Abstract:
A process and apparatus for planting aquatic plants underwater on the bottom of estuaries in propeller scars and blowouts and for encouraging plant growth in these propeller scars and blowouts. Aquatic plant shoots are transplanted by positioning shoots, plants or seeds in a sediment tube or sediment bag which is in turn placed in a propeller scar or blowout. When the sediment tube or sediment bag is placed in the propeller scar or blowout aquatic plant growth is facilitated. The sediment tubes and sediment bags may be preformed or they may be formed just prior to their placement in the estuary. A watercraft may be used to position the sediment tubes and sediment bags with and without sea grass shoots, plants or seeds, in propeller scar propeller scar. With the process and apparatus of this invention, sea grass plants can be replanted on the bottom of an estuary and new plant growth encouraged in propeller scars and blowouts.. Further in accordance with another embodiment of this invention a tube or other obstruction without plant shoots, plants or seeds is placed in a propeller scar in order to impede water flow through the propeller scar. When water flow through the propeller scar is impeded natural plant growth is encouraged. The material from which the sediment tube or bag is formed from degrades. The degration of the sediment tube or bag can be correlated to the growing cycle of seagrass plants, shoots or seeds as may be contained in the sediment tube or bag.

Description:
RELATED APPLICATIONS  
       [0001]    This application is a continuation in part application of application Ser. No. 10/278,219 filed Oct. 23, 2002, which in turn is a continuation in part application of application Ser. No. 09/593,724 filed May 18, 2000. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention is concerned with a process and related apparatus whereby aquatic propeller scars and blowouts may be repaired underwater for purposes of restoration. The restoration of all aspects of the environment has become extremely important in recent years. The three areas of restoration which are of primary import are reducing air pollution, restoring and cleaning up the land and cleaning up and restoring our waterways, the ocean and related estuaries. It is these related estuaries that are the primary thrust of the subject invention.  
           [0003]    As a result of the decrease in water quality, millions of acres of aquatic plant life, which form an important part of the aquatic Eco system, have been destroyed. While the restoration of aquatic plant life is difficult, it is possible, for example see the process and apparatus of co pending application Ser. No. 09/104,681 filed Jun. 25, 1998 now U.S Pat. No. 6,070,537 and application Ser. No. 09/573,724 filed May 18, 2000. While the process of this U.S. Pat. No. 6,070,537 is well suited to the planting of large underwater areas it is not particularly suited to the replanting of propeller scars or blowouts. Propeller scars are areas that have been striped of aquatic plant life, as a result of the propeller of the moving boat inadvertently being allowed to come into contact with the estuary bottom, thereby leaving a semicircular trench on the bottom of estuary. A blowout results when the hydraulic action of a propeller wash forms a hole in the estuary bottom.  
           [0004]    Because aquatic plant life is an important part of the complex aquatic environment, the restoration of the total estuary bottom is important including propeller scars and blowouts.  
           [0005]    The natural restoration of aquatic life, in propeller scars and blowouts is an extremely slow process. While it is possible to manually plant shoots of aquatic plants, in propeller scars this process is extremely slow and expensive. Due to the cost of labor, the manual planting of sea grass plants has at best been marginally successful. Further due to the peculiar nature of propeller scars manual planting is often unsuccessful. Also because propeller scars are widely dispersed the cost of manually planting just one propeller scar in an estuary can be prohibitive. Likewise manual planting in some instances is of questionable success as the person doing the planting, in walking over the bottom of an estuary, does further damage by crushing other plants which may be growing in the area. Blowouts present another problem in that they are usually so deep that sea grass can not recolonize the blowout.  
           [0006]    This invention is concerned with a process and apparatus whereby sea grass can be restored and quickly planted in an economical fashion in a propeller scar or blowout or the propeller scar or blowout can be filled in such a manner that the re-colonization of sea grass is encouraged. Generally it could be said that the process of this invention stabilizes the propeller scar or blowout such that plant growth is encouraged Generally, it could be said that the process of this invention stabilizes the propeller scar or blowout such that plant growth is encouraged.  
