Patent ID: 12203258

DETAILED DESCRIPTION

Embodiments relate generally to an underground stormwater storage system. More particularly, embodiments relate to an underground stormwater storage system which may capture stormwater and expel excess stormwater through outlets. The outlets may be disposed on the uppermost areas of the underground stormwater storage system. In embodiments, an underground stormwater storage system may comprise a structure that may be designed to collect stormwater and release the stormwater underground at a controlled rate of speed. The structure may be buried within an engineered pit under pavement and/or soil. Stormwater may be collected and disposed within the underground stormwater storage system by drain pipes and/or a series of drain pipes. Occasionally, stormwater may be collected in excess due to a flood and/or heavy rain. Large amounts of stormwater may overload underground stormwater storage system, which may prevent stormwater from being removed from the surface. To prevent an overload of the underground stormwater storage system, outlets may be disposed along the top most regions of the underground stormwater storage system. This may allow the water to flow out of the underground stormwater storage system and into an engineered pit in which the underground stormwater storage system is buried. Larger stones, rocks, and dirt may be porous and comprise void areas in which stormwater expelled from the underground stormwater storage system may be disposed, allowing the underground stormwater storage system to continue to function properly.

As illustrated inFIG.1, an underground stormwater storage system2may comprise a structure4, a pit6, and a porous backfill10. In embodiments, the pit6may be dug and/or created in any area in which stormwater may need to be collected and disposed of slowly overtime. Areas may include areas where concrete and/or pavement may be used, such as within a city. During rains, concrete and/or pavement may have a tendency to shed and/or collect stormwater. This may prevent stormwater from dissipating into the soil. Additionally, this may cause stormwater to pool and/or overfill natural stormwater collection areas such as rivers, bayous, and/or lakes. The underground stormwater storage system2may be designed to collect, store, and release stormwater within the structure4. In embodiments, there may be a plurality of the structures4that may be attached to one another to form the underground stormwater storage system2. The structure4may comprise any suitable cross-sectional shape; a suitable shape may be, but is not limited to a circle, an arch, a square, a rectangle, and/or any combination thereof. Additionally, structure4may be of a single radius or a multi-radius shape. In embodiments, the structure4may be any suitable material in which to house stormwater underground. Suitable material may be, but is not limited to, plastic, concrete, metal, fiberglass and/or any combination thereof. The structure4may further comprise ribbing, not illustrated, which may add additional strength to structure4. Once secured underground, the structure4may be able to retain and expel stormwater at any engineered rate of speed. When large amounts of stormwater are collected by the underground stormwater storage system2, the rate of speed in which stormwater may be expelled from the structure4may not be fast enough to allow for the stormwater to move through the underground stormwater storage system2, which may cause stormwater to collect and back up within the structure4. As stormwater is collected in the structure4, the stormwater level in the structure4may rise. In embodiments, stormwater may rise to the top of the structure4. Outlets12may be used to expel water out of the structure4, which may allow the underground stormwater storage system2to continue the disposal of stormwater from a surface22.

FIGS.2through4illustrate embodiments in which the structure4may comprise outlets12, which may be disposed on an area of the structure4closest to the surface. Outlets12may be disposed about the crown and/or top of the structure4and may further be disposed in any area above the springline or midrise of the enclosed structure4or within the crown and/or haunch of the arch of the structure4. The springline may be defined as the line at which an arch begins. Alternatively, in embodiments outlets12may be disposed at or below the springline or midrise. Outlets12may comprise any suitable shape; a suitable shape may be, but is not limited to, a square, rectangle, oval, circle, polyhedron, and/or any combinations thereof. Additionally, referring toFIG.2, outlets12may be a slot, for example, that traverses the length of the structure4and extends up and away from the structure4by any suitable length. A suitable length may be as long as about one inch to about twelve inches, about four inches to about ten inches, about six inches to about eight inches, or about six inches to about twelve inches. As illustrated inFIGS.2through4, outlets12may be disposed along the crown, a side of the structure4, and/or on top of the structure4. Without limitation, outlets12may be disposed in any area above, at, or below the springline of the structure4. Additionally, outlets12may be a single outlet or a plurality of outlets12. Outlets12may be disposed adjacent to one another and may be disposed in random patterns, straight lines, and/or offset from each other. The plurality of outlets12may further be disposed above the springline of the structure4. Outlets12may function to delay the expulsion of stormwater from the structure4until large amounts of stormwater are collected within the structure4. The structure4may collect and/or hold stormwater due to the ability of the structure4to retain stormwater.

An enclosed structure, as illustrated inFIGS.2and4, may be sufficiently water tight and may be able to collect stormwater. In embodiments, referring toFIG.3, the structure4may not be an enclosed structure. A liner8may be used to prevent stormwater from dissipating into the porous backfill10(not illustrated) continuously. The porous backfill10may be, but is not limited to, gravel, limestone, dolomite, stone, shale, and/or any combination thereof. Shaped as an arch, the structure4may comprise an open bottom. With an arched structure4, the liner8may act as a bottom to the structure4and sufficiently seal the arch. This may prevent stormwater from dissipating into the pit6(not illustrated), which may deposit sand and/or silt within the porous backfill10, making the porous backfill10impervious to stormwater. The saturation of the porous backfill10with sediment may clog the underground stormwater storage system2, which may cause stormwater to back up and prevent stormwater from dissipating properly in the underground stormwater storage system2. The liner8may contain sand and/or silt, preventing it from saturating the porous backfill10. The structure4may be configured to allow operators to remove sand and/or silt deposited within the structure4. By removing deposited sand and/or silt, the structure4may be able to increase the amount of stormwater the structure4may be able to retain. In instances where large amounts of stormwater are captured, sand and/or silt may settle to the bottom of the structure4. This may allow stormwater, void of sand and/or silt, to move upward within the structure4. Clean stormwater may then be free to move through outlets12and flow into the porous backfill10. Clean stormwater may not deposit sand/silt into the porous backfill10and may allow an engineer to take into account void areas within the porous backfill10in stormwater storage calculations.

In embodiments, outlets12may be utilized during storm events in which large amounts of stormwater may be collected by the stormwater storage system2. Events in which large amounts of stormwater may be collected may rarely occur. This may further prevent the expulsion of sand and/or silt, disposed within the structure4, into the porous backfill10. Additionally, preventing the expulsion of water into the porous backfill10may further prevent the exposure of subgrade soils to moisture, which may lead to the swelling and shrinkage, erosion and/or removal of subgrade soils. In embodiments, outlets12may be designed to allow for the release of stormwater into the porous backfill10, but may further prevent the porous backfill10from entering the structure4.

Outlets12may be configured to allow stormwater to be expelled from the structure4and prevent the porous backfill10from falling into the structure4. Outlet12may be inserted into the structure4before and/or after placement of the structure4within the pit6. Additionally, outlets12may be removable from the structure4and may be replaced. As illustrated inFIGS.5through8, outlets12may comprise different embodiments and/or shapes to prevent the porous backfill10from falling through outlets12into the structure4. Referring toFIG.4, outlets12may comprise a cover14. In embodiments, the cover14may have a domed shape, which may allow stormwater to move up and out of outlets12under the dome shape, while the top of the dome prevents the porous backfill10from falling into outlets12. The cover14may be made of any suitable material; suitable material may be, but is not limited to, metal, plastic, concrete and/or any combination thereof. The cover14may partially cover outlets12and/or completely cover outlets12. Additionally, the cover14may comprise partial hemispherical structures, which may be used to prevent the porous backfill10from moving through outlets12and may allow stormwater to move through the cover14. Referring toFIG.5, outlets12may comprise a screen16, which may cover the entirety of outlets12. The screen16may be made of any suitable material; suitable material may be, but is not limited to, metal, plastic, and/or any combination thereof. In embodiments, the screen16may be a mesh material, which may comprise a plurality of sections in which stormwater may pass through. The mesh design may prevent large-diameter porous backfill10from entering the structure4, but it may allow stormwater to pass through and be removed from the structure4. In embodiments, there may be any suitable number of screens16disposed on outlets12. A suitable number of screens16may be from about one to about six, about two to about four, or about three to about six. Further, outlets12may comprise an attachment point18as illustrated inFIG.6.

FIG.6illustrates outlets12with the attachment point18. Attachment point18may be any suitable shape; a suitable shape may be a hook, a bar, an arch, and/or any combination thereof. In embodiments, attachment point18may be used to connect outlets12, and thus the structure4, to a crane and/or other lifting mechanism. Attachment point18may allow the structure4to be positioned within the pit6for use. In embodiments, attachment point18may comprise the same material as outlets12. Additionally, attachment point18may be removable from outlets12after installation of the structure4.

