Which of the following methods is used to monitor groundwater losses?

Satellite missions like GRACE (Gravity Recovery and Climate Experiment) are crucial for monitoring groundwater losses because they measure variations in the Earth's gravitational field, which can indicate changes in the amount of water stored underground. When there is a significant loss of groundwater, the gravitational pull decreases, allowing scientists to infer the volume of water lost from aquifers. This remote sensing technique provides a comprehensive view over large areas, making it ideal for tracking groundwater resources on a regional and global scale.

In contrast, drilling more wells primarily serves to gain access to groundwater rather than monitoring its levels or losses. Building dams focuses on surface water management and does not directly relate to groundwater monitoring. Conducting surveys can provide localized information, but they may not capture the broader trends in groundwater loss as effectively as satellite measurements can. Hence, the use of satellite technology such as GRACE is a powerful method for understanding and managing groundwater resources.