           [0007]    As used in connection with this invention, the term aquatic plant life and sea grass includes many species of plant life such as halodule wrightii (shoal grass), thalassia (turtle grass), etc. The process and apparatus of this invention is particularly suited to the planting of thalossia sea grass in propeller scars and blowouts for the re-colonization of sea grass in these propeller scars and blowouts.  
           [0008]    Aquatic plant life as it exists in estuaries is important in preventing water pollution as this plant life acts as a filter for many pollutants and hence, this plant life helps to maintain water quality. Therefore it is important that the maximum area be covered with aquatic plants including those areas that have been denuded of plant life by the contact of a marine propeller with the estuary bottom or the hydraulic action of a marine propeller.  
           [0009]    The restoration of aquatic life to the bottom of our estuaries is extremely important as this aquatic plant life plays a critical function in the total marine Eco system. A large number of important marine animals, both warm and cold blooded, rely totally or in part on aquatic plants as a breeding area, for cover, for food, etc. For example, the endangered manatee relies solely on sea grass as its food source and sea turtles rely on sea grass for part of their diet.  
         OBJECT OF THE INVENTION  
         [0010]    The primary object of this invention is a process whereby aquatic plant life may be planted or restored in propeller scars or blowouts which are located in the bottom of an estuary.  
           [0011]    A further object of this invention is a process whereby a propeller scar or blowout can be filled in such a manner as to encourage the re-growth of sea grass. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a sectioned perspective view showing a propeller scar.  
         [0013]    [0013]FIG. 1 a  is a sectioned perspective view showing a propeller scar with a sediment tube therein.  
         [0014]    [0014]FIG. 1 b  is a sectioned perspective view showing a propeller scar with a baffle n therein.  
         [0015]    [0015]FIG. 1 c  is a perspective view showing a segmented sediment tube for use in this invention.  
         [0016]    [0016]FIG. 2 is a sectioned perspective view showing the placement of the sediment tube of this invention in an underwater propeller scar.  
         [0017]    [0017]FIG. 3 is a sectioned view of the continued placement of the sediment tube of this invention in the propeller scar and the restoration of aquatic plants in this scar.  
         [0018]    [0018]FIG. 4 is a perspective view of the discharge of a sediment tube of this invention into an estuary.  
         [0019]    [0019]FIG. 5 is a perspective view showing the formation of a sediment tube and it&#39;s discharge into an estuary.  
         [0020]    [0020]FIGS. 6 and 6 a  are perspective and end view showing a tube which is particularly suitable for forming a sediment tube for use in this invention.  
         [0021]    [0021]FIGS. 7 and 7 a  are perspective and end view showing the initial steps in the forming of a sediment tube for use in this invention.  
         [0022]    [0022]FIGS. 8 and 8 a  are perspective and end views showing sand being placed in the tube for use in this invention.  
         [0023]    [0023]FIGS. 9 and 9 a  are perspective and end views showing the final closure of the tube for use in this invention.  
         [0024]    [0024]FIG. 10 is a perspective view showing the sediment tube as produced in accordance with FIGS.  6  to  9   a.    
         [0025]    [0025]FIG. 11 is a perspective view showing an alternate embodiment of a sediment tube for use in this invention.  
         [0026]    [0026]FIG. 12 is a perspective view showing a brick which may be used to impede the flow of water through a propeller scar in accordance with this invention.  
         [0027]    [0027]FIG. 13 is a perspective view showing a method for positioning a sediment tube over a propeller scar.  
         [0028]    [0028]FIG. 14 is a perspective view showing a method for forming a sediment tube for use in accordance with this invention.  
         [0029]    [0029]FIG. 15 is a perspective view showing still another method for forming a sediment tube for use with this invention.  
         [0030]    [0030]FIG. 16 is a side section view showing a process for restoring sea grass to a blowout.  
         [0031]    [0031]FIG. 17 is a end view a plurality of sediment perspective end view showing a propeller scar with a plurality of sediment tubes therein.  
         [0032]    [0032]FIG. 18 is an end view showing the process of this invention wherein sediment bags are used with gravel. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    The subject invention relates to a process and apparatus for planting aquatic plants, and for encouraging aquatic plant growth in scars such as propeller scars and blowouts.  
