Abstract:
A sediment containment barrier capable of functioning in an outdoor environment for 18-24 months or more, while offering full rebound to compression impacts even after exposure to rain, construction traffic, and other harsh elements of an active construction site. Through a protected central core of foam or air surrounded by a water impermeable middle membrane and outer filtering shell, the barrier is able to withstand being run over by construction traffic hundreds of times while rebounding to its original shape and more importantly maintaining its compliance as an effective dirt and silt containment barrier. Due to the filtering qualities and the embedded nature of the barrier, the barrier offers high flow, reduction in the ponding of water, the effective filtration of sediment and silt, and a lower height than conventional sediment containment barriers.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority from U.S. provisional application with Ser. No. 60/872,371, which was filed on 30 Nov. 2006. The disclosure of this provisional application is incorporated by reference herein as if set out in full. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to construction job sites and large scale commercial developments, particularly with regard to the containment of dirt, sediment and silt runoff at such locations. 
       GENERAL BACKGROUND 
       [0003]    Erosion control is an issue societies have faced for centuries. Over the years various means have been used to adequately regulate erosion, and the related regulation of silt and runoff. One device commonly in use to achieve this is the wattle. A wattle is a fabrication of poles interwoven with slender branches, withes or reeds. They are typically laid continuously along a slope to intercept surface water runoff and create a “ponding” effect. This reduces the runoff water velocity allowing any sediment to settle, and significantly curtails and prevents erosion.  FIGS. 1 and 2  are a depiction of a conventional wattle. 
         [0004]    In the last 10 years straw or excelsior wattles have become more popular. This type of wattle is made by packing straw or excelsior into long tubular netting that forms a wattle or “log”. These straw or excelsior wattles are designed to perform the same function as a traditional wattle for runoff slope intercept and erosion sediment control. The tubular structure simplifies the construction process for these devices, allowing for their mass production. The straw or excelsior wattle was an advancement over the previous design. 
         [0005]    Several years ago construction sites began using straw and excelsior wattles in a new manner, namely, as a sediment or dirt barrier between the construction site and nearby street drain inlets. As Best Management Practice (BMP) requirements tightened under pressure to make construction sites less harmful to the environment, barriers of this manner between a construction site and nearby street drain inlets became compulsory in many states. Straw or excelsior wattles are at best only somewhat effective at this new function and worse are susceptible to damage, reducing their effectiveness even further. One major limitation of these conventional wattles is that they are prone to undermining, wherein water backed up behind the device flows underneath the device, bypassing any of the water-filtering qualities of the wattle altogether. Attempting to install the device around obstacles such as light poles or on uneven ground often causes portions of the device to lift, thereby exacerbating the undermining effect. 
         [0006]    The most frequent source of damage is the crushing force from construction vehicles such as back hoes, material delivery trucks, spreaders, cement trucks etc., which need to enter the jobsite on a frequent basis and must drive over the wattle. Because conventional wattles and barriers do not rebound completely after being crushed, they are transformed to a barrier of inconsistent height, allowing water to flow unfiltered over the lowest point in the barrier. Traffic of all kinds (both foot and vehicular), rain, ultraviolet radiation and other environmental hazards also contribute to the deterioration of straw or excelsior wattles at these locations, and the wattles must be replaced often and at considerable expense. Furthermore, to maintain compliance with typical BMPs, a minimum barrier height (generally 4″ to 5″) is often required. Due to the damaging forces mentioned above, conventional wattles are well known to quickly become non-compliant with BMPs and other building regulations. Thus, in order to avoid falling out of compliance and payment of heavy fines from the Environmental Protection Agency, it is typical for construction site operators to re-install wattles five to eight times during the construction process. 
         [0007]    Due to these shortcomings, there is a need for an improved wattle to help the environment and to reduce the time and monetary investment of staying in compliance with building regulations 
       DESCRIPTION OF THE PRIOR ART AND OBJECTIVES OF THE INVENTION 
       [0008]    Several products have been developed in an attempt to solve the deficiencies of traditional, as well as straw or excelsior wattles. These systems are outlined below: 
         [0009]    The Ertec Sediment Control Roll is manufactured with an outer shelling of High Density Polyethylene (HDPE) extruded netting, forming a semi rigid structure through which water can freely pass. A silt filtration woven fabric is added between the layers of HDPE net to provide containment and filtration. While effective as a dirt or silt containment barrier, the semi rigid outer shell is easily crushed by construction traffic, causing it to fall out of compliance with many building ordinances and BMPs. When used in active production areas of a construction site, the low durability prompts frequent costly repairs and replacements to be needed. Even before subjected to environmental and vehicular damage, the device is prone to undermining, as described above. Thus, this product is ineffective to meet the needs of dirt and silt containment barriers around jobsites. 