FIG.8illustrates an embodiment of a round structure4with various outlets12. As previously described, outlets12may be a slot and/or hole. As shown, outlets12may comprise the screen16that allows stormwater to pass through it. Outlets12may be disposed as a vertical slot about a top portion of the structure4. In embodiments, outlets12may extend along the length of the structure4. Alternatively, outlets12may be disposed as a hole along the top portion of the structure4.

Returning toFIG.1,FIG.1illustrates an embodiment with an outlet control structure20.FIG.1also shows the surface22, one or more inlet pipes24, a connector pipe26, and an outlet pipe28. The surface22may be cement, grass, asphalt, concrete pavement, or types of pavement, or any other ground cover. The one or more inlet pipes24may connect the surface22, directly or indirectly, to the structure4. For example, there may be a grating40on the surface22that allows stormwater to flow into the structure4, wherein the one or more inlet pipes24may be connected to the structure4. The one or more inlet pipes24may be any size and made from any material required for the particular circumstances. For example, in embodiments the one or more inlet pipes24may be made from high-density polyethylene (HDPE), corrugated metal, reinforced concrete, polyvinyl chloride (PVC), polypropylene (PP), fiberglass, or other piping materials. Further, in embodiments, the one or more inlet pipes24may have any diameter and may be of about 15 inches to 30 inches, 24 inches to 48 inches, 6 inches to 18 inches, and 42 inches to 96 inches. The connector pipe26may connect the outlet control structure20to the structure4. The connector pipe26may be any size and made from any material required for the particular circumstances and may be about 12 inches to 48 inches. The outlet pipe28may connect the outlet control structure20to an area for drainage. The outlet pipe28may be any size and made from any material required for the particular circumstances. For example, in embodiments, the outlet pipe28may be made of HDPE, metal, concrete, PVC, PP, or fiberglass, and in embodiments, the outlet pipe28may have a diameter of about 6 inches to 48 inches.

As illustrated inFIG.1, in embodiments, the outlet control structure20may be a rectangular column. Additionally, the outlet control structure20may be a column of any shape such as, but not limited to, squared or circular. The outlet control structure20may have a height greater than the height of the structure4. Further, the outlet control structure20may comprise an aperture30with a one-way valve or valve32. In embodiments, the outlet control structure20may connect to the connector pipe26on a wall20A of the outlet control structure20. In embodiments, the outlet control structure20may connect to the outlet pipe28on a wall20B of the outlet control structure20. The aperture30may have any shape including, but not limited to a rectangular shape, circular shape, or oval shape. In embodiments, the aperture30may be located near the bottom of one of the walls of the outlet control structure20. For example, the aperture30may be located on a wall20C of the outlet control structure20. The one-way valve32may be of any shape or material. In embodiments, it may have a circular shape and made of steel or it may be oval in shape and made of rubber. In embodiments, the one-way valve32may be hingedly attached to the top of the aperture30or it may be flanged and screwed, bolted, welded or otherwise adhered over aperture30. The one-way valve32may be attached to the outlet control structure20in such a way that gravity may assist with inclining the one-way valve32towards a closed position. Alternatively, in embodiments, the one-way valve32may be positioned at an angle to increase the effect of gravity. As illustrated inFIG.7, in embodiments, the one-way valve32may comprise a gasket44or some other similar material for the purpose of decreasing the ability for water to leak through the one-way valve32. Alternatively, the gasket44may be placed inside around the aperture30such that the one-way valve32may press against the gasket44when in or near the closed position.

As illustrated inFIG.1, in embodiments the outlet pipe28may connect to the outlet control structure20near the bottom of the outlet control structure20in order to improve water drainage. The outlet pipe28may be sized to restrict water flow.

In the event of a rainstorm, the following operation of an embodiment of the stormwater storage system2may occur. Rain may fall on the surface22. The stormwater may flow from the surface22to the structure4by way of the one or more inlet pipes24, directly or indirectly. As the stormwater flows to the structure4, the stormwater begins to fill the structure4, as well as the connector pipe26and the outlet control structure20. The water in the structure4, the connector pipe26, and the outlet control structure20may have substantially similar head pressures. At this point in the operation, the one-way valve32may be inclined to the closed position due, in part, to gravity. The surrounding porous backfill10may be relatively dry.

As the water levels in the structure4, the connector pipe26, and the outlet control structure20rise, the head pressure within the outlet control structure20may increase, which may place increased pressure on the one-way valve32to prevent the flow of stormwater into the porous backfill10.

