STORMWATER DRYWELL SYSTEM

Description

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 63/718,277 filed on Nov. 8, 2024, and entitled “STORMWATER DRYWELL SYSTEM,” which is incorporated by reference herein in its entirety.

FIELD

The disclosure relates to a stormwater drywell system that infiltrates filtered stormwater into the ground at a specified purity.

BACKGROUND

The background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the present disclosure, or that any publication specifically or implicitly referenced is prior art.

Modern cities have large areas covered in concrete or materials that are impervious or semi-pervious to water. Accordingly, stormwater systems collect the water that accumulates and runs off of these surfaces during a storm. The stormwater systems transport the water in an orderly manner to streams, retention tanks or ponds, or other locations to prevent the flooding of areas covered in the above materials.

Drywells are a type of stormwater system that seek to deposit water from storms into the ground. Ground water systems particularly in arid or semi-arid regions are often strained due to human development. Instead of channeling water into a stream or other location that might not have a positive impact on depleted ground water systems, drywells infiltrate the water into the ground to replenish deleted ground water systems mimicking the natural water cycle prior to development.

One potential issue with this infiltration of water is pollution in the water. Injecting water that has chemicals and debris from roadways can introduce contaminants into the ground water that were not previously present. Some governing bodies have introduced standards for stormwater water quality treatment. The State of Washington's Department of Ecology defines pretreatment as 50% removal of total suspended solids, basic treatment as 80% removal of total suspended solids, and phosphorous treatment as 50% removal of total phosphorous.

Existing stormwater systems have settling tanks and filters that can partially address this pollution problem. However, existing stormwater systems also have features like bypass conduits that bypass filters during a high flow rain event, and this introduces contaminants near groundwater systems when a deep infiltration stormwater drywell is utilized.

SUMMARY

Embodiments of the present disclosure relate to a stormwater drywell system that ensures that all water that is infiltrated into the ground has passed through a filter and meets standards put forward by governing bodies, including removing a sufficient amount or percentage of total suspended solids and phosphorus. As a result, the stormwater drywell system infiltrates only treated water into the ground to replenish strained ground water systems.

It is one aspect of various embodiments of the present disclosure to provide a stormwater drywell system that comprises a drywell chamber to provide the benefits described herein. In some embodiments, the drywell chamber has a modified manhole base in which at least one filter is positioned to filter water. The drywell chamber can also have a manhole riser that defines a riser space below the modified manhole base. The filtered water that meets specified standards for total suspended solids and phosphorus or any other pollutant flows into the riser space where the filtered water is deposited into the ground. The filtered water can be deposited as deep as 120 feet, in various embodiments.

It is another aspect of various embodiments of the present disclosure to provide a stormwater drywell system that ensures that all water that enters the drywell chamber is filtered to the specified standard. In some embodiments, the modified manhole base has apertures through a lower deck, and a filter is positioned on each aperture. Therefore, all water in the drywell chamber must flow through a filter to travel from the modified manhole base space to the riser space and into the ground.

It is a further aspect of various embodiments of the present disclosure to provide a stormwater drywell system that ensures that water flows through filters for a sufficient amount of time to meet specified standards. During a high flow rain event or when a storage tank is located upstream of the stormwater drywell system, the pressure head and resulting flowrate can be so high that the water flows through the filters too fast for the filters to trap a sufficient amount or percentage of total suspended solids, phosphorus, or other pollutants. A restrictor plate with an orifice can be positioned in each aperture in the lower deck of the modified manhole base to limit the flowrate. The orifice, in some embodiments, has a diameter of 0.5 inches to limit the flowrate of water through the orifice and thus the filter to 10.2 gallons per minute at no more than 9 feet of pressure head. This ensures that the water has been sufficiently filtered before traveling into the ground. With these filters, upstream pretreatment is optional, saving time, effort, and resources.

It is another aspect of various embodiments of the present disclosure to provide flexibility when sizing the orifices to meet any changing standards for filtering pollutants out of water prior to infiltrating the water into the ground. In some embodiments, an insert is positioned in the modified manhole base, and the modified manhole base has a plurality of orifices upon which filters are positioned. Water entering the modified manhole base flows through the filters and orifices to reach the riser space, and the orifices are sized to ensure the proper residence time for water in the filters. Different inserts with different orifice sizes and/or filters can be used with a standard size or sizes for the rest of the system.

