Lab Studies and Site Characterization for Permeable Reactive Barrier Walls
Implementing the Site Characterization
Historically, plume dimensions and site characteristics have been determined during the installation and use of monitoring wells. However, these are expensive, time-consuming to install and sample, and require special multi-level installations to provide adequate delineation in the vertical dimension. A better approach might be to begin with surface geophysical techniques such as ground-penetrating radar (gpr) and seismic studies. These techniques are of particular use when a site is completely unknown with regard to subsurface features. Geophysical techniques can locate buried drums, pipes, and power lines in addition to providing information on water table and bedrock depth, fractured zones, and strata thickness. Once this information is compiled, push tool technologies should be used for further characterization.
Push technologies, such as Geoprobe®, Hydropunch®, and cone penetrometers are rapidly becoming the tools of choice for evaluating shallow plume locations. They can be driven rapidly and relatively inexpensively, allowing more points to be sampled than could be accomplished with monitoring wells for the same amount of time and money. They can be used to collect soil, water, and soil gas samples. Additionally, they can be used to collect these samples over very thin vertical intervals, allowing better delineation of the contaminant concentrations in the plume and better stratigraphic characterization than could normally be acquired with exploratory monitoring wells.