A Call for New Directions in Drilling and Sampling Monitoring Wells

Keely, Joseph F.; Boateng, Kwasi; ,

A Call for New Directions in Drilling and Sampling Monitoring Wells

by Joseph F. Keely, Oregon Graduate Cent, Beaverton, OR, USA,
Kwasi Boateng, Oregon Graduate Cent, Beaverton, OR, USA,

Document Type: Proceeding Paper

Part of: Detection, Control, and Renovation of Contaminated Ground Water

Abstract:

The hollow-stem auger drilling technique has an inherent limitation of disturbing large volumes of subsurface materials around the borehole, thereby possibly affecting local permeabilities and creating annular channels for the movement of contaminants into previously clean strata. At hazardous waste sites where hydrogeologic conditions are not well defined, or where a known or suspected contaminated aquifer is perched above an important aquifer, the hollow-stem augering technique may not be advisible. Air rotary and cabletool drilling use a temporary casing that shields one strata from another, and allows the emplacement of an adequate filter pack. Air rotary drilling may result in the emission of noxious vapors from the borehole when contaminated strata are encountered, however; and may result in undesirable invasions of the near-borehole environment when water is used. The recommendations given to date regarding sampling devices may not have adequately considered the performance of mechanically-driven positive-displacement devices. A limited field test indicates that more work should be done in this area. Such work may have implications for the treatment of data from private wells, that are often included in contaminant plume definition efforts.

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