Abstract:
An article of manufacture produced by a process comprising the steps of: erecting a sediment-containment structure comprising a plurality of floating boom segments; and introducing sediment into the shape formed by the sediment-containment structure. A system for building up sediment in a water-covered area comprises: a plurality of floating boom segments connected in an essentially closed shape; a sediment source depositing sediment inside the area substantially enclosed by the essentially closed shape formed by the boom segments; and a wasteweir segment disposed so as to close the essentially closed shape formed by the floating boom segments. The wasteweir segment has two posts and a removable barrier element. A method for building up land in a water-covered or water-surrounded area comprises the steps of: erecting a sediment-containment structure comprising a plurality of floating boom; and introducing sediment into the shape formed by the sediment-containment structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of applicant&#39;s U.S. patent application Ser. No. 10/695,640, which is a continuation-in-part of applicant&#39;s U.S. patent application Ser. No. 10/349,599, filed Jan. 23, 2003, now U.S. Pat. No. 6,827,525 B2. The disclosures of U.S. patent application Ser. No. 10/695,640, U.S. patent application Ser. No. 10/349,599, and U.S. Pat. No. 6,827,525 B2 are incorporated herein by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT:  
       [0002]     Not applicable.  
       REFERENCE TO SEQUENCE LISTING, TABLE, OR COMPUTER PROGRAM LISTING SUBMITTED ON COMPACT DISK:  
       [0003]     Not applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     (1) Field of the Invention  
         [0005]     The invention relates to the field of building up land in water-covered or water-surrounded areas and more specifically to the field of restoring land in coastal wetlands where erosion has caused land loss. This invention also relates to the field of building land bodies in water-covered or water-surrounded areas.  
         [0006]     (2) Description of the Related Art  
         [0007]     Coastal wetlands historically have been rich in plant and animal life. This abundance of plant and animal life has made coastal wetlands productive areas for fishing (for fish and shellfish), trapping, and hunting.  
         [0008]     Coastal wetlands require a constant supply of sediment so that the process of sedimentation keeps pace with erosion. In a coastal wetland, the land is built up by sedimentation and broken down by erosion. In a stable coastal wetland, these processes are in balance when considered over the long term: land loss through erosion and land gain from sedimentation remain essentially equal. Seasonal or unusual events such as floods or storms may cause erosion and sedimentation to become unbalanced for a time. But in a stable wetland, erosion and sedimentation remain in balance over the long term.  
         [0009]     Over at least the last 100 years, human activities have affected the natural balance between erosion and sedimentation in many coastal wetlands. Levees and other developments have reduced the flow of fresh water into many coastal wetlands. These developments have reduced the amount of sedimentation in the affected coastal wetlands by eliminating the sediment flows that were carried by the fresh water flow.  
         [0010]     In addition to reducing sedimentation, the reduction of fresh water flow has also promoted erosion. The reduction of fresh water flow has changed the chemical composition—especially the salinity—of water in some coastal wetlands. Plants adapted to the previous (lower) salinity levels often die when salinity increases. Killing the plants increases erosion because many plants hold the land together and help to absorb impacts of waves and other water flows. When the plants die, erosion increases.  
         [0011]     With erosion increasing and sedimentation decreasing, land area in coastal wetlands has shrunk. Facing the loss of a valuable resource, public officials and citizens have sought ways to reduce erosion and increase sedimentation in coastal wetlands so that lost land may be restored. Fresh water diversion from rivers into coastal wetlands merely keeps salt water at bay and does little to promote land restoration, not only because of decreased sediment in leveed rivers but also because diversion of fresh water typically uses siphons or pipes that place sediment-containing water into a single location rather than over a broader plain. Rivers currently contain seventy percent less sediment than they did fifty years ago because of flood-prevention methods upstream.  
         [0012]     Applicant&#39;s U.S. patent application Ser. No. 10/695,640 and U.S. patent application Ser. No. 10/349,599, now U.S. Pat. No. 6,827,525 B2, disclose devices, systems, and methods for restoring wetlands and building up land using a cutterhead dredge and other devices.  