         [0010]    Gator Guard wattles comprise an outer shell of a very low flow slit tape, a woven black polypropylene ground cover and an inner material comprising small recycled pieces of closed cell polyethylene foam. It is manufactured in a 6″ diameter wattle form. The wattles fail in several ways at active construction sites: 1) Even with the slightest amount of construction traffic running over the device, the inner core of polyethylene foam becomes oblong, often times causing it to fall out of compliance. To prevent water from running over at these low spots, the wattle requires maintenance in the form of reshaping by hand. 2) The outer shell is not durable enough to hold up for long periods of time without maintenance or replacement, and is prone to tear. Breach of the outer shell can lead to the scattering of small pieces of foam over the construction site and ultimately into the very storm drains sought to be protected. 3) The outer shell is not made to filter or flow water. This causes the water to back up significantly thereby slowing the dewatering of a construction site after a rain event or water release. Thus, this product is similarly ineffective to meet the needs of dirt and silt containment barriers around jobsites. 
         [0011]    Triangular Silt Dike is manufactured from an outer shell of woven geotextile and an inner material of water-permeable angular or triangular foam barrier. The inner foam is designed to filter out sediment while water passes through. While using the foam as a filtering device, it acts as a sponge, absorbing water and weighing the product down. They are primarily used in erosion control applications as a ditch barrier and are placed perpendicular to the flow of moving water. While this device is an effective erosion control device, it also lacks sufficient durability for installations at home construction sites. Additionally, it has the undesirable effect of absorbing water and other materials, which weighs the device down, makes the device difficult to maneuver, and can cause disintegration of the internal foam. The product&#39;s outer shell and inner material offer considerable resistance to water flow, causing water to pool behind the device, rather than be filtered and passed through it. As the name suggests this product acts much like a dike. Finally, the outer shell is prone to tearing when subjected to the abuse seen on active construction sites. These are likely to make the device non-compliant with local regulations and BMPs. Like the other devices, this device is ineffective to meet the needs of dirt and silt containment barriers around jobsites due to its lack of durability and costly application. 
         [0012]    The above sediment barriers are also typically partially trenched into the ground, thereby reducing their effective height to potentially grade level. Finally, these current products are typically installed after roads and sidewalks are completed and after backfilling has occurred. Thus, the current products require additional trenching to be performed and at addition expense. 
         [0013]    Many other currently available barriers comprising permeable cores (i.e. cores of foam, straw, excelsior etc.) require replacement when the cores are filled with silt or else they will lose their ability to flow water, and behave more as a water damming device than a water filtration device. 
         [0014]    All of the above products fail to meet the needs of the home construction industry for an effective dirt and sediment barrier that will hold up to the harsh environment of an active job site. 
         [0015]    It is thus an objective of the present invention to provide a silt barrier capable of effectively filtering sediment while providing the durability to withstand typical construction and environmental hazards experienced on an active construction site. 
         [0016]    An additional objective of the present invention is to provide an effective barrier to keep dirt and silt on jobsites and off streets and out of drain inlets while maintaining a barrier height of at least 4 to 6 inches. 
         [0017]    An additional objective of the present invention is to provide a barrier that can remain effective in an active construction site environment for 18 to 24 months. 
         [0018]    An additional objective of the present invention is to provide a silt barrier rugged enough to withstand the harsh environment of a construction site, including but not limited to withstanding continuous impacts from construction vehicles, impacts from foot traffic, exposure to ultraviolet radiation, rain and other harsh weather, 
         [0019]    An additional objective of the invention is to provide a barrier comprising an impermeable core that collects silt and sediment on the outside of the barrier, thereby keeping the barrier permeable core uncontaminated, and facilitating cleanup by only requiring the removal by shovel of sediment piled against the side of the barrier. 
         [0020]    An additional objective of the invention is to provide a barrier that is easy to install around obstacles (light poles, electrical boxes, etc.) without being prone to undermining. 
         [0021]    An additional objective of the present invention is to provide a means for the construction industry to be in compliance with environmental regulations immediately after pouring a sidewalk, and to avoid the retrenching necessary to implement many of the current devices. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0022]      FIG. 1  depicts a prior art wattle with water pooled behind it and overflowing over it. 
