Aquifer testing is one of the many services Triad’s environmental team offers to our clients on a regular basis. Today, we’re going to break down a few different methods of aquifer testing and applications for when these tests are utilized.
But first, what is an aquifer? An aquifer is basically a rock unit that can reasonably supply and transmit water to wells and springs. Hydrogeologist use the information from studying aquifers to help make decisions for the proposed usages.
In general, there are three aquifer testing methods:
- PUMPING TEST
Water is pumped from a test well in an aquifer at a constant rate while water levels are measured in one or multiple surrounding observation wells. Pumping tests are used to estimate the hydraulic properties of an aquifer system and to help identify the boundaries of the aquifer. These tests can take only a few hours or go on for several weeks depending on the size and level of response of the aquifer.
Application: This test is commonly used to evaluate the aquifer capacity for new development and/or large demand for groundwater. It is the costliest of the three tests but provides the best data.
- SLUG TEST
A slug test is used to estimate aquifer properties on a smaller scale than pumping test. A slug test is initiated by causing the water level within a test well to suddenly rise or fall. The water level is then measured until the static water level is reached.
Application: Slug tests can be a good indicator of well performance. They are relatively inexpensive to execute. Because they involve little or no water added to or removed from a well, they can be particularly advantageous at groundwater contamination sites.
- CONSTANT HEAD TEST
As the name indicates, for this test, the water level in a pumping well is held constant and the declining discharge rate is recorded over time. Additional monitoring wells can be monitored during the test. These tests can also last a few hours to several weeks.
Application: This type of aquifer test can be used to determine the yield of a well if the discharge also remains constant over a determine period. It is also commonly used for a flowing artesian well in which groundwater under artesian pressure flows to the land surface without the use of a pump.
If you have a project need for aquifer testing, dewatering design or other groundwater concerns, the best course of action is to consult with one of our environmental specialists who can help prepare a testing plan that best fits your project needs and budget.
Check out one of Triad’s most recent projects that included aquifer testing: