Monitoring probe for groundwater flow

• US 5,339,694 A
• Filed: 05/25/1993
• Issued: 08/23/1994
• Est. Priority Date: 05/25/1993
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Department Of Energy
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Ballard, Sanford, Looney, Brian B.
• Primary Examiner(s): Chilcot, Jr., Richard E.
• Assistant Examiner(s): PATEL, HARSHAD R
• Application Number:
  US08/066,236
• Time in Patent Office: 455 Days
• Field of Search: 166/250, 166/66, 73/170.11, 73/861.07, 73/861.08, 73/195
• US Class Current: 73/861.07
• CPC Class Codes: G01F 1/7048 the concentration of electrical loaded particles giving an indication of the flow

Abstract

A monitoring probe for detecting groundwater migration. The monitor features a cylinder made of a permeable membrane carrying an array of electrical conductivity sensors on its outer surface. The cylinder is filled with a fluid that has a conductivity different than the groundwater. The probe is placed in the ground at an area of interest to be monitored. The fluid, typically saltwater, diffuses through the permeable membrane into the groundwater. The flow of groundwater passing around the permeable membrane walls of the cylinder carries the conductive fluid in the same general direction and distorts the conductivity field measured by the sensors. The degree of distortion from top to bottom and around the probe is precisely related to the vertical and horizontal flow rates, respectively. The electrical conductivities measured by the sensors about the outer surface of the probe are analyzed to determine the rate and direction of the groundwater flow.

Claims

1. Apparatus for monitoring the flow rate of groundwater, said apparatus for use with a fluid having an electrical conductivity different from that of said groundwater, said apparatus comprising:

means for releasing said fluid into said groundwater, said releasing means permeable to said fluid and having a first side and a second side, said fluid on said first side and said groundwater on said second side, said fluid permeating through said releasing means from said first side to said second side to form a mixture with said groundwater, said mixture having a mixture electrical conductivity, said mixture electrical conductivity being related to the relative concentration of said groundwater in said mixture, said concentration of said groundwater in said mixture being related to said rate of flow of groundwater proximate to said releasing means and related to the rate of said fluid permeating through said releasing means from said first side to said second side; and

means for measuring said mixture electrical conductivity, said measuring means carried by said releasing means.

2. The apparatus as recited in claim 1, wherein said measuring means further comprises a plurality of sensors spaced apart from each other, each of said sensors measuring electrical conductivity of said mixture at a different location near said second side of said releasing means and producing an output signal related thereto.

3. The apparatus as recited in claim 1, wherein said measuring means further comprises an array of sensors spaced apart from each other, each sensor of said array of sensors measuring electrical conductivity of said mixture at a different location near said second side of said releasing means and producing an output signal related thereto.

4. The apparatus as recited in claim 1, wherein said releasing means further comprises a membrane adapted to hold a quantity of said fluid, said membrane having an interior defined by said first side and an outside defined by said second side.

5. The apparatus as recited in claim 1, wherein said measuring means further comprises an array of sensors spaced apart from each other, each sensor of said array of sensors measuring electrical conductivity of said mixture at a different location near said second side of said releasing means and producing an output signal related thereto, said electrical conductivity of said mixture related to said groundwater flow at said different location of each of said array of sensors, and said apparatus further comprising means for analyzing said output signals from said array of sensors, said analyzing means in electrical communication with each sensor of said array of sensors and determining said flow of groundwater based on said location of each of said sensors of said array of said sensors and said electrical conductivity at said location.

6. The apparatus as recited in claim 1, further comprising means for supplying said fluid to said first side of said releasing means, said supplying means in fluid communication with said first side of said releasing means.

7. Apparatus for use in the ground for monitoring the flow rate and direction of groundwater, said apparatus for use with an electrical fluid having a electrical conductivity different from that of said groundwater, said apparatus comprising:

a cylindrical membrane adapted to hold a quantity of said fluid, said membrane permeable to said fluid and having a first side and a second side, said fluid on said first side and said groundwater on said second side, said fluid permeating through said membrane from said first side to said second side to form a mixture with said groundwater, said mixture having a mixture electrical conductivity, said mixture electrical conductivity being related to the relative concentration of said groundwater in said mixture, said concentration of said groundwater in said mixture being related to said rate of flow of groundwater proximate to said membrane; and

an array of sensors carried by said membrane and spaced apart from each other, each sensor of said array of measuring electrical conductivity of said mixture at a different location near said second side of said membrane and producing an output signal related thereto, said electrical conductivity of said mixture related to said groundwater flow at said different location of each of said array of sensors.

8. The apparatus as recited in claim 7, further comprising means for analyzing said output signals from said array of sensors, said analyzing means in electrical communication with each sensor of said array of sensors and determining said flow of groundwater based on said location of each of said sensors of said array of said sensors and said electrical conductivity at said location.

9. The apparatus as recited in claim 7, further comprising means for supplying said fluid to said first side of said membrane, said supplying means in fluid communication with said first side of said cylindrical membrane.

10. A method for monitoring the flow rate and direction of groundwater, said method for use with a fluid having an electrical conductivity different than that of said groundwater, said method comprising the steps of:

placing said fluid on a first side of a membrane permeable to said fluid so that said fluid permeates from said first side through said membrane to an opposing second side;

placing said membrane into the ground where groundwater is present on said second side of said membrane whereby said fluid permeates through said membrane from said first side to said second side and into said groundwater at a known rate and location, said fluid forming a mixture with said groundwater, said mixture having a mixture electrical conductivity, related to the relative concentration of said groundwater in said mixture, said concentration of said groundwater in said mixture being related to said rate of flow of groundwater proximate to said location and available for mixing said fluid.

11. The method as recited in claim 10, further comprising the step of:

placing said fluid on a first side of a membrane permeable to said fluid so that said fluid permeates from said first side through said membrane to an opposing second side;

placing said membrane into the ground where groundwater is present on said second side of said membrane whereby said fluid permeates through said membrane from said first side to said second side and into said groundwater forming said mixture; and

supplying said first side of said membrane with said fluid.

12. The method as recited in claim 10, further comprising the steps of:

mapping said output signals from each sensor of said array of sensors with an analyzer, said analyzer in electrical communication with each sensor of said array of sensors, and

determining the flow of said groundwater with said analyzer from said mapping step, said flow of groundwater based on said location of each of said sensors of said array of said sensors and said electrical conductivity at said location.