Abstract:
A method for constructing or rehabilitating a marsh or wetland comprises the step of inserting propagatable material into liquid or slurry emerging from a high-pressure spray nozzle to form a mixture. The liquid/ or slurry/propagatable material mixture is then sprayed over a marsh or wetland area desired to be constructed or rehabilitated.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to systems and methods for constructing and rehabilitating marshes and wetlands, and, more particularly, to such systems and methods that are ecologically beneficial. 
   2. Description of Related Art 
   The present inventor has previously disclosed methods for building or restoring marshes and beaches, and also for dredging waterways in an environmentally friendly and cost-effective manner. These methods, which are disclosed, inter alia, in U.S. Pat. Nos. 3,971,148; 4,240,243; 4,434,943; 4,517,754; 4,521,305; 4,575,960; 4,628,623; 4,759,664; 4,896,445; 5,167,469; and 5,211,511, which are incorporated by reference hereinto, utilize a high-pressure nozzle to spray a thin layer of slurry material over a large area. In the &#39;148 patent, a dredge cutter head is described that is self-cleaning; in the &#39;243 patent, satellite harvesters are used to harvest underwater aquatic growth; in the &#39;943 patent, a pump intake cutter head is disclosed for pumping an aquatic growth slurry from a waterway or body of water; in the &#39;754 and &#39;960 patents, a cutterhead attachment for a dredge is described; in the &#39;305 patent, a rotating self-cleaning screen is provided; in the &#39;623 patent is described a turbidity control system for a dredge cutterhead; in the &#39;664 patent, the slurry is formed of a solid material and water at a first location and pumped to a remote location for increasing the elevation of an area at the remote location; in the &#39;445 patent, a waterway is dredged, and the dredged material is used to form a slurry that is then distributed over the adjoining area in a layer sufficiently thin to avoid negative impact on the environment; in the &#39;469 and &#39;511 patents, a slurry distribution system is disclosed. 
   Natural habitat disappearance is a persistent problem, and can be caused by a variety of damaging factors, including, but not limited to, human-caused factors and pollution. Until now, marsh and wetland restoration has been an expensive and labor-intensive process, since re-planting heretofore has been performed manually. 
   SUMMARY OF THE INVENTION 
   An aspect of the present invention is directed to the construction and rehabilitation of marshes and wetlands in particular, and in the dispersion of seed and/or vegetative material in general. Such vegetative material may include, but is not intended to be limited to, fragments or plants that will propagate on their own. 
   In one embodiment is provided a method for rehabilitating a marsh or wetland. The method comprises the step of inserting seed and/or vegetative material into liquid or slurry emerging from a high-pressure spray nozzle to form a mixture. The mixture is then sprayed in a thin layer over a marsh or wetland area desired to be re-seeded or re-vegetated. 
   A system of the present invention in one aspect is for rehabilitating a marsh or wetland. The system comprises a container for holding seeds and a high-pressure spray nozzle. A hose is in fluid contact with a source of liquid at a first end and the spray nozzle at a second, opposed end. 
   A pump is provided for pumping liquid from the liquid source into the hose. Also provided is a conveyance tube that leads from the seed container to an aperture in the hose. The aperture is positioned downstream of the pump, so that, when the nozzle is in use, a vacuum is created at the aperture for drawing seed into a liquid stream being ejected by the spray nozzle to form a liquid-seed mixture. Means are also provided for directing the spray of liquid-seed mixture over a desired area remote from the liquid source. 
   In an alternate embodiment a system is provided that comprises a container for holding seeds and a mixing tank having means for agitating contents thereof. A means for transporting seeds from the container and liquid into the mixing tank is also provided, along with a high-pressure spray nozzle. 
   A hose is in fluid contact with the mixing tank at a first end and the spray nozzle at a second, opposed end. A pump is provided for pumping mixed seed and liquid from the mixing tank into the hose. Means are provided for directing the spray of liquid-seed mixture over a desired area remote from the liquid source. 
   The present invention provides considerable savings in cost and time to construct or rehabilitate a marsh or wetland. 
