Abstract:
An apparatus and method for promoting macrobenthic growth in a waterway is disclosed. The apparatus comprises a biodegradable net bag with a biodegradable panel insert that is adapted to receive a biomass suitable for attracting and promoting macrobenthic growth. The method comprises providing a suitable net bag, filling it with an appropriate biomass, deploying it in a healthy waterway until macrobenthic growth has become established, and transporting and redeploying it in a second waterway requiring remediation.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. provisional patent application Ser. No. 61/840,587 filed Jun. 28, 2013, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    This present invention relates in general to apparatuses and methods used in environmental remediation of waterways. In freshwater waterways such as streams, an important aspect of environmental remediation is the creation or restoration of habitat for benthic macro-invertebrate (macrobenthic) organisms. In saltwater waterways, an important aspect of environmental remediation often involves creation or recreation of oyster reefs in estuaries and other similar habitats. Apparatuses and methods disclosed herein are useful in creating or restoring such habitats in an efficient and environmentally friendly manner. 
         [0003]    As the design and monitoring processes for stream mitigation advance, the requirements from the regulatory community have become more stringent. Monitoring for a successful restoration project was originally based on the stabilization of the stream channel and providing macro-habitat for stream fauna. As the science of stream restoration has developed, a successful restoration project is more frequently defined as one that provides a functional uplift to the stream that results in the successful restoration of the stream&#39;s fauna. If the stream channel&#39;s physical characteristics have been stabilized and the substrate has been allowed to culture, then the organisms that are dependent upon this habitat can thrive. 
         [0004]    Since the first stream restoration project, restoration has worked under the premise that if you build a stable stream channel, then the aquatic fauna will return to the stream reach. The original restoration premise was that fish and large invertebrates will migrate upstream and downstream into stabilized stream reaches. However, research has shown that macrobenthics are extremely slow to re-populate any area. This was confirmed by an EPA study in 2002 by Mr. Dave Penrose and updated for the NC Ecosystem Enhancement Program in 2008. That study found that restored streams with healthy upstream and downstream populations of macrobenthics were very slow to re-populate. Post construction macrobenthic monitoring of restored streams found that many of these streams did not meet re-population goals or guidelines that were established to ensure a stable macrobenthic population. 
         [0005]    Unlike fish and many larger invertebrates, macrobenthic organisms are not very mobile. In many restoration projects, the upper reaches of the streams may never fully recover due to a lack of micro-habitat for the macrobenthics, nor can there be recruitment to the restored reach from upstream sources. Many of these organisms cannot swim upstream. While numerous individuals can move upstream during their adult stages, the larval microbenthics/microorganisms that support these individuals do not move as readily. 
         [0006]    Recently restored stream channels may also lack adjacent vegetation which can provide vegetative material for stream leaf packs, which form the basic platform of cover and food substrate for many macrobenthic organisms. 
         [0007]    These situations leave the organisms without the proper substrate or supportive habitat. 
         [0008]    During the early stages of wetland mitigation, it was found that seeding or planting more desirable tree species in a wetland system allowed for a faster recovery of the system. This ‘jump starting’ of the ecosystem concept was taken even further when current wetland soils were taken from impacted sites and used in restoration and creation projects to reseed the wetland soils. Both of these techniques were found to be effective in speeding up the restoration process. 
         [0009]    This result is consistent with the conclusion that one of the biggest restrictions that newly restored streams have in attracting macrobenthics is the lack of the proper medium/micro-habitat for them to grow. More particularly, most restoration or impaired streams lack the leaf pack that is mandatory for these organisms to live and reproduce. Embodiments of the apparatuses and methods disclosed herein address this problem by providing more effective means for restoring macrobenthics during stream remediation. 