In the event of a small or medium-sized rainstorm, the storage system2may fill partially and discharge the rain water at a given rate. In such instances, the backfill10may not be needed or used. In the event of a large storm event, the structure4may be completely filled with water and may allow water to escape or discharge out of the outlets12into the surrounding porous backfill10. The water discharging out of the outlets12may be potentially cleaner than the water in the structure4given that large sediments may be deposited at the bottom of the structure4. As the rain continues, the water level in the backfill10may continue to rise. The water level in the backfill10may rise to less than, equal to, or greater than the height of the structure4.

When the large storm event begins to subside and water is no longer entering the storage system2, the water level, and thus the head pressure, within the structure4and the outer control structure20may begin to decrease. A lower head pressure inside the outer control structure20may create a differential head pressure between the head pressure inside the outer control structure20and the head pressure outside the outer control structure20in the backfill10. This differential head pressure may move the one-way valve32from a closed position to an open position, as illustrated inFIG.12, allowing water to drain from the backfill10into the outer control structure20. The water may continue to drain from the backfill10, the structure4, and the outer control structure20until the storage system2may be substantially drained of water and relatively dry.

Alternatively, the one-way valve32may be employed on a wall of the structure4. For example, as illustrated inFIG.1, in one embodiment, there may be two or more structures4, side by side, in a horizontal position underground. These two structures4may be connected by an equalizing pipe34(not illustrated). In embodiments, as illustrated inFIG.1, the structure4may be a round pipe. In embodiments, the structure4may comprise a reinforced bullhead46at one end of the structure4. At the top of the reinforced bullhead46, the structure4may comprise an opening48, as illustrated inFIG.1. In embodiments, the opening48may comprise a wire mesh. Further, in embodiments, the wire mesh may be 0.5-inch galvanized wire mesh. In the embodiment illustrated inFIG.1, the reinforced bulkhead46further comprises the aperture30near the bottom. In embodiments, the aperture30may be round. In embodiments, a one-way valve32may be hingedly attached to the reinforced bullhead46in such a way as to cover aperture30when the one-way valve32is in the closed position. In embodiments, the one-way valve32may have a diameter of 6 inches. In embodiments, the elevation of the one-way valve32may vary. Further, in embodiments, the one-way valve32may be covered by a sleeve (not illustrated) extending out from the reinforced bulkhead46. In embodiments, the outlet pipe28may lead to a capped perforated riser36(not illustrated) in a sewer system38(not illustrated). In embodiments, there may be any number of structures comprising the storage system2.

As illustrated inFIG.1, reinforced bulkhead46may have an inlet control structure50as well as inverted pipe52, which may address problems with trash in the structure4. Other alternatives may include a redundant one-way valve32at higher elevations, riser filters, floc logs baskets, and trash baffles. Further, the storage system2may be used with pre/post treatment devices. In embodiments, structure4may have more than one one-way valve32. In embodiments, the outlet control structure20may have more than one one-way valve32. In embodiments, the structure4and the outlet control structure20may each have one or more one-way valves32. As discussed above, in embodiments, outlets12may be inverted pipe52with the downward inlet located within structure4or within outlet control structure20whereby trash, debris, oils, hydrocarbons or other floatable pollutants may rise above the downward facing inlet to prevent expulsion into porous backfill10.

As illustrated inFIG.15A, in another embodiment, structure4may comprise an additional reinforced bulkhead46internally. The additional reinforced bulkhead46may comprise one or more one-way valves32, and it may also comprise an opening48. In operation, stormwater flows into a portion of structure4referred to as a detention system54. As the level of stormwater in detention system54increases, the stormwater forces the one-way valves32open allowing stormwater to flow into a portion of structure4referred to as a cistern56. The opening48allows air to escape the cistern56. Additionally, the opening48may also allow stormwater to flow from detention system54into cistern56, which may allow silt and trash to remain in the detention system54. Stormwater may also exit the detention system54by way of outlet pipe28. The stormwater stored in cistern56may be employed for use in irrigation or other applications. Multiple cisterns56may be created throughout the system2and may be connected to one another with sufficiently watertight pipe or other connections to allow equal filling from rainfall harvesting and draining from irrigation or other use.

Alternatively, as illustrated inFIG.15B, the stormwater may flow directly into cistern56. In this embodiment, opening48allows stormwater overflow to flow into the detention system54.