         [0034]    Referring to FIGS. 1, 1 a ,  1   b ,  2  and  3 , a broad perspective of this invention can be seen.  
         [0035]    [0035]FIG. 1 shows the anatomy of a scar in the illustrated instance a propeller scar  2 . Propeller scar  2  is essentially a furrow that has been plowed into the bottom  4  of an estuary by the action of a rotating propeller. As can be seen estuary bottom  4  incorporates existing sea grass  6  which is naturally occurring. Further it can be seen that propeller scar  2  has been denuded of sea grass by the rotation of the propeller.  
         [0036]    In most instances propeller scars are the result of the inadvertent action of a boater. As is discussed above sea grass is an important part of the Eco system. In addition sea grass is beneficial in that it provides refuge and cover for small fish and other aquatic life, which in turn attracts larger fish. The presence of these larger fish is the start of the propeller scar problem as these large fish attract sport and commercial fisherman. These fisherman either as a result of their carelessness or enthusiasm sometimes let their boats enter water which is too shallow for the boat in question. Further this positioning of the boat in water which is too shallow often results from changing water levels i.e. a falling tide.  
         [0037]    When a boat is in water which is too shallow the propeller often comes into contact with the estuary bottom. When estuary bottom  4  is sandy it is possible for a boat to move forward even if the propeller is in contact with estuary bottom  4 . Regretfully this careless action of the boater causes the propeller to plow the estuary bottom  4  such that a propeller scar  2  is formed.  
         [0038]    The subject invention has multiple embodiments, the first embodiment relates to the placement of a sediment tube into the propeller scar in order to facilitate the reintroduction of sea grass into the propeller scar. The sediment tube in this instance incorporates shoots of an appropriate aquatic plant.  
         [0039]    The second embodiment relates to the interpretation of the natural flow of water in a propeller scar in such a manner that native aquatic plants can root in the propeller scar.  
         [0040]    As to the first embodiment of this invention referring to FIG. 2, it can be seen that sediment tube  10  is placed in propeller scar  2 . Sediment tube  10  is an elongated structure which is filled with a growing medium i.e. sand or other material which is conducive to plant growth. When positioned in propeller scar  2  sediment tube  10 , incorporates a plurality of sea grass plant shoots  8 , which over an extended period of time grow and take root in estuary bottom  4 .  
         [0041]    [0041]FIG. 3 illustrates the planting process of this invention when the restoration of growing sea grass  8  to propeller scar  2  is essentially complete. From this figure it can be seen that propeller scar  2  has essentially been filled in and sea grass plant shoots  8  have rooted and started to grow. Sediment tube  10  is formed from a biodegradable material which will degrade in a predetermined period of time. At the start of the planting process illustrated in figure  3  the degeneration of sediment tube  10  has started. Sediment tube  10  can be formed from a variety of materials such as natural and synthetic textiles, degradable polymers and biodegradable polymers, which contain materials such as starch, to aid in there biodegradation. Polymeric films which are formulated without ultraviolet inhibitors or limited amounts of ultraviolet inhibitors are also preferred as these films readily degrade as a result of exposure to sunlight. The most preferred material for use in the manufacture of sediment tube  10  is cotton fabric. Cotton being a natural fiber is completely compatible with estuary bottom environment. Further cotton is easy to work with, to sew and it is inexpensive. It has been found that sediment tubes which are formed from cotton essentially degrade in four to six months which is the proper time for sea grass shoots  8  to grow, take root and penetrate sediment tube  10  through to estuary bottom  4  or for runners  7  from naturally occurring sea grass  6  to take root. Other natural fibers which can be used are coconut fibers, hemp and burlap. Further mixtures of the above mentioned fibers and materials can be used to form the sediment tubes and sediment bags as are used in this invention.  