         [0010]    Similar problems persist in restoration projects in saltwater waterways. In the process of restoring oyster reefs, biologist have been restoring oyster reefs by dumping large amounts of oyster shells or limestone rock on the bottom so that oysters can establish on areas that remain above the estuary substrate. Such efforts have limited success in some projects, however, due to the material sinking into the substrate. To combat this problem, biologist have resorted to displacing the weight of the bags of shells or rock by placing wooden structure beneath the bags. The most common materials use are wooden pallets and nylon bags to hold the shells or rock. Such materials are bulky, however, are not fully biodegradable, and may contain contaminants that negatively impact the environment. Embodiments of the apparatuses and methods disclosed herein provide a more natural approach to oyster reef restoration uses biodegradable materials and is free of the typical toxic chemicals commonly used in processing lumber material. 
       SUMMARY 
       [0011]    Disclosed herein are embodiments of an apparatus for promoting macrobenthic growth in a waterway. The embodiments disclosed include a biodegradable net bag adapted to receive a biomass suitable for promoting macrobenthic (including without limitation oyster growth) growth in a waterway, and a biodegradable panel insert adapted to support the biomass. By filling the net bag with biomass, and deploying the net bag in a waterway, macrobenthic growth is promoted. Alternative embodiments disclosed herein further include an anchoring capability suitable to secure the net bag while it is deployed. 
         [0012]    Also disclosed herein are embodiments of a method of promoting macrobenthic growth in a waterway. The embodiments disclosed include the steps of providing a biodegradable net bag open at one end and adapted to receive a biomass suitable for promoting macrobenthic growth, inserting a suitable biomass into the net bag, and deploying the net bag in a healthy waterway. After macrobenthic growth has occurred, the net bag is transported to a waterway undergoing remediation and re-deployed. In this manner, macrobenthic growth is further promoted in the waterway undergoing remediation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Other features in the invention disclosed herein will become apparent from the attached drawings, which illustrate certain preferred embodiments of certain apparatuses and the steps of certain methods, wherein: 
           [0014]      FIG. 1  is a perspective view of a biodegradable net bag suitable for use with embodiments of apparatuses according to the present invention, prior to closure of at least one end and filling with a suitable biomass; 
           [0015]      FIG. 2  is a side view of the embodiment illustrated in  FIG. 1 , showing the placement of a panel insert in the interior of the net bag; 
           [0016]      FIG. 3  is a perspective view of the embodiment illustrated in  FIGS. 1 and 2 , prior to being formed into a bag; 
           [0017]      FIG. 4  is a perspective view of the embodiment illustrated in  FIGS. 1 and 2 , deployed in a stream; 
           [0018]      FIG. 5  is an exploded, perspective view of an alternate embodiment of an apparatus according to the disclosure herein that is suitable for use in oyster bed remediation projects in estuaries with soft bottoms; 
           [0019]      FIG. 6  is a side sectional view of the embodiment illustrated in  FIG. 5  with optional anchors included; and 
           [0020]      FIG. 7  is a schematic view of a method of promoting macrobenthic growth in a first waterway by using embodiments of apparatuses disclosed herein to collect and transport macrobenthic organisms from a second, healthy waterway. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    While the following describes preferred embodiments of apparatuses and methods according to the present invention, it is understood that this description is to be considered only as illustrative of the principles of the invention(s) described herein and is not to be limitative thereof. Numerous other variations, all within the scope of the claims, will readily occur to those of ordinary skill in the art. 
         [0022]    As used herein, the term “adapted” means sized, shaped, configured, dimensioned, oriented and arranged as appropriate, and the term “macrobenthic organism” means an organism living on or in the bottom of bodies of water that is large enough to be seen by the naked eye. Macrobenthic organisms include plants and animals. When referring to oyster bed remediation projects, “macrobenthic organisms” include, but are not limited to, oysters. 
         [0023]    As used herein, the term “biomass” means material that promotes macrobenthic growth in a given waterway. Because of the diversity of waterways and the ecosystems they support, suitable biomass can vary greatly from one remediation project to the next. In freshwater stream applications, for example, suitable biomass typically includes, but is not limited to, mixtures comprising leaves, sticks or other plant materials, optionally combined with cotton seed cake, leaf cake, fish meal cake, or other nutritional material such as fish food, dog food, etc. (either mixed in or alone). In oyster bed remediation, suitable biomass typically includes oyster shell clusters, other shell material, and limestone rock. Because the apparatuses and methods disclosed herein are not intended to be limited to a specific waterway type, it will be understood that the term “biomass” as used in this disclosure is intended to be used in a broad sense to indicate any material suitable for supporting macrobenthic growth in a given waterway, and is not intended to be limited to the specific examples of biomass described. 
