This application claims the priority of U.S. provisional application 61/151 ,039 filed on February 9, 2009 in the United States Patent office.

Field of the Invention

The present invention relates to the field of water retention and detention systems, and more particularly, to an underground stormwater management system for water recharging or reclamation.

Background of the Invention

Stormwater management systems accommodate runoff at a given site by diverting or storing stormwater and preventing pooling of water at the ground surface. Water collected by the stormwater management system may be used for recharging an aquifer, or may be reclaimed for a beneficial use, such as landscape irrigation, for example.

An underground stormwater management system is generally utilized when the surface area on a building site is not available to accommodate other types of systems such as open reservoirs, basins or ponds. The underground systems do not use valuable surface areas. Underground systems are also advantageous in that they present fewer public hazards. An underground stormwater management system must be able to withstand the traffic and earth loads that are applied to it without being prone to failure.

An example stormwater management system is provided by CULTEC, Inc. and is described in U.S. Patent 7,226,241. This stormwater management system comprises parallel rows of half-cylindrically shaped modules connected end-to-end. Connections are made between the spaceα apart rows of modules so that stormwater flows between them. During installation, fill gravel is placed between and on top of the spaced apart rows of modules. The fill gravel helps to strength the walls of the modules since there is normally about a 5" gap between the walls. However, a large amount of fill gravel is required because of the configuration and this adds to the installation cost. In addition the gaps between the rows of modules increases the land area required for such a system, which in turn adds to the installation costs. Consequently, there is a need for stormwater management systems that use much less land area for the same volume of liquid handled, that require less gravel fill, and that are much stronger to allow installation closer to the surface.

Summary of the Invention

This need is met by a stormwater management system including at least: a plurality of adjacent modules 30; with each module comprising alternating domed cell units 40 and interconnector units 42; and wherein each domed cell unit 40 of a module includes a pair of spaced apart vertical sidewalls 50 that curve outwards with respect to a centerline extending lengthwise through the module; and each interconnector unit 42 of a module includes a pair of spaced apart vertical sidewalls 52 that curve inwards with respect to the same centerline, wherein the outwardly curved vertical sidewalls 50 of the domed cell units 40 of any module are thus nested with the inwardly curved vertical sidewalls 52 of the interconnector units 42 of the next adjacent module.

In another aspect of the stormwater management system each module 30 can have an interlocking configuration on each end that can be used to extend the module lengthwise by connecting modules end to end.

In another aspect the stormwater management system adjacent modules 30 can be placed in fluid communication using portals 70 in the sidewalls 50, 52 of the domed cell units 40 and interconnector units 42.

In another aspect the stormwater management system the domed cell units 40 and the interconnector units 42 are produced from thermoplastic polymers.

In another aspect the stormwater management system of claim 1 the domed cell units 40 and the interconnector units 42 are produced from long-fiber-reinforced thermoplastic polymers. Brief Description of the Drawings

FIG. 1 is a partial cross-sectional side view of an underground stormwater management system adjacent a building site for recharging an aquifer under a parking lot in accordance with the present invention.

FIG. 2 is a top perspective view of an individual module making up the underground stormwater management system in accordance with the present invention.

FIG. 3 is a bottom perspective view of the individual module shown in FIG. 2.

FIG. 4 is a side perspective view of a plurality of individual modules stacked one on top of another for transportability in accordance with the present invention.

FIG. 5 is a top perspective view illustrating how individual adjacent modules are to be nested together in a sinusoidal or undulating fashion in accordance with the present invention.

FIG. 6 is a front perspective view of an individual module with an enclosed end in accordance with the present invention.

Detailed Description of the Preferred Embodiments

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Referring initially to FIG. 1 , the illustrated underground stormwater management system 10 is being used to recharge an aquifer 20. For illustration purposes, the underground stormwater management system 10 is installed under a parking lot 12 adjacent a building 14. Runoff water from a rainstorm, for example, is directed to a drainpipe 16 covered by a drainage grate 18. The drainpipe 16 directs the runoff water to the stormwater management system 10. The water retained by the stormwater management system 10 then passes through a granite liner 22 for penetrating through an underlying unsaturated region 24 before reaching the aquifer 20 within a saturated region.

