Since the advent of the electricity and the discovery of natural gas, utilities have been investing time and money to find effective ways to supply these resources to residences and industries. Over time it has become a growing concern to install these resources with minimal adverse impacts to the environment and communities.

The traditional open-cut trench method involves excavating the entire length of the installation area to install pipelines and conduits and then backfilling the trench. This results in a lot of disturbance from excavating, as well as the spoil piles that result from sidecasting the soil from the excavation area. This method for expanding a utility network runs into trouble when it needs to cross water bodies, railroads and roads. Also, the construction activities can create a lot of noise and dust, disrupting day-to-day activities. Sometimes it involves tearing up streets, which increases the overall repair costs. Such construction leads to traffic congestion, especially in big cities.

Horizontal directional drilling (HDD) is an alternative that has simplified — and made more convenient — the installation of power, telecommunications, and oil and gas networks underground. It has made it possible to install conduits and pipelines almost anywhere — including under wetlands, railroads, roads, rivers, lakes and more — with little or no disruption to the environment and other aboveground infrastructure.

This technique just requires entry and exit points, but otherwise keeps the surrounding environment unchanged. It involves drilling a well into the ground at an angle, as opposed to vertical drilling, along a determined pathway. By deploying advanced controls and positioning tools, operators can remotely steer the drill head to see that the bore path is in accordance with the engineering plan. After drilling, the pipes and conduits are pulled through the drilled well and other installation procedures are completed. Because HDD minimizes surface disruptions, it results in less restoration work being needed in comparison to traditional drilling methods.

HDD has become a preferred method and industry standard for utilities for several reasons, including:

  • For preserving the natural landscape and environmental balance by avoiding or minimizing impacts to wetlands and streams, cultural resource sites, and critical habitats for threatened and endangered species.
  • Minimizing earth disturbance and the amount of required erosion control measures.
  • Reducing permitting.
  • For requiring less earth-moving equipment.
  • For minimizing impacts to residents’ property, including lawns, trees and landscaping.

Unlike the traditional drilling process, HDD can continue undisturbed during rainfall and snow. It requires less manual labor and uses highly advanced drilling equipment. This technique has been used for decades; as its technology continues to be improved and refined, governments and municipalities increasingly advocate for it. They recognize its proven capacity to protect environmental and cultural resources when coupled with an inadvertent release (or “frac-out”) contingency plan. HDD also decreases restoration costs and reduces the inconveniences caused to residents through conventional methods.


A lot goes into planning, feasibility analysis and design for HDD projects. Learn more about HDD best practices.

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Kari Giles is a senior environmental scientist at Burns & McDonnell. She specializes in horizontal directional drilling (HDD) projects and inadvertent release contingency plans. She has thorough knowledge of permitting, environmental compliance, and erosion and sediment control for linear utility projects. Kari also has extensive experience in habitat restoration and streambank stabilization.