Abstract:
A modular block, useful for constructing liquid-storage tanks for water-recovery systems, is described. The blocks can support large vertical loadings, may be fabricated from synthetic materials, and can be assembled into a tank-like structure. Because of their small size, light weight and easy portability, custom-sized water-recovery tanks may be readily assembled and installed at competitive costs. The water-recovery tanks may be used to reclaim runoff rainwater from water-impervious surfaces.

Description:
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
       [0001]    The present continuation-in-part application claims priority to U.S. patent application Ser. No. 11/395,989 filed on 31 Mar. 2006, which is a continuation of U.S. patent application Ser. No. 10/651,570, now issued U.S. Pat. No. 7,025,076, which claims priority to Provisional Application No. 60/407,162, filed on 30 Aug. 2002. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to underground liquid-storage tanks or cisterns. In particular, modular blocks are described which can be assembled to form a cavity of an underground storage tank. The tank can be used for reclaiming and recovering rain water. 
       BACKGROUND 
       [0003]    Many urbanized areas in the United States are running out of potable water, and improvements in water quality are becoming increasingly difficult and expensive to attain. Most of these environmental problems are related to the proliferation of impervious (paved or constructed) surfaces. Imperviousness has a double-edged effect: it interrupts the natural hydrologic cycle, and it contributes to flooding-related problems. Interruption of the hydrologic cycle disconnects rainfall from replenishing groundwater supplies, particularly by natural water infiltration into soil covered with vegetation. Impervious surfaces also contribute to storm-water runoff, flooding problems, in-stream erosion, and increased frequency of Combined Sewer Overflow (CSO) discharges. For a general treatise on the hydrologic cycle, the interaction of ground water and surface water, and water management, see Winter et al., Ground Water and Surface Water: A Single Resource, U.S. Geological Survey Circular 1139, U.S. Government Printing Office, Denver, Colo., 1998, 79 pp., the teachings of which are incorporated herein by reference. 
         [0004]    Imperviousness is generally associated with growth, and growth is associated with greater water demand. The consequence is that there is less water stored while more water is demanded. Additionally, each summer demand for potable water doubles in many communities as residents seek to irrigate their lawns, while in urbanized areas a preferred method of treating wastewater is through large regional systems that move water out of a basin or sub-basins. The result is that demand for potable water frequently exceeds supply and causes many communities to enforce restrictive water bans during the summer months. 
         [0005]    One system used to mitigate the effects of urbanization on water resources has been disclosed in U.S. Pat. No. 7,025,076. Such a system employs underground water storage tanks to capture and hold rainwater runoff for later use. 
       SUMMARY 
       [0006]    There is a need for low-cost, easily-transportable, readily-installable liquid-storage tanks that are useful for such applications as rainwater reclamation. To this end, an interconnecting block system, useful for constructing liquid-storage tanks, is described. In various embodiments, a connectable modular block has a substantially rectangular lower surface element perforated with holes, and a similar rectangular upper surface element also perforated with holes. The lower surface and the upper surface are substantially parallel to each other, and connected to each other with at least one vertical support having multiple perforations. In some embodiments, one or more reinforcing braces attach to the vertical supports to provide greater rigidity to the block, and a block having upper and lower surfaces measuring about two feet by two feet can support at least about 1,000 pounds. 
         [0007]    In some embodiments, integrated onto the block are male-type and female-type fastening mechanisms. These fasteners permit aligned and registered assembly of multiple blocks, so that a large liquid-storage volume can be readily formed from smaller, easily-transportable modular blocks. Once assembled, the ensemble can be reinforced with synthetic cord and wrapped with a water-impermeable barrier to form a tank suitable for underground storage of water for various non-potable uses. 
         [0008]    The blocks can be fabricated from a variety of low-cost materials using any one of several fabrication processes. Materials that may be used to form the blocks include various plastics such as, but not limited to, nylon, vinyl, polyvinylchloride, polycarbonate, acrylic, polyethylene, polyurethane, or polystyrene. The blocks may be formed by extrusion, injection molding, rotational molding, or casting processes known to those skilled in the art of forming plastics. 
         [0009]    A liquid-storage tank formed from multiple interconnected blocks may contain at least one inlet port and at least one outlet port. In some embodiments, rainwater collection system may be connected to the tank&#39;s inlet port, and a pump may be connected to an outlet port from the tank. The pump may be used to move the stored water for irrigation purposes, washing purposes, ornamental purposes, or other non-potable applications. 
         [0010]    In various embodiments, one or more tanks formed from the interconnecting blocks may be connected by piping or tubing. In other embodiments, one or more tanks may further be connected to a dry well, such that collected water in excess of the total tank volume flows into the dry well for infiltration into groundwater supplies and aquifer recharge. 
         [0011]    In some embodiments, a roofwasher first-flush system may be disposed between a roof-water collection system and a tank&#39;s inlet. The roof washer system collects a first runoff water volume, and diverts it away from the storage tank. Accordingly, debris and pollutants that may accumulate during non-rainy periods are diverted away from the storage tanks. 
         [0012]    The present invention offers the following environmental benefits: increased ground water recharge; decreased runoff volume and peak flows to storm drains; decreased potential for flooding; improved storm-water quality; reduced potable water demand; strategic emergency non-potable water supply; potential to offset the effect of local well withdrawals by recharging groundwater supply. 
         [0013]    When used by a homeowner, the present invention offers the following benefits: a supply of non-potable water for lawn care, car washing, plantings etc.; a reduction in municipal water expense by reducing the dependency on municipal water supplies for non-potable uses; a source of water during town watering bans and restrictions; knowledge that you are helping to restore our natural environment. 
         [0014]    The foregoing and other aspects, embodiments, and features of the present teachings can be more fully understood from the following description in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The skilled artisan will understand that the figures, described herein, are for illustration purposes only. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. In the drawings, like reference characters generally refer to like features, functionally similar and/or structurally similar elements throughout the various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the teachings. The drawings are not intended to limit the scope of the present teachings in any way. 
           [0016]      FIG. 1A  is an elevation view of an embodiment of a modular block useful for constructing a liquid-storage tank. The block has substantially flat top surfaces and bottom surfaces. 
           [0017]      FIG. 1B  is a top-down view of the modular block of  FIG. 1A . 
           [0018]      FIG. 2A  is an elevation view of a liquid-storage tank. The volume of the tank is substantially defined by an assembly of modular blocks. The blocks are covered or wrapped with a water impermeable barrier. In the illustration, the barrier is portrayed in cut-away view to reveal the blocks inside the tank. 
           [0019]      FIG. 2B  is a bottom-up view of the tank of  FIG. 2A . 
           [0020]      FIG. 3  is a schematic illustration of a rainwater recovery system according to one embodiment of the invention. In this embodiment, water is collected from a building&#39;s roof and directed into a storage tank  335  formed from multiple blocks. 
           [0021]      FIG. 4  is a schematic illustration of a first flush diverter system according to one embodiment of the invention. The first flush of water is collected in a lower tank  329  until the stopper  325  closes the entry port  324 . 
           [0022]      FIG. 5A  is an elevation view of an embodiment of a modular block useful for constructing a liquid-storage tank. 
           [0023]      FIG. 5B  is a top-down view of the modular block of  FIG. 5A . 
           [0024]      FIG. 6A  is an elevation view of the top element of a modular block, and depicts and embodiment for registering and interlocking the modular blocks. 
           [0025]      FIG. 6B  is a schematic illustration of an interlocking system for the modular blocks. A dumbbell-shaped fastener, shown in top view and side view at left, snaps into receptacles in the top and bottom of the block, as indicated in the diagram on the right. 
       
    
    
       [0026]    The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. 
       DETAILED DESCRIPTION 
       [0027]    The present invention is useful for capturing runoff water and storing some of the water for non-potable uses, such as but not limited to, irrigation, car washing, exterior building washing, walkway cleaning, and ornamental purposes. The present invention can reduce the demand of potable water and depletion of valuable potable water supplies for such non-potable uses. The present invention can be used to construct one or more liquid-storage tanks that may be located above ground or underground, and these tanks can be used to collect and store runoff rainwater. 
         [0028]    In overview and referring to  FIG. 1A-1B , a modular block  100 , useful for constructing liquid-storage tanks, is depicted in elevation view and top-down view. The modular block has substantially flat or smooth top  110  and bottom  190  surfaces, and these surfaces are joined to vertical members  140 . In various embodiments, holes  150 ,  160 , and  105  are distributed throughout the structure. The block may have width, depth and height dimensions represented substantially by W, D, and H. Any number of blocks may be joined together to form a skeleton which defines the cavity or volume of a tank as indicated in  FIG. 2A-2B . 
         [0029]    The block shown in  FIG. 1A-1B  may be formed from a variety of materials using various forming processes. For example, the material used to make the block may be any one of the following synthetics: nylon, vinyl, polyvinylchloride, polycarbonate, polystyrene, polyurethane, polyethylene, acrylic, lexan, and other similar plastics. Other materials such as fiberglass, cermamics and cement may be used, as well as aluminum. The block may be comprised of a coated material, such as rubber- or plastic-coated steel. In various embodiments, the block may be formed by casting, rotational molding, extrusion or injection-molding processes, as well as mechanical assembly. 
         [0030]    The enclosed volume V e  of a block  100  may be defined substantially by its overall dimensions: V e =W×D×H. The occupancy volume V o  of the block may be defined as the actual volume filled by the block material, and can be found from the following relation: 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     o 
                   
                   = 
                   
                     M 
                     ρ 
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
         [0000]    where M is the mass of the block, and ρ is the density of the material comprising the block. The occupancy ratio R o  can be defined according to the following expression: 
         [0000]    
       
         
           
             
               
                 
                   
                     R 
                     o 
                   
                   = 
                   
                     
                       V 
                       o 
                     
                     
                       V 
                       e 
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
       In various embodiments, the occupancy ratio may be less than about 0.15. In other embodiments, it may be less than about 0.10, and in yet other embodiments it may be less than about 0.05. 
       [0031]    The block may be formed into various sizes. For example, the W×D×H measurements may be 2 ft×2 ft×3 ft, 1 ft×2 ft×3 ft, 1 ft×1 ft×2 ft, 2 ft×2 ft×2 ft, or other dimensions scaled from these values. Reinforcing members  120  join to the vertical members  140  for the embodiment shown in  FIG. 1A  and increase the rigidity of the block structure. Holes  160  and  105  disposed in the vertical members  140  and top  110  and bottom  190  members reduce the amount of material required to form the block, and reduce its occupancy volume V o  without significantly reducing the block&#39;s vertical compression strength. These holes additionally increase the amount of volume available for liquid storage and facilitate movement of liquid throughout the enclosed volume. In some embodiments, holes  150  may be used for strapping multiple blocks together as indicated in  FIG. 2A . A synthetic cord or strap  220  may be threaded through holes  150  to secure an assembly of blocks. 
         [0032]    The structure of the blocks provide substantial vertical strength, so that a tank could be located under about 18 inches of topsoil, and support additional loading. The thickness of the vertical members  140  and the top  110  and bottom  190  members can be dimensioned such that the block supports a pre-selected amount of weight. For example, a block measuring 2 ft×2 ft×3 ft is designed to support at least about 1,000 pounds, or about 2 pounds per square inch, in some embodiments. This loading capability of the block permits safely the support of about 18 inches of topsoil and one large person. In some embodiments, a block of similar outer dimensions is designed to support at least about 4,000 pounds. 
         [0033]    In various embodiments, a modular block  100  has registration features  104  and  108 , which may be located on the outer edges of the top  110  and bottom  190  members. These features may be used to align and lock together plural blocks. In the illustrated embodiment, a protruding wedge  104 , representing a male-type fastening mechanism, of one block inserts into a V-groove receptacle  108 , representing a female-type fastening mechanism, of an adjacent block. This fastening system prevents vertical displacement of a block with respect to its adjoining blocks. 
         [0034]    Any number of blocks  100  may be assembled to form a liquid-storage tank  200 , as indicated in  FIGS. 2A-2B . The blocks may be assembled using the registration features  104  and  108 , and then bound together using synthetic cord  220 . The blocks may be formed into a two-dimensional array as shown in  FIGS. 2A-2B , and they may be stacked to form a three-dimensional array (not shown). In various embodiments after assembly, the skeleton of blocks is encased in a material  210  which substantially prevents the outflow of water. This material may comprise, but not be limited to, a waterproofed fabric, a water-resistant fabric, a fiber-reinforced plastic, a rubber membrane, a vinyl sheet or a heat-shrinkable wrap. An advantageous feature of the blocks&#39; smooth and substantially flat upper and lower surfaces is that they provide a substantially uniform surface against the encasing fabric. This helps prevent wear and puncturing of the fabric when the tanks are located underground. Additionally, all outer edges of the block may be rounded and smoothed to further reduce the possibility of puncturing the encasing fabric. 
         [0035]    In some embodiments, the covering  210  may include one or more entry ports ( 331  in  FIG. 3 ) and exit ports  239  for attaching a hose, tubing, pipe, vent or fluid-level guage. In other embodiments, the entry and exit ports may be added after encasing the blocks. For example, a hole may be formed in the covering  210 , and a threaded hole may be formed in the top  110  or bottom  190  members of the block. A hose fitting or pipe fitting with a sealing gasket may then be screwed securely into the block, where the fitting presses against the sealing gasket which presses against the underlying covering  210  and block  100 . 
         [0036]    As shown in  FIGS. 1A-1B  and  2 A- 2 B the modular block provides a convenient and potentially low-cost system for constructing liquid-storage tanks useful for rainwater recovery and reuse. The materials can be lightweight, and easily transported. An average homeowner could purchase the materials at a local supply store, transport them easily to the home, and assemble them without the need of hiring professional, specialized tank-installation services. Additionally, safety considerations are reduced for the tank structure shown in  FIGS. 2A-2B , since there is no large free-space volume into which a child or animal could fall. 
         [0037]    The potential low profile of a tank formed from the blocks reduces the depth of excavation necessary for subsurface installation of the tank. As an example of water storage capability, the tank depicted in  FIGS. 2A-2B , comprising 18 blocks measuring about 2 ft×2 ft×3 ft, would hold about 1600 gallons of water, a volume equivalent to about six standard-size home-heating-oil tanks. 
         [0038]      FIG. 3  is a schematic illustrating the incorporation of a liquid-storage tank into a rainwater-recovery system  330  for roof-top runoff. In various embodiments, the tank is connected to roof gutters  312  and downspouts or tubing  315 . In some embodiments, a multiple tanks may be used. The tanks collect and store rainwater runoff during rainfall, and make it available for later non-potable uses. A pump  370  may be connected to the tank  335  for future retrieval of the stored water, or depending on the local grade of the land and location of the tanks, the water may be extracted from the tank by a gravity-feed system. All of a building&#39;s roof area can be linked to the tank with aboveground or belowground piping  315 . 
