What is it?
Slug testing is a method to determine aquifer hydraulic conductivity or transmissivity by observing how the head in a well returns to equilibrium after removing or adding a "slug" (volume of water or other dense material).Slug tests are easier to conduct than pump tests as they can be conducted with a single well, and no pumping equipment is required. However, with a slug test the portion of the aquifer "sampled" may be less representative of the aquifer as a whole. In general the following assumptions are used when conducting slug test analyses:
-the aquifer has an infinite areal extent, and is homogeneous and of uniform thickness.
-the watertable is initially horizontal,
-the propogated head change is instantaneous.
Bouwer & Rice (1976)
How to use it:
Choose or Input Well Geometry and Observed Data
The user can enter their own data or choose to analyze an example dataset.Example data sets:
-USGS Bouwer-Rice .xls
-AQTest
Pick Method and Run Analysis
Several methods for analyzing slug tests are provided.| Method | Add'l. Assumptions | Notes |
| Bouwer-Rice (1976) | well can be fully or partially penetrating in confined or unconfined AQ, flow is steady. | The user must choose a shape factor equation (analytical formulations of Bouwer-Rice solution).** |
| Hvorslev (1951) | well can be fully or partially penetrating in confined or unconfined AQ, flow is steady | |
| Cooper (1967) | well is fully penetrating, flow to well is horizontal, AQ is nonleaky confined, flow is unsteady, water is released instantaneously from storage | This method uses type curve matching, storage parameter (ε) should be entered after matching the curve |
Additional References
**Bouwer-Rice shape factors:-DeBisschop 3% reported error for small values of B, otherwise <1%.
-Yang & Yeh, 2004(2008) <10% reported error.
-Butler, 1998. The Design, Performance, and Analysis of Slug Tests (1st ed.), Lewis Publishers, New York, 252p.
Cooper, Bredehoeft and Papadopulos (1967)
Hvorslev (1951)