       BRIEF SUMMARY OF THE INVENTION  
       [0013]     It is an object of this invention to provide a method and system for building up land in a water-covered area. It is another object of this invention to provide a structure capable of confining sediment. It is another object of this invention to provide a structure capable of protecting land against impacts of waves and other water movement. To achieve these and other advantages and objects, and in accordance with the purpose of the invention as embodied and broadly described herein, in one aspect the inventor describes a system method for building up land in a water-covered area and a system and method for protecting land against impacts of waves and other water movement.  
         [0014]     In a first embodiment, the method includes the steps of: supplying a floating structure having an essentially closed shape and capable of confining sediment; selecting a location in which land is to be built up; placing the floating structure at the location; and introducing a sediment-containing water flow into the interior of the essentially closed shape. In a second embodiment of the method, the steps remain substantially the same, but the floating structure is of a different configuration, with the floating structure comprising a pair of spaced and essentially parallel bodies defining the area in which sediment is to be confined.  
         [0015]     Further in accordance with the purpose of the invention as embodied and broadly described herein, in another aspect, the inventor describes an embodiment of a system for building up land in a water-covered area. The system includes a plurality of floating boom segments, a wasteweir segment, and a sediment source. The boom segments and the wasteweir segment are connectable to form a shape that encloses an area wherein land is to be built up. The boom segments are connectable by connecting means as described further below. Each boom segment has a body that has a sieve panel attached thereto. Thus the assembled device includes an essentially closed shape formed by the boom segments and interrupted by the wasteweir segment. The assembled device also includes an essentially closed shape extending essentially between the water surface and the water bottom and interrupted by the wasteweir segment. The wasteweir segment enhances the rate of land formation by increasing the rate at which water from the sediment source may leave the enclosed area. Other embodiments of the invention may include multiple wasteweir segments or may omit wasteweir segments entirely. The wasteweir segment may be removed when the desired land body has been formed.  
         [0016]     In the first embodiment of a system for building up land in a water-covered area, each boom segment has a floatable body having a first end portion, a second end portion, and a lower side portion; a first means for connecting the body attached to the first end portion and a second means for connecting the body attached to the second end portion; and a sieve panel attached to the lower side portion. The floating body is formed from buoyant material and may be formed in any convenient fashion allowing attachment of the sieve panel and the means for connecting the body. In the first embodiment, the floatable body is preferably made from a buoyant foam material. The foam material is preferably sealed within a skin of vinyl cloth. The skin is preferably equipped with grommeted holes for attaching means for connecting the body.  
         [0017]     In the first embodiment, the sieve panel of each boom segment is preferably heat-bonded to the vinyl skin of the floatable body. The sieve panel of each boom segment has a generally rectangular shape and an upper portion, a lower portion, and first and second side portions, the first and second side portions of the sieve panel being respectively aligned with the first and second end portions of the body. Each first side portion of the sieve panel has disposed thereon a first means for connecting sieve panel; likewise, each second side portion of the sieve panel has disposed thereon second means for attaching sieve panel. In the first embodiment the means for connecting sieve panels are two connectible portions of a zipper. Other means, including ropes, cords, snaps, interlocking rigid connectors, and heat bonding, may also be used as sieve-panel connecting means. Each sieve panel has a height greater than or approximately equal to the depth of the water in the water-covered area and preferably has a height approximately twice the depth of the water in the water-covered area in order to create a terracing effect around the perimeter and to thereby mimic a naturally-sloped shoreline. Here the height of a sieve panel is the distance between its upper portion and its lower portion, measured with the sieve panel laid out upon a flat surface. When the sieve panel has a height greater than the depth of the water in which the sieve panel is used, the fact that the height of the sieve panel itself is greater than the water depth allows the sieve to bulge outward in a curved shape; for example, see  FIG. 7 .  
         [0018]     In a preferred embodiment, the mesh of the sieve panel is approximately 1/16 inch. This allows for vegetation to take root and be anchored to the sieve panel. In some embodiments, the mesh of the sieve panel may be a biodegradable mesh material.  
