LevelVent loggers 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, LevelVent loggers provide readings of the actual pressure of just water above the pressure sensor zero point (A).
A = (W + +B) + (-B)
A = LevelVent readings
W = Water column height
+B = Barometric pressure detected by the pressor sensor
-B = Barometric pressure applied through the vented cable
Compare LevelVent readings (A) with a measured depth to water level value (d) (Using a Water Level Meter). The deployment depth of the LevelVent (D), minus the manual depth to water measurement (d), should equal the LevelVent reading:
D - d = A
To adjust all readings in your LevelVent 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 date and time with an actual LevelVent recording. Use this as a reference datum in the Manual Data Adjustment option in the Levelogger Software Data Wizard.