Patent Publication Number: US-6702517-B2

Title: Pipe assembly for collecting surface water runoff and associated methods

Description:
This application claims the benefit of Provisional Application No. 60/311,099, filed Aug. 10, 2001. 
    
    
     DESCRIPTION OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to water storage systems and associated methods in general. More particularly, the present invention relates to a pipe assembly for collecting surface water runoff and associated methods. The pipe assembly includes both primary and secondary pipes. 
     2. Background of the Invention 
     Storm water retention/detention systems are useful wherever there is a need to prevent water from collecting on a surface. Some traditional locations for these systems are near buildings or parking lots, the construction of which have altered the ability of the ground to absorb the water. Some states even require that these systems be provided to, at a minimum, maintain the original amount of water absorption in that area. As a result, these storm water retention/detention systems have become a staple feature of construction sites. 
     Traditionally, the storm water retention/detention system included a plurality of substantially parallel pipes disposed in the ground. Such systems were placed in a bed dug in the earth and a fill material was placed around the pipes. The traditional approach required a minimum spacing between the pipes, which served several purposes. One such purpose was to provide a load path for the pipes to transmit loading to the surrounding material. However, in providing a minimum spacing ensure stability of the storm water retention/detention system, the footprint of the system was large. 
     As a result of the minimum spacing, the area needed for the known storm water retention/detention system was often greater than the area available on the property. Therefore, small businesses could not afford a traditional system because they would need to purchase additional property just to install the system. 
     The present inventor has proposed a new pipe assembly that can assist in decreasing the footprint size of a storm water retention/detention system among other advantages. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a pipe assembly for collecting surface water, a water storage system, and associated methods for collecting surface water and installing the water storage system that substantially obviates one or more problems associated with the traditional storm water retention/detention system. 
     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the present invention includes a pipe assembly for collecting water runoff. The pipe assembly includes a plurality of elongated primary pipes disposed in adjacent contact along their lengths. Each pair of adjacent elongated primary pipes define upper and lower elongated voids between adjacent pipe haunches and upper and lower imaginary planes tangential thereto. An elongated secondary pipe is disposed in each void in tangential contact along its length with the two adjacent elongated primary pipes defining the void. A material transversely encompasses the plurality of elongated primary pipes and elongated secondary pipes. 
     In a preferred embodiment of the pipe assembly, the primary and secondary pipes are formed of a flexible material such as corrugated plastic, smooth wall plastic, or corrugated metal. 
     In another preferred embodiment, the walls of the primary and secondary pipes are perforated. 
     Preferably, the material transversely encompassing the plurality of elongated primary and secondary pipes comprises two layers, one of the two layers having sufficient strength to hold the plurality of elongated primary and secondary pipes in tangential contact, and the other of the two layers being porous to fluid but preventing passage of particulates. 
     The present invention is also directed to a water storage system for collecting surface water. The water storage system includes a pipe assembly arranged on the bottom of a hole in the earth, and a fill material substantially covering the pipe assembly and substantially filling the hole in the earth. The pipe assembly includes a plurality of elongated primary pipes disposed in tangential contact along their lengths. Each pair of primary pipes defines upper and lower voids between adjacent pipe haunches and upper and lower imaginary planes tangential to the adjacent primary pipes. An elongated secondary pipe is disposed in each void in tangential contact along its length with both adjacent primary pipes. A material encompasses the plurality of elongated primary pipes and elongated secondary pipes. 
     The present invention is also directed to a method of installing a water storage system. The method includes digging a hole in the earth, such that the hole has a substantially planar bottom surface. Placing a material on the planar surface, wherein the material has opposed ends. Arranging a first plurality of elongated secondary pipes on the material, wherein the elongated secondary pipes are spaced from and substantially parallel to each other. Disposing a plurality of elongated primary pipes on the material in elongated tangential contact, wherein each pair of adjacent primary pipes defines upper and lower voids between adjacent pipe haunches and upper and lower imaginary planes tangential to the adjacent primary pipes. The primary pipes are disposed to locate one of the first plurality of elongated secondary pipes in each lower void in tangential contact with both adjacent elongated primary pipes along their lengths. Next, arranging an elongated secondary pipe in each of the upper voids in elongated tangential contact with the primary pipes defining the void. Finally, connecting the opposed ends of the material to encompass the plurality of elongated primary and secondary pipes with the material to form a pipe assembly. 