FIG.9illustrates an alternative embodiment employing treatment chambers58and storage chambers60. The embodiment ofFIG.9may function similarly to the embodiment shown inFIG.1, but the embodiment ofFIG.9may preferentially discharge to storage chambers60. Further, the embodiment ofFIG.9may allow for the drainage of stormwater from storage chambers60back into treatment chambers58through one-way valves32. In embodiments, stormwater enters the treatment chambers58through inlet pipes24. In embodiments, a small rain storm and/or first flush runoff may be contained in the treatment chambers58, and treatment chambers58may also capture sediment, trash, and other debris. In embodiments, as the amount of stormwater in treatment chambers58increases, the head pressure against the one-way valves32may increase, keeping the one-way valves32in the closed position. In embodiments, treatment chambers58must fill with stormwater to the top before spilling into the storage chambers60. In embodiments, treatment chambers58may be connected to storage chambers60by one or more overflow pipes68. In embodiments, trash and other floatable debris may be prevented from entering storage chamber60by employing a downturned connector pipe26, a baffle wall, or a screen. Further, storage chambers60, in embodiments, may also be connected to treatment chambers58by return pipes62. In embodiments, return pipes62may fill with stormwater at the same time storage chambers60fill with stormwater. In embodiments, one-way valves32in the bulkhead of treatment chamber58may prevent stormwater from entering treatment chamber58when the head pressure inside treatment chamber58exceeds the head pressure inside return pipe62. In other embodiments, a return pipe62may be connected to an outlet control structure20, wherein the outlet control structure20may also be connected to treatment chamber58by way of a connector pipe26. In such embodiments, the outlet control structure20may fill with stormwater when the treatment chamber58fills with stormwater, and the head pressure inside outlet control structure20may maintain the one-way valves32until the head pressure inside return pipe62exceeds the head pressure inside outlet control structure20. In embodiments, as treatment chambers58drain through outlet pipes28, directly or indirectly, the level of stormwater in treatment chambers58decreases, which may ultimately create a differential head pressure needed to open the one-way valves32. In embodiments, once one-way valves32are open, the treatment chambers58and storage chambers60drain approximately simultaneously and substantially completely. This alternative embodiment may allow for easier maintenance since the trash, debris, and pollutants may be isolated, and it may allow for the use of filters, chemicals, and other finer treatment methods and devices. Further, this alternative embodiment may further protect the backfill10given that the backfill10may only receive the cleanest discharge from the tops of storage chambers60in very large storm events. Additionally, there may be other alternative embodiments in which a perforated pipe (not illustrated) may be set into or buried under backfill10for additional drainage. Further, in this alternative embodiment, a pump (not illustrated) may be employed to assist with this additional drainage.

FIGS.10A-10Cillustrate embodiments of bell siphons64that may be employed to assist with stormwater drainage. In the embodiment ofFIG.10A, a small volume of an outlet control structure20may be dedicated to fill very quickly during a storm event. This small volume may be referred to as the siphon area66in embodiments. In embodiments, the siphon area66may comprise one or more inlet pipes24and grating40. In embodiments, the siphon area66may begin filling up with stormwater before the structure4. In embodiments, as the amount of stormwater in siphon area66increases, the head pressure inside the siphon area66increases forcing the one-way valves32to remain in the close position. In embodiments, when the stormwater reaches the required elevation to prime the siphon64, stormwater may begin to discharge from the outlet pipe28of siphon64. In embodiments, any excess water in the siphon area66may overflow into the detention structure4through an overflow pipe68. In embodiments, as the stormwater outside of the siphon64draws down, the elevation of the stormwater in the siphon area66may decrease lower than the elevation in the detention structure4, creating a differential head pressure, which may open the one-way valves32. In embodiments, the siphon64may drain the entire system2.FIG.10Billustrates an alternative embodiment comprising a bulkhead46within detention structure4with one or more inlet pipes24or gratings40. In the embodiment shown in FIG.10B, the siphon area66may be inside structure4. Further, any overflow of stormwater may flow over bulkhead46similar to the embodiment shown inFIG.8A.FIG.10Cillustrates another alternative embodiment employing an internal inlet riser70for housing siphon64(not illustrated). In embodiments, any overflow in the embodiment ofFIG.10Cmay flow out of inlet riser70through openings72at the top of inlet riser70into structure4. In embodiments, siphon64, a hydrobrake, or other flow-control device that may benefit from increased head pressure may be placed within the siphon area66. In embodiments, the benefit of employing a siphon64may be that, once primed, siphons operate at a nearly constant discharge rate versus a simple outlet orifice, which only reaches peak discharge when the system2is completely full of water. Further, the required detention volume may be the amount of water flowing into the system2less the amount of water flowing out of system2. Thus, in embodiments, the siphon64may drain more water thereby reducing the amount of required storage volume.