           [0023]      FIG. 2  depicts a prior art wattle with water pooled behind it, and flowing through the indentations caused by a vehicle tire impacts. 
           [0024]      FIG. 3  depicts a cross sectional view of a preferred embodiment of the invention installed and filtering on a jobsite. 
           [0025]      FIG. 4  depicts an environmental view of the preferred embodiment of the invention in use on top of a sidewalk. 
           [0026]      FIG. 5  depicts an environmental view showing the preferred embodiment of the invention formed around the corner of a sidewalk. Dirty water is depicted behind the wattle and clean water is depicted filtering through the barrier and on to the sidewalk. 
           [0027]      FIG. 6  depicts the barrier of the preferred embodiment of the invention installed in a trench in an open field. Dirty water is depicted to the left of the barrier and clean water is depicted filtering through the barrier. 
           [0028]      FIG. 7  depicts an exploded perspective view of two barriers of the preferred embodiment of the invention. Phantom lines depict the location the barriers and the tail portion of the barriers after connecting the male end of one barrier with the female end of a second barrier. 
           [0029]      FIG. 8  the cross section view taken by cut line  8 - 8  in  FIG. 7 . 
           [0030]      FIG. 9  depicts an enlarged fragmentary cross section of the preferred embodiment of the invention. Phantom lines depict the location of the central portion of the barrier and the tail portion of the barrier after connecting the male end of one barrier with the female end of a separate barrier. 
           [0031]      FIG. 10  depicts the cross sectional view taken by cut line  10 - 10  in  FIG. 9   
           [0032]      FIG. 11  depicts the cross sectional view taken by cut line  11 - 11  in  FIG. 9 . 
           [0033]      FIG. 12  depicts an enlarged view of the area shown by circle  12  in  FIG. 11 . 
       
    
    
     SUMMARY OF THE INVENTION 
       [0034]    The invention is a sediment containment barrier capable of functioning in an outdoor environment for 18-24 months or more, while offering full rebound to compression impacts even after exposure to rain, construction traffic, and other harsh elements of an active construction site. Through a protected central core of foam or air surrounded by a water impermeable middle membrane and outer filtering shell, the barrier is able to withstand being run over by construction traffic hundreds of times while rebounding to its original shape and more importantly maintaining its compliance as an effective dirt and silt containment barrier. Due to the filtering qualities and the embedded nature of the barrier, the barrier offers high flow, reduction in the ponding of water, and the effective filtration of sediment and silt. The high flow rate of the barrier allows the barrier to be shorter than conventional barriers. Finally, the unique overall construction allows for a previously unattained combination of durability, full rebound, resistance to water absorption, sediment filtration and cost effectiveness, in a construction site dirt and sediment containment barrier. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    The present invention is a sediment containment barrier  1  comprising an outer shell  10  and tail  15  made from a filtering material (in a preferred embodiment a high flow monofilament woven polypropylene filter fabric), and an inner core  30  of rebounding foam (preferably polyurethane foam) sealed in a water impermeable (preferably polyethylene) middle layer  20 . See  FIGS. 4 ,  5 ,  7  and  10 . In order to accomplish the above-stated objects of the invention, the barrier combines three layers of materials that work together to improve overall performance. Throughout this application the term sediment containment barrier may be interchanged with the common term for the device, wattle. 
         [0036]    Outer shell  10  preferably consists of a high tensile strength (preferably 250-375 lb and less preferably 200-600 lb), high silt and sediment filtration, high water flow and high resistance to clogging, heavy duty, UV stabilized geotextile fabric that is capable of holding up to construction area abuse. Further, the fabric comprises is a woven monofilament filter fabric, specifically #40 US sieve with a flow rate of 100 gal/ft 2 ′, although a range of #25 US sieve and #60 US sieve may be used, depending on the size of particulate matter to be filtered. An effective range of between 50 gal/ft 2  and 200 gal/ft 2  may be used. The fabric described above is preferred because it offers a small enough opening size to allow the effective filtering of particulate matter while still allowing a considerable amount of water flow. This combination of properties provides an outer shell capable of handling the repeated impacts and crushing forces of construction vehicles while filtering sediment, being resistant to clogging, and allowing the flow through a large amount of water. 
