for Geoprofessionals and Engineers
The Slug Test Method is one of a number of different methods that are used to evaluate the permeability (or hydraulic conductivity) of an aquifer. The procedure involves either adding or removing a measured quantity of water from a well rapidly, followed by making a rapid series of water-level measurements to assess the rate of water-level recovery (either rising-head or falling-head). These evaluations have advantages and disadvantages when compared with other methods.
Advantages of the slug test method include:
Disadvantages of the slug test method include:
The type of procedure that is used to evaluate a well is often determined by aquifer conditions. A bail-down evaluation may be conducted in aquifers that are poorly transmissive and require many minutes to recover after they have been bailed. However, it is difficult or impossible to test a highly transmissive aquifer by bail-down methods because water level recovery is so rapid. Assessments using transducer measurements and a data-logger may be used to evaluate hydraulic conductivity in situations where water-level recovery is either slow or rapid. In either situation, more accurate results are generally obtained when using an in-well transducer to collect periodic water-level versus time measurements.