Groundwater monitoring system and method

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.

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.

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.