         [0037]    Outer shell  10  is constructed from material sewn into a tube while still leaving considerable fabric for the tail  15 . In a typical preparation, the overall fabric width is 36 inches, and is folded into a tube approximately 22 inches in circumference or 7 inches in diameter. This leaves approximately 12 to 14 inches of fabric that composes tail  15 , which generally runs the length of the barrier with exceptions as detailed below. The fabric width, hem size, diameter, and tail length may be modified in dimension to fit different applications. Although there are numerous ways of affixing two of the tub-like structures together to create a longer barrier, in a preferred method one end of outer shell  10  is shaped into a male connector  11  and the other end is shaped into a female connector  12 , thereby allowing the connecting ends to bring together multiple wattles into a continuous barrier. 
         [0038]    Referring now to  FIG. 7  in detail, a male female connection is shown. The area shown by phantom lines represents two barriers once they are joined together. This male and female connection is preferably about 18″ long to allow for significant overlap and to resist the connection coming apart. In vehicle impacts it has been found that inner core  30  will have the tendency of lifting each end of the barrier, which can cause the male female connection to come apart. The significant overlap prevents this. On the male end, the tail of the barrier ends at approximately the same distance as the overlap, as shown in  FIG. 7 . This ensures the material of the tail of two barriers does not bunch together. Preferably, the tail of the barrier ends at a distance a few inches shorter than the length of overall male to female overlap, to allow the slightest of tail overlap, referred to in  FIG. 9  as overlapped tail portion  16 . A slit  13  having a length approximately equal to the distance of the male to female overlap minus the length of tube not having a tail accommodates this small bit of excess tail present on the male end  11  by allowing it to fold over the tail on the female end  12 . Preferably slit  13  is approximately two inches long, as shown in  FIG. 7 . The overlapped tail portion  16  is shown again in  FIG. 11 , along with two tails  15 . The close view in  FIG. 12  depicts the slit  13  as a gap in one tail through which the other tail passes. The slight overlap of the tail  15  at the male female connection of two barriers helps stem water leakages at the connection. Although the slit has been described in this embodiment on the male end, by engineering the barrier with many components in reverse one could easily require the slit on an alternative embodiment to be described on the female end. 
         [0039]      FIGS. 10 and 11  depict the internal structure of the male female connection. Referring first to  FIG. 10 , for ease of understanding, the male and female ends of the outer shell have been specifically labeled. Outer shell male end  19  is shown within outer shell female end  18 .  FIG. 11  is a cross sectional view taken specifically at the point of overlap of the tails of two devices, as shown by cutline  11 - 11  in  FIG. 9 . As such, two tails appear in  FIG. 11 . One tail is continuous with outer shell male end  18  and a second tail is continuous with outer shell female end  19 .  FIG. 12  shows a close cross sectional view of the point of overlap of the two tails. 
         [0040]    Ideally, the outer shell will be approximately 3-4 inches larger in circumference as compared to the inner core, allowing for a loose fit to facilitate the absorption of impact and to aid the ability of water to flow through the filter fabric and around and largely under the core material. 
         [0041]    Finally, it is noted that the overall height of the barrier may be slightly shorter than conventional wattles and filters. Because a large amount of water flows through this barrier compared to conventional barriers, the barrier experiences less upstream ponding and as a result is generally shorter than conventional barriers. 
         [0042]    Inner core  20  of the present invention comprises a full rebound, open cell polyurethane foam shaped into a rectangular tube, although other shapes may be used. In a typical embodiment each section of barrier comprises two 6 foot by 4.5 inch by 4.5-inch rectangular tubes. For purposes of this patent application, full rebound means the material returns to substantially its original shape after being crushed to a height of less than 100% its original size. Importantly, inner core  20  is sealed within a water impermeable middle layer, described below. 
         [0043]    In an alternative embodiment of the structure of the barrier, the foam inner core is omitted entirely. In this configuration (not depicted in the figures), the device merely comprises the outer shell  10  and middle layer  20  filled with gas such as air. The middle layer may be constructed of a stronger material such as a rubber tube with or without a rigid structure. This configuration may allow for a more inexpensive construction, and potentially decreased weight, however, without the foam core the device would not rebound in the event the middle layer ruptures. Because in this alternative embodiment the middle layer functions as an air bladder, in the event of a rupture the air would leak out and barrier would lose its rebounding qualities. Barring a rupture, however, the barrier would exhibit rebound due to the pressure inside the middle layer. Optionally, a valve could be placed on the middle layer for on-site inflation. This would allow the device to be inflated on location and would decrease shipping costs. It would also allow for slow leaks that may develop to be compensated for through re-inflation of the device. 