         [0019]     Optionally, each sieve panel has an anchor segment attached to and preferably running the length of its lower portion, the anchor segment being a segment of lead-core line, chain, or other similar dense, non-floating, generally linear material. The anchor segment helps to hold the lower portion of the sieve panel to the bottom of the water-covered area. Each boom segment has an anchor segment having a first end portion aligned with the first end portion of the floatable body and a second end portion aligned with the second end portion of the floatable body. Each anchor segment has first anchor connecting means disposed upon the first end portion thereof and second anchor connecting means disposed upon the second end portion thereof.  
         [0020]     Optionally, each boom segment can also include a tiedown having a first end portion and a second end portion, the first end portion being attached to the body. The tiedown is secured so that its length under tension is approximately equal to the depth of the water and the length of the tiedown is at least approximately equal to the depth of the water. Preferably, the tiedown is fastened to the anchor line such that its length approximately equals the depth of the water. Tiedowns are intended to add strength to the boom segments and to keep the boom segments at the height of the wasteweir.  
         [0021]     In the first embodiment the wasteweir segment is an essentially U-shaped frame having a height at least approximately equal to the depth of the water in the water-covered area. The frame is constructed so that it is denser than water. Aluminum, steel, or other appropriate materials can be used for the frame material. The wasteweir segment includes a first wasteweir-to-body connecting means allowing it to be connected to the second body-connecting means and a second wasteweir-to-body connecting means allowing it to be connected to the first body-connecting means. The wasteweir segment also includes means for connecting it to the first and second sieve-panel attaching means. The wasteweir segment also includes wasteweir-to-anchor connecting means disposed thereon to allow for connection to the anchor segments of boom segments adjacent to the wasteweir segment. By use of its various connecting means, the wasteweir segment may be inserted and connected as part of an assembly of boom segments. The wasteweir segment also includes barriers, which in the first embodiment are preferably ordinary wooden boards. The barriers are connectible to the wasteweir frame via barrier receiving means, which are grooves in the wasteweir frame as in the second embodiment.  
         [0022]     The first embodiment also has a sediment source disposed so as to provide sediment flow into the interior of the closed shape formed by the boom segments and the wasteweir segment. The sediment source in the first embodiment is preferably the discharge of a dredge.  
         [0023]     In an alternative embodiment, the wasteweir segment may comprise a pair of barrier-support posts, which are elongated elements of sufficient strength and stiffness to be driven into the water bottom in the water-covered area. The barrier-support posts are equipped with barrier receiving means, which may be grooves or any other suitable means for receiving barriers. See  FIG. 16 .  
         [0024]     In an alternative embodiment, the sieve panel of each boom segment does not have an anchor line attached thereto. Instead, one or more non-floating objects may be attached to one or more boom segments. For example, a single anchor line of the desired length may be attached to the sieve panels, to the tiedowns of each segment, and to the wasteweir segment, thus running the length of the device. In the embodiments described above, the essentially closed shape may preferably be about 900 to 1000 feet in circumference; and the embodiment may preferably be employed in water with a depth less than about 4 feet, although the use of the embodiment is not limited to that depth.  
         [0025]     In another embodiment, the device may comprise parallel sets of floatable bodies disposed opposite one another, with a wasteweir segment at each end of each set of floatable bodies. In this embodiment, the parallel sets of floatable bodies are attached to opposite edges of a shared sieve panel. Note that each floatable body may comprise multiple segments linked together as described elsewhere herein, although this discussion focuses on an embodiment in which each floatable body is a single item rather than a combination of shorter floatable bodies. The shared sieve panel is preferably heat-bonded to the vinyl skin of the floatable body and may be made from the same meshes that are discussed herein or in the material incorporated by reference. The shared sieve panel has a generally rectangular shape and an upper portion, a lower portion, and first and second side portions, the first and second side portions of the sieve panel being respectively aligned with the first and second end portions of the floatable bodies. Each first side portion of the sieve panel has disposed thereon a first means for connecting sieve panel; likewise, each second side portion of the sieve panel has disposed thereon second means for attaching sieve panel. The means for connecting sieve panels may be two connectible portions of a zipper. Other means, including ropes, cords, snaps, interlocking rigid connectors, and heat bonding, may also be used as sieve-panel connecting means. Each sieve panel preferably has a height greater than two times the depth of the water in the water-covered area and preferably has a height approximately equal to the sum of (a) twice the depth of the water in the water-covered area, plus (b) the dimension of the land to be built up, as measured perpendicular to the floatable bodies. Here the height of a sieve panel is the distance between its upper portion and its lower portion, measured with the sieve panel laid out upon a flat surface. This embodiment preferably has, at each end of the floatable boom segments, a wasteweir segment connectible to the boom segments and sieve panel by the same means described above. Preferably the result of assembling this embodiment is one or more roughly rectangular structures for containing sediment as shown in the drawing  FIGS. 22 and 25 . The shared sieve panel is suspended from the floatable bodies so that, when sediment is introduced into the interior of the structure, a portion the shared sieve panel can rest on the water bottom as shown in drawing  FIG. 23 . Note that the structure optionally may include transverse tension cords, ropes, or rigid members connecting the transverse bodies. Although this embodiment most advantageously has two wasteweir segments, embodiments substituting a boom segment of appropriate length for one or more of the wasteweir segments also may be used.  
