Groundwater monitoring system and method

• US 10,208,585 B2
• Filed: 08/08/2016
• Issued: 02/19/2019
• Est. Priority Date: 08/11/2015
• Status: Active Grant

• Current Assignee: Intrasen, LLC
• Original Assignee: Intrasen, LLC
• Inventors: Surowinski, Steve, Guo, Liang
• Primary Examiner(s): Schmitt, Benjamin R
• Application Number:
  US15/230,750
• Publication Number:
  US 20170044894A1
• Time in Patent Office: 925 Days
• Field of Search: 7315218, 7315254
• CPC Class Codes: E21B 47/00 Survey of boreholes or wells monitoring pressure or flow of drilling fluid E21B21/08
• CPC Class Codes: E21B 47/047 Liquid level measuring depth or liquid level using radioactive markers E21B47/053
• CPC Class Codes: G01C 5/06 by using barometric means
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration

Abstract

The present invention provides a groundwater monitoring system and method. The system in one aspect uses sound-based distance measurement techniques to measure groundwater level with one transducer generating an acoustic burst and another receiving it. At least one sonic transducer is installed in each of a processor-based controller and traveling probe. The system may use an accelerometer and the pressure sensor installed in the probe to measure groundwater thickness. While the probe moves upward or downward in the groundwater, water properties measured by sensors installed on the probe and corresponding depths of the measuring spots to the groundwater surface level measured by the pressure sensor are recorded. The system measures and saves data, including groundwater level, groundwater thickness, and a depth-related profile of water properties. In certain embodiments, the probe includes a microprocessor operable to control the transducer and sensors mounted thereto and effect two-way communication with the controller.

Claims

1. A groundwater monitoring system comprising:

a borehole extending downwards through terra firma and defining a borehole head at grade;

a controller disposed proximally to the borehole head and comprising programmable electronic circuitry having a processor;

a rotatable cable drum positioned at the borehole head;

a movable probe disposed in the borehole and operably coupled to the drum via a cable, the drum rotatable in a first direction to raise the probe and in a second direction to lower the probe in the borehole;

a drive mechanism operable to rotate the drum in the first or second directions;

a first sonic transducer mounted at the borehole head;

a second sonic transducer mounted to the probe, the first and second sonic transducers in communication with the controller which is operable to measure a distance between the first and second transducers;

one of the first or second transducers being a transmitter operable to emit an acoustic wave which is received by the other of the first or second transducers being a receiver; and

a conductivity sensor mounted to the probe and operable to detect groundwater in the borehole;

wherein when the conductivity sensor detects the groundwater, the transmitter emits the acoustic wave which is received by the receiver and the controller converts a time delay between transmission and reception of the acoustic wave to a distance indicative of a surface level of the groundwater below grade.

2. The groundwater monitoring system according to claim 1, wherein when the conductivity sensor initially detects the groundwater, the probe sends a control signal to the controller to record the distance between the first and second sonic transducers which represents the surface level of the groundwater.

3. The groundwater monitoring system according to claim 1, wherein the drive mechanism is an electric motor mechanically coupled to the drum which is operable to rotate the drum in the first or second directions.

4. The groundwater monitoring system according to claim 3, further comprising an auto-reverse feature wherein:

when the drum is rotated in the second direction to lower the probe and the conductivity sensor is initially immersed in and detects the groundwater a first time, the probe sends a control signal to the controller which automatically rotates the drum in the opposite first direction to withdraw the conductivity sensor from the groundwater, and the controller then automatically rotates the drum in the second direction again to re-immerse the conductivity sensor and detect the groundwater a second time; and

the controller records the distance between the first and second sonic transducers the second time which represents a surface level of the groundwater.

5. The groundwater system according to claim 3, wherein the motor automatically lowers the probe at a first speed until the probe detects the surface level of the groundwater, and then automatically lowers the probe at a slower second speed through the groundwater below the surface level for profiling properties of the groundwater.

6. The groundwater monitoring system according to claim 1, wherein the probe further includes a temperature sensor operable to measure temperature of the ambient environment surrounding the probe and transmit the first temperature to the controller.

7. The groundwater monitoring according to claim 6, wherein when the probe travels down the borehole in an air column above the groundwater surface level, the temperature sensor measures air temperature, the controller receiving the air temperature from the probe and operates to apply a temperature correction factor to the distance measured between the first and second sonic transducers for improving measurement accuracy.

8. The groundwater monitoring system according to claim 7, wherein the temperature sensor in the probe continuously measures air temperature from the borehole head to the groundwater surface level and the controller builds an air temperature profile for the air column.

9. The groundwater monitoring system according to claim 7, wherein the controller or the probe further includes a pressure sensor operable to measure barometric pressure of the ambient environment, and the controller is operable to apply a pressure correction factor based on the measured barometric pressure to the distance measured between the first and second sonic transducers for improving accuracy.

10. The groundwater monitoring system according to claim 1, wherein the probe further includes a pressure sensor operable to measure a pressure of the ambient environment surrounding the probe and transmit the pressure to the controller.

11. The groundwater monitoring system according to claim 10, wherein as the probe travels downwards through the groundwater, a first depth of the probe within the groundwater is determined by the controller comparing a pressure measured at the first depth and atmospheric pressure in the borehole.

12. The groundwater monitoring system according to claim 11, wherein as the probe stays at the first depth under groundwater surface level, the controller raises the probe upwards out of the groundwater which is detected by the conductivity sensor, and the pressure sensor on probe is calibrated with reference to ambient barometric pressure in the borehole.

