A review of recent developments in using directpush technologies for rapid, highresolution hydraulic conductivity measurements

Despite the clear importance of highresolution hydraulic conductivity estimates, the current generation of field methods is not capable of providing such information at the level of detail required for predictive transport modeling in highly heterogeneous formations. Directpush injection logger (DPIL) and directpush permeameter (DPP) are a new generation of novel site characterization tools that hold much promise for hydraulic conductivity measurements at a level of resolution and costeffectiveness that has not previously been possible. By monitoring injection flow rates, hydraulic pressures and potentially other hydrogeophysical parameters during tool advancement, direct push (DP) methods provide quick and accurate information about vertical variations of subsurface hydraulic properties. DP methods can be used virtually in any unconsolidated environment and have minimal site disturbance, thus overcoming many of the limitations associated with conventional methods based on existing wells for aquifer testing. A recent case study at the MADE site in the United States shows that with DPIL/DPP tools, it is possible to achieve a spatial resolution of about 15 cm in measuring the hydraulic conductivity distribution along vertical profiles. In the future, highresolution DP tools can be further combined with a new generation of geophysical methods such as highprecision ground penetrating radar (GPR) surveys to interconnect K features identified in the DP profiles and develop a threedimensional model of the K field across an entire site.