As will be discussed in greater detail below, the stormwater management system 10 comprises a plurality of adjacent modules 30 nested together in a sinusoidal or undulating fashion. Each module 30 comprises a series of interconnected domed cell units that allow for a tightly nested field drain installation. An advantage of the nested, domed cell unit configuration is that a much smaller land area is required for increasing drain field capacity efficiency while providing structural integrity of the modules 30 themselves.

The nested, domed cell unit configuration also requires less fill gravel 28 during installation, which helps to reduce installation costs. Referring now to FIGS. 2 and 3, each individual module 30 comprises a series of domed cell units 40 connected by an interconnector unit 42. FIG. 2 is a top perspective view and FIG. 3 is a bottom perspective view. The domed cell units 40 and interconnector units 42 are formed as a single monolithic unit. A typical monolithic unit might consist of three domed units connected by two interconnector units, as shown in FIGS. 2 and 3. The interconnector units 42 serve as a transition between the domed cell units 40, while maintaining stress concentration. The dome design, coupled with the use of a high strength polymer composite material gives 25% higher compressive strength over prior art designs that allows closer to the surface installation.

Example dimensions of a module 30 are 138"(L) by 47"(W) by 36"(H). These dimensions correspond to three domed cell units 40 and two interconnector units 42, as illustrated in the FIGS. Other dimensions are readily acceptable depending on the intended application, including modules with a different number of domed cell units 40 and interconnector units 42. For transportability, the modules 30 may be stacked on top of each other without spreading or swaybacking, as illustrated in FIG. 4, leading to much tighter shipping density for lower cost shipping on trucks or by rail.

Each module 30 may be formed out of a molding material comprising a thermoplastic material, as readily appreciated by those skilled in the art.

The molding material may be based on a polymer or elastomeric polymer.

A preferred embodiment is long-fiber-reinforced thermoplastic polymers for highest compressive strength. The increased compressive strength can allow installation of the stormwater system closer to the surface, lowering cost and further reducing gravel fill needs. Each domed cell unit 40 includes a pair of spaced apart vertical sidewalls 50 that curve outwards with respect to a centerline extending lengthwise through the module 30. In contrast, each interconnector unit 42 includes a pair of spaced apart vertical sidewalls 52 that curve inwards with respect to the same centerline. Alternating outward/inward curving between the pairs of spaced apart sidewalls 50, 52 generate a sinusoidal or undulating shape. This advantageously allows the modules 30 to be nested together, as best illustrated in FIG. 5.

The outwardly curved vertical sidewalls 50 of the domed cell units 40 of any module are thus nested with the inwardly curved vertical sidewalls 52 of the interconnector units 42 of adjacent modules.

This staggered configuration allows for the modules 30 to be tightly nested together. Consequently, less fill gravel 28 is required during installation.

The upper enclosed portion 54 of each domed cell unit 40 curves outwards toward the centerline of the module 30. Similarly, the upper enclosed portion 56 of each interconnector unit 42 curves outwards toward the centerline of the module 30. The outwardly curved portions 54, 56 advantageously increase the storage capacity of each module 30 while maintaining structural integrity.

Using the above noted dimensions of 138"(L) by 47"(W) by 36"(H), this corresponds to a volume of about 83 ft ³ , which can hold about 618 gallons of runoff water. When a module 30 is formed out of a thermoplastic material, it has a weight of about 130 pounds.

The modules 30 are connected together end-to-end using an overlapping, interlocking ridge configuration. The opposing ends of each module 30 have an outwardly protruding ridge or lip 60 with a corresponding recess on the underside. The ridge 60 from one end of a module 30 is received by the recess on the end of the module 30 to be connected to, as besi inusiraieα by the overlapping connection 62 in FIG. 5. The ends 64 of the modules 30 are normally closed, as illustrated in FIG. 6. If two modules 30 are to be connected together, then the respective ends 64 of each module are cut away. Alternatively, the end 64 of a module may be removed to interface with an above ground drainpipe 16.

When the modules 30 are nested together in a side-by-side configuration, collected runoff water is allowed to flow between the adjacent modules. This is accomplished by cutting the corresponding portals 70 in each module 30. The portals 70 in each module are deployed to coincide with matching portals on adjacent modules. A header or manifold 80 may be connected to a module 30, as illustrated in FIG. 5. The header 80 compensates for the staggered configuration of the modules 30, and allows the ends of the modules to be aligned with one another.

Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.