         [0042]    [0042]FIG. 4 shows apparatus in accordance with this invention whereby preformed sediment tubes  10  and  11  may be positioned in a propeller scar. In this embodiment a boat  12  is provided, this boat being propelled by one or more outboard engines  14 . A plurality of sediment tubes  10  and  11  are formed, preferably onshore. These sediment tubes are filed with a growing medium and may have a plurality of sea grass shoots  8  planted therein. These preformed sediment tubes  10  and  11  are then positioned in tubular support  16  which in their simplest forms are 10 to 20 foot sections of PVC pipe. In operation a tubular member  16  is loaded into a support  20  which may be elevated by a hydraulic motor  22 . Upon the elevation of support  20 , in accordance with arrow  26 , the preformed tube slides out of tubular member  16  and slips below water surface  24  and into a propeller scar, not shown. The slippage of tubes  10  or  11  out of tubular support  16  is in accordance with arrow  24 . Support  20  is further pivotally mounted to hydraulic motor  22  such that horizontal rotation in the direction of arrow  28  is possible. With this rotational capability an operator in the rear of boat  12  is able to move end  30  of tubular member  16  in such a manner that tubes  10  or  11  may be precisely guided into the propeller scar.  
         [0043]    [0043]FIG. 5 illustrates still another embodiment of this invention, wherein the deck of boat  12  is further supplied with a roll  26  of textile or film material which is supported on stand  29  via rollers  30 . Upon the rotation of roll  26  in the direction of arrow  32  a section of material  34  is played off of roll  26 . Sheet material  34  is then partially closed and granular material (sand)  38  is fed out of hopper  36  and into the partially closed section of sheet material  34 . The closure of sheet material  34  is then completed and the closure is secured with an adhesive or by, stapling or heat sealing in a conventional manner. This closure is effected by means  40 .  
         [0044]    Plant shoots  8  are then placed in the preformed sediment tube  10  at station  42  this placement may be either manual or automated.  
         [0045]    Referring back to FIG. 1 it has been found that because of the semicircular nature of propeller scar  2  if water flow through the propeller scar is impeded organic debris will accumulate in the bottom of propeller scar  2 . This ongoing accumulation of debris is conducive to the colonization of sea grass in propeller scar  2 . In order to assist in the re-colonization of seagrass it is preferred that sediment tube  10  be filled with pure sand and preferably sand which incorporates fertilizer. It is preferred that the sand incorporate about 10% percent fertilizer. While the preferred fertilizer is granular as an alternate means of fertilizing the propeller scar  2  liquid fertilizer may be injected into the area on either side of the propeller scar after sediment tube  10  is placed in said propeller scar. The fertilizer may be of the granular time release variety wherein the time release of the fertilizer is timed for the optimum encouragement of plant growth.  
         [0046]    The above discussion and drawings show the placement of a plurality of plant shoots  8  in sediment tube  10 . In the second embodiment of this invention plant shoots  8  may be omitted from sediment tube  10 . In this embodiment tube  11  without plant shoots  8  is placed in propeller scar  2  in order to stabilize and fill propeller scar  2 . Once this propeller scar is filled and stabilized natural re-colonization of sea grass will occur from either side of the propeller scar It is preferred that sediment tube  10  be if such a size that the filling of propeller scar  2  is slightly higher than the surrounding estuary bottom.  
         [0047]    As to this second embodiment of this invention, it can be seen from FIGS. 1 and 1 a  propeller scar  2  is essentially a trough through which water can flow unimpeded. With water flow i.e. tidal currents, water is moving back and forth on a constant basis, through propeller scar  2 . As a result of this constant water movement existing native grass  6  cannot spread into propeller scar  2 . That is as native grass puts out runners into propeller scar  2  the rooting of these runners is constantly being disrupted by the constant water flow through propeller scar  2 . In accordance with this embodiment of this invention water flow through propeller scar  2  is impeded in such a manner that sediment builds up and the runners from native grass  6  can root in propeller scar  2 .  
         [0048]    Referring to FIG. 1 a  it can be seen that when tube  11  is placed in propeller scar  2  the flow of water through propeller scar  2  is restricted. Because water no longer freely flows through propeller scar  2  runners  7  from native grass  6  can root in propeller scar  2 . It should be noted that in this embodiment tube  11  does not incorporate plant shoots. Referring to FIG. 1 b  a variation of the second embodiment of this invention is disclosed in this structure a baffle  13  is placed across propeller scar  2  in such a manner that the water flow is interrupted thereby allowing sediment  15  to build up in propeller scar  2 . With this build up of sediment shoots  7  from native aquatic plants  6  can root in propeller scar  2  which incorporates sediment build up  15 .  