     The present invention is also directed to a method of collecting surface water from a surface. The method includes providing a pipe assembly arranged on the bottom of a hole in the earth. Disposing the pipe assembly between an input flow path and an output flow path. Draining at least a portion of the surface water using the input flow path. Collecting the portion of the surface water in the pipe assembly. Draining at least some of the portion of the surface water collected in the pipe assembly through the output flow path The pipe assembly including a plurality of elongated primary pipes disposed in tangential contact along their lengths. Each pair of primary pipes define upper and lower voids between adjacent pipe haunches and upper and lower imaginary planes tangential to the adjacent primary pipes. An elongated secondary pipe is disposed in each void in tangential contact along its length with both adjacent primary pipes. A material encompassing the plurality of elongated primary pipes and elongated secondary pipes. 
     The present invention is also directed to a system for use in a water flow path. The system includes a pipe assembly arranged in a water flow path and a path formed over the pipe assembly. The pipe assembly includes a plurality of elongated primary pipes disposed in adjacent contact along their lengths. Each pair of adjacent elongated primary pipes define upper and lower elongated voids between adjacent pipe haunches and upper and lower imaginary planes tangential thereto. An elongated secondary pipe is disposed in each void in tangential contact along its length with the two adjacent elongated primary pipes defining the void. A material transversely encompasses the plurality of elongated primary pipes and elongated secondary pipes. 
     Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings, 
     FIG. 1 is an isometric right side view of the pipe assembly of the present invention; 
     FIG. 2 is a close up view of one embodiment of the material of FIG. 1; 
     FIG. 3 is a top plan view of another embodiment of the material of FIG. 1; 
     FIGS. 4A and 4B are partial isometric views of a single primary pipe of different construction; 
     FIGS. 5A and 5B are partial isometric views of a single primary pipe with different wall profiles; 
     FIG. 6 is a schematic cross-section view of a water storage system; 
     FIGS. 7A and 7B are schematic representations of a method of installing a preformed pipe assembly in a water storage system; 
     FIGS. 8A-8D are schematic representations of another method of installing a water storage system. 
     FIGS. 9A-9C are schematic drawings showing the layout of different water storage systems for collecting surface water using a pipe assembly of the invention; 
     FIG. 10 is a schematic drawing showing a low water crossing using a pipe assembly of the invention; and 
     FIG. 11 is a schematic used to determine an optimal size for a secondary pipe. 
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     In accordance with the present invention, the pipe assembly for collecting water runoff comprises a plurality of elongated primary pipes disposed in adjacent contact along their lengths. Each pair of adjacent elongated primary pipes define upper and lower elongated voids between adjacent pipe haunches and upper and lower imaginary planes tangential thereto. As embodied herein and depicted in FIG. 1, the pipe assembly  20  for collecting water runoff includes a plurality of elongated primary pipes  22  disposed in adjacent contact along their lengths. Each pair of adjacent elongated primary pipes  22  define upper elongated voids  24  between adjacent pipe haunches  26 ,  28  and an upper imaginary plane  30  tangential to the adjacent primary pipes  22 . Each pair of adjacent elongated primary pipes  22  also define lower elongated voids  32  between adjacent pipe haunches  34 ,  36  and a lower imaginary plane  38  tangential to the adjacent primary pipes  22 . 
     The pipe assembly of the present invention further comprises an elongated secondary pipe disposed in each void in tangential contact along its length with the two adjacent elongated primary pipes defining the void. In the embodiment depicted in FIG. 1, elongated secondary pipe  40  is disposed in each of the upper and lower elongated voids  24 ,  32  in tangential contact along its length with the two adjacent elongated primary pipes  22  defining the voids  24 ,  32 . 