         [0026]     In alternative embodiments of the sediment-containment structures described herein, an optional support frame may be used. The support frame or ribbed skeleton is fixed to the sieve panel or shared sieve panel of a sediment-containment structure for the purpose of giving the structure additional stiffness and a defined shape. Embodiments of the support frame may be used in conjunction with the upper and lower portion of a sieve panel as shown in drawing  FIGS. 26 and 27 .  
         [0027]     Optionally, a sediment-containment structure disclosed herein may use a secondary sieve panel and secondary boom to decrease loss of sediment over a floatable body of a sediment-containment structure. The secondary boom is a floatable body and may optionally be connectible in the same manner as segments of the sediment-containment boom described above. The sieve panel of the secondary boom is connected is any suitable manner (tying, fusing, stapling, adhesives, and other methods known or stated herein) to either a floatable body or a mesh portion of a sediment-containment structure. In use, the secondary boom is positioned outside the sediment-containment structure. As the sediment-containment structure fills, the secondary boom provides secondary containment for sediment spilling over the floatable body of a sediment-containment structure.  FIG. 28  an embodiment of such a device.  
         [0028]     Further optionally, a sediment-containment structure may comprise one and preferably a plurality of stakes inserted into the water bottom outside the sediment-containment structure. These stakes may take the form of PVC or other pipes or any other body suitably stiff and strong for the application. Each stake is connected to a stake rope, which is connected to a stake-rope-to-mesh connector, which may take the form of a plastic clip attachable or attached to the mesh of a sieve panel or shared sieve panel. The stake-rope-to-mesh connector may include rings, apertures, cleats or other structures around which a cord or rope may be fastened. Where stakes and stake ropes are used, the height of a sieve panel may be selected to be substantially greater than the depth of the water, because the stake can hold the sieve panel under tension, there is less risk of fouling of the device. Also, the stakes may provide more precise control of the location and shape of the land mass formed using the structure. In this application, a land mass includes land built up above the water level in a water covered area and also includes a buildup of sediment on a water bottom decreasing the depth of water in that area. See  FIG. 12  through  19 . Note  FIGS. 14 through 15  and  17  through  19 ; each set of figures shows a sequence in which sediment is added to an embodiment of the invention having stakes.  
         [0029]     In another embodiment of the invention comprising stakes, the invention is used to provide a wave-bumper structure capable of protecting land against impacts of waves and other water movement. See drawing  FIG. 29 , which depicts an embodiment of such a device. The wave-bumper structure may use one or more boom segments as disclosed herein and additionally includes a ring attached to the anchor segment thereof so that a wave-bumper-stake, having the characteristics of a stake as described above, may be driven through the ring to fix the structure to a land mass to be protected from the action of waves or other moving water. The wave-bumper stake could also be attached to the anchor segment of a boom segment in any conventional manner, such as ties, staples, and other methods disclosed above.  
         [0030]     Both the foregoing general description and the following detailed description are exemplary and explanatory only and do not restrict the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]      FIG. 1  is a top view showing an embodiment of the invention, including the assembled components thereof.  
         [0032]      FIG. 2  is a partial side view of an embodiment of the invention.  
         [0033]      FIG. 3  is a view of the frame of the wasteweir segment depicted in  FIG. 2 , taken along sections A-A of  FIG. 2 .  
