AquaVent vented water level dataloggers detect both water (W) and barometric pressure (+B). However, a vent tube to surface allows barometric effects on the pressure sensor to be eliminated (-B). Therefore, AquaVent loggers provide readings of the actual pressure of just water above the pressure sensor zero point (A).
A = (W + +B) + (-B)
A = AquaVent readings
W = Water column height
+B = Barometric pressure detected by the pressor sensor
-B = Barometric pressure applied through the vented cable
It is recommended to take a manual water level measurement before installing an AquaVent logger, shortly after installation, periodically during your monitoring interval, and at the end of your measurement period. Use these measurements to verify AquaVent readings, and for data adjustments later on. Ensure you take manual readings as close in time as possible to a scheduled AquaVent reading.
Compare AquaVent readings (A) with a measured depth to water level value (d) (Using a Water Level Meter). The deployment depth of the AquaVent (D), minus the manual depth to water measurement (d), should equal the AquaVent reading:
D - d = A
To adjust all readings in your AquaVent data file to depth to water below a well casing (d), record a manual water level measurement using a water level meter. This reading should correspond in data and time with an actual AquaVent recording. Use this as a reference datum in the Manual Data Adjustment option in the Software Data Wizard.