Methods and module for an underground assembly for storm water retention or detention

1. A method for retaining or detaining storm water beneath a ground surface comprising the steps of:

connecting a plurality of longitudinal channels each defined by at least one substantially horizontal deck and at least one substantially vertical side wall, each side wall having a bottom edge, said longitudinal channel extending upwardly from said bottom edge;

connecting a plurality of lateral channels each defined by a portion of a corresponding deck and a portion of a corresponding side wall so that said longitudinal channels are in fluid communication with said lateral channels, said lateral channel extending upwardly from a corresponding bottom edge, said channels being in longitudinal and lateral alignment to form at least one continuous longitudinal channel and at least one continuous lateral channel for relatively unconstrained flow of the stormwater in the longitudinal and lateral directions;

providing an outer boundary for said channels, said outer boundary being formed by a plurality of peripheral walls;

placing said peripheral walls around said channels to form an assembly which receives the storm water through at least one assembly access port;

providing an impermeable floor for said channels; and

placing said floor to form a bottom surface of said channels.

2. The method of claim 1 wherein said longitudinal channels and said lateral channels are defined by a plurality of elongated U-shaped modules which are longitudinally and laterally aligned to form a modular assembly, each module formed from a corresponding deck and two corresponding side walls extending from opposite longitudinal sides of the deck, wherein the steps of connecting said channels include installing a plurality of U-shaped modules within the ground in an inverted configuration at a predetermined depth to form said modular assembly.

3. The method of claim 2 further comprising the step of increasing a depth of said assembly by placing a first level of said U-shaped modules within the ground in an upright configuration to form at least a lower level of said modules, prior to installing said U-shaped modules in an inverted configuration, said inverted U-shaped modules being supported by the first level in vertical alignment.

4. The method of claim 2 further comprising the step of placing a top deck on top of the modules.

5. The method of claim 1 further comprising the steps of providing a support member and placing said support member beneath the ground surface prior to the steps of connecting said longitudinal and lateral channels.

6. The method of claim 1 wherein the step of placing the floor comprises placing a portion of the floor prior to the steps of connecting said longitudinal and lateral channels.

7. The method of claim 1 wherein said peripheral walls include some wall portions which define no openings and other wall portions which define no openings other than at least one assembly access port located therein.

8. An assembly for retaining or detaining storm water beneath a ground surface comprising:

at least one first module having a horizontally disposed deck portion and at least one substantially vertically disposed side portion extending therefrom, said deck portion and said side portion have respective end edges, and said side portion having bottom edges;

said side portion and said deck portion defining a longitudinal channel in said first module;

said side portion having at least one opening therein and defining a lateral channel in said first module;

said longitudinal channel and said lateral channel being in fluid communication with one another;

each said channel extending upwardly from said bottom edges to allow relatively unconstrained flow of the stormwater in the longitudinal and lateral directions; and

the assembly further including at least one side module, said side module having a corresponding horizontally disposed deck portion and at least one corresponding substantially vertically disposed side portion extending from a longitudinal side of said side module deck portion so as to define a corresponding longitudinal channel, said deck portion and said side portion of said at least one side module having corresponding end edges, and said side portion of said at least one side module having corresponding bottom edges, wherein said at least one side portion of said at least one side module defines no openings;

wherein said assembly is supported on an impermeable floor.

9. The assembly of claim 8 wherein one side module is positioned adjacent selected one of a longitudinal side or one end edge of said at least one first module.

10. The assembly of claim 8 wherein two side portions extend from opposite longitudinal sides of said deck portion of a selected one of said at least one first module or at least one side module.

11. The assembly of claim 8 wherein a substantially vertical end portion extends integrally from one of said end edges of said deck portion of said first module, and is further integrally formed with at least one of said end edges of said side portion of said first module so that one end of said first module is closed.

12. The assembly of claim 8 wherein a substantially vertical end portion extends integrally from one of said end edges of said corresponding deck portion of one side module, and is further integrally formed with at least one of said end edges of said corresponding side portion of said side module so that one end of said side module is closed.

13. The assembly of claim 8 wherein said side module includes two corresponding substantially vertically disposed side portions extending from opposite longitudinal sides of said deck portion of said side module.

14. The assembly of claim 8 wherein the assembly includes a plurality of side modules, each side module having two corresponding substantially vertically disposed side portions extending from opposite sides of said side module deck portion, some of said side modules having one of said side portions which define no openings, all of said side modules having another of said side portions having at least one opening therein.

15. The assembly of claim 8 wherein each said channel has about the same cross section.

16. An assembly for retaining or detaining storm water beneath a ground surface comprising:

a plurality of first modules;

each first module having a horizontally disposed deck portion and at least one substantially vertically disposed side portion extending therefrom, said deck portion and said side portion have respective end edges, and said side portion having bottom edges;

said side portion and said deck portion defining a longitudinal channel in said first module which is open at least at an end of said module;

said side portion having at least one opening therein and defining a lateral channel in said first module;

said longitudinal channel and said lateral channel being in fluid communication with one another;

each said channel extending upwardly from said bottom edges to allow relatively unconstrained flow of the stormwater in the longitudinal and lateral directions;

said plurality of first modules being aligned in a lateral direction and a longitudinal direction of said assembly, said lateral channels and said longitudinal channels of adjacent first modules being in fluid communication therebetween, said plurality of first modules forming at least one continuous lateral channel and at least one continuous longitudinal channel; and

wherein said assembly is supported on an impermeable floor.

17. An assembly of claim 16 wherein each said channel has about the same cross section.

18. An assembly of claim 16 wherein the floor includes at least one assembly access port defined therein.