It is a further aspect of embodiments of the present disclosure to provide a stormwater drywell system with a variable orifice size to variably control the flowrate of water through filters in the system. In some embodiments, the system has at least one sensor to detect at least one characteristic of water such as flowrate or pressure head. Once the characteristic meets a condition (e.g., above, below, or at a threshold value), the orifice changes sizes in response. In an exemplary embodiment, a motor controls the position of a plate over the orifice. Thus, to increase the flowrate of water through the filter, the motor moves the plate to expose more of the orifice, and to decrease the flowrate of water through the filter, the motor moves the plate to cover more of the orifice.

A first aspect of the present disclosure is to provide a stormwater drywell system, comprising a riser having at least one sidewall extending from a bottom end to a top end to define a riser space, wherein the riser has an upper opening at the top end; a base having at least one side wall extending from a bottom end to a top end to define a base space, wherein a lower deck of the base defines the base space, and the base space is in fluid communication with the riser space via only a plurality of apertures through the lower deck of the base; and a plurality of filters positioned in the base space of the base such that each aperture of the plurality of apertures is positioned below an output of a filter of the plurality of filters, and wherein the base space is configured to receive water that flows through a filter of the plurality of filters, through an aperture of the plurality of apertures, and into the riser space where the filtered water is deposited into the ground.

The stormwater drywell system of the first aspect may include, optionally, a riser pipe extending between a top end and a bottom end, wherein the top end is offset from the bottom end in a vertical direction, and wherein the riser pipe is configured to transport filtered water from the riser space into the ground.

The stormwater drywell system of the first aspect may include one or more of the previous embodiments and, optionally, a barrier positioned below the riser and at least partially defining the riser space such that water is channeled into the riser pipe and deposited into the ground.

The stormwater drywell system of the first aspect may include one or more of the previous embodiments and, optionally, that the barrier is at least one of a slurry material or a geotextile liner.

The stormwater drywell system of the first aspect may include one or more of the previous embodiments and, optionally, a primary settling chamber configured to screen at least some particulates out of the water; and a crossover pipe configured to transport the water from the primary settling chamber to the base space.

The stormwater drywell system of the first aspect may include one or more of the previous embodiments and, optionally, that the primary settling chamber comprises a liner having at least one sidewall extending from a bottom end to a top end to define a liner space; a first aperture extending through the at least one sidewall of the liner, wherein the first aperture is configured to receive water; a second aperture extending through the at least one sidewall of the liner, wherein the second aperture is configured to expel water, and the second aperture is positioned higher than the first aperture; and a third aperture extending through the at least one sidewall of the liner, wherein the crossover pipe is at least partially positioned in the third aperture, and the second aperture is positioned higher than the first aperture.

The stormwater drywell system of the first aspect may include one or more of the previous embodiments and, optionally, a plurality of restrictor plates, wherein each aperture of the plurality of apertures in the lower deck of the base is configured to receive a restrictor plate of the plurality of restrictor plates, each restrictor plate having an orifice configured to limit the flowrate of water through the plurality of filters.

The storm water drywell system of the first aspect may include one or more of the previous embodiments and, optionally, that the plurality of filters is a plurality of filter modules, and each filter module of the plurality of filter modules has at least one filter cartridge.

A second aspect of the present disclosure is to provide a stormwater drywell system, comprising a riser having at least one sidewall extending from a bottom end to a top end to define a riser space, wherein the riser has an upper opening at the top end; a base having at least one side wall extending from a bottom end to a top end to define a base space, wherein a lower deck of the base further defines the base space, and the base space is in fluid communication with the riser space via a plurality of apertures through the lower deck of the base; a plurality of outer and inner conduits, wherein each aperture of the plurality of apertures is configured to receive an outer conduit of the plurality of outer conduits extending from an upper surface of the lower deck and is configured to receive an inner conduit of the plurality of inner conduits extending from a lower surface of the lower deck, wherein the inner conduit at least partially extends into the outer conduit; and a plurality of restrictor plates, wherein the top end of each inner conduit is configured to receive a restrictor plate of the plurality of restrictor plates, each restrictor plate having an orifice configured to limit a flowrate of a fluid through each orifice.

