will grow quickly and stabilize the landform.
In some embodiments, the apparatus 100 includes marsh pillows 190. The pillows 190 may be installed between the apparatus 100 and the shoreline. The pillows 190 are described in greater detail below with respect to FIG. 8 .
FIG. 2 is a side view of an erosion control apparatus 100, according to some embodiments. In these embodiments, the apparatus 100 includes at least one wire basket 165. In some embodiments, the wire basket 165 is a vinyl coated, welded, and galvanized gabion. The wire basket may be utilized as a substitute of the anchor posts 160 or in conjunction with the anchor posts 160. In some embodiments, the dimensions of the wire baskets 165 are at least 1′×2′×6″. The wire baskets 165 can be filled with heavy materials such as rock or shells.
In an embodiment, the apparatus 100 further comprises at least one erosion control blanket 180. In an embodiment, the blanket 180 is biodegradable and may degrade over approximately a three year period. In a further embodiment, the blanket 180 comprises coir fiber netting. The blanket 180 may be secured with the posts 160. In some embodiments, the blanket 180 may be secured with the earth anchors 120. If multiple blankets are employed, an interior blanket is typically a straw/coir/jute, short term, composite erosion control blanket and an exterior blanket is typically 700 or 900-gram woven coir fabric. The blanket 180 is further configured to provide UV protection to the coir fiber rolls 110. The blanket 180 is further configured to prevent chafing between the coir fiber rolls 110 and the cables 116 during storm events.
In an embodiment, a composite erosion control blanket 185 is installed within forty-eight hours of grading the soil above (up gradient) the coir fiber rolls 110 relative to the shoreline, riverbank, lakefront, or other waterfront. In an embodiment, the composite erosion control blanket 185 is secured with a first trench located at a first end of the apparatus 100, the first end being positioned substantially parallel to the shoreline and at a highest end of the apparatus 100 furthest from the shoreline. In a further embodiment, the mesh 140 is secured with a second trench at a second end of the apparatus 100, the second end being positioned substantially parallel to the shoreline and at a lowest end of the apparatus 100 closest to the shoreline. In an embodiment, the trenches are 6″×6″ (that is at least six inches wide and six inches deep) lock-in trenches at the top and bottom of the slope with a minimum of 6″ overlaps in the transition from one horizontal width of erosion control blanket to the next. 30″ hardwood stakes 135 can be used at a spacing of 36″ on center with ¼″ biodegradable twine used to secure the composite 185 to the ground surface. The trenches may be backfilled, seeded, and lightly mulched with sterilized, weed-free chopped straw or comparable equivalent mulch product.
FIG. 3 is a side view of an erosion control apparatus 100, according to some embodiments. In some embodiments, the apparatus 100 includes at least one stake 135. The stakes 135 may be inserted through the soil lifts 130. The stakes are described in more detail below with respect to FIG. 9 .
FIG. 4 is a close-up side view of a coir fiber roll 110 according to some embodiments. A coir fiber roll 110 includes an inner portion 112 of coir fiber. In some embodiments, the inner portion 112 of coir fiber is 20″ in diameter. The inner portion is surrounded by a layer 114 of coir fabric. In some embodiments, the weight of the layer 114 of coir fabric may range between seven hundred to nine hundred grams. The layer 114 of coir fabric may be covered by the mesh 140. Cables 116 may be secured around the mesh 140. The cables 116 are attached to the anchors 120. In some embodiments, the cables 116 are spaced at two and a half feet distances across the coir fiber rolls 110.
FIG. 5A depicts a side view of an erosion control apparatus including a plurality of slope angles, according to some embodiments. The coir fiber rolls 110 may be arranged at varying slopes throughout the apparatus 100. The preferred configuration of the coir fiber rolls 110 may be determined based on the factors such as the shape of the shoreline at the excavation site, the anticipated forces the apparatus 100 will endure, and the desired slope after insertion of the apparatus 100. An embodiment can use a first contiguous set of rolls 102 at a first slope angle, a second contiguous set of rolls 104 at a second slope angle that is steeper than the first set, extending at a greater angle, and a third set contiguous set of rolls 106 can be at a third angle that is situated at a greater or lesser angle as required.
The soil behind the coir fiber rolls 110, relative to the shoreline, riverbank, lakefront, or other waterfront, may be graded. In some embodiments, the soil is graded at the same slope angle as the coir fiber rolls 110. In some embodiments, the soil is graded at a different slope angle than the coir fiber rolls 110. The coir fiber rolls 110 and/or the soil may be graded at a slope angle in a range of 0 to 45 degrees (1:1 slope). In an embodiment, coir fiber rolls 110 and/or the soil is graded at a slope angle in a range of 20 to 50 degrees. In a further embodiment, coir fiber rolls 110 and/or the soil is graded at a slope angle no greater than 26.6 degrees (2:1 slope). In a further embodiment, coir fiber rolls 110 and/or the soil is graded at a slope angle no greater than 18 degrees (3:1 slope). The slope angle may be 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 degrees, or any angle in between. In some embodiments, the soil of the apparatus 100 can include varying slope angles throughout the apparatus 100.
Each anchor 120 may be inserted at varying angles throughout the apparatus 100. FIGS. 5A and 5B depict multiple anchors 120 inserted at various angles with the cable passing through one or more elements of the apparatus 100. An anchor 120 may be inserted with the cable oriented at an angular range θ₁relative to the slope angle of the soil at the insertion point of the anchor 120 or, if different, the slope angle θ₂of the coir fiber rolls 110. An anchor 120 may be inserted as described previously herein in a direction orthogonal to the soil grade or coir fiber rolls 110. An anchor 120 may be inserted at an angle up to 45 degrees relative to the orthogonal direction (normal) to the plane. In some embodiments, an anchor 120 may be inserted up to 10 degrees relative to the orthogonal direction or plane. In some embodiments, an anchor 120 may be inserted up to 20 degrees relative to the orthogonal direction. In some embodiments, an anchor 120 may be inserted up to 30 degrees relative to the orthogonal direction. In some embodiments, an anchor 120 may be inserted up to 40 degrees relative to the orthogonal direction.
The anchors 120 may all be inserted at the same angle throughout the apparatus 100 or the insertion angle of the anchors 120 may vary throughout the apparatus 100. In some embodiments, each anchor 120 is inserted at the same angle relative to the orthogonal plane. In some embodiments, each anchor 120 is inserted at varying angles relative to the orthogonal plane. In such embodiments, some of the anchors 120 may be inserted at similar angles relative to the orthogonal plane.
In some embodiments, the anchor 120 inserted closest to the shoreline may be inserted vertically. A vertical anchor 120 is advantageous when the apparatus 100 is installed above a seawall, bulkhead, or other traditional structure used to reduce erosion from adjacent water courses or water bodies to connect the apparatus 100 to the seawall, bulkhead, or other traditional structure.
An anchor 120 may secure one or more coir fiber rolls 110. In some embodiments, an anchor 120 may pass through one or more soil lifts 130. In some embodiments, an anchor 120 may pass through the mesh 140 and sand 150. In some embodiments, each individual anchor 120 may secure the same or different elements of the apparatus 100 as other anchors 120.
FIG. 5B depicts a side view of a section of an erosion control apparatus and the angular positioning of elements of the apparatus, according to some embodiments. The one or more coir fiber rolls 110 are installed along a plane (depicted in FIG. 5B) relative to a base layer of earth. Sections of the apparatus 100 may be installed along multiple planes. The angle between such a plane and the base layer is labeled as θ₂.
Each anchor 120 is inserted at an angle relative to a plane relative to a base layer of earth. The insertion angle of the anchor 120 may be normal (orthogonal) to a plane as depicted in FIG. 5B. In some embodiments, an anchor 120 is inserted an angle relative to the normal. The angle of the anchor 120 is labeled as θ₁. In some embodiments, each anchor 120 is inserted at an angle within 30 degrees of the normal. An anchor 120 includes a rod or cable that extends at the defined angle.
FIG. 6A depicts a side view of an anchor's load according to some embodiments. In some embodiments, an anchor 120 is driven into the soil at a ninety-degree angle relative to the soil. In some embodiments, an anchor 120 is locked into place by applying stress to the anchor tendon 125, the connecting segment or element of the anchor 120 in the opposite direction to which the anchor 120 was driven. The tendon 125 is generally a steel aircraft cable or a metal rod. The anchor 120 rotates ninety degrees and a frustum cone 126 of soil is formed as the soil is compacted and bonded. The frustum cone 126 enables an anchor 120 to support a large load. In some embodiments, each anchor 120 supports three thousand pounds of force.
The anchors 120 utilized in the apparatus 100 may be helical-style anchors, duckbill-style anchors, or any other type of anchor that can be driven below grade. In a preferred embodiment, the apparatus utilizes duckbill-style anchors. In some embodiments, the anchors 120 may be installed approximately every twenty-four to thirty inches along the top and bottom edge of each coir fiber roll 110.
The density of the anchors 120 per square foot is dependent on the height of the apparatus 100. In an embodiment with 2.5′ and 3.3′ spacing between the center axes of adjacent coir fiber rolls 110, the apparatus includes three to four cables 116 per coir fiber roll 110. Therefore the range of anchor density for an apparatus 100 from one coir fiber roll 110 high to one hundred coir fiber rolls 110 high is generally in a range of eighteen to forty-eight anchors 120 per one hundred square feet.
In an embodiment including four cables 116 per 10′ coir fiber roll 110, the anchor density can be twenty-four to forty-eight anchors 120 per one hundred square feet. In embodiment including one coir fiber roll 110, the anchor density can be thirty-six to forty-eight anchors 120 per one hundred square feet. In an embodiment including five coir fiber rolls 110, the anchor density can be twenty-two to twenty-nine anchors 120 per one hundred square feet. In an embodiment including ten coir fiber rolls 110, the anchor density can be twenty to twenty-six anchors 120 per one hundred square feet. In an embodiment including one hundred coir fiber rolls 110, the anchor density can be eighteen to twenty-four anchors 120 per one hundred square feet.
In one embodiment, at least twenty to twenty-nine anchors 120 are inserted per one hundred square feet. In an embodiment, the anchors 120 are driven into the soil by a hydraulic hammer. Typically, the anchors 120 have a distal portion comprising an anchor point 127 that can comprise a duckbill or helical segment, or a plate, for example. This anchor point 127 has a surface area 129 that supports a cone shaped load 126 of overlying soil and structure. The anchor point 127 surface area 129 is preferably at least four square inches or larger. The anchors 120 are positioned so that the cone shaped load 126 at least overlaps the cone 128 of an adjoining anchor 120.
FIG. 6B depicts overlapping frustum cones 126 in an apparatus according to some embodiments, FIG. 6C depicts overlapping frustum cones 126 in an apparatus with reinforced anchoring elements according to some embodiments, and FIG. 6D depicts overlapping frustum cones 126 in an apparatus with concrete according to some embodiments. The overlapping frustum cones 126 provide reinforced support across the apparatus 100 as multiple anchors support the overlapping sections. Each frustum cone in FIG. 6B originates from an anchor point surface area 129. Each frustum cone in FIG. 6C and FIG. 6D originates from an anchor point 127 embedded in a reinforcement element. The cones 126 depicted in FIGS. 6B, 6C, and 6D are illustrative and do not necessarily portray the exact load supported by each anchor. This will depend on the effective loaded surface area of the anchoring system.
In a further embodiment, the anchors 120 are driven into the soil by an impact of eighteen ft/lb of impact energy at a rate of two thousand three hundred (2300) blows/minute, for example. This impact energy can vary depending on soil conditions and the anchor depth requirements at a given installation.
FIGS. 7A and 7B are side views of coir fiber rolls 110 covered in sand 150 according to some embodiments. The coir fiber rolls 110 may be covered solely by sand 150, by sand 150 within a burlap layer 155, or a combination of sand 150 and burlap 155. In some embodiments, the burlap layer 155 is covered by two layers of coir fiber 156. The burlap layer 155 and the two layers of coir fiber 156 may be secured in the soil by at least one stake 135. The burlap layer 155 may be biodegradable. In some embodiments, coir fiber rolls 110 disposed closer to the shoreline are covered by sand 150 with the burlap layer 155 and the coir fiber rolls disposed furthest from the shoreline are covered by sand 150.
FIG. 8 is a side view of marsh pillows or containers 190 according to some embodiments. In some embodiments, the marsh pillows 190 are disposed between the coir fiber rolls 110 and the shoreline. In some embodiments, the marsh containers 190 are composed of coir material filled with loose coir fiber and compost. In some embodiments, the marsh containers 190 range from 2″-7″ thick and 1′-6′ wide. In further embodiments, the marsh containers 190 range from 4″-5″ thick and 3′-4′ wide. In some embodiments, the marsh containers 190 range from 2′-4′ thick and 1′-6′ wide. In some embodiments, the marsh containers 190 are surrounded by biodegradable rope 195.
The marsh containers 190 may be secured to the soil by an anchor 120, a stake 135, or combinations thereof. In some embodiments, the marsh containers 190 are fastened to cables 116 with four anchors 120 per marsh container 190 In some embodiments, the marsh containers 190 are filled with plant material 170. In further embodiments, the plant material 170 may be maritime grasses native to the shoreline.
FIG. 9 is a side view of stakes 135 utilized in an erosion control apparatus 100 according to some embodiments. At least one stake 135 is driven through each soil lift 130. The stakes 135 may be driven through a soil lift 130 into the soil or driven through a first soil lift 130 into another soil lift 130 disposed beneath the first soil lift. In some embodiments, the stakes 135 are wooden stakes. In some embodiments, the stakes 135 may be substituted with earth anchors such as duckbill anchors. The soil lifts 130 can have apertures or slots through which the anchors are inserted or enable cable placement through the apertures or slots, or between soil lift containers that are positioned after anchor placement.
FIGS. 10A, 10B, 10C, and 10D are a top view, side view, perspective view, and a front view of an assembled apparatus 100 according to some embodiments. FIGS. 10A, 10C, and 10D depict the spacing of the cables 116 across the coir fiber rolls 110 according to some embodiments. FIGS. 10A, 10C, and 10D also depict the spacing of the posts 160 across the closest coir fiber roll 110 according to some embodiments.
FIG. 11A depicts a method of installing an erosion control apparatus, according to some embodiments. The method begins when a layer of mesh is placed within an excavated site (Step 1010). The soil behind the site, relative to the shoreline, riverbank, lakefront, or other waterfront, may be graded. The mesh may comprise raschel polypropylene knotless netting (or comparable equivalent), 3 mm high tenacity (rip resistant), 1½″ mesh opening, with UV stabilization, or may comprise polyethylene or coir fiber. The netting can be biodegradable or in a preferred embodiment is non-photodegradable. In some embodiments, the mesh opening can range from ½″ to 7″. Next, at least one layer of coir fabric is placed over the mesh (Step 1020). In some embodiments, two layers of seven hundred gram (or heavier) coir fabric is layered over the mesh. In some embodiments, one or two layers of 700-gram woven coir fabric encased by high tenacity (rip resistant) polypropylene synthetic mesh comprise a soil lift.
Coir fiber rolls are then arranged in the site relative to the shoreline and connected within the soil lifts (Step 1030). A coir fiber roll may be a 20″ diameter by 10′ long, measured at a nine pound per cubic foot density, comprised of a mattress of inner coir fibers encased in a UV stabilized synthetic polypropylene mesh. Alternatively, the coir fiber roll may be a mattress of inner coir fibers encased in a 100% biodegradable coir rope mesh. The soil lifts are filled with sediment and the sediment is compacted (Step 1040). All sediment in each soil lift has a consistent depth of approximately 12″. The sediment in each soil lift is compacted using a portable plate compactor at 6″ soil depth intervals. Thus, the fill material positioned between the fiber rolls and the anchors can include soil, rocks, or other biodegradable materials either within, or instead of, soil lifts. Optionally, all of the fill material can be contained within a single container that envelopes the volume between the fiber rolls and the anchor system.
Then the mesh and the coir fabric are folded over the coir fiber rolls and soil lifts (Step (1050). In an embodiment, the number of coir fiber rolls in the apparatus and the number of coir fiber rolls covered by the mesh are determined by specific design criteria varying with each installation site. In an embodiment, the mesh is installed as each lift is constructed. The completed series of coir fiber rolls and soil lifts may be referred to as a protection array.
The method continues when a plurality of anchors are inserted and coupled to the rolls to secure the rolls to the soil lifts. (Step 1060). Step 1060 is described in further detail below in regards to FIG. 11B. Steps 1010 through 1060 may be repeated as necessary to construct additional soil lifts. The additional soil lifts may be constructed on the top or the side of the rolls.
After construction of the soil lifts is completed, at least one coir fiber roll is filled with plant material (Step 1070). The plant material may be any vegetation with suitable roots for securing the apparatus from eroding. In an embodiment, the plant life is American beachgrass. In other embodiments, the plant material may be any native plantings appropriate to the site conditions, which will grow quickly and stabilize the landform. Next at least one biodegradable erosion control blanket is installed and secured with posts inserted along at least a first fiber roll (Step 1080). The blanket may be installed along all disturbed and/or unstable ground located above the protection array. In an embodiment, the blanket is biodegradable. In a further embodiment, the blanket comprises coir fiber netting. If multiple blankets are employed, an interior blanket is typically a straw/coir/jute, short term, composite erosion control blanket and an exterior blanket is typically 700 or 900 gram woven coir fabric. The at least one blanket is secured when a plurality of posts are inserted through the blanket along at least a first roll of the apparatus relative to the shoreline, riverbank, lakefront, or other waterfront. The plurality of posts may be 4″ by 4″ or 6″ by 6″, and spaced at 5 foot intervals along the first coir fiber roll. The blanket may additionally be secured by a biodegradable twine used to secure the blanket firmly to the soil. The twine may extend from the highest elevation of destabilized or disturbed soil down the uppermost soil lift.
A first trench is excavated at a highest end of the apparatus and a second trench is excavated at a lowest end of the apparatus. (Step 1090). In some embodiments, only a first trench is excavated. In an embodiment, the trenches are 6″×6″ (that is at least six inches wide and six inches deep) lock-in trenches at the top and bottom of the slope with a minimum of 6″ overlaps. 30″ hardwood stakes may be used at a density of 36″ on center with ¼″ biodegradable twine used to secure the mesh to the ground surface. The trenches are be backfilled, seeded, and lightly mulched with sterilized, weed-free chopped straw or comparable equivalent mulch product. (Step 1095).
FIG. 11B depicts a method of inserting anchors to secure fiber rolls and soil lifts according to some embodiments. The method begins when duckbill anchors including a rod connected to an anchor point surface sized to support an overlying cone of material are selected (Step 1110). Anchors providing at least 3,000 pounds of holding force at each insertion point (Step 1120). After the anchors are selected, the anchors are spaced approximately every twenty-four to thirty inches along the top and bottom edge of each coir fiber roll (Step 1130). In one embodiment, at least twenty to twenty-nine anchors are inserted per one hundred square feet.
The anchors are passed through the mesh, coir fabric, and soil lift (Step 1040). In a preferred embodiment, the anchors pass through the mesh and soil lifts, which operates to distribute the anchoring force across the entire embedded structure. The coir fiber rolls are anchored with the use of earth anchors and the earth anchors can be inserted through the rolls. Next, the anchors are inserted adjacent to a coir fiber roll and through a soil lift adjacent to another coir fiber roll or through an adjacent soil lift, mechanically coupling the coir fiber rolls and soil lifts (Step 1150). The anchors pass through the mesh and soil lifts to distribute the anchoring force across the system.
In an embodiment, the anchors are inserted at a fixed depth into soil underneath the apparatus; the depth being at least forty-two inches (Step 1060). In the above methods, the anchors may be earth anchors. The earth anchors may be helical-style anchors, duckbill-style anchors, or any other type of anchor that can be driven below grade.
In one embodiment, after a soil lift is compacted, a roll is placed along the “water” side of the lift and the blanket and mesh are folded back toward the landform. In one embodiment, the anchors are driven into the soil after each grouping of the lift, roll, blanket, and mesh are constructed. In another embodiment the anchors may be driven into the soil after each individual lift is constructed, after 2-3 lifts have been constructed or after all the lifts are constructed. In an embodiment utilizing duckbill anchors, anchors should be installed after a lift is constructed. In an embodiment utilizing helical anchors, the anchors may be installed prior to construction of the lifts and steel cables would need to be pulled up through the lifts.
FIG. 12A and 12B are side views of an inserted anchor according to some embodiments. An anchor 1220 a or 1220 b can be coupled to a longitudinally extending element, such as a rod, cable, or roll insert that can be centered within the roll or, alternatively, against the outer wall of the roll or positioned with an internal frame positioned within the wall, into an apparatus 100 by extending a cable of the anchor 1220 a or 1220 b through a coir fiber roll 1210 a or 1210 b. In some embodiments, the coir fiber roll 1210 a may be constructed to include an anchor 1220 a within the coir fiber roll 1210 a. After the coir fiber roll 1210 a is arranged within an excavated site, the anchor 1220 a is extended from within the coir fiber roll 1210 a to a desired depth.
In some embodiments, the anchor 1220 b can be secured to the coir fiber roll 1220 b with a clamp 1221. The clamp 1221 is attached to a surface of the coir fiber roll 1210 b. In some embodiments, the clamp 1221 is attached to the surface of the coir fiber roll 1210 badjacent to the slope surface of the apparatus 100. A plurality of clamps 1221 are secured to the surfaces of the plurality of coir fiber rolls 1210 b, each clamp 1221 securing a cable of an anchor 1220 b to the plurality of coir fiber rolls 1210 b. In some embodiments, each coir fiber roll 1210 b is attached to one clamp 1221. In other embodiments, multiple clamps 1221 and anchors 1220 b are attached to one or more coir fiber rolls 1210 b.
FIG. 13 is a side view of an anchoring system configured relative to soil saturation according to some embodiments. In some embodiments, the angle at which anchors 1320 are inserted into the soil are determined relative to the saturation level of the soil surrounding the anchor point surface of the anchor 1320. The saturation level refers to the amount of water retained by the soil, either at the time of installation or during a weather event such as flooding, a storm, a hurricane, and the like. Each anchor 1320 may be inserted at varying angles throughout the apparatus 100 relative to the saturation level of soil at each anchor point.
The anchor 1320 may be inserted with the cable 1316 oriented at an angular range θ₁relative to the slope angle of the soil at the insertion point of the anchor 1320 a or, if different, the slope angle θ₂of the coir fiber rolls 110. In some embodiments, an anchor 1320 may be inserted as described previously herein in a direction orthogonal to the soil grade or coir fiber rolls 110 if the soil surrounding the anchor point surface is unsaturated or will remain unsaturated during a weather event. In some embodiments, an anchor 1320 may be inserted at an angle up to 45 degrees relative to the orthogonal direction (normal) to the plane if the soil surrounding the anchor point surface is fully saturated or will be fully saturated during a weather event. In some embodiments, an anchor 1320 may be inserted up to 10 degrees relative to the orthogonal direction or plane. In some embodiments, an anchor 1320 may be inserted up to 20 degrees relative to the orthogonal direction. In some embodiments, an anchor 1320 may be inserted up to 30 degrees relative to the orthogonal direction. In some embodiments, an anchor 1320 may be inserted up to 40 degrees relative to the orthogonal direction.
FIG. 14A is a side view of an anchoring system including reinforcement elements according to some embodiments. In some embodiments, the anchors may be coupled to reinforcement elements 1420 a. The reinforcement elements 1420 a can include one or more rocks, stones, or boulders, concrete formations or other formed materials, or a combination thereof. In some embodiments, the reinforcement elements 1420 a are coupled to friction anchors. In further embodiments, an end of the friction anchors are embedded within the reinforcement elements 1420 a. In some embodiments, the anchors are duckbill anchors, helical anchors, or other earth anchors. The anchors comprise cables 1416 a extending from the reinforcement elements 1420 a to the coir fiber rolls 110. In some embodiments, the reinforcement elements 1420 a include the cables 1416 a that extend to the coir fiber rolls 110.
The reinforcement elements 1420 a can be inserted at a depth of at least 42 inches below the slope surface of the apparatus. In some embodiments, the reinforcement elements 1420 a may be native to the soil and the apparatus can be constructed over the native reinforcement elements 1420 a. In some embodiments, the reinforcement elements 1420 a may be coupled to anchors prior to inserting the reinforcement elements 1420 a into the soil. The anchors are extended from the reinforcement elements 1420 a after insertion of other elements of the apparatus such as the mesh 140, blanket 180, soil lifts 130, and coir fiber rolls 110. In some embodiments, the anchors are inserted through mesh 140 and at least one soil lift 130 then coupled to the reinforcement elements 1420 a.
FIG. 14B is a side view of an anchoring system including concrete according to some embodiments. In some embodiments, the reinforcement element 1420 b is concrete. The concrete 1420 b is poured into place over anchors previously inserted into soil, embedding the anchor point surfaces in the concrete 1420 b. In some embodiments, the concrete 1420 b is poured into place prior to installation of the soil lifts 130. In some embodiments, the concrete 1420 b is poured at a depth of at least 42 inches below the slope surface of the apparatus. Such formed blocks, cylinders, or other desired shapes can be attached to fiber rolls by cables, rods, or other coupling fixtures. These can be attached by threaded fixtures or formed loops to the formed components.
FIG. 15A and 15B are side views of an anchoring system including helical anchors according to some embodiments. Each helical anchor 1520 includes a cable 1516. The cables 1516 are coupled to fiber rolls 110 with crimps 1517. The crimps 1517 tighten and fasten the cables 1516. In some embodiments, the crimps 1517 are zinc plated copper crimps. A method of installing an erosion control apparatus including helical anchors 1520 is described below.
According to some embodiments, installation of an erosion control apparatus begins with preparation of the soil at an excavation site. The soil is compacted and graded at a specified slope angle. In some embodiments, the soil is graded at a slope angle in a range of 0 to 45 degrees (1:1 slope). In an embodiment, the soil is graded at a slope angle in a range of 20 to 50 degrees. In a further embodiment, the soil is graded at a slope angle no greater than 33 degrees (2:1 slope). The slope angle may be 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 degrees, or any angle in between. In some embodiments, the soil of the apparatus can include varying slope angles throughout the apparatus.
Next a plurality of anchors are selected. The anchors may be helical anchors including a cable connected to an anchor point surface sized to support an overlying cone of material. The anchors provide at least 3,000 pounds of holding force at each insertion point. After the anchors are selected, the anchors are spaced approximately every twenty-four to thirty inches. In one embodiment, at least twenty to twenty-nine anchors are inserted per one hundred square feet.
Then, a layer of mesh is placed within an excavated site. The mesh may comprise raschel polypropylene knotless netting (or comparable equivalent), 3 mm high tenacity (rip resistant), 1½″ mesh opening, with UV stabilization, or may comprise polyethylene or coir fiber. The netting can be biodegradable or in a preferred embodiment is non-photodegradable. In some embodiments, the mesh opening can range from ½″ to 7″. Next, at least one layer of coir fabric is placed over the mesh. In some embodiments, two layers of seven hundred gram (or heavier) coir fabric is layered over the mesh. In some embodiments, one or two layers of 700-gram woven coir fabric encased by high tenacity (rip resistant) polypropylene synthetic mesh comprise a soil lift.
Coir fiber rolls are then arranged in the site relative to the shoreline and connected within the soil lifts. A coir fiber roll may be a 20″ diameter by 10′ long, measured at a nine pound per cubic foot density, comprised of a mattress of inner coir fibers encased in a UV stabilized synthetic polypropylene mesh. Alternatively, the coir fiber roll may be a mattress of inner coir fibers encased in a 100% biodegradable coir rope mesh.
Next the anchor cables are passed through the mesh, the layer of coir fabric, the plurality of coir fiber rolls, and the soil lifts. Passing the anchors through the mesh, coir fabric, fiber rolls, and soil lifts of the apparatus overlaps the frustum cone of each anchor with the mesh, coir fabric, fiber rolls, and soil lifts, sharing the loads of each anchor with the mesh, coir fabric, fiber rolls, and soil lifts of the apparatus. Such an overlap provides for stronger reinforcement of the area within the frustum cone of each anchor.
Then the mesh and the coir fabric are folded over the coir fiber rolls and soil lifts. In an embodiment, the number of coir fiber rolls in the apparatus and the number of coir fiber rolls covered by the mesh are determined by specific design criteria varying with each installation site. In an embodiment, the mesh is installed as each lift is constructed. The completed series of coir fiber rolls and soil lifts may be referred to as a protection array.
The cables are then tightened and fastened to the coir fiber rolls. In some embodiments, each cable is tightened and fastened with a crimp. In further embodiments, the crimps are zinc plated copper crimps. The crimps may be attached an end of the cable opposite the end of the anchor comprising the anchor surface area.
In some embodiments, after the cables are fastened at least one coir fiber roll is filled with plant material as described above. Next at least one biodegradable erosion control blanket is installed and secured with posts inserted along at least a first fiber roll as described above. A first trench is excavated at a highest end of the apparatus and a second trench is excavated at a lowest end of the apparatus as described above. The trenches are backfilled, seeded, and lightly mulched with sterilized, weed-free chopped straw or comparable equivalent mulch product.
FIG. 16A is a side view of an anchor cable system according to some embodiments. In some embodiments, anchors 1620 a are shared across multiple coir fiber rolls 110. Multiple anchors 1620 a may share a cable. Each cable is extended over at least one coir fiber roll 110. For example, two anchors 1620 a may share one cable that extends over two coir fiber rolls 110. Each of the anchors 1620 a may be inserted between two coir fiber rolls 110 or along the outer surface of the first or last coir fiber roll 110 in an array of coir fiber rolls 110. The cable shared between each anchor 1620 a is laid over the coir fiber rolls 110. In one exemplary embodiment depicted in FIG. 16A, a portion of anchors 1620 a share a cable that extends over two inner coir fiber rolls 110 and a portion of anchors 1620 a extends over on outer coir fiber roll 1620 a.
FIG. 16B is a side view of an anchor cable system according to some embodiments. In some embodiments, each anchor 1620 b is connected to a connecting cable 1621. The connecting cable 1621 extends over the plurality of fiber rolls 110. In some embodiments, the connecting cable 1621 extends over the surface of the coir fiber rolls 110 adjacent to the slope surface of the apparatus 100.
FIG. 17 is side view of an erosion control apparatus including helical anchors, according to some embodiments. In some embodiments, the helical anchors 1720′ connected to the bottom fiber roll 110 may be placed at a deeper depth than other helical anchors 1720 in the apparatus. Helical anchors 1720′ may be placed at a depth between 42″ and 72″. The helical anchors 1720′ may be referring to as “toe anchors.” The toe anchors 1720′ may be the most seaward or bottom most anchors in the apparatus. In some embodiments, only the single most seaward anchor is referred to as the toe anchor 1720′.
In some embodiments, the apparatus may include both helical and duckbill anchors 1720. The helical and duckbill anchors 1720 may alternate or be arranged in any suitable combination. In some embodiments, the toe anchor 1720′ is a helical anchor and the apparatus includes alternating helical and duckbill anchors 1720 starting from the helical toe anchor 1720′.
Helical anchors can be used in locations where the soil lifts cannot be used due to limited space or in which the soil lifts may have a limited size or where a single lift is used behind a plurality of coir fabric containers. The soil lift cross-sectional shape and the coir fabric container cross-sectional shape (e.g. circular, oval, square, rectangular) can be selected to match the site requirements.
Helical anchors may be advantageous as toe anchors because, as explained below with regards to FIG. 18 , a frustum cone created by a helical anchor possesses more surface area as compared to a duckbill anchor. The larger surface area results in a stronger frustum cone in the surrounding wet sand. In some embodiments, a helical toe anchor 1720′ is placed into sand before placement of the fiber rolls 1710.
The apparatus may include elements discussed above in regards to other depicted embodiments such as plant material 170. The apparatus may also include additional elements such as matrix 1750, including about 50% cobblestone, about 25% coir fiber and compost, and about 25% sediment encased in layers of coir fiber and jute-burlap. The apparatus may also include a marsh installation 1790 including cobblestones encased in layers of coir fiber and jute-burlap. Voids between the cobblestones may be filled with sediment. In some embodiments, the matrix 1750, the marsh installation 1790, or both, include cobblestones encased in two layers of coir fiber. In some embodiments, the matrix 1750, the marsh installation 1790, or both, include cobblestones encased in a single layer of jute-burlap. In some embodiments, the matrix 1750, the marsh installation 1790, or both, include cobblestones encased in two layers of coir fiber and a single layer of jute-burlap. In some embodiments, a single layer of jute-burlap weighs 20 ounces. In some embodiments, the cobblestones range between 8″ to 12″ in length.
FIG. 18 is a side view of an inserted helical anchor according to some embodiments. The helical anchors 1720 of the apparatus may be Tripleye® anchors available from MacLean Power Systems in Franklin Park, IL, or other sources wherein the anchors have a helical surface 1821 with a diameter of at least four inches, optionally six inches. The helical anchors 1720 can include a rod 1816 sixty-six inches in length and ¾ of an inch in diameter. The helical anchor 1720 creates a frustum cone 1826 with a surface area ranging from about 90 square inches to 220 square inches. In some embodiments, the surface area of the frustum cone 1826 is about 156 inches. In some embodiments, the surface area of the frustum cone 1826 of the helical anchor 1720 is greater than that of a duckbill anchor of equal length. Each helical anchor 1720 may exhibit a holding capacity ranging from 2500-6500 pounds per kiloNewton when installed in the apparatus. The helix can have one or more ridges of threading extending along the central rod. More ridges increases the surface area of the helical anchor and thereby increases the holding force. The plurality of ridges can have a uniform or tapering diameter.
In some embodiments, the anchoring system of the apparatus further comprises zinc-coated copper crimps 1817. The crimps are used to form a loop 1818 in each anchor 1720. Loops 1818 may be welded near the top of each helical anchor 1720. In some embodiments, the loops 1818 are welded between 12″ to 16″ from the lower surface of the fiber roll 110 connected to the helical anchor 1720. The loop structure of the helical anchor 1720 is easier to repair and tighten than the loop of a duckbill anchor 1720 due to the placement of the loop 1818.
FIG. 19 is a side view of an erosion control apparatus including one fiber roll, according to some embodiments. In some embodiments, an apparatus may include one coir fiber roll 1910. The coir fiber roll 1910 may be either high density (9 lb/ft³coir fabric) or low density (7 lb/ft³coir fabric). In some embodiments, the coir fiber roll 1910 is low density. The coir fiber roll 1910 may be encased in a mesh composed of either natural or synthetic material as described above. The coir fiber roll 1910 may be pre-vegetated with any vegetation with suitable roots for securing the apparatus from erosion. The vegetation may be native planting appropriate to the site conditions, capable of growing quickly and stabilizing the landform.
The coir fiber roll 1910 is anchored with the use of anchors 1920. In some embodiments, the anchors 1920 are duckbill anchors or can be helical anchors as described herein. The anchors 1920 are inserted at a specified depth into the soil. In some embodiments, the specified depth may be in a range of thirty to fifty inches. In some embodiments, the specified depth may be in a range of thirty to ninety inches. In other embodiments, the anchors 1920 are embedded into the soil at, or just above, the soil surface.
The anchors 1920 are inserted around the coir fiber roll 1910 such that a cable 1916 connecting a set of at least two anchors 120 is situated across a face of the coir fiber roll 1910. In some embodiments, multiple cables 1916 extend from a top point of the coir fiber roll 1910. Each cable 1916 is coupled to the coir fiber roll 1910 with a crimp 1917. The crimp 1917 tightens and fastens the cable 1916. In some embodiments, the crimp 1917 is a zinc plated copper crimp. In some embodiments, ends of the cables 1916 connected to a crimp 1917 are looped.
Each coir fiber roll 1910 is connected to a soil lift 1930. Each soil lift 1930 comprises at least three layers of coir fabric containing sediment 1950. In some embodiments, the sediment 1950 is sand. The sediment 1950 is arranged within the soil lift 1930 at a grade.
The apparatus further includes an erosion control blanket 1980. In some embodiments, the blanket 1980 is a single layer of coir fabric. In further embodiments, the blanket 1980 is a 700-gram or a 900-gram woven coir fabric. The blanket 1980 is biodegradable and may degrade over approximately a three year period. The blanket 1980 may be secured with at least one stake 1935. The at least one stake 1935 may be driven through the blanket 1980 and the soil lift 1930 into the soil, driven through the blanket 1980 and partially driven into the soil lift 1930 from a top surface of the soil lift 1930, or a combination thereof. In some embodiments, the at least one stake 1935 is a wooden stake. In some embodiments, the blanket 1980 is further secured by the anchors 1920.
In some embodiments, at least one stone 1990 is disposed between the coir fiber roll 1930 and the shoreline. The at least one stone 1990 may be one or more stones excavated from an installation site and deposited in or on the soil after installation of the coir fiber roll 1910 and the soil lift 1930.
The combination of the coir fiber roll 1910 and the soil lift 1930 may be replicated and installed in series along a shoreline. The total combination of coir fiber rolls 1910 and soil lifts 1930 may be referred to as a protection array, configured to protect the shoreline. The protection array may be combined with the planting of vegetation.
FIGS. 20A, 20B, 20C, 20D, 20E, and 20F are side views depicting the installation of a connecting cable threaded through a plurality of cables in an erosion control apparatus according to some embodiments. A connecting cable threaded in such a manner may be referred to as a whip cable. The connecting cables serve to harness the adjacent rolls together so that each roll abuts one or more adjacent rolls to substantially reduce water intrusion between the rolls. As fiber rolls can be more buoyant than synthetic materials, the tensioned harnessing of the rolls together reduces or eliminates this issue.
FIG. 20A depicts the installation of a lowest anchor 2020 attached to a threaded whip cable 2019. The lowest anchor 2020 is inserted adjacent to the lowest coir fiber roll 2010. The threaded whip cable 2019 is threaded in such a manner to connect a plurality of fiber rolls or containers in the array together to form an integrated array structure. This further reduces water intrusion and erosion of sediment through the array.
FIG. 20B depicts threading the whip cable 2019 through the loops 2018 of anchor cables 2016. After the whip cable 2019 is threaded through the loops 2018, the anchors 2020 are driven into the soil. FIG. 20C depicts the anchors 2020 after having been driven into the soil. The loop 2018 of the highest anchor cable 2016 remains exposed after driving the anchors 2020. At this stage of installation, the threaded whip cable 2019 remains loose, i.e. is not fully tensioned.
FIG. 20D depicts how tension is applied to the threaded whip cable 2019. The threaded whip cable 2019 is tensioned, starting from the lowest coir fiber roll 2010, by pulling the threaded whip cable 2019 at about a 90 degree angle until the anchor cable 2016 below the coir fiber roll 2010 is abutting against the coir fiber roll 2010. This operation is repeated at each subsequent coir fiber roll 2010 moving up the array. FIG. 20D depicts an exemplary numbered sequence for this operation. FIG. 20D also provides a close-up view of the threaded whip cable 2019 tensioned while in a loop 2018.
FIG. 20E depicts the threaded whip cable 2019 pulled through the loop 2018 of the highest anchor cable 2016. As depicted in the close up view of FIG. 20E, tension is applied to the threaded whip cable 2019 to tighten the threaded whip cable 2019. After tension is applied, the threaded whip cable 2019 is held in place with a crimp 2017 as depicted in the close up view FIG. 20F. In some embodiments, the crimp 2017 may be a zinc plated copper crimp. A threaded whip cable 2019 may be installed at intervals across an apparatus. In some embodiments, a threaded whip cable 2019 is installed about at every 2-3 feet across the face of a fiber roll array.
FIG. 21 is a side view of an erosion control apparatus 2100 including a reinforced salt marsh container or “pillow” according to some embodiments. The container can comprise a woven material that has a generally rectangular shape with a length and width that are both greater than the depth upon installation. In some embodiments, apparatus 2100 can include fiber rolls 2110 appreciably similar to the fiber rolls discussed herein above. Each roll 2110 may be anywhere from 12″ to 30″ in diameter. In some embodiments, each roll 2110 has a substantially similar diameter. In some embodiments, each roll 2110 has a diameter of 20″.
The apparatus 2100 may further include a plurality of helical earth anchors 2120 connected to the fiber rolls 2110 as described herein above. In some embodiments, the apparatus 2100 may include both helical and duckbill anchors 2120. The helical and duckbill anchors 2120 may alternate or be arranged in any suitable combination.
The apparatus may include a reinforced marsh, for example a reinforced salt marsh container 2190. FIG. 22 is a side view of the reinforced salt marsh container 2190 according to some embodiments. The marsh container 2190 may be secured to the soil by one or more anchors 2121. The anchors 2121 may be duckbill anchors or other anchoring systems described herein. In some embodiments, one anchor 2121 is situated at opposing sides of the marsh container 2190. For example, one anchor 2121 may be attached to a seaward end of the marsh container 2190 and another anchor 2121 may be attached to an end of the marsh container facing or contacting the fiber rolls 2120.
The marsh container 2190 can include additional elements such as matrix 2191, including, for example, about 50% cobblestone (in a range between 40%-60% of the total container volume), about 25% coir fiber (in a range of about 20% to 30% of the total container volume) and compost, and about 25% sediment (in a range of about 20%-30% of the total container volume) encased in layers of one or more materials such as coir fiber and/or jute-burlap. The matrix 2191 may act as a ballasted core for the salt marsh container 2190.
In some embodiments, an outer layer of the marsh container 2190 includes a coir blanket 2192. In further embodiments, the coir blanket 2192 only covers a top surface of the marsh container 2190. In some embodiments, the coir blanket 2192 may include a planting matrix 2195 of loose coir and compost.
In some embodiments, grasses 2193 may be planted into the marsh container 2193. The grasses 2193 may be selected from species that are native to the installation area. In some embodiments, the grasses 2193 are planted in, or extend through, the planting matrix 2195 of the coir blanket 2192.
In some embodiments, the coir blanket 2192 is secured to the marsh container 2190 by one or more cables 2194. The cable 2194 may be composed of a polymeric material. In some embodiments, the cable 2194 is the cable connecting the one or more anchors 2121 to the marsh material container 2190.
In some embodiments, a layer of high-tenacity polyethylene mesh may be secured over the surface of the coir blanket 2192 to help bind the blanket 2192 and marsh container 2190 together. In further embodiments, the mesh may be secured temporarily until the roots of the grasses 2193 can successfully attach the blanket 2192 to the marsh container 2190.
Further embodiments for the stabilization of shorelines can employ cobble reinforced marshes (CRM) in which shellfish can be embedded within the natural fiber container. A further layer of synthetic or natural fiber mesh, typically an open weave of fibrous material to enable plant growth, can be used to retain the structure in position and reduce the rate of biodegradation of the natural materials. A further embodiment can employ additional biodegradable layers such as a mesh made with polylactic acid (PLA). PLA is a thermoplastic material made from natural food products (plant starches) and can be blended with other polymers to engineer the rate of biodegradation. As the material is being used in a marsh environment that can be frequently exposed to salt water tidal or storm cycles, the material can be selected based on the particular environment.
Shown in FIG. 23 is a cross-section view of a marsh stabilization system 2400 used to stabilize the shoreline relative to an existing grade 2424 at which tidal flow occurs. The area 2418 above an existing marsh area 2420 that is being eroded over time, can be supplemented with a cobble stone structure 2404 configured to support further marsh plant species. As previously described, this structure can support 4-10 inch or 6-12 inch diameter cobble, but preferably contains cobble in the 8-10 inch range that are encased in a surrounding mesh such as 1000 gram coir fiber layers. The contained cobble structure is typically about 25% by volume of coir fiber and compost (plus or minus 5%) and 25% sediment (plus or minus 5%) that has a grain size compatible with the fringing marsh with similar organic material. This cobble structure 2404 can comprise a matrix as previously described in connection with FIG. 17 , for example, and can be anchored with one of more anchors as described herein and covered with a natural or PLA material that biodegrades over time to leave the maturing plants intact. The system 2400 can be adjacent to the existing marsh vegetation 2406. At the point where the marsh ceases at the tidal high water edge, a sediment filled coir fiber envelope or container 2414 is first installed. This can be followed by one or more ballasted coir fiber containers 2448 having cobble and shellfish 2450 such as live mussels and oyster shells distributed along the water exposed top of the cobble and surrounded by one or more coir fiber layers. The colonizing shellfish, such as ribbed mussels, can be in an inner layer 2452 and also on a sheet of coir fiber 2454 surrounded by an outer mesh or coir fiber layer 2456. Stakes 2464 can be used to secure a lower ballasted coir fiber container 2458 with additional shellfish material 2460 within an outer coir layer 2462 and an optional mesh. A further cap with further plant material 2446 can extend above the coir envelope 2414 and can include a further shellfish colonizing container 2470 as shown in FIG. 25 in which ribbed mussels or other species 2476 are formed on a coir sheet 2472 which can be surrounded by a coir fiber fabric 2474. Note that live oysters can also be used, however as these are suitable for human consumption, their use may cause further disturbance of the marsh. The stabilizing structure can also employ beach nourishment 2402 that can be periodically restored depending on the level of seasonal erosion.
A biodegradable mesh 2480, such as a PLA material, can be used to anchor the container using stakes 2408. The shellfish includes a live species to restore the shellfish population of the marsh. The marsh installation as described herein can be installed relative to a fiber roll array as previously described herein that can also be ballasted using cobblestones installed within one or more fiber rolls. A further embodiment comprises colonizing one or more fiber rolls with a live shellfish material as described herein that are being used to stabilize a shoreline.
The reinforced marsh containers described herein can be used to reinforce a shoreline to inhibit erosion or can be added to an existing fiber roll array installation. In other embodiments, reinforced marsh containers can be used in conjunction with the repair of an existing fiber roll array as described in U.S. application Ser. No. 17/866,143, filed on Jul. 15, 2022 and published as US 2022/0349139, the entire contents of this application being incorporated herein by reference. In this process, the helical anchors of the fiber roll array can be driven to a deeper depth in to the soil underneath and behind the array to reestablish sufficient anchoring force to retain the repaired fiber roll or fiber roll array to the shoreline. In other conditions the reinforced marsh containers can be installed with new fiber roll array installations as described herein.
Further embodiments employ systems and methods for installing and/or repairing fiber roll arrays as previously described herein. These embodiments pertain to the installation, reinstallation and repair of damaged fiber rolls. As the purpose of such fiber roll arrays is to reduce the erosion of shorelines that can occur during storms, tidal surges and flooding events, such arrays are frequently exposed to immersion in flood waters with high flow rates and/or the high impact of wave action. This can occur for extended periods of time of many days during significant coastal storms including hurricanes, tropical storms, tsunamis or winter storms that can result in storm surges, swells, tidal motion and wind driven waves from a few feet to many dozens of feet in height. The oscillatory nature of such wave action can push and pull obstacles in their path. Moreover, when fiber rolls are immersed in such wave action for extended periods, water can penetrate into and liquefy the contents of the fiber rolls and any soil or fill material behind or underneath the fiber rolls including any soil lifts that are included in the array. Such liquification can result in both vertical and lateral motion of the fiber rolls relative to the shoreline and also relative to each other. Soil or fill material in or underneath such structures can be transported away for the fiber roll array causing it to be damaged, or potentially partially or fully dislodged from the shoreline. Even with anchoring systems as described herein, such large storm events can require repairs to be made to fiber roll systems that have been severely damaged. Such repairs can be relatively simple, such as re-tensioning of cables and/or harnesses that couple the anchors to the fiber rolls. For duckbill anchors that remain in place after a severe storm event it can be possible to simply tighten the cables connecting anchors to the fiber rolls. Even if a fiber roll at the top of an array becomes dislodged, it can be possible to attach a new fiber roll to the top of the array with the existing anchoring and soil lift system in place. If any of the duckbill anchors are pulled out by one or more storm events, however, this can require dismantling of the entire array and a complete reconstruction may be necessary to restore the integrity of the system.
As described herein, another option for anchoring fiber rolls is to employ helical anchors to anchor fiber rolls to a shoreline. Preferred embodiments further include soil lifts that are coupled to the fiber rolls and thereby anchor fiber rolls to the soil lifts that are positioned behind the fiber rolls so that the fiber rolls face the water on the shoreline to reflect wave energy. Shown in FIG. 26 is a system 2100 for installing and/or repairing a fiber roll array. In this embodiment, a tracked vehicle 2102 used for construction on the shoreline, is configured to include a rotating drive mechanism 2106 mounted on the hydraulic arm system 2104 of the tracked vehicle. The tracked vehicle can also be used to lift and place the fiber rolls during construction and/or repair of the fiber roll array. The tracked vehicle has a weight sufficiently heavy to apply a large tension to the cable system or harness that holds the fiber rolls relative to the anchors. The tensioning system can employ the hydraulic arm system to apply a force much greater than manual tension to the cables and/or harness to apply at least 2000 pounds of holding force, and preferably more than 3000 pounds of force at each anchor. In preferred methods of installing fiber rolls as described generally herein and applying tension to the cable system that couples the fiber rolls to the anchors, a tension is applied to at least one or more cables in a range of 2500 pounds to 6500 pounds of holding force. In preferred embodiments at least one or more of the anchors is installed with an applied tension of at least 5000 pounds of holding force for coupling of a fiber roll to an anchor. In preferred embodiments, one or more of the fiber rolls in an array can be installed with a soil lift coupled to at least one fiber roll. The rotating drive mechanism 2106 can be coupled with a linkage or rotating rod 2108 to one end of a helical anchor which comprises a anchor rod 2116 at one end that extend to an opposite threaded end 2117 that is inserted into the soil embankment 2160 that extends behind the array. The anchor rod 2112 is coupled to the driving rod or arm 2108 at connector 2110 shown in the detailed view 2140 where a pin 2142 connects the distal end 2146 of connector 2110 to the top 2144 of anchor rod 2112 which can have an opening 2145 through which the pin 2142 extends. The connector 2110 serves to apply sufficient torque to the helical anchor such that the threaded portion 2114 of the anchor rod 2112 to rotationally drive the helical anchor into the soil directly behind the top roll of the array. The rotational drive unit can comprise, for example, a backhoe auger drive available from Premier Attachments, Fort Wayne, Indiana or other similar commercially available systems that generate sufficient torque. Such systems can have one or two speeds and generate torque outputs in the range of 3000 ft. lbs to 35,000 ft. lbs.
In the embodiment of FIG. 26 , the top roll does not have a soil lift extending behind it, however, other examples described herein can employ a soil lift with each fiber roll. In this embodiment the lower soil lift mesh 2126 encloses a fill material 2128 within the soil lift. The mesh can extend around the fiber roll 2122, or alternatively, the soil lift can have a second layer of mesh that extends around the soil lift and the fiber roll as described previously herein. It is desirable to prevent the leakage of fill material from the soil lift which can occur during partial or complete immersion of the array in periods of high water levels, so that the mesh is configured to inhibit such leakage. Stakes 2124 are frequently used during initial construction but these typically decay over the many years that the system serves to stabilize the slope on the shoreline. As the soil lift mesh 2126 can be tightly woven, in order to drive the helical anchors into and through the mesh during initial construction, it can be necessary to form an opening 2150 in the top surface of the soil lift 2127 during initial construction. This can entail cutting a small opening in the top surface of the mesh in each soil lift sufficient to insert a 4 inch or 6 inch thread diameter helical anchor, for example. Once inserted through the opening, the threads of the helical anchor can gain sufficient traction in the compacted soil within the soil lift to drive the anchor through the underlying mesh layer(s) and the shoreline embankment upon rotation of the drive rod. The use of such tractor mounted drive units greatly increases the speed and efficiency of installation and can also facilitate repair or partial replacement of installed fiber roll arrays many months or years after initial construction.
Shown in FIG. 27 illustrates a further embodiment relating to the installation and repair of fiber roll arrays anchored by one or more helical anchors. The helical anchors can have shaft lengths in a range of 40 to 80 inches and preferably in a range of 54-66 inches driven into undisturbed soil or soil or other fill material compressed to a state that approximately emulates undisturbed soil. The increased anchor depth for the helical anchors can increase the holding force applied to the upper low density fiber rolls 2158 and the lower high density fiber rolls 2160 of the array. The grade of the shoreline bank 2164 is altered to a new grade 2166 at installation to form a more stable grade for the installation of plant material above the array. As described previously herein, stakes 2154 can be used during installation to stabilize the soil lifts 2156 during insertion of anchors through the soil lifts and the placement of fiber rolls. Sand is typically placed over the array to provide further stabilization. Note that in a further embodiment, the fiber rolls in the array can also all be fabricated with a high density mesh. When the upper fiber rolls are also high density, they do not readily support plant material within the fiber rolls. In this method, plant material such as bare root American beach grass can be introduced into the seams between fiber rolls where the roots of the plant material can more easily access mineral soils through the seams. The high density roll design is also more survivable during large storm events.
A detailed view 2170 of the coupling of the anchors to the fiber rolls is seen in FIG. 28 . As seen in previous figures herein, stakes 2174 can stabilize the mesh 2184 and coir fabric 2182 used to enclose the fill material such as sand within the soil lift, and can also extend around the fiber roll that is coupled to the soil lift. The upper shaft 2186 portion of the helical anchor can include an opening or eyelet 2145 which can be used to couple the shaft to the drive mechanism as described previously, and can also be used to connect the shaft to a cable 2180 with connector 2188 or loop. The cable 2180 can extend around the fiber roll to pass through the shaft eyelet of the next helical anchor on the opposite side of the first roll 2178, and then extends around the next roll in the array. The sand layer 2176 is placed over the array as described previously.
An important advantage of helical anchors is that they can be used to repair damaged arrays using the procedure 2200 described in connection with FIGS. 29A and 29B. In this method, an existing fiber roll array 2202 as described herein can be damaged due to storms or aged fiber rolls, for example, that need to be removed and replaced. The helical anchors must first be detached 2204 from the fiber rolls, for example, by removing the cables if they are still attached. A rotatable drive assembly must be attached 2206 to the installed anchor that is positioned at a first depth under the fiber roll. By actuating 2208 the rotatable drive assembly the helical anchor is rotated to cause the anchor to be moved to a deeper second position in the soil underneath the array. One or more of the rolls can be replaced or, optionally, additional anchors can be detached 2210 and sequentially connected 2212 and driven to a deeper position with the rotational drive mechanism 2214. Any new anchors 2216 and/or additional anchors that have been driven deeper can be reattached 2218 to the cable(s) and tension can be applied 2220 to the cables using the hydraulic arm of the tractor, for example.
Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of this disclosure. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the disclosed devices and methods being indicated by the following claims.

