Demonstration/Validation of Long-Term Monitoring Using Wells Installed by Direct-Push Technologies

Abstract : During environmental site characterization, remediation, and compliance efforts, groundwater monitoring wells have served as the conventional tool-of-choice for accessing groundwater samples. Recently developed direct pushed (DP) technologies provide the means for collecting faster, less expensive groundwater samples when compared to conventionally drilled wells. The most extensive use of these cost-effective technologies, initially used almost exclusively as temporary installations for characterization purposes, have not been widely accepted for long-term monitoring at remedial action sites. For broad acceptance of DP well long-term monitoring applications, comparisons between conventionally drilled wells and DP wells needed to be conducted to validate these innovative approaches. The purpose of this project was to rigorously compare the results of laboratory analyses conducted on samples obtained from DP wells to those obtained from wells installed utilizing conventional techniques (e.g., hollow-stem auger [HSA] wells). The demonstration consisted of these side-by-side comparisons followed by comprehensive statistical analyses over several years of quarterly monitoring. Five sites (located in New Hampshire, Delaware, California, Massachusetts, and Florida) comprised of various geologic regimes and contaminants of concern were included in this demonstration. Ultimately, the goal of this demonstration was to determine whether DP wells can yield representative data for long-term monitoring applications.