         [0034]      FIG. 4  is a view of the frame of the wasteweir segment depicted in  FIG. 2 , taken along sections C-C of  FIG. 2 .  
         [0035]      FIG. 5  is a view of the frame of the wasteweir segment depicted in  FIG. 2 , taken along sections B-B of  FIG. 2 .  
         [0036]      FIG. 6  is a flow chart showing the steps, the steps being those which one embodiment of the method of the invention comprises.  
         [0037]      FIG. 7  is a sectional view of an embodiment of the invention shown in  FIG. 2 , taken along section D-D thereof.  
         [0038]     The invention will be better understood in view of the following description presented with reference to the accompanying drawings:  
         [0039]      FIG. 8  is a partial side view of an amphibious dredging vehicle according to the invention.  
         [0040]      FIG. 9  is a partial top view of an amphibious dredging vehicle according to the invention.  
         [0041]      FIG. 10  is a partial rear view of an amphibious dredging vehicle according to the invention.  
         [0042]      FIG. 11  is a schematic diagram showing a hydraulic circuit according to the invention. 
     
    
       [0043]     The invention will be better understood in view of the following description presented with reference to the accompanying drawings:  
         [0044]     Both the foregoing general description and the following detailed description are exemplary and explanatory only and do not restrict the invention as claimed.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0045]     The inventor now moves to a detailed description of an embodiment of the method of the invention, which is shown in the drawings, where like parts are labeled with like reference numerals.  FIG. 6 , is a flow chart depicting the steps that are involved in the embodiment depicted therein.  
         [0046]     1. Select a site where the method will be practiced. The site is typically a coastal marsh or wetland that has been eroded through a process that includes salt-water intrusion. Islands that have been degraded due to erosion can also be selected.  
         [0047]     2. Measure the dimensions of the site including the depth of the water contained at various locations around the site.  
         [0048]     3. Erect a sediment-containment structure in the manner described below.  
         [0049]     4. Introduce sediment into the substantially closed shape formed by the sediment-containment structure.  
         [0000]     Additionally, board or other blocking means can be added to a wasteweir segment as the height of sediment buildup increases.  
         [0050]     The inventor now moves to a detailed description of an embodiment of the system of the invention, which is shown in the drawings, where like parts are labeled with like reference numerals. In  FIGS. 1 through 5 , system  10  for building up land in a water-covered area includes boom segments  20 , wasteweir segment  80 , and dredge discharge  500 , which discharges sediment-containing flow  520  inside the closed shape formed by the assembly of boom segments  20  and wasteweir segment  80 .  
         [0051]      FIG. 2  is a partial side view of the system  10  in use, with floatable bodies  22  of boom segments  20  floating upon water surface  40 . In this embodiment, each floatable body segment is preferably constructed from a buoyant foam material that has a waterproof vinyl skin. Each boom segment  20  has first body-connecting means  23 , for connecting one boom segment to an adjacent boom segment, and second body-connecting means  27  for the same purpose. Means  23  and  27  are disposed on opposite end portions of a boom-segment  20 . The first body-connecting means  23  is connectible to the second body-connecting means  27  for connecting adjacent segments  20 . These body-connecting means are rings in the depicted embodiment, but they may be any suitable known connecting means including ropes, straps, rings, hooks, and interlocking rigid connectors. The connectors may be attached to the floating body by any convenient means, including fixation with adhesives, heat-bonding, or passing the connectors through grommeted perforations in the vinyl skin of the floating body.  
         [0052]     In the embodiment depicted in the  FIGS. 1 through 7  of the drawing, each boom segment  20  also has attached, to its lower side portion, sieve panel  60 . Sieve panel  60  has an upper portion, a lower portion, and first and second side portions aligned with the first and second end portions  23  and  27 , respectively, of body  22 . Sieve panel  60  is made from a mesh or cloth having a weave sufficiently tight to trap a significant portion of the sediment carried by a water flow passing through the mesh and potentially sized so as to allow roots to attach or anchor to or through the sieve panel. Optionally, a biodegradable material my be selected. Sieve panel  60  has first means  66  for connecting sieve panel  60  disposed upon its first side portion and second means  68  for connecting sieve panel disposed upon its second side portion. Each sieve panel  60  is connected by its first means  66  for connecting sieve panel to an adjacent sieve panel  60  or to an adjacent wasteweir segment  80 ; each sieve panel  60  is connected by its second means  68  for connecting the sieve panel to an adjacent sieve panel  60  or to an adjacent wasteweir segment  80 . The first means  66  and second means  68  for connecting sieve panels may be any suitable connecting device, including two compatible portions of a zipper; a row of eyelets for securing with cord or rope, or even the mesh itself, through which a securing cord, thread, staple, or other device may be looped, woven, or otherwise secured.  