FIG.11illustrates the internal components of a double-bell siphon74. In embodiments, the double-bell siphon74may comprise a siphon64, guides76, floats78, a cup82, and a warning indicator80. In the embodiment ofFIG.11, stormwater may enter the siphon area66and enter a first area84. In embodiments, when the stormwater reaches a level higher than cup82, the stormwater may begin to fill cup82. Further, in embodiments, as stormwater rises inside siphon area66, floats78may cause a floating bell86to rise as well. Additionally, stormwater may also begin to fill siphon64in embodiments. In embodiments, when the stormwater reaches the required elevation to prime the siphon64, stormwater may begin to discharge from the outlet pipe28of siphon64. The benefit of this double-bell siphon alternative is that it may prevent sediment and debris from clogging the bottom of siphon64. In embodiments, warning indicator80may be attached to the top of floating bell86, and warning indicator80may exit an aperture in the surface22. In embodiments, warning indicator80may warn property owners, property management, or other individuals that the siphon area66may contain excessive debris or have other issues, if the warning indicator80fails to return to its subsurface position after the storm has ceased for a reasonable amount of time.

FIG.12illustrates an alternative embodiment employing a first solid pipe100, a second solid pipe102, and a perforated pipe104. In embodiments, first solid pipe100and second solid pipe102may comprise an inner diameter between 24 and 144 inches. Further, in embodiments first solid pipe100and second solid pipe102may be placed horizontally on liner8or porous backfill10, as illustrated inFIG.12. Additionally, in embodiments first solid pipe100and second solid pipe102may be placed horizontally at the same elevation. In embodiments, first solid pipe100and second solid pipe102may be connected to each other by a connector pipe106. In embodiments, connector pipe106may be attached to the lower half of first solid pipe100and also attached to the lower half of second solid pipe102. In embodiments, connector pipe106may be oriented horizontally and level with a slope at or near zero. In embodiments, perforated pipe104may comprise an inner diameter between 18 and 136 inches. In embodiments, the inner diameter of perforated pipe104may be less than the inner diameters of first solid pipe100and second solid pipe102. In embodiments, perforated pipe104may comprise a plurality of perforations108, which may allow water to flow into and out of perforated pipe104. In embodiments, perforated pipe104may be placed on liner8or porous backfill10in a horizontal orientation. Further, in embodiments, perforated pipe104may be connected to second solid pipe102by a flowline pipe110. In embodiments, perforated pipe104may be placed at a higher elevation than first solid pipe100and second solid pipe102. In embodiments, flowline pipe110may be attached to the lower half of second solid pipe102and also attached to the lower half or upper half of perforated pipe104. In embodiments, flowline pipe110may be positioned with a higher elevation than connector pipe106. Further, in embodiments, flowline pipe110may be positioned at an elevation that does not allow silt-laden water from small storms to flow from second solid pipe102into flowline pipe110. Therefore, in such embodiments, the silt-laden water would remain at the bottom of first solid pipe100, possibly connector pipe106, and possibly the bottom of second solid pipe102.

In embodiments, stormwater may enter first solid pipe100through one or more inlet pipes112. In embodiments, water from a small rain storm and/or first flush runoff may be contained in first solid pipe100connected to inlet pipe112. In embodiments, first solid pipe100may also capture sediment, trash, and other debris. In embodiments, water from the small rain storm and/or first flush runoff may flow into connector pipe106and second solid pipe102. In embodiments, as the amount of stormwater increases in first solid pipe100, water may begin to flow into connector pipe106and second solid pipe102. In embodiments, as the amount of stormwater increases in second solid pipe102, stormwater may begin to flow into flowline pipe110once the stormwater in second solid pipe102reaches the level of flowline pipe110. In embodiments, this stormwater flowing into flowline pipe110may then flow into perforated pipe104. In embodiments, stormwater flowing in to perforated pipe104may eventually reach the elevation of one or more of the plurality of perforations108, which would allow the stormwater to flow from inside perforated pipe104into porous backfill10. In embodiments, once the storm begins to subside, water from porous backfill10may flow back into perforated pipe104, through flowline pipe110, and into second solid pipe102and first solid pipe100, through connector pipe106, and through an outfall113. Alternatively, some or all of water from porous backfill10may percolate into surrounding soil withing pit6.

