Underground alluvial water storage reservoir and method

• US 20020172559A1
• Filed: 05/15/2002
• Published: 11/21/2002
• Est. Priority Date: 05/15/2001
• Status: Active Grant

• Current Assignee: RAR Group LLC
• Original Assignee: RAR Group LLC
• Inventors: Summers, Donald O., Peters, Stanley R., Beeson, Randall R.
• Granted Patent: US 6,840,710 B2
• Time in Patent Office: Days
• US Class Current: 405/52
• CPC Class Codes: E03B 11/14 of underground tanks
• CPC Class Codes: E03B 3/36 of surface water
• CPC Class Codes: Y02A 20/00 Water conservation; Efficient water supply; Efficient water use

Abstract

Abstract of the Invention An underground reservoir for storing water in alluvial deposits utilizes slurry walls keyed to an aquiclude beneath the reservoir to form a substantially impermeable water seal. A plurality of water extraction/recharge means provides for rapid and complete filling and draining of the underground reservoir. Such means include a plurality of wells distributed about the underground reservoir and a series of perforated pipes buried at a predetermined depth within the underground reservoir. A method of mitigating water table fluctuations resulting from the construction of an underground utilizes perforated pipes buried outside of the reservoir to transfer excess water from an uphill land parcel to a downhill land parcel that would otherwise experience a water shortage after construction of the underground reservoir.

Claims

1. An underground reservoir for storing water in alluvial deposits comprising:

a slurry wall defining a closed boundary for the underground reservoir, the slurry wall extending from a surface level to an aquiclude beneath the reservoir so that a bottom surface of the slurry wall is keyed into the aquiclude to form a substantially impermeable water seal between the slurry wall and the aquiclude; and

a plurality of water extraction/recharge means distributed about the underground reservoir to provide for substantially even filling and draining operations of the underground reservoir.

2. An underground reservoir as defined in claim 1 wherein the plurality of water extraction/recharge means comprises:

a plurality of wells distributed about the underground reservoir;

a plurality of pipes connecting each of the plurality of wells to a common point; and

a pump to direct water under pressure through the plurality of wells and into the alluvial deposits of the underground reservoir during a recharging operation and to extract water from the alluvial deposits during an extraction operation.

3. An underground reservoir as defined in claim 2 wherein the plurality of water extraction/recharge means further comprises a series of recharge ditches and open ponds to distribute recharge water directly to a top surface of the underground reservoir.

4. An underground reservoir as defined in claim 1 wherein the plurality of water extraction/recharge means comprises:

a series of perforated pipes buried at a predetermined depth within the underground reservoir; and

a central pressurized well in fluid communication with the series of perforated pipes to direct water under pressure through the perforated pipes and into the alluvial deposits during a recharging operation and to extract water from the alluvial deposits through the perforated pipes during an extraction operation.

5. An underground reservoir as defined in claim 4 wherein the series of perforated pipes includes an outer perimeter of perforated pipes connected to the central pressurized well by a series of feeder perforated pipes in a rim-and-spoke configuration.

6. An underground reservoir as defined in claim 4 wherein the series of perforated pipes is installed at a predetermined depth within the underground reservoir utilizing a trench excavation method, and wherein each perforated pipe is supported on a pipe bedding formed from materials that are more coarse than the surrounding alluvial deposits.

7. An underground reservoir as defined in claim 6 wherein the trenches formed to bury the series of perforated pipes are filled with materials that are more coarse than the excavated alluvial deposits to enhance water flow to and from the perforated pipes.

8. An underground reservoir as defined in claim 4 wherein the plurality of water extraction/recharge means further comprises:

a plurality of wells distributed about the underground reservoir;

a plurality of pipes connecting each of the plurality of wells; and

a pump to direct water under pressure through the plurality of wells and into the alluvial deposits of the underground reservoir during a recharging operation and to extract water from the alluvial deposits during an extraction operation.

9. An underground reservoir as defined in claim 1 further comprising a mitigation system to reduce water table fluctuations in land parcels positioned upstream and downstream of the underground reservoir, the mitigation system comprising:

an uphill perforated pipe installed outside of the slurry wall within an upstream land parcel at a depth between a historic high and a historic low groundwater level of the upstream land parcel;

a downhill perforated pipe installed outside of the slurry wall within a downstream land parcel at a depth between a historic high and a historic low groundwater level of the downstream land parcel; and

a non-perforated conduit extending outside the slurry wall and connecting the uphill perforated pipe to the downhill perforated pipe to remove excess groundwater from the upstream land parcel and transport the excess groundwater to the downstream land parcel.