         [0044]    Middle layer  20  is a heavy mil thickness polyethylene film that wraps and protects inner core  30 . The middle layer  20  comprises a water impermeable, UV resistant polyethylene barrier film such as LDPE film, coated woven polypropylene or polyethylene fabric, polyester or nylon film or coated fabric. In a preferred embodiment of the invention LDPE film is used. Middle core  20  is roughly the shape of a long tube, sealed shut at both ends and sewn to outer shell  10  on one end to prevent removal. The water impermeable and UV resistant middle layer results in the inner core being completely impermeable to water and resistant to UV degradation. 
         [0045]    The middle layer  20  also serves as a buffer between the tough and durable outer shell  10  and the soft inner core  30 . An inner core of soft material would not normally be able to be used with outer shell  10  because abrasion from construction vehicle impacts against the outer shell  10  would be enough to rip apart or crumb the inner core  30 . However, the smooth middle layer  20  absorbs the sliding friction from the outer shell  10 , and does not significantly transfer the sliding movement through to the inner core  30 . 
         [0046]    During installation, the male end  11  of the outer shell  10  of a first barrier is inserted into the female end  12  of the outer shell  11  of a second barrier. This allows the barriers to be joined together into long continuous sections of any length desired. Slit  13  for overlap prevents water from flowing unfiltered through the connection area. 
         [0047]    In a preferred embodiment the barrier is placed on top and on the edge of a sidewalk or road with the tail section draping over the corner, pinned to the soil (via pin  60 ) and backfilled at the same time that the forms are taken off and the road or sidewalk is backfilled.  FIGS. 3 and 4  depict this installation. The preferred rectangular shape of the wattle allows it to be installed flat on top of a curb or sidewalk, thus allowing for a greater and more constant barrier height. 
         [0048]    After placement, the installer can then quickly and easily secure the tail section into the ground with staples or stakes. In a preferred installation, the barrier is installed with 2 to 4 inches of slack in the tail. After the tail is secured, the area behind the sidewalk is backfilled with dirt covering the tail section. Although staking the tail to the ground is the preferred embodiment, any means of securing or fastening the tail to the ground is adequate. In an alternative embodiment of the invention, the tail is not staked to the ground but is just buried where is lies. The weight of the earth on top provides a measure of securing force. 
         [0049]    The tail  15  of the barrier may also be placed into a preformed trench, pinned in place and then backfilled, as shown in  FIG. 3 . In a preferred use, the preformed trench runs parallel to the roadway or sidewalk. If installed immediately after a sidewalk is poured and molded, the backfilling of the barrier is accomplished through the ordinary backfilling step of finishing a sidewalk installation. When the barrier is not used next to a roadway or sidewalk, any trench may be used to secure tail  15 , regardless of whether it is near a roadway or sidewalk. Once tail  15  is dropped into the trench, it is pinned in place with staples, stakes, pins (as in  FIG. 3 ) or approximately six-inch nails approximately every three feet. Other means of securing the device to the ground may be employed. Finally, after being pinned, the excavated trench is refilled with material, which typically consists of the soil removed but may include any object heavy enough to hold the barrier down, such as gravel or rocks. As before, the pinning step may be omitted and tail  15  may be held in place with soil placed on top of it. 
         [0050]    There are several benefits to the preferred installation described above. 
         [0051]    First, it allows the placement of the wattle immediately after the sidewalk cement has been poured, thereby giving a regulation-compliant barrier before re-grading and backfilling up to the sidewalk procedures even begin. Typically, conventional wattles must be installed after the roads are built and backfilled with soil. Hence, additional labor must be expended to retrench an area for the wattle. 
         [0052]    Second, this installation method allows a barrier to be higher than would be provided by installation on soil. This is because as shown in  FIG. 3 , the tail section extends from deep in the soil all the way up to and on top of the sidewalk. Much of the filtered water, thus, only needs pass through the tail section of the barrier rather than through the core-containing central section of the barrier. The added support from the sidewalk prevents the barrier from settling as much as it would in soil, thereby adding to the effective height of the barrier. 
         [0053]    Third, the installation method protects the edge of the sidewalk or roadway due to its placement over and on top of said edge. 
         [0054]    Fourth, the installation method buries the stakes that pin the wattle in to place. In conventional wattles, the stakes are above ground and cause a risk to vehicles driving over the wattle. 
