DEPARTMENT OF THE ARMY
ETL 1110-1-178
U.S. Army Corps of Engineers
Washington, D.C. 20314-1000
CEMP-RT
Technical Letter
No. 1110-1-178
10 December 1996
Engineering and Design
HORIZONTAL DIRECTIONAL DRILLING
FOR
ENVIRONMENTAL APPLICATIONS
1. Purpose. The purpose of this letter is to raise the awareness of horizontal well technology,
identify Hazardous, Toxic, and Radioactive Waste (HTRW) applications for horizontal drilling,
and call attention to the Environmental Protection Agency Manual (EPA) "Alternative Methods
for Fluid Delivery and Recovery (EPA/625/R-94/003)." This manual describes four alternative
methods for fluid delivery and recovery - horizontal wells, slant wells, induced fractures, and
(HDD) as it relates to the installation of horizontal environmental wells.
2. Applicability. This letter applies to HQUSACE elements, major subordinate commands,
districts, laboratories, and field operating activities (FOA) having HTRW investigation, design
and remedial action responsibility within the military or civil works program.
3. Reference. U.S. EPA. 1994. Manual: Alternative Methods for Fluid Delivery and Recovery.
EPA/625/R-94/003. Prepared by: Murdoch, L., and Wilson, D.D.
4. Background. The environmental industry began modifying directional drilling technology in
1988 to install horizontal extraction and injection remediation systems where it was not practical
to excavate trenches. The first directionally drilled horizontal environmental wells were installed
at the Department of Energy's Savannah River Site in 1988. Since that time horizontal
environmental wells have been installed at several Department of Defense sites and various private
industry sites.
5. Discussion.
a. Horizontal wells used for environmental projects are being used predominantly for air
sparging, soil vapor extraction, ground-water extraction and injection, and bioremediation. In
addition, horizontal wells can be used for pump-and-treat systems, leachate collection, soil
monitoring and sampling, and grouting. Possible future uses may include the chemical treatment
of heavy metals in place, and in-situ vitrification of nuclear wastes.
v Printed on Recycled Paper
Previous Page
