Groundwater Sampling Methods
by: Sebastien Fortin, E.I.T., M.Sc.
Direct-Push Sampling
Direct push (DP) is an alternative method to conventional drilling techniques for sampling soil and groundwater, and installing monitoring wells in unconsolidated materials such as clay, silt, sand, and gravel. Many sites where groundwater is contaminated are located over aquifers of unconsolidated sands and gravels. DP methods do not use rotary augering to advance tools or install wells as conventional drilling methods do. DP methods use percussion hammers and static vehicle weight combined with hydraulic cylinders to advance tools to depth. The DP methods do not generate a large volume of potentially contaminated drill cuttings as conventional drilling methods do. The U.S. Environmental Protection Agency (USEPA) provides a detailed discussion of the direct-push sampling method and its application to environmental engineering.
A large-scale U.S. Navy sponsored performance comparison study was conducted at a major MTBE cleanup site in Port Hueneme, California. The study found almost no difference between samples collected from small diameter direct push wells and those collected from conventional drilled wells. However this comparative study demonstrated that DP methods permit faster and cheaper monitoring well installation, generates no cuttings and generates 3-4 times less liquid than rotary drilling methods.
The ASTM 2002 Standard Guide for Direct Push Soil Sampling (D 6282) and Standard Guide for Direct Push Groundwater Sampling (D 6001) have been published and are now available from ASTM for determining the most appropriate sampling methods for a site investigation project.
Links to on-line resources and vendors of DP technology are provided below.
Forward to BAT sampling.
Return to Overview.
|
|
/ Surface Water