The stormwater drywell system of the second aspect may include, optionally, a plurality of filters positioned in the base space of the base such that each aperture of the plurality of apertures is positioned below an output of a filter of the plurality of filters, and wherein the base space is configured to receive a fluid that flows through a filter of the plurality of filters, through an orifice of a restrictor plate of the plurality of restrictor plates, and into the riser space where the filtered fluid is deposited into the ground.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that the plurality of filters is a plurality of filter modules, and each filter module of the plurality of filter modules has at least one filter cartridge.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that a diameter of each orifice is approximately 0.5 inches to limit the flowrate of the fluid through each orifice and through each filter to approximately 10.2 gallons per minute.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, a riser pipe extending between a top end and a bottom end, wherein the top end is offset from the bottom end in a vertical direction, and wherein the riser pipe is configured to transport filtered fluid from the riser space into the ground.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that the plurality of apertures in the lower deck of the base is three apertures arranged about a longitudinal axis of the base.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, a liner having at least one side wall extending from a bottom end to a top end to define a liner space, wherein the liner space is configured to transport the fluid from a pipe to the base space, and wherein the riser, the base, and the liner are configured to be positioned in the ground.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that the plurality of outer and inner conduits are made from one of a metal material or a plastic material, and the plurality of restrictor plates are made from one of a metal material or a plastic material.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that each orifice sets a discharge coefficient that is lower than a discharge coefficient of the related aperture in which the orifice is located.

The stormwater drywell system of the second aspect may include one or more of the previous embodiments and, optionally, that the discharge coefficient of each orifice is between approximately 0.53 and 0.57.

A third aspect of the present disclosure is to provide a stormwater drywell system, comprising a riser having at least one sidewall extending from a bottom end to a top end to define a riser space, wherein the riser has an upper opening at the top end; a base having at least one side wall extending from a bottom end to a top end to define a base space, wherein the base has an aperture at the bottom end; an insert configured to be positioned in the base space and configured to cover the aperture at the bottom end, the insert having a plurality of orifices such that the base space is in fluid communication with the riser space via only the plurality of orifices in the insert; and a plurality of filters positioned in the base space of the base such that each orifice of the plurality of orifices is positioned below an output of a filter of the plurality of filters, and wherein the base space is configured to receive a fluid that flows through a filter of the plurality of filters, through an orifice of the plurality of orifices, and into the riser space where the filtered fluid is deposited into the ground.

The stormwater drywell system of the third aspect may include, optionally, that the insert comprises a plurality of couplers, wherein a coupler of the plurality of couplers extends upward from an orifice of the plurality of orifices to engage a filter of the plurality of filters.

The stormwater drywell system of the third aspect may include, optionally, that a rod extends upwardly from a base of the insert such that the rod is configured to be engaged by a lift device and lowered into the base space.

The stormwater drywell system of the third aspect may include, optionally, that the plurality of orifices is arranged about the rod and spaced equidistant from each other.

The stormwater drywell system of the third aspect may include, optionally, that a diameter of each orifice is approximately 0.5 inches to limit the flowrate of the fluid through each orifice and through each filter to approximately 10.2 gallons per minute.

The stormwater drywell system of the third aspect may include, optionally, that the base is a reinforced precast concrete material.

The stormwater drywell system of the third aspect may include one or more of the previous embodiments and, optionally, that the plurality of filters is a plurality of filter modules, and each filter module of the plurality of filter modules has at least one filter cartridge.

The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about” or “approximately”. As used herein, unless otherwise specified, the terms “about,” “approximately,” etc., when used in relation to numerical limitations or ranges, mean that the recited limitation or range may vary by up to 10%. By way of non-limiting example, “about 750” can mean as little as 675 or as much as 825, or any value therebetween. When used in relation to ratios or relationships between two or more numerical limitations or ranges, the terms “about,” “approximately,” etc. mean that each of the limitations or ranges may vary by up to 10%; by way of non-limiting example, a statement that two quantities are “approximately equal” can mean that a ratio between the two quantities is as little as 0.9:1.1 or as much as 1.1:0.9 (or any value therebetween), and a statement that a four-way ratio is “about 5:3:1:1” can mean that the first number in the ratio can be any value of at least 4.5 and no more than 5.5, the second number in the ratio can be any value of at least 2.7 and no more than 3.3, and so on.