FIG.13illustrates an alternative embodiment of a bulkhead120. In embodiments, bulkhead120may comprise an opening122and a first orifice124. Thus, in embodiments employing alternative bulkhead120, stormwater would be permitted to flow through first orifice124into porous backfill10. In embodiments, this flow of stormwater into porous backfill10may occur even during small storm events with less volume of water flowing into system2. In embodiments, first orifice124may comprise a diameter between 1 inch and 15 inches. Alternatively, first orifice124may be comprised of a trapezoidal shape with parallel sides between 3 inches and 48 inches and non-parallel sides between 1 inch and 30 inches. Alternatively, first orifice124may be comprised of an irregular shape with varying dimension between 2 inches and 100 inches. Further, in embodiments, first orifice124may comprise a diameter that restricts flow so that the stormwater may fill the pipe employing bulkhead120faster than stormwater may flow through first orifice124and limit use of backfill10. In embodiments, the interior of bulkhead120may comprise a filter fabric126, which may cover first orifice124. In embodiments, filter fabric126may prevent silt, trash, sediment, or other materials from flowing through first orifice124while still allowing stormwater to flow through first orifice124. Additionally, in some instances, filter fabric126may clog with silt, trash, sediment, or other materials, which may prevent the stormwater from flowing through the first orifice124and thus causing the stormwater to initially be stored in the first solid pipe100and/or second solid pipe102, which may result in delayed use of the porous backfill10. Further, in embodiments as a storm event subsides and stormwater levels in the pipe attached to bulkhead120decrease, water may begin to flow from porous backfill10through first orifice124into the pipe attached to bulkhead120.

FIG.13also illustrates an embodiment comprising a second orifice128. In embodiments, second orifice128may be a plurality of additional orifices. In embodiments, second orifice128may comprise a diameter between 1 inch and 15 inches. Alternatively, second orifice128may comprise a trapezoidal shape with parallel sides between 3 inches and 48 inches and non-parallel sides between 1 inch and 30 inches. Alternatively, second orifice128may be comprised of an irregular shape with varying dimension between 2 inches and 100 inches. In embodiments, second orifice128may be positioned above first orifice124. In embodiments, second orifice128may allow for additional water flow out of the pipe attached to bulkhead120in larger storm events resulting in higher levels of stormwater in the pipe attached to bulkhead120.

FIG.14illustrates another alternative embodiment of bulkhead120, which comprises a plurality of orifices130.FIG.14illustrates an embodiment in which the plurality of orifices130are laid out in horizontal rows wherein the number of orifices130increases as the elevation increases. In embodiments, the first row of orifices130may begin with a single orifice130and then increase by one additional orifice130for each row. In alternative embodiments, each row of orifices130may comprise a single orifice130or any other design or number of orifices130. In embodiments, the number and orientation of orifices130may allow for control of water flow through bulkhead120.

FIG.15illustrates the inside of bulkhead120that comprises filter fabric126covering the plurality of orifices130. In embodiments, filter fabric126may be cut in order to cover any design, orientation, and number of orifices130. Additionally, in embodiments any type of appropriate filter media may be used instead of filter fabric126. In embodiments, filter fabric126as illustrated inFIG.13orFIG.15may be placed directly against first orifice124, second orifice128, and/or the plurality of orifices130. Alternatively, filter fabric126may be placed against a weir (not illustrated), which may allow for some space between the filter fabric126and first orifice124, second orifice128, and/or the plurality of orifices130. Additionally, filter fabric126employing a weir may aid in slowing the flow of water to porous backfill10as well as collect silt. Further, in embodiments a structure employing filter fabric126and a weir may be configured so that the top of the weir may allow stormwater to spill over the weir when stormwater levels reach a certain elevation. In embodiments, such a weir structure would act as a safety release of stormwater to porous backfill10in the event filter fabric126became completely clogged or blocked.