         [0039]    A buildings roof  302  can serve as a catchment area to collect rainwater. For a description of the use of a building roof as a catchment area and the amount of water typically available, see A. W. Selders, SW-12, Agricultural Engineering, U.S. Department of Agriculture and West Virginia University, Cooperative Extension Service, Oct. 17, 1971, the teachings of which are incorporated herein by reference. Water flows from the roof  302 , through a roof gutter  312 , and through gutter conduit and piping system  315 . The gutter conduit and piping system can comprise 1-inch, 2-inch or 3-inch diameter PVC pipe with 45-degree and 90-degree elbows, or flexible tubing. The collected water flows through a first-flush system  320 , and then to an entry port  331  of a storage tank  335 . 
         [0040]    In various embodiments, the one or more tanks can be located in one central area or distributed around a building  300 , and they may be located underground or above ground. Because of their lightweight construction, a tank located above ground may be moved and stored inside during winter months and placed in service outside during summer months. Because of their low profile, the tanks may be placed in about a three-foot-deep hole, easily dug by a homeowner, and covered with about 18 inches of soil for gardening. Multiple tanks may be linked together easily with tubing or piping  315  to increase storage capacity for the irrigation of larger lawns or gardens, or a tank of virtually any size may be assembled due to the modularity of the blocks. 
         [0041]    Most any type of hose or piping can be used to link multiple storage tanks together. Hose connections can be made with 1-inch-diameter or larger hose, tubing or piping. Various length hoses, tubes or pipes and hose nipples, clamps, pipe junctions, couplers and elbows and bulkhead fittings may be used. For example, an entire water-recovery system  330  may be interconnected with inexpensive and readily-available PVC tubing. In some embodiments, any of a variety of valves can be used to provide manual control of liquid flow within a multiple tank system. 
         [0042]    In embodiments to provide for heavy and excessive rainfall, the one or more storage tanks  335  may be connected to a dry well  355 . Any excess water is directed to the dry well, which permits infiltration of the water into the ground and assists in recharging the groundwater supply. Any additional overflow from the dry well can be directed away from the house or building structure  300 . In various embodiments, the dry well construction requires excavation of about 85 cubic feet for a 600 gallon dry well and 2000 square foot roof area. Examples of dry well systems are described in U.S. Pat. Nos. 6,095,718 and 5,848,856 both to Bohnhoff and U.S. Pat. No. 4,689,145 to Mathews et al., the teachings of which are incorporated herein by reference. 
         [0043]    The pumping system  370  can be used to convey water from the storage tank  335  to various non-potable applications  390  such as, but not limited to, irrigation of lawn, shrubs, trees and garden, and washing of cars, building, driveways and walkways, and supplying ornamental fountains. The pump may be located within the tank  335  or located external to the tank system. In some embodiments, the pump may be located within the basement of a building  300  for convenient servicing. The pump may also be located above ground or below ground. Various adaptor valves and fittings, and pipes, tubing and hoses  315  may be used to connect the pump to the tank  335 . 
         [0044]    The water-recovery system  330  can be equipped to deal with many possible forms of contamination from the rooftop. A first level of protection can be in the form of a removable, cleanable screen, disposed over the gutter  315  to catch leaves and large solids. A second level of protection is a flow diverter  320  which minimizes potential chemical contamination by diverting a first-flush runoff water away from the recovery system  330 . A third level of protection is in the storage tanks themselves. They serve as a settling basin for any suspended solids that enter the tanks. Finally, the dry well can include a maintenance port enabling periodic cleanout. 
         [0045]    An embodiment of the first-flush system  320  is depicted in greater detail in  FIG. 4 . Water entering an inlet from the catchment area flows into a primary tank  321 , and flows into an empty secondary tank  329  through an opening  324  located at the bottom of the primary tank. As water collects in the secondary tank  329 , float  328  attached to arm  327  mounted securely on hinging assembly  326  rises. As more first-flush water enters the lower tank, the arm rises and the attached stopper  325  plugs the opening  324 . Once the hole  324  is plugged, subsequent water will flow out the exit port and to the cistern or storage tank system. In this manner, the contaminated first flush of water is diverted away from the water-recovery system  330 . 
         [0046]    In various embodiments, the amount of water collected in the secondary tank  329  can be adjusted according to the size of the catchment area. This can be done coarsely by selecting a size of the secondary tank  329 , and finely by adjusting the height of the stopper  325  with respect to the float  328 . In some embodiments, the first-flush system can be configured to collect the first 1 millimeter of water that falls on the catchment area. 
         [0047]    The secondary tank  329  can be adapted to provide evaporative removal of the collected water, e.g. holes may be located along its upper exterior surface, or it may extend and open outwards in the form of an evaporative pan. First-flush water with contaminants can collect in the pan during a storm, and the water may evaporate between storms leaving a solid residue. The solid residue may be easily cleaned from the pan. 
         [0048]    In some embodiments, the first-flush system can be automated with electronic valves. In such an embodiment, a rainfall sensor can detect the start of a rain storm and actuate an electronic valve which provides an opening for fluid flow into the secondary tank  329 . A float within the tank could then trigger the closing of the electronic valve. 