13. The groundwater monitoring system according to claim 1, wherein the first and second sonic transducers communicate with the controller via wired or wireless means.

14. The groundwater monitoring system according to claim 1, wherein the drive mechanism is a manual crank mechanically coupled to the drum for rotating the drum.

15. The groundwater monitoring system according to claim 1, further comprising an accelerometer disposed in the probe, wherein when the probe travels through the groundwater and contacts a hard surface at a bottom of the groundwater, the accelerometer becomes tilted which triggers the system to measure a thickness of the groundwater.

16. The groundwater monitoring system according to claim 1, wherein the probe includes a microprocessor configured to establish two-way communication with the controller at the borehole head.

17. The groundwater monitoring system according to claim 1, wherein the controller continuously measures a distance of the probe between the borehole head and groundwater surface level as the probe travels downwards in the borehole.

18. A groundwater monitoring system comprising:

an underground aquifer;

a borehole extending underground between the aquifer and a borehole head at top located at a ground surface;

a rotatable cable drum positioned at the borehole head and comprising a spool of cable;

a drive mechanism coupled to the cable drum and operable to rotate the drum in opposing directions;

a movable probe disposed in the borehole and operably coupled to the cable, the drum rotatable via the drive mechanism in a first direction to raise the probe and in a second direction to lower the probe in the borehole;

a controller comprising programmable electronic circuitry including a processor and memory, the controller operably connected to and controlling operation of the drive mechanism;

a stationary sonic transducer mounted at the borehole head;

a movable sonic transducer mounted to the probe and spatially separable from the first sonic transducer, the stationary and moving transducers in communication with the controller;

one of the stationary or movable sonic transducers being a transmitter emitting an acoustic wave which is received by the other transducer being a receiver; and

a conductivity sensor mounted to the probe and operable to detect a groundwater in the borehole; and

an accelerometer disposed in the probe, wherein when the probe contacts a hard surface at a bottom of the groundwater, the accelerometer becomes tilted which triggers the system to measure a thickness of the groundwater.

19. The groundwater monitoring system according to claim 18 wherein when the conductivity sensor initially detects the groundwater, the probe sends a control signal to the controller to record the distance between the first and second sonic transducers which represents the surface level of the groundwater.

20. The groundwater monitoring system according to claim 19, wherein the drive mechanism is an electric motor mechanically coupled to the drum which is operable to rotate the drum in the first or second directions.

21. A method for monitoring groundwater, the method comprising:

providing a probe having at least one sensor and an electronic controller with a processor and electric drive mechanism controlled by the processor, the drive mechanism operably coupled to the probe for lowering or raising the probe in a borehole having a top accessible at ground grade;

the controller automatically lowering the probe down the borehole at a first speed with the drive mechanism;

contacting and sensing groundwater in the borehole with the probe a first time;

a sonic transmitter at the probe generating and directing an acoustic wave upwards in the borehole upon sensing the groundwater;

receiving the acoustic wave with a sonic receiver at the top of the borehole;

the controller automatically calculating a first time delay between transmission and reception;

the controller automatically converting the first time delay into a first distance measured between the transmitter and receiver which is indicative of the groundwater level below grade;

the controller automatically raising the probe out of the groundwater with the drive mechanism for a distance after sensing the groundwater the first time; and

the controller automatically lowering the probe again with the drive mechanism to contact and sense the groundwater a second time, the probe being lowered at a second speed the second time which is slower than the first speed;

the controller automatically calculating a second time delay between transmission and reception; and

the controller automatically converting the second time delay into a second distance measured between the transmitter and receiver which is indicative of the groundwater level below grade.

22. The method according to claim 21, wherein the groundwater is sensed by a conductivity sensor mounted to the probe.

23. The method according to claim 21, further comprising a step of the controller automatically lowering the probe through the groundwater at a second speed slower than the first speed, and measuring properties of the groundwater with a sensor array mounted to the probe.

24. A method for monitoring groundwater, the method comprising:

providing a probe having at least one sensor and an electronic controller with a processor and electric drive mechanism controlled by the processor, the drive mechanism operably coupled to the probe for lowering or raising the probe in a borehole having a top accessible at ground grade;

the controller automatically lowering the probe down the borehole at a first speed with the drive mechanism;

contacting and sensing groundwater in the borehole with the probe a first time;

a sonic transmitter at the probe generating and directing an acoustic wave upwards in the borehole upon sensing the groundwater;

receiving the acoustic wave with a sonic receiver at the top of the borehole;

the controller automatically calculating a first time delay between transmission and reception;

the controller automatically converting the first time delay into a first distance measured between the transmitter and receiver which is indicative of the groundwater level below grade;

the controller automatically lowering the probe through the groundwater;

engaging a bottom of the groundwater with the probe a first time, the probe changing from a vertical position to a tilted position;

detecting the tilted position of the probe with an accelerometer mounted to the probe;

the controller automatically determining a thickness of the groundwater between the surface level of the groundwater and the bottom of the groundwater.

25. The method according to claim 24, further comprising:

the controller automatically raising the probe with the drive mechanism for a distance after engaging the bottom of the groundwater the first time;

the controller automatically lowering the probe again with the drive mechanism to engage the bottom of the groundwater a second time, the probe being lowered at a third speed the second time which is slower than the first speed; and

the controller automatically determining a thickness of the groundwater between the surface level of the groundwater and the bottom of the groundwater a second time.