         [0024]    As used herein, the term “anchor” refers to any structure suitable for securing an apparatus according to the present invention within a waterway. Examples of anchors include, but are not limited to, (i) hooks, chocks, wedges, or the like attached to an apparatus by a line and held in place by a stable structure in a waterway such as a rock, (ii) spikes, posts, or rebar structures that pass through an apparatus (or a line operably attached to an apparatus) and driven into the bottom of a waterway, (iii) a structure similar to a marine anchor that is adapted to burrow into the bottom of a waterway and is operably attached to an apparatus, (iv) a large and/or heavy structure such as a large rock or other item of sufficient weight and size to resist forces generated by ordinary flows in a waterway and operably attached to an apparatus, (v) an apparatus designed to be buried in the bottom of the waterway and operably attached to an apparatus to be secured, and (vi) other types of anchors known and understood by those of ordinary skill in the art. 
         [0025]    The definitions and meanings of other terms herein shall be apparent from the following description, the figures, and the context in which the terms are used. 
         [0026]      FIG. 1  is an illustration of a preferred embodiment of a net bag  10  according to present invention, prior to the closing of at least one end.  FIG. 2  illustrates an end view of the embodiment shown in  FIG. 1 . The illustrated net bag  10  is essentially a tubular bag having an open top end, formed from a rectangular sheet of biodegradable net material  12 , with two parallel edges joined. Net bags  10  having diameters between four and forty-eight inches, and lengths between six and sixty inches are suitable for many remediation applications. The edges of rectangular panels of net material  12  may be joined by stitching or by any other means known to those of ordinary skill in the art. Embodiments of net bag  10  could also be formed, however, as pillow shapes (not illustrated) by joining multiple edges of separate panels of net material  12 , or by taking a single panel of net material  12  and forming it into a pouch (not illustrated). Thus, while tubular embodiments of net bag  10  formed from a single panel of net material  12  have been found to be suitable for a variety of remediation projects, other embodiments of net bag  10  having different shapes and configurations may also be utilized. 
         [0027]    As shown in  FIG. 2 , along one side of the interior of the net bag  12  is placed a preferably flexible biodegradable panel insert  14  adapted to support a biomass (not illustrated) placed into net bag  12  prior to deployment in a waterway. Panel insert  14  may optionally be a solid matt of coir, wood by-product, coconut fiber fabric, jute matting, or any of a variety of other environmentally friendly, biodegradable materials known to those of skill in the art. 
         [0028]    Referring to  FIG. 3 , panel insert  14  as illustrated covers approximately one half of the interior side of net bag  10 . Larger or smaller panel inserts  14  could also be used, depending on the application, provided that a substantial portion of the interior of net bag  10  is covered such that panel insert  14  can support the necessary biomass (not illustrated). Panel insert  14  may also be a variety of thicknesses depending on the characteristics of the biomass to be supported (not illustrated) and bottom characteristics of the waterway in which net bag  10  is to be deployed. Thicknesses of between one-quarter of an inch and two inches have been found to be suitable for many applications, with a thickness of one-half inch being suitable for many stream remediation projects. 
         [0029]    Prior to deployment, net bag  10  is filled with a biomass material (not illustrated) and the ends are closed (by stitching or any of a variety of other means known in the art). A variety of biomass materials may be used depending on the application and the nature of the macrobenthic organisms to be promoted. In freshwater stream applications, for example and without limitation, leaves and sticks may be used. An optional biomass matrix of cotton seed cake, leaf cake, fish meal cake, or other material such as: fish food, dog food, etc. (either mixed in or alone) can be used as well to provide additional nutrients or attract other organisms deemed desirable in the remediation effort. 