     The pipe assembly  20 , shown in FIG. 1, includes four elongated primary pipes and six elongated secondary pipes. It is understood that the number of primary pipes and the number of secondary pipes may be increased or decreased depending on two factors: the desired size of the system and the amount of water runoff to be collected. The relationship of the size of the pipes can be optimized by solving the following equations: 
     
       
           x   2   +r   2   2 =( r   1   +r   2 ) 2 ;  (1)  
       
     
     and 
     
       
           x+r   1   =r   2 .  (2)  
       
     
     In the proceeding equations r 1  is the radius of the secondary pipe, r 2  is the radius of the primary pipe, and x is equal to the vertical height between the center of the primary pipe and the center of the secondary pipe, as shown in FIG.  11 . Solving for r 1 , the preferred radius of the secondary pipe is equal to ¼ the radius of the primary pipe. It is understood that existing pipes may not provide the exact relationship described above. Therefore, a ratio of approximately 1:4 is preferred, but not required. 
     For example, in one embodiment, the primary pipes  22  may be 42 inch N-12 Ultra pipes available from Advanced Drainage Systems, Inc. Using the above relationship, the secondary pipes  40  may be 10 inch N-12 pipes available from Advanced Drainage Systems, Inc. 
     The pipe assembly  20  provides a spring-like effect when it is installed in the ground. This spring-like effect helps the pipe assembly to carry loads similar to traditional storm water retention/detention systems without the required spacing of the pipes. 
     Also in accordance with the invention, the pipe assembly comprises a material transversely encompasses the plurality of elongated primary pipes and elongated secondary pipes. As embodied herein and depicted in FIG. 1 the material  42  transversely encompasses the plurality of elongated primary pipes  22  and elongated secondary pipes  40 . 
     The material  42 , as seen in FIG. 1, has sufficient strength to hold the plurality of elongated primary and secondary pipes  22 ,  40  in tangential contact and is porous to fluid but prevents passage of particulates. The material  42  may substantially encompass the length of the plurality of elongated primary and secondary pipes  22 ,  40  to hold them in tangential contact. 
     In another embodiment, shown in FIG. 2, the material  42  may include two layers. One of the two layers, or first layer  44 , may have a plurality of holes  46  formed in the first layer  44 . The plurality of holes  46  may be sized to allow fluid and small particulates to pass through but prevent passage of larger particulates and also may have a sufficient strength to hold the primary and secondary pipes  22 ,  40  in tangential contact. The first layer  44  may be a standard geogrid or any other suitable wrap material. Geogrids are typically formed of a single layer of material having a plurality of holes formed in the layer of material. Alternatively, the first layer  44  may be a geonet material or other net type of material. Geonets are typically woven from strands of material to form a net capable of allowing passage of fluids but prevents passage of large particulates For example, ADS 2312 available from Advanced Drainage Systems may be used. This type of geonet is a biaxial 3 layer net with a peak tensile strength of 2100 pounds per foot and has a tensile modulus of 30,800 pounds per foot. It is to be understood that other geonets could be used depending on the size of the pipe assembly. 
     The other of the two layers, or second layer  48 , may be formed of a filter material. The filter material allows fluid to pass through but prevents substantially all particulate matter from passing through it. The filter material may be formed from a geotextile material, such as a non-woven needle punched polypropylene fabric, or any other suitable filter material. The filter material may have a minimum weight of about 4 ounces per square yard of fabric, although other weights may be used depending on the size of the pipe assembly. 
     FIG. 3 shows another embodiment of the material  42 , wherein the material  42  is formed as a plurality of straps  50  disposed to hold the plurality of elongated primary and secondary pipes  22 ,  40  in tangential contact. The material  42  may further include the second layer  48  disposed between the plurality of straps  50  and the plurality of elongated primary and secondary pipes  22 ,  40 . By using straps, as opposed to using a material  42  that substantially encompasses the plurality of primary and secondary pipes  22 ,  40 , the cost of the pipe assembly  20  can be reduced. 