         [0053]     Each boom segment has anchor segment  50 , which is attached to the lower portion of the sieve panel  60 . Anchor segment  50  is made from a dense material (at least denser than water) such as lead-core line or heavy chain. Anchor segment  50  secures the device to the bottom of the water-covered area in order to prevent unwanted movement. Each anchor segment  50  has first anchor-connecting means  51  aligned with first body-connecting means  23  and second anchor-connecting means  57  aligned with second body-connecting means  27 . These first and second anchor-connecting means may be any suitable known connecting means, including those listed for use as body-connecting means. Alternatively, a single, continuous anchor segment can be used to anchor all of the sieve panels.  
         [0054]     Each boom segment  20  has tiedown  70  having first and second end portions. The first tiedown end portion is attached to body  22 , and the second tiedown end portion is attached to anchor segment  50 . Tiedown  70  has a length approximately equal to the depth of the water.  
         [0055]     Wasteweir segment  80  is a three-sided frame having a base  82  having first end portion  84  and second end portion  86  and having first side element  88  and second side element  90  joined in substantially perpendicular relation to base  82 . First side element  88  has first body-wasteweir connecting means  83  attached near the end thereof most remote from base  82 ; second side element  90  has second body-wasteweir connecting means  87  attached near the end thereof most remote from base  82 .  
         [0056]     First body-wasteweir connecting means  83  is a connector connectible to second body-connecting means  27 . Second body-wasteweir connecting means  87  is a connector connectible to first body-connecting means  23 . In addition, the first end portion of base  82  has attached thereto first wasteweir-anchor connecting means  96  and second wasteweir-anchor connecting means  98 . First wasteweir-anchor connecting means  96  is connectible to second anchor-connecting means  57 , and second wasteweir-anchor connecting means  98  is connectible to first anchor-connecting means  51 .  
         [0057]     Wasteweir first side  88  has attached thereto first wasteweir-sieve connecting means  92 ; second wasteweir side  90  has attached thereto second wasteweir-sieve connecting means  94 . First wasteweir-sieve connecting means  92  is connectible to second sieve-panel connecting means  68 . Second wasteweir-sieve connecting means  94  is connectible to first means sieve-panel connecting means  66 .  
         [0058]     The frame of wasteweir segment  80  includes longitudinal opening  100  in base  82 , longitudinal opening  102  in first side  88 , and longitudinal opening  104  in second side  90 , each longitudinal opening being a groove adapted for receiving a board  110 . These longitudinal openings constitute the barrier receiving means of this embodiment of the invention. Other barrier-receiving means would include pegs to which barriers may be affixed, magnets, rigid interlocking connectors, and holes with screws or bolts allowing the barriers to be screwed or bolted to the frame. Barriers  110  are preferably wooden boards fitted into the wasteweir segment as the level of built-up land rises in order to contain sediment while allowing for a rapid discharge of water from the water-covered area.  
         [0059]     The inventor now moves to a detailed description of an embodiment of an amphibious dredging vehicle  700 , which is an element of some embodiments of the invention.  
         [0060]     As best seen in  FIG. 9 , amphibious dredging vehicle  700  has first floatable pontoon  610  and second floatable pontoon  620  with a link disposed therebetween and fixed thereto in conventional fashion, such as by welding or bolting the link to floatable pontoons  610  and  620 . In this embodiment, floatable pontoons  610  and  620  are constructed of lightweight and sturdy metal and are equipped with conventional internal baffles, which increase the strength of the pontoons and render the pontoons less likely to lose their buoyancy due to a leak or puncture. The link between the floatable pontoons  610  and  620  may take any convenient and sufficiently sturdy form. In the embodiment depicted, the link takes the form of a conventional metal frame  631  having a generally flat deck  630  mounted thereon. The deck  630  allows for a convenient mounting point for other components of the invention and for other components of the amphibious dredging vehicle  700 . The total width and length of the amphibious dredging vehicle  700  may preferably be selected to allow the amphibious dredging vehicle  700  to be transported by truck.  