         [0049]    Baffles  13  can be formed from any convenient material such as plastics, metals fibers or wood. In the case of plastic baffles the polymer utilized can be biodegradable an can be designed to disintegrate in a set period of time i.e. 12 months.  
         [0050]    In the case of metals baffle  13  it can be designed to corrode away in a set period of time i.e. a ferrous metal baffle which will rust away in 12 months.  
         [0051]    Further it is understood that baffle  13  can assume any convenient shape an can incorporate legs to facilitate its placement in propeller scar  12 . The means whereby the water flow through the propeller scar may be impeded can assume other forms. For example as is shown in FIG. 1 c  the water flow through propeller scar  2  can be impeded by the placement and staking of a bundle of tied plants  17  in propeller scar  2 . Bundle  17  is weighted in order to prevent movement by the current of water moving through propeller scar  2 .  
         [0052]    Further as is shown in FIG. 12. the water flow through propeller scar  2  may be impeded by putting a dam like structure in propeller scar  2 . Dam like structure may be brick  19  which is further illustrated in FIG. 12. Brick  19  has an arcuate bottom  21  which roughly corresponds to the arcuate shape of propeller scar  2 .  
         [0053]    Brick  19  may be formed from clay which is fired in such a manner that it will disintegrate over a predetermined period of time in an aqueous environment. That is because brick  19  is not completely fired it tends to disintegrate when exposed to water for an extended period of time. The degree to which brick  19  is fired controls the rate of disintegration of brick  19 .  
         [0054]    A series of baffles  13  can be placed along propeller scar  2  at distances of from 1 to 6 feet apart.  
         [0055]    As can be seen in FIG. 11 tube  11  can incorporate means whereby a plurality of tubes may be joined together.  
         [0056]    In the illustrated instance the joining means are loops  63  on the terminal ends of tube  11 . Via these loops a series of tubes  11  may be joined together i.e. by tying the loops together or by placing a pin through overlapping loops.  
         [0057]    Referring to FIGS.  6 - 10  a method for filing tubes  10  and  11  with sand can be seen. In the embodiment an elongated tubular support  44  having a slot  46  cut therein is created, tubular support  44  is usually 10 or 20 ft. long. An elongated section of cloth  46  is then tucked into tubular support  44  with the ends protruding from the ends of tubular support  44  and the transverse edges  48  and  50 , of cloth segment  46 , protrude from slot  46 . As is shown in FIG. 8 tube  44  is then filled with sand  52 . Transverse edges  48  and  50  are then secured together by sewing, stapling or with an adhesive. For purposes of illustration stitching  54  is shown. End  46  and the opposite end not shown, are then tied off and the sediment tube  10  or  11  is removed from tubular support  44 . As an alternate embodiment the finished sediment tube  10  or  11  can be transporting to the job site in tube  44 .  
         [0058]    [0058]FIG. 13 discloses an alternate method whereby sediment  10  may be positioned over a propeller scar (not shown). In this embodiment of this invention as sediment tube  10  reaches the waters edge a workman  50  places a series of flotation devices around (rings shown) sediment tube  10 . Flotation rings  53  are of such a buoyancy that they can float sediment tube  10  which can weigh many hundreds of pounds. When sediment tube  10  is free floating it can then be readily maneuvered to a desired location, whereupon floatation rings  52  are removed one at a time in order to allow sediment tube  10  to settle into the propeller scar.  
         [0059]    [0059]FIG. 14 shows an alternate method for forming a sediment tube  10 . In this method a preferred tube  54  is positioned over a section  56  through which is pumped a slurry of sand and water. Sediment tube  10  has walls which are porous, whereby the water component of the slurry passes through the tube walls. As pipe section  56  is slowly withdrawn in the direction of arrow  58  preformed tube section  54  is gradually filled with sand  64  in such a manner as to form a completed sediment tube.  
         [0060]    [0060]FIG. 15 illustrates still another method for forming a sediment tube  10 . Here a preformed tube  65  is positioned over a pipe section  60  which incorporates an internal auger  62 . As auger  62  is rotated sand  64  is propelled to the head  66  of tube section  65 . As pipe section  60  is withdrawn in the direction of arrow  68  preformed tube section  65  is filled with sand  64  thereby forming a completed sediment tube which can be used with or without plant shoots in accordance with the above description.  
         [0061]    The material from which sediments tubes  10  and  11  are formed may be in brightly colored in order to facilitate present and future placement and location of the sediment tube. These observations are useful in determining the effectiveness of the overall restoration.  
         [0062]    Sediment Tubes  10  and  11  for use in accordance with this invention for most applications should be 6 to 12 inches in diameter. Smaller diameter tubes are usually used for the propeller scars from pleasure craft whereas the larger diameter tubes are useful in conjunction with propeller scars from commercial craft. Tubes  10  and  11  are usually 3 to 20 ft. long and the length of the sediment tube is at least ten times the diameter of the tube. A more preferred range is that the length is 10 to 30 times the diameter of the sediment tube.  
         [0063]    As is discussed above sediment tubes  10  and  11  are filled with a medium which is conducive to plant growth. While it is preferred that sediment tubes  10  and  11  be filled with sand these tubes can be filled with other media such as cement, slag, gravel, stones, rocks, clay etc.  
         [0064]    While the above description relates primarily to propeller scars it is understood by one skilled in the art that scars in an estuary bottom can be created by other than the contact of a propeller with the estuary bottom. For example a scar can be created by the keel or rudder of a boat coming into contact with the estuary bottom or by something being dragged across the estuary bottom. As will be described below blowouts are formed by the hydraulic action of a propeller wash.  
         [0065]    Further the above description relates to the use of various types of apparatus for the placement of the sediment tube in the scar. It is understood that the sediment tubes and the other disclosed devices can be manually placed in the scar without the need for specialized apparatus.  
         [0066]    The subject invention further includes a process for repairing blowouts. A blowout is a hole which has been formed by the wash action of a boat propeller or by the mechanical action of a boat keel on an estuary bottom. A blow out is usually formed when a boat runs aground and tries to pull itself free by using the action of ts own propeller. i.e. a boat runs aground and the operator of the tries to free the boat by putting the boat in reverse and applying maximum power. In many cases the boat does not free itself on the first try. The concentrated and continuing action of the propeller wash tends to dig a hole as a result of the hydraulic action of the propeller wash. In many cases these blow out holes are one to eight feet deep when compared to the surrounding estuary bottom. In the process of digging the hole all plant life is uprooted and destroyed. At the end of the process a bare hole remains which is devoid of plant life. Further, as is discussed above, plant life such as sea grass has a difficult time in repopulating the bare blowout due to elevation differences between the seabed and the blowout and the action of tidal currents.  
         [0067]    In order for the blowout to be repopulated with seagrass the blowout must be stabilized.  
         [0068]    In accordance with one embodiment of this invention this stabilization is effected by planting a large number of sediment bags in the blowout.  
         [0069]    As can be seen from FIG. 16 sediment bag  70  comprises a bag member  70  which is filled with a growing medium such as sand.  
         [0070]    Sediment bag  70  is formed from a biodegradable material such as cotton fabric, burlap, a biodegradable polymeric sheet etc. The materials from which bag  70  is formed can be engineered to degrade in a predetermined period of time.  
         [0071]    As can further be seen from FIG. 16 upper layers of bags  70  may further in corporate a plurality of seagrass seeds, plants, shoots or root cuttings. Upon placement of bag  70  the integral seeds, seagrass plants, shoots and root cuttings start growing. The ultimate goal is to repopulate the whole upper surface of the filled blow hole with seagrass  8 .  
         [0072]    When filled with a growing medium sediment bag  70  is usually about 18 to 24 inches long and has a generally circular cross section of from about 12 to about 18 inches. It is understood that sediment bag  70  can be of any convenient size.  