         [0055]    In an alternative installation embodiment the step of trenching prior to pinning is omitted. In this alternative installation embodiment, the tail is extended out perpendicularly to the sidewalk, and is stapled or staked into place as is. Because the trenching step may be bypassed in this installation, the worksite may be more quickly brought into compliance with BMPs and regulations until the preferred installation is completed. The drawback to this alternative installation is that under normal water level conditions, the effective height of the barrier is reduced. As described below, the barrier may still be able to float due to its low-density internal core, thereby raising the effective barrier height. 
         [0056]    In alternative installation embodiments of the invention, the barrier may be placed on the ground alone, without reference to a sidewalk or roadway. In this embodiment the barrier may be optionally trenched in and optionally secured to the ground similar to as described above. The product is flexible enough to round typical corners experienced on jobsites, such as around light poles and power boxes.  FIG. 5  depicts the barrier installed near a roadway and rounding a tight corner where the roadway meets a sidewalk entrance. 
         [0057]    The above installations allow for a secure barrier that cannot under normal conditions be undermined. Because in a preferred embodiment the tail is the only component under grade level, the full height of the barrier is available for soil runoff protection. Conventional wattles must be trenched in, thereby reducing their effective height. In the alternative installation embodiment no trench is needed, and thus there is no reduction in effective height. 
         [0058]    An additional advantage of securing the tail of the barrier to the ground is that in the event of a high flow in which the runoff level rises, the light weight of the barrier can allow the barrier to float on the high water level, all while the tail is secured to the ground. In effect this creates a dynamic barrier that extends with rising water as necessary. The extent to which the barrier can rise is only limited by the amount of slack in the tail during installation. 
         [0059]    Referring now to  FIG. 3 , the wattle is shown in operation. Here, runoff water  40  contacting the wattle is filtered by the outer shell  10  while flowing into and through the device around, but primarily under, the water-impermeable middle layer  20 . From this space between middle layer  20  and outer shell  10 , the once filtered water  41  then again passes through the outer mesh out to the side of the barrier opposite the pooled runoff water. Twice filtered water  42  is depicted on the right side of the device. Silt, dirt, sediment and other runoff materials will not substantially pass through the barrier, but will instead collect against outer shell  10 . At the male female connection, slit  15  in the tail for overlap prevents water from flowing unfiltered through the connection area. 
         [0060]    The spongy inner core  30  gives the sediment containment barrier  1  the ability to remain flexible and to exhibit full rebound after being crushed. In conventional wattles polyurethane or other spongy materials were not often used because of their undesirable characteristic of being an absorber of water, hydrocarbons, heavy metals, and other contamination. Additionally, when foam filled with water has its water forced out upon crushing, this process causes the foam to break apart, tear, and crumble. By sealing the inner core  30  inside a polyethylene or similar tube, the inner core  30  may be used in harsh weather and will not absorb moisture or other materials from its environment. In freezing environments, the dual layers surrounding inner core  30  protect it from freezing. Additionally, the middle layer  20  provides a friction-reducing barrier between the inner core  30  and the rough outer shell  10 . Tail  15  in essence provides a larger filtration area for the barrier. The effective filtered area extends from the lowest point at which the tail section is trenched up to the top of the outer shell above the core. See  FIG. 3 . Typically this effective height is between 4-6 inches above ground and extending several inches below ground as well. 
         [0061]    In use, dirt and sediment will accumulate on the upstream side of the barrier. This property makes clean up after a storm a simple process of merely removing the built up dirt and sediment with a shovel. Typical filter flow rates for the barrier are approximately 1 gallon per foot per minute, enough for the effective dewatering of a typical jobsite. This offers a significant benefit at construction sites, where ponding water can cause delay on a construction site, the requirement of taller barriers, in addition to pressure on the barriers that can cause undermining or blowing out of the barriers. 
         [0062]    The barrier can withstand being hit and crushed hundreds of times by construction vehicles, while still remaining an effective barrier. This durability allows the product to be placed on both main and secondary entranceways to jobsites, where traffic over the barrier is heaviest. As an added benefit it reduces vehicle tracking of and pulling of loose soil from construction sites into street areas, thereby reducing the need for street sweeping. 
         [0063]    During the eventual breakdown of the product after years of use, the double seal (middle layer  20  and outer shell  10 ) around the inner core  10  will prevent environmental damage from fragments of broken and degraded foam from washing away from a worksite. 
         [0064]    With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. 
         [0065]    Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.