Claims

What is claimed is:

1. An erosion control apparatus comprising:

a marsh installation placed relative to the shoreline, wherein the marsh installation comprises a plurality of stones wrapped in a layer of coir fiber with sediment and a plant matrix over the plurality of stones;

a plurality of anchors, each anchor connected to the marsh installation such that the anchors extend to a depth into a slope; and

a fill material positioned between the marsh installation and the anchors, at least a portion of the marsh installation and the fill material being positioned over the anchors.

2. The apparatus of claim 1 wherein the plurality of stones comprise cobblestones have a size range between 6-12 inches. 3, The apparatus of claim 2 wherein a majority of the cobblestones are in a size range between 8-10 inches.

4. The apparatus of claim 1 further comprising a biodegradable mesh covering the layer of coir fiber.

5. The apparatus of claim 4 wherein the biodegradable mesh comprises polylactic acid.

6. The apparatus of claim 1 wherein the plurality of anchors includes at least one helical anchor.

7. The apparatus of claim 1 further comprising a container including shellfish.

8. The apparatus of claim 7 wherein the shellfish includes a plurality of mussels to restore a shellfish population in the marsh.

9. The apparatus of claim 1 further comprising a plurality of anchored fiber rolls positioned adjacent the marsh installation.

10. The apparatus of claim 9 wherein at least one fiber roll is coupled to the marsh installation.

11. The apparatus of claim 1 further comprising live plant material within the plant matrix that is configured to grow through a coir fabric layer.

12. The apparatus of claim 1 wherein the marsh installation has a depth and a length and a width greater than the depth.