|
ABSTRACT |
|
|
TITLE: |
A Comparative Assessment of Horizontal Directional Drilling and Traditional Construction Techniques for Wetland and Riparian Area Crossings in Natural Gas Pipeline Rights-of-Way |
|
AUTHOR(S): |
John Hair David Cameron - dcameron@ensr.com
James Evans - JamesMEvans@lightfirst.com |
|
Horizontal Directional Drilling (HDD) is
increasingly advocated as the preferred, and often required, construction
method (as opposed to traditional trenching) for natural gas transmission
line crossings of ecologically-sensitive areas including wetlands and
riparian areas. As a result, a closer look at the technical rationale,
environmental and cost implications, and construction procedures in these
areas is required to determine the benefits and drawbacks of these crossing
techniques. The focus of this evaluation was to examine crossing techniques
such as the traditional open-cut trenching and HDD in the context of the
above-mentioned criteria. Variables common to both crossing technologies
which were evaluated included assessing physical elements such as landform
and subsurface conditions and limitations; operational components such as
workspace requirements, staging area locations, and equipment mobilization;
engineering design; manpower requirements; and ecological restoration.
Representative cost comparisons were developed and correlated with matrices
of potential environmental concerns.
This comparative analysis can be used as a template to assist
planners, designers and permitting specialists in decision-making relative to
application and implementation of these construction techniques. Keywords:
Drill method, inadvertent
returns, bentonite, engineering limitations, cost |
|