         [0030]      FIG. 4  illustrates net bag  10  deployed in a shallow stream setting, after the biomass (not illustrated) has been inserted. As illustrated, net bag  10  is deployed in rocks suitable to retain it in the desired position. Optional anchors (not illustrated) adapted to attach to net bag  10  and to secure net bag  10  in a waterway may also be used. While a wide variety of anchors may be used (including without limitation hooks, chocks, wedges, rebar, spikes, etc.), one configuration that has been found to be convenient in stream remediation projects is to attach a hook (not illustrated) to a line (not illustrated) of biodegradable material tied to net bag  10 , and then to wedge that hook (not illustrated) into the stream bottom or rocks in the stream. After deployment, desirable macrobenthic growth will occur on the biomass, which will in turn promote further macrobenthic growth in the waterway. 
         [0031]    For remediation projects in waterways having soft silt or mud bottoms (such as those encountered in oyster reef remediation projects for example), additional steps may be desirable to help support net bag  10  above the bottom of the waterway.  FIGS. 5 and 6  illustrate embodiments of apparatuses according to the present invention suitable for use in such environments. As illustrated, net bag  10  in this embodiment is adapted to receive oyster shell clusters or rocks to which oysters may attach. Net bag  10  rests on optional bottom fabric layer  25 , which may be formed from the same materials described above in connection with panel insert  14 . Depending on the characteristics of the bottom, attaching net bag  10  to optional bottom fabric layer  25  (by stitching, using anchor spikes as described below, or other means known in the art) may be sufficient to prevent net bag  10  from sinking too far into the bottom. 
         [0032]    Where additional support is needed, frame  26  (which may be a simple wood frame formed of untreated wood) may be used underneath optional bottom fabric layer  25 . Untreated wood is preferred because it is biodegradable and lacks chemicals that might be harmful to the environment to be remediated. In particularly soft bottoms, second bottom layer of fabric  28  (which may also be formed from the same materials as has been described above in connection with panel insert  14 ) may be used to provide additional resistance to sinking. While a variety of thicknesses may be used, thicknesses of between one-quarter of an inch and two inches for bottom layer of fabric  25  and second bottom layer of fabric  28  are suitable for many remediation projects. 
         [0033]    In tidal areas where tidal flow may move net bags  10 , anchors may be used. As shown in  FIG. 6 , optional anchors  30  are spikes that pass through net bag  10 , panel insert  14 , bottom layer of fabric  25 , frame  26 , and second bottom layer of fabric  28  and into the waterway bottom (not illustrated). In such embodiments, optional anchors  30  secure the apparatus together (thereby eliminating the need to operably attach net bag  10 , panel insert  14 , bottom layer of fabric  25 , frame  26 , and second bottom layer of fabric  28  to one another). It should also be noted, however, that in particularly calm waterways, neither attachment nor anchoring may be necessary. It should still further be noted that while optional anchors  30  in the form of spikes may be used, many other types of anchor known in the art may also be used depending on the characteristics of the waterway and goals of the remediation project. 
         [0034]    As is shown in  FIG. 7 , methods of promoting macrobenthic growth in a waterway are possible using the apparatuses herein disclosed. In step  32 , a biodegradable net bag (such as net bag  10  previously described) is provided, and an appropriate biomass is inserted in step  34 . In step  36 , the biomass and net bag are inserted into healthy waterway. In step  38 , time is given for macrobenthic growth on the biomass to develop. In step  40 , the net bag with biomass (and its attendant macrobenthic organisms) are removed and transported to a second waterway, which is in need of remediation. In step  42 , the net bag with biomass is placed in the second waterway and anchored, as necessary. The seeding of macrobenthic organisms from the first healthy waterway into the second waterway promotes further development of macrobenthic organisms in the second waterway, thereby accelerating the remediation process. Over time, the materials used will biodegrade, leaving the second waterway to develop in a natural state. 