The use of “substantially” in the present disclosure, when referring to a measurable quantity (e.g., a diameter or other distance) and used for purposes of comparison, is intended to mean within 5% of the comparative quantity. The terms “substantially similar to,” “substantially the same as,” and “substantially equal to,” as used herein, should be interpreted as if explicitly reciting and encompassing the special case in which the items of comparison are “similar to,” “the same as” and “equal to,” respectively.

The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.

The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein. The use of “engaged with” and variations thereof herein is meant to encompass any direct or indirect connections between components.

It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C. § 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts and the equivalents thereof shall include all those described in the Summary, Brief Description of the Drawings, Detailed Description, Abstract, and claims themselves. Moreover, any Appendixes enclosed herein are incorporated herein in their entireties.

These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. The Summary is neither intended nor should it be construed as being representative of the full extent and scope of the present disclosure. Moreover, references made herein to “the present disclosure” or aspects thereof should be understood to mean certain embodiments of the present disclosure and should not necessarily be construed as limiting all embodiments to a particular description. The present disclosure is set forth in various levels of detail in the Summary as well as in the attached drawings and the Detailed Description and no limitation as to the scope of the present disclosure is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary. Additional aspects of the present disclosure will become more readily apparent from the Detailed Description, particularly when taken together with the drawings.

It is to be appreciated that any feature or aspect described herein can be claimed in combination with any other feature(s) or aspect(s) as described herein, regardless of whether the features or aspects come from the same described embodiment.

Any one or more aspects described herein can be combined with any other one or more aspects described herein. Any one or more features described herein can be combined with any other one or more features described herein. Any one or more embodiments described herein can be combined with any other one or more embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Those of skill in the art will recognize that the following description is merely illustrative of the principles of the disclosure, which may be applied in various ways to provide many different alternative embodiments. This description is made for illustrating the general principles of the teachings of this disclosure and is not meant to limit the inventive concepts disclosed herein.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosure.

FIG. 1A is a partial cross-sectional side elevation view of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 1B is a top plan view of a liner and a modified manhole base of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 1C is a cross-sectional side elevation view of a liner of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 1D is a cross-sectional side elevation view of a modified manhole base of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 1E is a cross-sectional side elevation view of a manhole riser of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 2A is a partial cross-sectional side elevation view of a modified manhole base of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 2B is a cross-sectional side elevation view of an orifice system of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 2C is a partial cross-sectional top plan view of a modified manhole base in accordance with an embodiment of the present disclosure;

FIG. 2D is a top plan view of a restrictor plate in accordance with an embodiment of the present disclosure;

FIG. 2E is a cross-sectional side elevation view of a restrictor plate in accordance with an embodiment of the present disclosure;

FIG. 3A is a partial cross-sectional side elevation view of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 3B is a top plan view of a liner and a modified manhole base of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 4A is a partial cross-sectional side elevation view of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 4B is a top plan view of a liner and a modified manhole base of a stormwater drywell system in accordance with an embodiment of the present disclosure;

FIG. 5A is a partial cross-sectional side elevation view of a modified manhole base with an insert in accordance with an embodiment of the present disclosure;

FIG. 5B is a side elevation view of an insert in accordance with an embodiment of the present disclosure;

FIG. 5C is a top plan view of a modified manhole base without an insert in accordance with an embodiment of the present disclosure; and

FIG. 5D is a top plan view of a modified manhole base with an insert in accordance with an embodiment of the present disclosure.

It should be understood that the drawings are not necessarily to scale, and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein. It is noted that any line in the drawings may be illustrated as solid or broken lines, including any section or length of each individual line, without departing from the scope of the present disclosure. It will be appreciated that recitation of, for example, reference character 116, 116A, 116B, etc. may apply to any combination of reference characters 116, 116A, 116B, etc.

