Conducting and interpreting slug tests in monitoring wells with partially submerged screens
- Univ. of Connecticut, Storrs, CT (United States). Dept. of Geology and Geophysics
Slug tests conducted in ground water monitoring wells are the most widely used method by the environmental consulting industry for determining hydraulic conductivity at contamination sites. Conducting and interpreting slug tests in wells with screen sections and sand packs that span the water table are severely complicated by sand pack drainage and resaturation. Sand pack drainage greatly reduces the actual head difference between the well and the formation. Resaturation of the drained sand pack must be properly accounted for, or the formation hydraulic conductivity will be underestimated. The magnitude of error is a function of the well geometry, sand pack properties, and the model chosen to interpret the data. A method has been developed to correct for sand pack resaturation by calculating the specific yield of a drained sand pack using the early recharge data of a slug test. Slug tests were conducted in one well in which the water table varied over time, creating both partially and fully submerged screen and sand pack conditions for comparative testing. The mid-time, log-linear portion of slug test data was corrected using the calculated specific yield of the drained sand pack to yield essentially the same hydraulic conductivity value as the fully submerged screen results. Not accounting for sand pack resaturation would have yielded a hydraulic conductivity value that was lower than the submerged screen results by a factor of seven.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 577323
- Journal Information:
- Ground Water, Vol. 36, Issue 2; Other Information: PBD: Mar-Apr 1998
- Country of Publication:
- United States
- Language:
- English
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