         [0061]     The front end portions of first floatable pontoon  610  and second floatable pontoon  620  are aligned with the front end portion of deck  630 . First floatable pontoon  610  has conventional drive track  612  mounted thereon. Second floatable pontoon  620  has conventional drive track  622  mounted thereon. The pontoons may be constructed of any material that is sufficiently light and durable to allow construction of a sturdy and floatable pontoon; examples include aluminum and steel.  
         [0062]     Mounted to the front end portion of the deck  630  is cutterhead  640 . Cutterhead  640  may be of any convenient design, including cylindrical or disk-shaped rotating devices or arrays of high-pressure water jets; a cylindrical rotating design is shown here. Also mounted to the deck  630  is dredge pump  650 , which is operatively connected to cutterhead  640  in conventional fashion. Dredge pump  650  includes both impeller housing  651  and ten-inch hydraulic pump  652 .  
         [0063]     Also mounted near the front end portion of deck  630  is control house  632 . Control house  632  provides a convenient location for operating the amphibious dredging vehicle. Tank housing  638  includes therein tanks for both diesel fuel and hydraulic fluid. A powerplant in the form of diesel engine  636  provides power to the amphibious dredging vehicle  700  through three separate paths. The powerplant also may take the form of other fuel-air engines, electric motors, or other power-providing mechanisms. Diesel engine  636  powers pump  637 A that pressurizes hydraulic fluid in a conventional hydraulic circuit  737 , which includes conventional tubing linking the hydraulic pump  637 A to all devices that are powered by the hydraulic circuit  737 .  FIG. 11  is a schematic diagram showing that the hydraulic circuit  737  links hydraulic pump  637 A to first hydraulic drive motor  614 , second hydraulic drive motor  624 , hydraulic drive motor  653  mounted adjacent to dredge pump  650 , hydraulic drive motor  691  mounted adjacent to water pump  690 , hydraulic ram  663 , and hydraulic ram  699 ; the devices are linked in conventional fashion by pairs of hydraulic lines.  
         [0064]     In one path, the hydraulic circuit  737  powers the drive tracks, which allow the amphibious dredging vehicle to track forward across land or shallow water. The hydraulic circuit  737  powers a first track-driving means in the form of a first hydraulic drive motor  614  and second track-driving means in the form of second hydraulic drive motor  624 . The first hydraulic drive motor  614  drives first drive track  612  through a chain and sprocket  616 . The second hydraulic drive motor  624  likewise drives second hydraulic drive motor  624  drives second drive track  622  through a chain and sprocket  626 . The claimed first track-driving means and the claimed second track-driving means do not have to be hydraulic drive motors. Instead, the claimed first track-driving means and the claimed second track-driving means may take the form of any device capable of providing sufficient motive power, including electric motors and mechanical transmissions driven either by a central powerplant or by individual powerplants for each track.  
         [0065]     In the second path, the hydraulic circuit  737  provides power to a dredge-pump-driving means in the form of hydraulic drive motor  653  that drives dredge pump  650 . When the dredge is being moved across deeper water from one dredging site to another, dredge pump  650  may be used to pump water through directable discharge  660  to move the amphibious dredging vehicle  700 . By controlling the aim or orientation of directable discharge  660 , the operator may control the direction of the amphibious dredging700 vehicle when the dredge pump  650  is being used to move the amphibious dredging vehicle  700  through water. The claimed dredge-pump-driving means does not have to be a hydraulic drive motor. Instead, the claimed dredge-pump-driving means may take the form of any device capable of providing sufficient motive power, including electric motors and mechanical transmissions driven either by a central powerplant or a powerplant dedicated to driving the dredge pump  650 .  
