A slug test is a method used to measure the hydraulic properties of an aquifer, particularly its permeability. In this test, a sudden change in water level is created by quickly adding or removing a known volume of water, called a "slug," from a well. The rate at which the water level returns to equilibrium is then monitored, providing valuable data about the aquifer's ability to transmit water. The results from a slug test can help hydrogeologists understand groundwater flow and inform decisions related to water resource management. This technique is often used in conjunction with other methods, such as pumping tests, to gain a comprehensive view of an aquifer's characteristics.