• • 2 Stormwater Drywell System
  • 4 Primary Settling Chamber
  • 6 Drywell Chamber
  • 8 Ground
  • 10 Input Pipe
  • 12 Input Pipe
  • 14 Crossover Pipe
  • 16 Eccentric Manhole Cone (Primary Settling Chamber)
  • 18 Liner (Primary Settling Chamber)
  • 20 First Barrier (Primary Settling Chamber)
  • 22 First Bedding (Primary Settling Chamber)
  • 24 Second Bedding (Primary Settling Chamber)
  • 26 Eccentric Manhole Cone (Drywell Chamber)
  • 28 Liner (Drywell Chamber)
  • 30 Modified Manhole Base
  • 31a, 31b Filter Cartridge
  • 32 Filter Module
  • 34 Aperture
  • 36 Manhole Riser
  • 38 Second Barrier (Drywell Chamber)
  • 40 Riser Pipe
  • 42 Riser Pipe Aperture
  • 44 Third Bedding (Drywell Chamber)
  • 46 Third Barrier (Drywell Chamber)
  • 48 Fourth Bedding (Drywell Chamber)
  • 50 Sidewall (Liner)
  • 52 Lower Opening (Liner)
  • 54 Bottom End (Liner)
  • 56 Upper Opening (Liner)
  • 58 Top End (Liner)
  • 60 Liner Space
  • 62 Sidewall (Modified Manhole Base)
  • 64 Bottom End (Modified Manhole Base)
  • 66 Upper Opening (Modified Manhole Base)
  • 68 Top End (Modified Manhole Base)
  • 70 Modified Manhole Base Space
  • 72 Lower Deck
  • 74 Sidewall (Manhole Riser)
  • 76 Lower Opening (Manhole Riser)
  • 78 Bottom End (Manhole Riser)
  • 80 Upper Opening (Manhole Riser)
  • 82 Top End (Manhole Riser)
  • 84 Riser Space
  • 86 Aperture (Lift)
  • 88 Plug
  • 90 Orifice System
  • 92 Outer Conduit
  • 94 Inner Conduit
  • 96 Restrictor Plate
  • 98 Orifice
  • 100 Riser Pipe (Primary Settling Chamber)
  • 102 Apertures (Riser Pipe)
  • 104 Insert
  • 106 Coupler
  • 108 Modified Manhole Base
  • 110 Rod
  • 112 End

DETAILED DESCRIPTION

Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The Detailed Description is to be construed as exemplary only and does not describe every possible embodiment of the stormwater drywell system since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. Additionally, any combination of features shown in the various figures can be used to create additional embodiments of the present disclosure. Thus, dimensions, aspects, and features of one embodiment of the stormwater drywell system can be combined with dimensions, aspects, and features of another embodiment of the stormwater drywell system to create the claimed embodiment.

Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of the description is defined by the words of the claims set forth at the end of this disclosure. The Detailed Description is to be construed as exemplary only and does not describe every possible embodiment of the stormwater drywell system since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. Additionally, any combination of features shown in the various figures can be used to create additional embodiments of the present invention. Thus, dimensions, aspects, and features of one embodiment of the stormwater drywell system can be combined with dimensions, aspects, and features of another embodiment of the stormwater drywell system to create the claimed embodiment. Furthermore, the term “filter” may refer to a filter cartridge and/or a filter module as described herein.

FIG. 1A shows a partial cross-sectional elevation view of a stormwater drywell system 2 that comprises an optional primary settling chamber 4 and a drywell chamber 6 to filter pollutants out of water prior to depositing the water in the ground 8 at the outlet of the riser pipe 40. The modular nature of the instant stormwater drywell system 2 allows for easier construction and more accurate manufacturing. An input pipe 10 transmits water into the primary settling chamber 4, and an outlet pipe 12 can transmit water out of the primary settling chamber 4 in the event of a substantial flow of water. An optional filter 15 can filter pollutants such as large debris, trash, or sediment out of the water as the water flows out of the primary settling chamber 4, through a crossover pipe 14 and into the drywell chamber 6.

In the depicted embodiment, the primary settling chamber 4 comprises one or more liners 18 stacked on top of each other to define a liner space within the primary settling chamber 4. In some embodiments, and with reference to FIG. 1C, each liner 18 has at least one sidewall 50 that extends from a lower opening 52 at a bottom end 54 to an upper opening 56 at a top end 58. At least one sidewall 50 can be a single cylindrical sidewall, and a liner space 60 is defined therein. On top of the uppermost liner 18 in FIG. 1A is an eccentric manhole cone 16 to provide access into the primary settling chamber 4 from the surface of the ground 8 to, for instance, clean out debris from the primary settling chamber 4 or serve other maintenance functions.

