This technique involves the controlled introduction of a tracer, often a chemical or traceable dye, at a specific point in the aquifer system. The tracer is then monitored by collecting water samples from various monitoring points, such as wells or springs, at defined intervals.

Analyzing the collected samples allows hydrogeologists to trace the path of the tracer and determine the speed and direction of groundwater flow. These tests provide crucial information for managing water resources, assessing environmental risks and designing groundwater protection strategies.