     In addition to choosing a variety of material  42  to secure the elongated primary and secondary pipes  22 ,  40  in tangential contact, it is possible to provide a variety of different types of pipes for the pipe assembly  20 . For example, in the embodiment shown in FIG. 1, at least some or all of the plurality of elongated primary pipes and secondary pipes  22 ,  40  may be formed from flexible material. In addition, at least some or all of the plurality of elongated primary pipes and secondary pipes  22 ,  40  have a smooth inner surface and a smooth outer surface. This particular embodiment of the pipe assembly  20  may be desirable in a water storage system where the surrounding ground has a low permeability. In this situation, the pipe assembly  20  may be used to collect water from a surface and/or transport the surface water to a different location. These different approaches will be described in more detail below. 
     As shown in FIGS. 4A and 4B, the shape of the elongated primary pipes and secondary pipes  22 ,  40  may be different from those shown in FIG.  1 . For example, FIG. 4A shows a primary pipe  22  with perforations  52 . The perforations  52  can be used to serve different purposes as described below. The perforations  52  may be any suitable size and can have any desired distribution. 
     FIG. 4B shows a primary pipe  22  that is corrugated. The corrugated pipes can be used in situations where a more flexible pipe is desired. In addition to using corrugated or perforated pipes, profiled pipes may be used, as seen in FIGS. 5A and 5B. 
     A profiled wall is formed wherein either the inner surface or the outer surface of the pipe has a smooth surface, while the other of the inner surface or the outer surface has an raised annular shape. For example, FIG. 5B shows a primary pipe  22  having a smooth inner surface  54  and an outer surface  56  having standing ribs  58  disposed axially the length of the pipe  22 . It is also understood that a profiled wall may have both a smooth inner and outer surface and the wall of the pipe may have some internal structure arranged annularly. For example, FIG. 5A shows a profiled wall having both a smooth inner surface  54  and a smooth outer surface  56 . A plurality of hollow spaces  60  are formed in the wall of the pipe  22  between the inner surface  52  and outer surface  54 . These hollow spaces  60  may be disposed annularly in axial-spaced bands  62  along the length of the pipe  22 . The hollow spaces  60  are provided to reduce the weight of the pipes. 
     In FIGS. 4A-5B, the pipes have been shown as primary pipes  22 . It is understood that similar pipes could be used for secondary pipes  40  as well. It is also understood that the pipes can be mixed to form many different combinations to be used in a pipe assembly. 
     Besides varying the size and shape of the primary and secondary pipes  22 ,  40 , both the primary and secondary pipes  22 ,  40  can be formed out of different materials. For example, at least some of the plurality of elongated primary and secondary pipes  22 ,  40  may be formed out of plastic or metal. Some suitable plastics may include high-density polyethylene, polyvinyl chloride, polypropylene, or fiberglass, although the present invention is not limited to such plastics. Some suitable metals may include steel, steel alloy, aluminum, or aluminum alloy, although the present invention is not limited to such metals. These materials may be selected based on cost and desired features for the pipe assembly. 
     In accordance with the invention, a water storage system for collecting water runoff comprises a pipe assembly arranged on the bottom of a hole in the earth, and a fill material substantially covering the pipe assembly and substantially filling the hole in the earth. The pipe assembly includes a plurality of elongated primary pipes disposed in tangential contact along their lengths. Each pair of primary pipes defines upper and lower voids between adjacent pipe haunches and upper and lower imaginary planes tangential to the adjacent primary pipes. An elongated secondary pipe is disposed in each void in tangential contact along its length with both adjacent primary pipes. A material encompasses the plurality of elongated primary pipes and elongated secondary pipes. As embodied herein and shown in FIG. 6, a water storage system preferably includes the pipe assembly  20  arranged on the bottom  72  of a hole  74  in the earth. A fill material  80  substantially covers the pipe assembly  20  and substantially fills the hole  74 . The fill material  80  may be any suitable material, such as, but not limited to, gravel, sand, and soil. In a preferred embodiment, the fill material  80  is a gravel that can be substantially compacted around the pipe assembly  20 . 
