Which of the following is NOT a method of measuring water level in groundwater?

To understand why the chosen answer is correct, it's important to know the various methods for measuring groundwater levels. Electric Sounders, Air Lines, and Wetted Tapes are all recognized methods that utilize different principles for gauging the water level in wells or boreholes.

Electric Sounders use an electric sensor to detect the presence of water, providing accurate measurements. Air Lines involve using a tube filled with air where the pressure difference signals the water level inside the well. Wetted Tape is a simple method that uses a tape with a moisture-sensitive indicator, allowing direct measurement of the water depth.

In contrast, Pneumatic Testing primarily refers to measuring the integrity of geological formations or testing the properties of aquifers by observing how air pressure changes within a groundwater system. While it is essential for assessing the hydraulic properties of groundwater systems, it does not function as a direct method for measuring water levels. This distinction makes it the correct answer to the question regarding methods of measuring water level in groundwater.

Understanding these methods provides clarity in groundwater management and helps in selecting the appropriate techniques based on specific needs or conditions in the field.