         [0035]    As has been discussed above, net bag  10  may be used alone, or may be supported by a combination of bottom layer of fabric  25 , frame  26 , and second bottom layer of fabric  28  (all as shown in  FIG. 6 ) as convenient depending on the needs of the remediation project. For example, and without limitation, in saltwater remediation projects, oyster growth may be promoted with an embodiment, of the method previously described by using oyster shell clusters (not illustrated) or rocks suitable for oyster attachment (not illustrated) as the biomass and supporting net bag  10  as shown in  FIG. 6 . In such applications, net bag  10  may be left in the first waterway to develop oyster growth in that location. Alternatively, oyster growth may be started in a first waterway, and then moved to a second waterway as described above and shown in  FIG. 7 . 
         [0036]    It will thus be understood that the present invention provides an apparatus for cultivating and relocating leaf pack material and associated macrobenthic growth in riverbed(s) (or streambed, or any other underwater, freshwater location). 
         [0037]    As illustrated, net material  12  (shown in  FIG. 3  for example) is a large net with holes passing there through to allow water flow and ingress and egress of aquatic organisms. Panel insert  14  (shown in  FIG. 3 ) and optional lower fabric layer  25  and optional second lower fabric layer  28  may conveniently be more of a solid matt of material to provide support for the biomass. In certain embodiments, net material  12  is made of coir fabric, and panel insert  14  is made of solid coir liner. In other embodiments, panel insert  14  can be made of jute matting or other biodegradable material that meets the needed criteria. The biomass materials selected should promote macrobenthic growth and, as has been discussed, the materials used throughout the apparatus are all preferably biodegradable. 
         [0038]    Where transport of net bag  10  is required, the operator lifting net bag  10  out of a first waterway should ensure that the macrobenthic growth does not all exit through the holes in net material  12 . Balancing the biomass in net bag  10  on top of panel insert  14  helps ensure the biomass does not simply slip through the holes in net material  12 . The most advantageous time period for relocation will vary, but is typically the time period that most of the macrobenthic organisms would be in an egg or larvae stage and living in or attached to the substrate/micro-habitat. The exact time period would be determined during by a biologist familiar with macrobenthic organisms. 
         [0039]    The advantages of the embodiments disclosed herein thus include providing: a simple way to recreate in-channel leaf pack and woody debris; a simple way to create a stable platform for macrobenthics to habitat; a simple system to grow, develop and transfer macrobenthics from a ‘nesting’ area to a restored/impaired stream channel or riverbed/streambed; and the ability to transfer macrobenthic growth from a nursery stream or riverbed to a receiver/restored stream or riverbed will enhance the restoration in the receiver stream. A further advantage is providing a biodegradable platform to attract and grow oysters and promote oyster reef restoration. 
         [0040]    It should further be understood that embodiments illustrated herein can also be linked together to form larger mats in streams or woody structures. Such stabilized reaches of woody debris can be used both in stabilization efforts in banks and slopes, and to promoter an increase in microhabitat for macrobenthics as well as smaller amphibians, fish and reptiles. The subsequent increase is the base of the food web then has subsequent beneficial effects on higher level organisms. 
         [0041]    Similarly, in saltwater the described embodiments can be used to restore oyster reefs by stacking a single layer or multi-layer mattress(es) of solid fabric that can be supported by a wooden frame. The net bags can be filled with a proper substrate to attract oyster spat such as, but not limited to, oyster shells and/or limestone rock. As designed, the mattress will displace weight and keep the current invention from sinking into the substrate. The size of the apparatus used for this application depends on the site specific needs of handling and to minimize shifting of stuffed material. The apparatuses can be linked to make a larger structure if project needs determine a larger size is required. In addition, lower fabric layer  25  or second lower fabric layer  28  (both illustrated in  FIG. 6 ), could be adapted to be larger layers sufficient to support a plurality of net bags  10 . As noted above, an anchoring system can also be utilized to anchor the current invention to the existing substrate. 
         [0042]    Other variations and embodiments of the present invention will be apparent to those of ordinary skill in the art in light of this specification, all of which are within the scope of the present invention as claimed. Nothing in the foregoing description is intended to imply that the present invention is limited to any preferred embodiment described herein.