Abstract |
Three case histories are presented to illustrate the problems encountered using some monitoring well installation, purging, and sampling techniques. Hollow-stem augering was found to pose problems during the installation of monitoring wells in terms of potential for cross-contamination of strata, the inability to emplace an adequate filter pack, the potential for smearing natural clays into sand and gravel strata, and the possible need for excessive purging of sediments that accumulate between sampling events. A hybrid drilling technique, augering with temporary casing, was able to provide the advantages, and minimize the disadvantages, of the foregoing drilling methods. |