FIG.16illustrates an alternative embodiment of the underground stormwater storage system2. In the alternative embodiment, the underground stormwater storage system2comprises at least one solid pipe150and a perforated pipe152. In embodiments, solid pipe150may comprise an inner diameter between 24 inches and 180 inches. Further, in embodiments solid pipe150may be placed horizontally on liner8or porous backfill10, as illustrated inFIG.16. Additionally, in embodiments solid pipe150may be connected to one or more inlet pipes112. In embodiments, perforated pipe152may comprise an inner diameter between 24 inches and 180 inches. In embodiments, the inner diameter of perforated pipe152may be less than or greater than the inner diameter of solid pipe150. In embodiments, perforated pipe152may comprise a plurality of perforations108, which may allow water to flow into and out of perforated pipe152. In embodiments, perforated pipe152may be placed on liner8or porous backfill10in a horizontal orientation. Further, in embodiments, perforated pipe152may be connected to solid pipe150by connector pipe110. In embodiments, connector pipe110may be attached to the lower half of solid pipe150and also attached to the lower half of perforated pipe152. Further, in embodiments, connector pipe110may be positioned at an elevation that does not allow silt-laden water from small storms to flow from solid pipe150into connector pipe110. Therefore, in such embodiments, the silt-laden water would remain at the bottom of solid pipe150. Additionally, in embodiments a cap154may be employed at the junction of connector pipe110and perforated pipe152. Further, in embodiments a plurality of solid pipes150and/or perforated pipes152may be employed.

In embodiments, the alternative embodiment illustrated inFIG.16may provide for solid pipe150to receive stormwater through inlet pipes112. However, during the construction phase of a surface project, in which debris may be washed into the inlet pipes112and solid pipe150, the cap154may be employed to prevent usage of perforated pipe152and porous backfill10. In embodiments, the cap154may be installed at the junction of the connector pipe110and perforated pipe152. Thus, in embodiments, stormwater containing dirt and/or debris may be held in solid pipe150until the construction site is stable. In embodiments, once the construction site is stable, the cap154may be removed allowing full usage of the volume in the perforated pipe152and porous backfill10. Thereafter, in embodiments, stormwater may enter solid pipe150through one or more inlet pipes112. In embodiments, solid pipe150may capture sediment, trash, and other debris.

FIG.17illustrates a perspective view of an additional embodiment of the underwater stormwater storage system2. In embodiments, more than one solid pipe150may be placed in line as shown inFIG.17. In embodiments, the bulkheads120of each solid pipe150may be removed, and the solid pipes150may be connected to each other using a connecting joint180. In embodiments, the connecting joint180may be uncovered or the connecting joint180may be covered with a band182. In embodiments, the band182may comprise a standard band that would be known to a person of ordinary skill in the art. In embodiments, the band182may comprise a plurality of orifices. In embodiments in which the band182comprises a plurality of orifices, stormwater may be discharged from the solid pipes150through the gap184into the porous backfill10at a slower rate than the stormwater collecting in the solid pipes150. Alternatively, in embodiments the connecting joint180may be covered with fabric126(not illustrated). In such embodiments, stormwater may be discharged from the solid pipe150and through the fabric126at a slower rate than the stormwater collecting in the solid pipes150. In embodiments, the connecting joint180may provide a gap184of roughly ½ inch between the solid pipes150, wherein the connecting joint180may allow for the free flow of stormwater from the solid pipe150into the porous backfill10. However, in embodiments the stormwater may contain sediment, trash, and other debris. In such embodiments, the sediment, trash, and/or other debris may create a barrier186to the free flow of the stormwater into the porous backfill10. In embodiments, the barrier186created by the sediment, trash, and/or other debris may delay the flow of stormwater into the porous backfill10until the stormwater in the solid pipe150reaches an elevation higher than the barrier186created by the sediment, trash, or other debris. In embodiments employing a band182over the connecting joint180, the band182may be loosened to allow stormwater to flow from the gap184into the porous backfill10. In such embodiments, the barrier186created by any sediment, trash, and/or other debris may likewise cause stormwater to build up within the gap184until the stormwater reaches an elevation higher than the barrier186. Similarly, in embodiments employing fabric126over the connecting joint180, stormwater may freely flow through the fabric126into the porous backfill10. However, in embodiments the barrier186may delay the flow of the stormwater into the porous backfill10until the stormwater in the solid pipes150reaches an elevation higher than the barrier186. Additionally, in embodiments the more than one solid pipe150laid in line may not be connected by the connecting joint180. In alternative embodiments, the gap184between the more than one solid pipe150may be created by simply placing the solid pipes150close together without touching. In embodiments, this gap184may likewise be covered with band182or fabric126. Thus, in embodiments the connecting joint180and/or gap184may protect the void space within the porous backfill10from contamination.

The foregoing figures and discussion are not intended to include all features of the present techniques to accommodate a buyer or seller, or to describe the system, nor is such figures and discussion limiting but exemplary and in the spirit of the present techniques.