10. An underground reservoir as defined in claim 9 wherein:

the uphill perforated pipe is installed at a depth substantially equal to the historic high groundwater level of the upstream land parcel; and

the downhill perforated pipe is installed at a depth substantially equal to a historic average groundwater level of the downstream land parcel.

11. An underground reservoir as defined in claim 10 further comprising:

a second uphill perforated pipe installed at a depth substantially equal to the historic low groundwater level of the upstream land parcel, the second uphill perforated pipe in fluid communication with the downhill perforated pipe; and

a valve controlling water flow from the second uphill perforated pipe to the downhill perforated pipe, whereby selective activation of the valve alters a groundwater level of the upstream land parcel between the historic high and the historic low groundwater levels.

12. An underground reservoir as defined in claim 1 further comprising an open reservoir formed within the closed boundary of the slurry wall.

13. An underground reservoir as defined in claim 1 wherein:

the slurry wall defines an open boundary along one side of the underground reservoir; and

the open boundary of the underground reservoir abuts an open reservoir to permit an exchange of water between the open reservoir and the underground reservoir.

15. The method according to claim 14 wherein the step of alternately extracting and recharging the alluvial deposits with water includes the steps of:

constructing a plurality of wells distributed about an interior area of the slurry wall;

pumping water under pressure through the plurality of wells and into the alluvial deposits; and

extracting water from the alluvial deposits through the plurality of wells.

16. The method according to claim 14 wherein the step of alternately extracting and recharging the alluvial deposits with water includes the steps of:

burying a series of perforated pipes at a predetermined depth within the alluvial deposits;

constructing a central well in fluid communication with the series of perforated pipes;

pumping water under pressure through the central well and the series of perforated pipes and into the alluvial deposits; and

extracting water from the alluvial deposits through the series of perforated pipes and the central well.

17. The method according to claim 16 wherein the step of burying a series of perforated pipes at a predetermined depth within the alluvial deposits includes the steps of:

excavating an open trench;

supporting the perforated pipes within the open trench on a pipe bedding formed from materials that are more coarse than the surrounding alluvial deposits; and

filling the open trench with materials that are more coarse than the excavated alluvial deposits to enhance water flow to and from the perforated pipes.

18. The method according to claim 14 further comprising the steps of:

burying an uphill perforated pipe outside of the closed boundary of the underground slurry wall within an upstream land parcel at a depth between a historic high and a historic low groundwater level of the upstream land parcel;

burying a downhill perforated pipe outside of the closed boundary of the underground slurry wall within a downstream land parcel at a depth between a historic high and a historic low groundwater level of the downstream land parcel; and

connecting a non-perforated conduit between the uphill perforated pipe and the downhill perforated pipe to remove excess groundwater from the upstream land parcel and transport the excess groundwater to the downstream land parcel to mitigate water table fluctuations resulting from the construction of the underground slurry wall.

20. The method according to claim 19 wherein:

the uphill perforated pipe is buried at a depth substantially equal to the historic high groundwater level of the upstream land parcel; and

the downhill perforated pipe is buried at a depth substantially equal to a historic average groundwater level of the downstream land parcel.

21. The method according to claim 20 further comprising the steps of:

burying a second uphill perforated pipe outside of the boundary of the underground reservoir at a depth substantially equal to the historic low groundwater level of the upstream land parcel;

fluidly connecting the second uphill perforated pipe with the downhill perforated pipe; and

positioning a valve between the second uphill perforated pipe and the downhill perforated pipe and selectively activating the valve to alter a groundwater level of the upstream land parcel between the historic high and the historic low groundwater levels.

14. A method for storing water in underground alluvial deposits comprising the steps of:

constructing an underground slurry wall defining a closed boundary around the underground alluvial deposits, the slurry wall extending from a surface level to an aquiclude beneath the alluvial deposits so that a bottom surface of the slurry wall is keyed into the aquiclude to form a substantially impermeable water seal between the slurry wall and the aquiclude; and

alternately extracting and recharging the underground alluvial deposits with water.

19. A method of mitigating water table fluctuations resulting from the construction of an underground alluvial reservoir comprising the steps of:

burying an uphill perforated pipe outside of a boundary of the underground reservoir within an upstream land parcel at a depth between a historic high and a historic low groundwater level of the upstream land parcel;

burying a downhill perforated pipe outside of the boundary of the underground reservoir within a downstream land parcel at a depth between a historic high and a historic low groundwater level of the downstream land parcel; and

connecting a non-perforated conduit between the uphill perforated pipe and the downhill perforated pipe to remove excess groundwater from the upstream land parcel and transport the excess groundwater to the downstream land parcel.