A first barrier 20 covers the lower opening of the lowermost liner 18. In some embodiments, this first barrier 20 is one of a slurry material or a geotextile liner. The first barrier 20 depicted in FIG. 1A is a geotextile liner that is permeable such that the first barrier 20 allows for draindown after a rain event and infiltration of screened water into the ground 8 near grade. Water infiltrated near grade is naturally filtered through many feet of soil before reaching ground water versus being directly injected deep in the ground 8 near ground water. Furthermore, the primary settling chamber 4 is situated over a bedding 22 such as rock to provide a base upon which to bear the weight of the primary settling chamber 4. Finally, the primary settling chamber 4 is surrounded by a second barrier 24 such as a slurry material or a geotextile liner. The second barrier 24 depicted in FIG. 1A is a slurry that can channel water to a particular location such as the liners 18.

Once the water travels through the crossover pipe 14, the water enters the drywell chamber 6. The drywell chamber 6 comprises a manhole riser 36 that defines a riser space (84 in FIG. 1E), a modified manhole base 30 that receives filter modules 32 within a modified manhole base space (70 in FIG. 1D), a liner 28 defining a liner space (60 in FIG. 1C), and an eccentric manhole cone 26 that provides access into the drywell chamber 6 from the surface of the ground 8 to, for instance, clean out debris from the drywell chamber 6 or serve other maintenance functions. The eccentric manhole cones 16, 26 described herein can be, in some embodiments, 24 inches tall with an outer diameter of 60 inches and an inner diameter of 48 inches. In this embodiment, the water from the crossover pipe 14 enters the liner 28 and then travels into the modified manhole base 30. In some embodiments, the modified manhole base 30 receives three filter modules 32 where two filter cartridges 31a, 31b stacked on top of each other form a single filter module 32. It will be appreciated that the present disclosure encompasses embodiments with more or fewer than three filter modules 32 and/or different arrangements and types of filter modules 32 and filter cartridges 31a, 31b. The water surrounds and permeates the filter module 32, and once the water travels through the filter module 32 the water emerges through an aperture 34 in the modified manhole base 30. The filtered water accumulates in the riser space (84 in FIG. 1E) defined by the manhole riser 36. The filtered water then travels through slots or apertures 42 in a manhole riser pipe 40, which directs the filtered water out of the drywell system 2 and into the ground 8 to recharge strained ground water systems. Notably, there is no bypass around the slots or apertures 42 such that all water must be filtered before entering the riser pipe 40 and ground 8, and this can be critical to the operation of the drywell system 2.

Like the liners 18 of the primary settling chamber 4, the liner 28 of the drywell chamber 6 defines a liner space (60 in FIG. 1C). Similarly, and with reference to FIG. 1D, the modified manhole base 30 has at least one sidewall 62 extending from a bottom end 64 to an upper opening 66 at a top end 68, and the at least one sidewall 62 defines a modified manhole base space 70. However, the modified manhole base 30 has a lower deck 72, and the lower deck 72 has an aperture 34 under each filter module as described in further detail herein. With reference to FIG. 1E, the manhole riser 36 has at least one sidewall 74 that extends from a lower opening 76 at a bottom end 78 to an upper opening 80 at a top end 82, and the at least one sidewall 74 defines a riser space 84. Moreover, a second barrier 38 covers the lower opening 76 of the manhole riser 36 with the exception of the manhole riser pipe 40 such that filtered water flows through the manhole riser pipe 40. In some embodiments, the second barrier 38 is a geotextile liner that functions like the first barrier 20 to allow for draindown after a rain event and infiltration of screened water into the ground 8 near grade. Further still, the drywell chamber 6 rests on third bedding 44 of, for instance, rock to support the drywell chamber 6. A third barrier 46 and a fourth bedding 48 are provided. The third barrier 46 can allow infiltration of water near grade, and the fourth bedding 48 can be a slurry, in some embodiments, that channels water to the manhole riser 36.

FIG. 1B shows a top plan view of the modified manhole base 30, filter modules 32 positioned within the modified manhole base 30, and the liner 28. In this embodiment, three filter modules 32 are arranged about a longitudinal axis of the modified manhole base 30. Each filter module 32 can be a cartridge-based media filtration system with filter cartridges (31a, 31b in FIG. 1A) that utilize a particular media configuration to remove specific pollutants of concern through sedimentation, filtration and sorption, reducing downstream contaminants. In some embodiments, the water enters a filter module 32 in a lateral direction through an outer media layer and then passes into an inner media layer. Finally, the water collects in a central space of the filter module 32, passes through an aperture (34 in FIG. 1A) and into the manhole riser 36. In other embodiments, the filter module 32 can be or include membranes and screens. A peak capacity of this arrangement of multiple filters modules 32 can be approximately 61.2 gallons per minute of water.