         [0049]    Introducing the catchment runoff water to the water-recovery system  330  in this manner helps prevent the introduction of pollutants, such as oil and other contaminants which may collect on catchment surfaces during dry periods, into storm drains, surface and ground waters. Further examples of systems for removing pollutants from stormwater are described in U.S. Pat. No. 6,241,881 to Pezzaniti and U.S. Pat. No. 6,086,756 to Roy, the teachings of which are incorporated herein by reference. 
         [0050]    Although the embodiments described above pertain substantially to a particular modular block style and a particular use in a roof-top, rainwater catchment application, other embodiments of block styles and applications exist. 
         [0051]    Examples of other modular block styles are illustrated in  FIGS. 5A-5B  and  FIGS. 6A-6B . The modular block shown in  FIGS. 5A-5B  is similar to that shown in  FIGS. 1A-1B  except for the vertical members  140 . For the block shown in  FIGS. 5A-5B , the vertical member  540  comprises a cylindrical tube. Holes  550  and  560  are disposed in the tube for similar purposes as described in connection with  FIGS. 1A-1B . 
         [0052]    In an additional variation to the block style, slight convex or concave shapes may be incorporated into the upper  110  and lower  190  surfaces of the block  100 . A convex shape may provide added compressive strength, and still provide a substantially smooth outer surface. Also, convex or concave upper and lower surfaces may reduce any tendency for lateral motion of the blocks when located underground. 
         [0053]    Two embodiments depicting interlocking systems for the modular blocks are shown in  FIGS. 6A-6B . A dovetail-type interlocking system is depicted in  FIG. 6A . For this embodiment, a flared bar  604  having a central slot  603  extends along one or more edges of the upper block element  610 A. (Although not shown, the same features can be included on the blocks lower element.) Receptacles  608  are located on the opposing sides of the element  610 A. When the blocks are pressed together, the slot  603  allows compression of the outer edges of the flared bar  604 , so that the bar snaps into the receptacle  608  in the adjacent block. 
         [0054]      FIG. 6B  depicts an embodiment for interlocking the blocks wherein one or more fasteners  680  are pressed into receptacles on the block&#39;s upper and lower surfaces. The fastener  680  is dumbbell shaped having two enlarged ends  682  and a linking bar  681 . The receptacles can be readily formed in the upper and lower block surfaces during block manufacture and comprise holes  105  and channels  675 . After the blocks are aligned, the fastener is pressed into the receptacles such that the enlarged ends  682  recess into a portion of the holes  105  and the linking bar  681  recesses into the channels  675 . The fasteners may be fabricated from synthetic material, e.g. nylon, vinyl, polyvinylchloride, polycarbonate, etc. For the embodiment shown in  FIG. 6B , it may not be necessary to use synthetic cord or straps  220  to bind the blocks as shown in  FIG. 2A . 
         [0055]    In other embodiments, synthetic or metallic pins or pegs may be used to attach the blocks. For example, holes may be formed in the outer edges of the block&#39;s upper  110  and lower  190  elements. One or more pins may be driven into the holes such that about one-half of a pin&#39;s length remains outside the block. An adjacent block with matching holes may then be driven onto the protruding pins. 
         [0056]    The modular blocks  100  and water-recovery system  330  can be used in other embodiments. For example, the system may be used to collect runoff water from other water impervious surfaces such as driveways, walkways, decks and patios. Larger systems may be employed for parking lots. The tanks may also be used for septic systems in some locations where conforming to local code. 
         [0057]    The water recaptured by this system will help relieve demand on municipal water systems in urban and sub-urban areas, particularly during the summer months. This can help sustain public drinking water supplies. Any water infiltrated by the dry well  355  will promote recharge of groundwater supplies and enhance aquifer storage. The water-recovery system provides useful storage and reduces loss of storm water runoff. 
       EXAMPLES 
     Example 1 
       [0058]    As an example of the rainwater-handling capability of the water recovery system  330  illustrated in  FIG. 3 , a system servicing a 2000 square-foot roof area is considered. The system of this example has only one 800-gallon storage tank  335  and one 600-gallon dry well  355 . A storage tank for holding about 800-gallons of water can be constructed from nine modular blocks  100  measuring about 2 ft×2 ft×3 ft. Construction for a 600-gallon dry well requires excavation of about 85 ft 3 . The total volume of the system, about 1400 gallons of water in this example, can be collected and recovered for subsequent use. The actual amount of recovered water may be greater than this amount depending on the rate of rainfall and rate of infiltration of water from the drywell  355 . For this example, a rainfall of about 1.12 inches falling on the 2000-ft 2  roof area would substantially fill the system, assuming no infiltration of water into the ground from the drywell. 
         [0059]    All literature and similar material cited in this application, including, but not limited to, patents, patent applications, articles, books, treatises, and web pages, regardless of the format of such literature and similar materials, are expressly incorporated by reference in their entirety. In the event that one or more of the incorporated literature and similar materials differs from or contradicts this application, including but not limited to defined terms, term usage, described techniques, or the like, this application controls. 
         [0060]    The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in any way. 
         [0061]    While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. 
         [0062]    The claims should not be read as limited to the described order or elements unless stated to that effect. It should be understood that various changes in form and detail may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims. All embodiments that come within the spirit and scope of the following claims and equivalents thereto are claimed.