     In accordance with the invention, a method for installing a water storage system comprises assembling a pipe assembly, disposing the pipe assembly on the bottom of a hole in the earth, and disposing a fill material over the pipe assembly and substantially filling the hole. 
     As seen in FIGS. 7A and 7B, the method preferably includes assembling the pipe assembly  20  and disposing it on the bottom  72  of the hole  74  in the earth  78 . Next, the method includes disposing a fill material  80  over the pipe assembly  20  and substantially filling the hole  74 . The method may also include placing a layer of fill material  80  on the bottom  72  of the hole  74  before the pipe assembly  20  is disposed in the hole. In this method the pipe assembly may be preassembled before delivery to the site, or it may be assembled at the site and placed in the hole  74 . 
     In accordance with another aspect of the invention, as seen in FIGS. 8A-8D, an alternative method of installing a water storage system comprises digging a hole in the earth, such that the hole has a substantially planar bottom surface. Placing a material on the planar surface, wherein the material has opposed ends. Arranging a first plurality of elongated secondary pipes on the material, wherein the elongated secondary pipes are spaced from and substantially parallel to each other. Disposing a plurality of elongated primary pipes on the material in elongated tangential contact, wherein each pair of adjacent primary pipes defines upper and lower voids between adjacent pipe haunches and upper and lower imaginary planes tangential to the adjacent primary pipes. The primary pipes are disposed to locate one of the first plurality of elongated secondary pipes in each lower void in tangential contact with both adjacent elongated primary pipes along their lengths. Next, arranging an elongated secondary pipe in each of the upper voids in elongated tangential contact with the primary pipes defining the void. Finally, connecting the opposed ends of the material to encompass the plurality of elongated primary and secondary pipes with the material to form a pipe assembly. 
     As seen in FIG. 8A, the method includes digging a hole  74  in the earth  78 , wherein the hole may have a substantially planar bottom surface  72 . Next, the method includes placing a material  42  having opposed ends  90 ,  92 , on the planar surface  72 . Next, the method includes arranging a first plurality of elongated secondary pipes  40 ′ on the material, where the elongated secondary pipes  40 ′ are spaced from and substantially parallel to each other. 
     The method further includes disposing a plurality of elongated primary pipes  22  on the material  42  in elongated tangential contact, as seen in FIG.  8 B. Each pair of adjacent primary pipes  22  define upper and lower voids  24 ,  32  between adjacent pipe haunches  26 - 28 ,  34 - 36  and upper and lower imaginary planes  30 ,  38  tangential to the adjacent primary pipes  22 . The primary pipes  22  are disposed to locate one of the first plurality of elongated secondary pipes  40 ′ in each lower void  32 , each of the first plurality of elongated secondary pipes  40 ′ are in tangential contact with both adjacent elongated primary pipes  22  along their lengths. 
     Next, as seen in FIG. 8C, the method includes arranging an elongated secondary pipe  40 ″ in each of the upper voids  24  in elongated tangential contact with the primary pipes  22  defining the void  24 . Finally, the method includes connecting the opposed ends  90 ,  92  of the material  42  to encompass the plurality of elongated primary pipes  22  and elongated secondary pipes  40 ′,  40 ″ with the material  42  to form a pipe assembly. This material  42  may be any of the materials described in relation to FIGS. 1-3. 
     As seen in FIG. 8D, the method may further include placing a fill material  80  to substantially cover the pipe assembly  20  and substantially filling the hole  74 . This step may be performed after any other connections to the input flow path  82  and output flow path  84  (shown in FIGS. 9A-9C) are made. In addition, the method may include placing a portion of the fill material  80  on the planar surface  72  of the hole  74  before placing the material  42  in the hole  74 . 
     In accordance with the invention, a method for collecting water runoff comprises disposing a pipe assembly a predetermined distance below a surface, providing an input flow path from the surface to the pipe assembly, the input flow path allowing fluid flow communication between the surface and the pipe assembly, and collecting at least a portion of the surface water through the input flow path into the pipe assembly. This method may be used with several different water storage systems. 
     In general, as seen in FIG. 9A, a water storage system may include a pipe assembly  20  arranged a predetermined distance H below the surface  71  on the bottom  72  of a hole  74  in the earth  78 . A fill material  80  substantially covers the pipe assembly  20  and substantially fills the hole  74 . The pipe assembly  20  can include any number of primary pipes and a number of secondary pipes disposed in the voids. 
     In a further aspect, as seen in FIG. 9A, the water storage system includes an input flow path  82  connecting the pipe assembly  20  to the surface  71 . This will allow fluid flow communication between the surface  71  and the pipe assembly  20 . Any suitable manifolds or connectors may be used to join the input flow path  82  to the pipe assembly  20 , so long as they do not interfere with the contacts between the primary and secondary pipes  22 ,  40 . 
     The input flow path  82  can take many forms including a drainage pipe and a water inlet when the surface  71  is the ground or a paved surface. The input flow path  82  can also be a waterspout when the surface is a roof of a building (not shown). The pipe assembly  20  can collect, by draining, at least a portion  86  of the surface water  70  through the input flow path  82  and storing it there until it can be removed. 
     Such a system shown in FIG. 9A, may be used in the method for collecting water runoff that includes disposing the pipe assembly  20  the predetermined distance H below the surface  71 . The method further includes providing the input flow path  82  from the surface  70  to the pipe assembly  20 . The input flow path  82  allows fluid flow communication between the surface  70  and the pipe assembly  20 . Finally the method includes collecting at least a portion  86  of the surface water  71  through the input flow path  82  into the pipe assembly  20 . 
     FIGS. 9B and 9C show other alternative embodiments of water storage systems and methods. The alternative embodiments of the water storage systems and methods differ primarily from the water storage system and method shown in FIG.  6 A. by disposing the pipe assembly  20  between the input flow paths  82  and the output flow paths  84 . 
     In the water storage system, as seen in FIG. 9B, the output flow path  84  is created by allowing the portion  86  of the surface water  70  to seep through perforations provided in the pipes of the pipe assembly  20 . The water then percolates into the surrounding fill material  80  and through the bottom  72  of the hole  74 . This water storage system may be best suited for areas where the permeability of the soil is high. In areas where the permeability of the soil is low, water storage system depicted in FIG. 9C may work the best. 
     FIG. 9C shows the water storage system  68  where the outflow path  84  is provided by a channel connecting the pipe assembly  20  to a water system  88 . In this embodiment, the water system  88  is underground and the channel may be any suitable piping that connects the water system  88  to the pipe assembly. Alternatively, the water system may be a natural or manmade pond, a water treatment system, river or other body of water. 
     In both of the water storage systems, as seen in FIGS. 9B and 9C, the method of collecting surface water  70  from a surface  71  preferably includes disposing pipe assembly  20  on the bottom  72  of the hole  74  in the earth  78  between an input flow path  82  and an output flow path  84 , draining at least a portion  86  of the surface water  70  using the input flow path  82 , and collecting the portion  86  of the surface water  70  in the pipe assembly  20 . In either system, the input flow path may be a drainage pipe. 
     In addition, the portion  86  of the surface water  70  can be removed from the pipe assembly  20  using the output flow path  84 . 
     As an alternative to the input flow path  82  shown in FIG. 9C, the input flow path  82  may be a path surface water takes when it percolates through the fill material  80 . The water can seep into perforated pipes of the pipe assembly  20 . In this arrangement, the perforations would be provided on portions of the pipes  22 ,  40  nearest the surface  71 . 
     In a different system, the pipe assembly  20  may be used in a low water crossing  94  of a water flow path  96 , such as a stream, as seen in FIG. 10. A low water crossing  94  may include a path  98 , such as a roadway, that is designed to handle low volumes of traffic. In this embodiment, the pipe assembly  20  is disposed in the water flow path  96  and paved over with the roadway  98 . These low water crossings may be used in parks, state forests, national forests, or anyplace it is necessary to provide a crossing over a water flow path. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.