What is the difference between the readings collected with the dipper-T or water tape2 and the data downloaded from the dipperLog? Aren’t they both water level measurements? Why would you need both types of data?
This is a common question we receive. In reality, these instruments provide very different information.
A water lever meter such as a dipper-T(2), dipper-Tough or water tape2 will give you an immediate linear measurement of the distance below the measuring point to reach the top of the water table or whatever liquid may be in the reservoir you are monitoring.
A dipperLog is a pressure transducer with a built in data logger. It will measure and record the pressure being exerted upon it from above at pre-set intervals which have been established by the user.
For example: if deployed in a monitoring well with the interval defined as 10 minutes, the dipperLog will record a pressure measurement every 10 minutes until it is stopped by the user or the memory is full, after 32,000 readings are recorded.
When the recorded data is downloaded, the software will generate a spread sheet of the pressures recorded along with a graphical representation of any changes. This pressure will represent the depth of the water above the dipperLog.
The above graph illustrates the depth of the water above the dipperLog. To determine the level of the water below the reference point, you must subtract this depth from the depth at which the dipperLog is deployed. This calculated measurement may now be compared with the reading obtained by the water level meter to establish accuracy.