Detecting Groundwater Velocity with the Point Velocity Probe

This study was conducted to determine the repeatability of groundwater velocity estimates using the 2-inch diameter, prototype-printer Point Velocity Probe (PVP).  PVPs are relatively new instruments used to measure groundwater velocities in support of treatment efforts and contaminated site characterization problems.  This study is important because it establishes the detection limits of the PVP, in both velocity magnitude and flow direction, under ideal conditions.  All measurements were made in a simulated aquifer constructed from a sand-filled plastic storage bin.  The PVPs were held in place while the sand was wet packed around them to assure full saturation.  Water was pumped from one side of the bin to the other at velocities ranging from 1.5 RPM to 3 RPM, which were subsequently measured with the PVP 5 times per velocity.  The experiments revealed that PVPs produce data that is both accurate and precise.  For example, at a velocity of 554 cm/day with a standard deviation of 4.52 at 46^o with a standard deviation equaling to 1.55^o; these results show that PVPs can provide excellent estimations of groundwater velocity.  Given that they are inexpensive to construct, they should be very practical for use at contaminated sites where groundwater flow magnitude and directions are issues of concern.  In the future I would like to use my knowledge and skills to remediate contaminated sites on reservations.