   The features that characterize the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description used in conjunction with the accompanying drawing. It is to be expressly understood that the drawing is for the purpose of illustration and description and is not intended as a definition of the limits of the invention. These and other objects attained, and advantages offered, by the present invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic diagram of a system for distributing a liquid-seed mixture over an area to be rehabilitated. 
       FIG. 2  is a top plan view of a second embodiment of a system for distributing a liquid-seed mixture over an area to be rehabilitated. 
       FIG. 3  is a side view of the system of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A description of the preferred embodiments of the present invention will now be presented with reference to  FIGS. 1-3 . 
   A first embodiment of a system  10  ( FIG. 1 ) of the present invention, believed at the time of filing to represent a preferred embodiment, in one aspect is for constructing or rehabilitating a marsh or wetland  11 . The system  10  comprises a container for holding seeds and/or other propagatable vegetative material  12 . The vegetative material will in the following be referred to as “seed,” although other propagatable material is also intended to be subsumed under this term. In addition to the seeds and/or vegetative material, other additives may be included, such as, but not intended to be limited to, fertilizer, a pH-adjusting composition, seed stabilization and placement enhancers, and slurry stabilization enhancers. 
   In a preferred embodiment the container comprises an agitator tank  13  into which the seeds  12  are directed and mixed with water or with a slurry of dredged material and water. A hose  14  is in fluid contact with a source of liquid, such as a body of water  15 , at a first end  16 . A high-pressure spray nozzle  17  is attached to the hose  14  at a second end  18  opposed to the first end  16 . 
   In the first embodiment  10 , a pump  19  is positioned upstream of the agitator tank  13  for pumping liquid or slurry (which will be referred to hereinafter as “liquid”) from the liquid source  15  into the hose  14 . A conveyance tube  20  leads from the agitator tank  13  to an aperture  21  in the hose  14 . The aperture  21  is positioned downstream of the pump  19 , so that, when the nozzle  17  is in use, a vacuum is created at the aperture  21  for drawing seed  12  into a liquid stream  22  being ejected by the spray nozzle  17  that comprises a mixture of the contents of the agitator tank  13  and liquid from the source  15 . The angle  23  at which the tube  20  meets the hose  14  will determine the rate at which the seed  12  is drawn into the stream  22 . 
   Means are also provided for directing the spray  22  of liquid-seed mixture over a desired area  11  remote from the liquid source  15 . Such a directing means may comprise, for example, devices such as are disclosed in the previously cited &#39;664 or &#39;445 patents, although these are not intended as limitations. 
   A second embodiment of the reseeding system  30  ( FIGS. 2 and 3 ) includes a container  31  for holding seeds  32  and a mixing tank  33  having means for agitating contents thereof. A pump  34  is used for transporting liquid  35  from, for example, a body of water  36  into the mixing tank  33 . 
   A hose  37  is in fluid contact with the mixing tank  33  at a first end. The hose  37  extends to the suction side of the pump  34 , with the suction drawing the mixture  40  into the stream. A high-pressure spray nozzle  38  is in fluid contact with the pressure side of the slurry pump  34  at a second, opposed end  39 . The pump  34  also serves to pump, by suction, the seed and liquid mixture  40  from the mixing tank  33  into the suction hose  37 . 
   As described above, means are provided for directing the spray of liquid-seed mixture  40  over a desired area remote from the liquid source  36 . 
   In another embodiment, a separate pump  23  could be provided for pumping seed from the container into the slurry on the pressure side of the slurry pump, pumping at a greater pressure than that of the pressurized slurry. 
   These systems  10 , 30  can be a component of a unitary dredging unit having a cutting head  41  at a front end  42  and means for channeling the dredged material in a slurry to the nozzle  38 , as described in the present inventor&#39;s previously issued patents. Thus in a single step, both dredging, construction, and rehabilitation are effected, positively affecting the environment. 
   In the foregoing description, certain terms have been used for brevity, clarity, and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for description purposes herein and are intended to be broadly construed. Moreover, the embodiments of the apparatus illustrated and described herein are by way of example, and the scope of the invention is not limited to the exact details of construction.