FIG. 2A shows a partial cross-sectional elevation view of a modified manhole base 30, FIG. 2B shows a detailed view of a coupler and orifice system, FIG. 2C shows a partial cross-sectional plan view of the modified manhole base 30, FIG. 2D shows a top plan view of a restrictor plate of the coupler and orifice system, and FIG. 2E shows a cross-sectional side elevation view of the restrictor plate. In FIG. 2A, the modified manhole base 30 can be made from a precast concrete material with reinforcement such as rebar, and the modified manhole base 30 can be constructed in a first pour where the at least one sidewall 62 is formed and then a second pour where the lower deck 72 is formed. Also, depicted are apertures 86 into which lifting lugs can be inserted. Lifting systems can engage lifting lugs to move and place the modified manhole base 30 within the ground. Moreover, plugs 88 can be inserted into apertures (34 in FIG. 1A) to protect the apertures 34 and filter modules when the system is not in use. FIG. 2C shows various exemplary dimensions of the modified manhole base 30. Of note, the thickness of the sidewall (62 in FIG. 1D and 74 in FIG. 1E) is larger in the modified manhole base and in the manhole riser compared to, for instance, the sidewall of the liner (50 in FIG. 1C) so that the modified manhole base and manhole riser can support the weight of the drywell chamber and its components.

FIG. 2B is a detailed view of an orifice system 90 that limits the rate at which water flows through a filter module positioned over the orifice system 90 to ensure the water is sufficiently filtered before passing through the orifice system 90 and into the manhole riser, riser pipe, and ground. In this embodiment, orifice system 90 is positioned in the aperture 34 of the modified manhole base 30, and the orifice system 90 comprises an outer conduit 92, an inner conduit 94, a restrictor plate 96, and an orifice 98 in the restrictor plate 96. The outer conduit 92 extends downward from a top surface of the lower deck 72 of the modified manhole base 30, and an inner conduit 94 extends upward from a bottom surface of the lower deck 72 of the modified manhole base 30. The conduits 92, 94 at least partially overlap such that the inner conduit 94 is at least partially positioned with the outer conduit 92. Thus, the conduits 92, 94 completely extend from the top surface to the bottom surface of the lower deck 72, and the top end of the inner conduit 94 serves as a shoulder. The restrictor plate 96 is securely positioned on this shoulder, and the orifice 98 in the restrictor plate 96 is sized for the appropriate flowrate of water. Further views of the restrictor plate 96 and the orifice 98 are shown in FIGS. 2D and 2E. In some embodiments, the orifice 98 has a circular shape, and the diameter of the orifice 98 is approximately 0.5 inches to limit the flowrate of the fluid through each orifice 98 and through each filter module (30 in FIG. 1A) to 10.2 gallons per minute. In addition, the flowrate through each filter cartridge (31a, 31b in FIG. 1A) is limited to 10.2 gallons per minute.

The formula for fluid flowrate through an orifice can be expressed as:

Q = C d ⁢ A ⁢ 2 ⁢ P ρ

• • where Q is the flowrate, Ca is a discharge coefficient, A is an area of the orifice, P is a pressure head, and p is a fluid density. Based on the above orifice 98 size (0.5″ diameter), shape (circular), and expected flow rate (10.2 gallons per minute) as well as assuming a maximum pressure head of 9 feet and a water density of 62.4 lbs/ft³ or 1000 kg/m³, the Ca can be calculated as 0.544. Thus, it will be appreciated that in various embodiments, the discharge coefficient is between approximately 0.5 and 0.6. In some embodiments, the discharge coefficient is between approximately 0.53 and 0.57. In various embodiments, the discharge coefficient is approximately 0.544. It will be appreciated that the restrictor plate 96 and the related orifice 98 reduce the discharge coefficient compared to the aperture 34 in which the restrictor plate 96 is located to limit the flow rate through the orifice 98 and increase the dwell time of the fluid in the filter, which can be critical to the operation of the system.