         [0066]     The rear end portion of the deck  630  is disposed opposite the front end portion of the deck  630 . Mounted near the rear end portion of the deck  630  is directable discharge  660 , which is more easily seen in  FIG. 10 . Directable discharge  660  is made from conventional sturdy, flexible tubing such as reinforced rubber or flexible PVC pipe and is joined to discharge plumbing  670  by flange  672  or by another conventional joint. Directable discharge  660  is operatively connected to cutterhead  640  and dredge pump  650  by conventional discharge plumbing  670 , which preferably is aluminum pipe with a diameter between 4 inches and 10 inches. Directable discharge  660  is made from flexible material that allows the directable discharge  660  to be aimed as needed to provide the desired propulsion to the amphibious dredging vehicle  700 . The directable-discharge-control means takes the form of ring  662  secured to directable discharge  660  and operatively connected to hydraulic ram  663 , which is in turn attached to second floatable pontoon  620 . The hydraulic ram  663  may be controlled to select and maintain the desired aim of the directable discharge  660 . The directable-discharge-control means also may take the form of any of several known devices capable of aiming directable discharge  660 —for example, hydraulic cylinders, cables, links, electric motors, solenoids, and other devices operatively connected to directable discharge  660  and capable of changing and maintaining the aim of the directable discharge  660  in the desired orientation.  
         [0067]     In the third path, the hydraulic circuit  737  provides power to a water-pump-driving means in the form of a hydraulic drive motor  691  that drives water pump  690 . Water pump  690  may be used to pump water from water intake  694  through water discharge  692  to move the amphibious dredging vehicle  700 . By controlling the aim or orientation of water discharge  692 , the operator may control the direction of the amphibious dredging700 vehicle when the water pump  690  is being used to move the amphibious dredging vehicle  700  through water. The claimed water-pump-driving means does not have to be a hydraulic drive motor. Instead, the claimed water-pump-driving means may take the form of any device capable of providing sufficient motive power, including electric motors and mechanical transmissions driven either by a central powerplant or a powerplant dedicated to driving the water pump  690 .  
         [0068]     The rear end portion of the deck  630  is disposed opposite the front end portion of the deck  630 . Mounted near the rear end portion of the deck  630  is water discharge  692 , which is more easily seen in  FIG. 10 . Water discharge  692  is operatively connected to water intake  694  and water pump  690  by conventional water-discharge plumbing  696 , which preferably is aluminum pipe with a diameter between 4 inches and 10 inches. Water discharge  692  may be made from conventional sturdy, flexible tubing such as reinforced rubber or flexible PVC pipe and is joined to water-discharge plumbing  696  by flange  698  or by another conventional joint. Water discharge  692  is made from flexible tubular material that allows the water discharge  692  to be aimed as needed to provide the desired propulsion to the amphibious dredging vehicle  700 . The water-discharge-control means is operatively connected to water discharge  692 . The water-discharge-control means may take the form of ring  697  secured to water discharge  692  and operatively connected to hydraulic ram  699 , which is operatively connected to ring  697  and attached to second floatable pontoon  620 . Ring  697  and hydraulic ram  699  operate in the same manner as ring  662  and hydraulic ram  663  described above. Likewise the water-discharge-control means may take the same forms as the directable-discharge-control means described above. Note that in  FIG. 8  water pump  690 , water discharge  692 , and water intake  694  are shown, but associated hardware such as ring  697 , flange  698 , and hydraulic ram  699  are omitted from  FIG. 8  for clarity; these items appear in  FIG. 9  and  FIG. 10 .  
         [0069]      FIG. 8  shows several optional components not previously discussed. Winch  634  is attached to deck  630 . Cable  635  is wound onto winch  634 . Cable  635  then passes through dredge pulley  637  and is attached to cutterhead  660 . Winch  634  thus can raise and lower cutterhead  640  as desired. Overhead frame  680  provides a mounting point for dredge pulley  637 . Overhead frame  680  also provides guide-wire pulleys  682  and  684 , which attached to guide wire  686 . Guide wires sometimes are used in dredging to provide a reference grid for dredging operations. Dredge pulley  637 , overhead frame  680 , guide-wire pulleys  682  and  684 , and guide wire  686  are omitted from the other figures for clarity.