         [0073]    In operation the process of this embodiment of this invention is effected by essentially filling the blow hole with bags  70  which contain a stabilizing medium such as sand or native sediment. A topmost layer of bags  70  is then added to the essentially filed blow hole wherein the top most layer incorporates seagrass seeds, plants, shoots or root cuttings  8 . It is preferred that the uppermost layer of the filled blow hole be slightly higher than the adjacent seabed. The reason for this slightly higher elevation is that it has been found that seagrass in its growing process prefers to grow up, to a higher elevation as to grow down to a lower elevation. In addition to filling a blowout with sediment bags it is within the scope of this invention to fill the blowout with sediment tubes.  
         [0074]    [0074]FIG. 17 shows still another embodiment of this invention where a large deep propeller scar  2  is stabilized and filled with a plurality of sediment tubes  10 . Propeller scars do not come in standard sizes i.e. the size of a propeller scar from an outboard motor will vary with the size of the outboard motor. Further the size of a propeller scar from a tug boat will be larger than a propeller scar caused by a large outboard motor. As is stated above, sediment tubes in accordance with this invention can vary in diameter between 6 and 12 inches. Regardless it is understood by one skilled in the art that sediment tubes in accordance with this invention can be any convenient diameter or length. In accordance with this embodiment of this invention a plurality of sediment tubes can be used to fill a propeller scar. For example if the propeller scar was a large 24″ scar from a tug boat it could be filled with four 6″ diameter sediment tubes or two twelve inch tubes. Further it is understood that the number of layers of sediment tubes used to repair a given propeller scar can vary depending on the depth of the propeller scar which is being repaired.  
         [0075]    As is discussed above sediment tubes for filling propeller scars and sediment bags for filling blow holes can incorporate, plants, plant cuttings and plant seeds. In accordance with this invention the growth of the plant cuttings and the germination of the plant seeds can be coordinated with the degradation of the sediment tube or bag. For example if a given sea grass seed germinates in 60 days, the material from which a given sediment tube or bag can be designed to start its degradation in 60 days. Once the degradation of the sediment tube or bag has started the sprout of a germinating seed or plant shoot can easily poke through the degrading material from which the sediment tube or sediment bag is formed.  
         [0076]    [0076]FIG. 18 shows another embodiment of this invention wherein a blowout  3  is filled partially with a gravel or aggregate layer  72 , over which is placed a plurality of sediment bags  70 .  
         [0077]    Further the degradation of a sediment tube or bag can be coordinated with the natural temperature cycle of body of water in which the planting is to occur. In most bodies of water there is a natural temperature rhythm and the growth and/or germination of seeds and the growth of plant shoots is timed to the natural temperature variations. That is seeds are dominant and plant shoots do not grow until a certain temperature cycle occurs.  
         [0078]    In accordance with this invention the degradation and placement of the sediment tube or bag can be timed to this natural temperature cycle. If a given seed will not germinate or a plant shoot will not grow until the water temperature reaches a given temperature the degradation and placement of the sediment tubes or sediment bags in the growing area can be timed to this natural cycle.  
         [0079]    The relationship of the natural temperature variations to when seeds germinate or plant shoots grow is easy to determine by simple observations. For example if it is known that a given species of seagrass seed will not germinate until the water temperature reaches 25° C. a sediment tube or bag can be selected or designed to degrade in 60 days and the placement of the sediment tube or bag in the water is effected 60 days prior to the date when the water temperature reaches 25° C. Hence the sediment tube or bag has had 60 days to stabilize and just as the plant shoots or seeds as are contained in the sediment tube or bag start to germinate or grow, the sediment tube or bag starts to degrade. As a result of this degradation the resulting new plant life can penetrate the sediment tube or bag thereby allowing the natural growth cycle to proceed.  
         [0080]    The above discussion relates to the filling of sediment tubes and sediment bags with a growing medium. While the preferred growing medium is sand it is understood that the growing medium can encompass bundled seagrass, fine aggregate which is commonly sold under the term “fines”, clay or other natural materials. Generally, it could be said that the sediment tubes and bags can be filed with any medium in which seagrass will root and grow.  
         [0081]    Further, as is discussed above the growing medium can incorporate fertilizer. The term fertilizer in accordance with this invention includes growth enhancers, plant stimulants, root stimulants, hormones, growth regulators etc.  
         [0082]    The above description and drawings are illustrative of modifications that can be made without departing from the present invention, the scope of which is to be limited only by the following claims.