Further still, the cross-sectional relationship between the filters 31a and the base 30 in which the filters 31a are positioned can be critical to sufficiently filter particulates and pollution out of water prior to the water moving into the ground through a riser pipe. If the filters are too small, the water may not be properly filtered, and if the filters are too large, the water can have difficulty flowing around and into the filters, thereby reducing the flowrate. Here, there are three filters with each having a circular cross sectional shape, and the base has a circular cross sectional shape. The diameter of each filter is 18″ and the inner diameter of the base is 48″. Thus, the area of each filter, in cross section, is 254.5 inches², and the relevant area of the base, in cross section, is 1809.5 inches². With three filters, the total filter cross sectional area is 763.5 inches². Accordingly, the total filter cross sectional area is approximately 42.2% of the cross sectional area of the base. In various embodiments, the total filter cross sectional area is between approximately 37% and 47% of the cross sectional area of the base.

It will be appreciated that the present disclosure encompasses other embodiments of the orifice system 90, the orifice 98, and/or the restrictor plate 96. In some embodiments, a single restrictor plate 96 has multiple orifices 98 so that the water flows in a more laminar and controlled manner. In various embodiments, the orifices 98 can be initially sealed or blocked. Then, a user can selectively remove one or more seals or blockages to establish a limiting flowrate through the restrictor plate 96 and the associated filter module. Further dimensions and configurations of the modified manhole base and orifice system can be found in the enclosed Appendix, which is incorporated herein in its entirety by reference.

FIGS. 3A and 3B show a further embodiment of a stormwater drywell system 2. In FIG. 3A, the stormwater drywell system 2 has a first riser pipe 100 extending into the primary settling chamber 4 and a second riser pipe 40 extending into the drywell chamber 6, as depicted in FIG. 1A. The first riser pipe 100 can have an upper end 102 with slots, apertures, a fabric filter, and/or another filter to filter at least some pollutants before allowing water to flow into the riser pipe 100 and into the ground 8. Then, the remaining water travels to the drywell chamber 6 where the water is more thoroughly filtered before entering the second riser pipe 40, which deposits the filtered water to a location in the ground 8 that is deeper than the first riser pipe 100. The inclusion of a first riser pipe 100 in the primary settling chamber 4 can deposit some water into the ground 8. In addition, the fourth bedding 48 for the drywell chamber 6 extends directly below the manhole riser 36. FIG. 3B shows a top plan view of the modified manhole base 30 in FIG. 3A.

FIGS. 4A and 4B show another embodiment of the stormwater drywell system 2. In FIG. 4A, the riser pipe 40 does not have an upper end with multiple slots or apertures 42. Instead, the riser pipe 40 in FIG. 4A simply has a single opening 42 at the upper end. FIG. 4B shows a top plan view of the modified manhole base 30 in FIG. 4A.

FIG. 5A shows a partial cross-sectional elevation view of an insert system for a modified manhole base 30, FIG. 5B shows a side elevation view of an insert 104, FIG. 5C shows a top plan view of the modified manhole base 30 without an insert 104 installed, and FIG. 5D shows a top plan view of the modified manhole base 30 with an insert 104 installed. In this embodiment, the modified manhole base 30 has a single aperture 34 in the lower deck 72 such that the upper surface of the lower deck 72 forms a shoulder to receive an insert 104. FIG. 5B shows that the insert 104 has a coupler 106 for each filter module 32, and an orifice 98 through the insert 104 is located in the coupler 106 to serve the function and benefits described herein. A rod 110 extends upwardly from a modified manhole base 108 of the insert 104 such that an end 112 of the rod 110 is configured to be engaged by a lift device and lowered into the modified manhole base 30. FIG. 5C shows the single aperture 34 in the lower deck, and FIG. 5D shows the insert 104 positioned in the modified manhole base 30 to completely cover the single aperture 34. Also shown in FIG. 5D are the orifices 98 through which the filtered water flows and that restrict the flow of water through the filter modules 32. The insert 104 adds flexibility as the modified manhole base 30 can be constructed to a standard size and configuration, and then different inserts 104 can be selectively added to the modified manhole base 30 to meet the specific standards of a specific application.

While various embodiments of the present disclosure have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be understood that such modifications and alterations are within the scope and spirit of the present disclosure, as set forth in the following claims. Further, the invention(s) described herein is capable of other embodiments and of being practiced or of being carried out in various ways. It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.