Construction managers and contractors are no strangers to job-related risks—particularly those associated with the excavation activities that accompany everything from utility installations and maintenance plans to building and landscaping projects. Cables, pipes and other obstructions that reside below the ground’s surface present critical exposure to safety hazards and property damage.

In fact, poorly planned or mismanaged excavations continue to result in injuries, deaths, collapses, fires and explosions at construction and utility sites across the country, rendering excavation one of the most dangerous construction jobs out there. Over the last several decades, however, innovation in excavation practices has enabled construction teams to deploy much safer and far less risky approaches.

Such is the case with the increasingly utilized application of hydro excavation.

So, what makes hydro excavation a prudent alternative to the outdated deployment of mechanical excavators, backhoes and other industrial machines? This article takes you through the ins and outs of hydro excavation, highlighting the distinct attributes, applications and benefits that characterize this modern option for today’s excavation needs. With a more informed approach to safe digging methods, you can leverage a process that brings greater peace of mind to you and your workers.

What exactly is hydro excavation?

Hydro excavation—also referred to as hydrovac, hydro trenching or soft digging—is a sophisticated process of digging trenches or holes through the use of highly pressurized, heated streams of water to break up the soil. The muddy, watered-down soil is then suctioned out by a heavy-duty vacuum and stored in nearby debris tanks or trucks, which transport it to a designated off-site location.

This practice is quickly becoming the preferred method of excavation for digging in high-risk areas that contain obstructions like underground utility lines, cables or other sensitive infrastructure. It allows for safe, precise and non-destructive excavation, mitigating the potential for property damage, minimizing the need for backfill, cutting down on labor and significantly diminishing environmental impact.

How has hydro excavation evolved?

The concept of hydro excavation can be traced back to its Canadian roots. In the northern country’s cold-weather climate, petrochemical and construction industries were challenged to work around the formidable obstacle of frozen soil, which typically rendered conventional drilling tools and methods ineffective. They realized that leveraging hot water to melt the frost and soften the soil could be a major opportunity for meeting excavation needs all year long.

Here’s a brief historical snapshot of how the technology has emerged and evolved:

• 1960s: Catch basin cleaners were adapted for use in hydro excavation, and the first (and only) hydro excavation machine was built.
• 1970-80s: Vacuum trucks and sewer cleaners were modified for hydro excavation use, with the various components repurposed and mounted on all-terrain vehicles for easier access to remote locations.
• 1990s: Numerous companies realized the growing demand for hydro excavation machines, so they began manufacturing truck- and trailer-mounted units.
• 2000: The use of hydro excavation was prevalent throughout Canada and began to be embraced by industry players in the United States.
• Present: Hydro excavation has gained major traction in the U.S. and is widely implemented by utility contractors across the country.

What are the most common applications for hydro excavation?

The most prevalent application for hydro excavation is “daylighting,” or digging to expose underground utility lines and cables. In this regard, the practice is leveraged to:

• Locate, install and repair lines for utilities and pipelines
• Rehabilitate sewers and pipes
• Maintain and repair water lines
• Maintain and repair cables for telecommunications
• Install signs and poles
• Prepare for landscaping projects

In addition, hydro excavation is often used for applications including:

• Slot trenching, or digging narrow trenches to install cables, pipelines or other systems
• Piling hole excavation, or digging holes of various diameters and depths to lay different types of pilings)
• Potholing, or creating a test hole to expose underground infrastructure
• Debris removal
• Cold-weather digging
• Directional drilling
• Excavation in tight or congested spaces

What are the distinct advantages of hydro excavation?

There are a number of benefits associated with employing this method of excavation. Here are some of the most defining:

SAFETY

Hands down, one of the top benefits of choosing hydro excavation over other excavation methods is its ability to foster a safer work environment. Without a reliable way to locate and bypass crucial underground utility infrastructure, excavation can seriously endanger the lives of work crews.

Strikes on natural gas lines, in particular, have proven to be extremely hazardous and all too frequent. A recent FracTracker Alliance report reveals that in the U.S., an average of 1.7 pipeline incidents are reported each day, requiring 9 people to be evacuated. It also indicates that a pipeline catches fire every 4 days and results in an explosion every 11 days. These incidents result in an injury every 5 days, on average, and a fatality every 26 days.

When it comes to protecting people and prioritizing safety, hydro excavation is the leading option, which is a major part of the reason why it has gained so much popularity over the years.

PRECISION

Hydro excavation is the smarter, more precise method of excavation. Instead of blindly digging and hoping for the best, teams that utilize hydro excavation can dig slots and trenches to find or install lines and pipes without destroying anything in the process.

Accuracy is highly important when digging around potential obstructions because there’s always a risk of hitting or puncturing something you didn’t know was there. Accidental damage to underground utilities can disrupt vital services for both consumers and public safeguards, like traffic controls and emergency response. And just a few hours without power and internet has the potential to cost millions of dollars.

Hydro excavation gets as close to perfect as possible—without harming anything below or above ground in the surrounding areas.

EFFICIENCY & ENVIRONMENTAL IMPACT

Hydro excavation speeds up project turnaround times (and, consequently, saves money over the long term) by eliminating time spent cleaning up piles of soil and debris or repairing any damage caused by huge industrial machines.

This method is also less intrusive from an environmental point of view. It does not require any toxic substances, and it eradicates the need for digging equipment that could jeopardize plant or tree roots.

COMPLIANCE

There are state and local regulations governing the protection of underground lines from damages caused by excavation work. In Pennsylvania, for example, there’s Act 287, the Underground Utility Line Protection Law (also known as PA One Call Law):

“An act to protect the public health and safety by preventing excavation or demolition work from damaging underground lines used in providing electricity, communication, gas, propane, oil delivery, oil product delivery, sewage, water or other service; imposing duties upon the providers of such service, recorders of deeds, and persons and other entities preparing drawings or performing excavation or demolition work; and prescribing penalties.”

Current U.S. laws also prohibit the use of mechanical means to dig within 18 inches of buried cable and pipe. Hydro excavation supports compliance with these types of regulations to ensure that contractors are taking steps to safely excavate and protect underground utilities.

What’s the big takeaway?

Excavation is a serious business—one that remains necessary for construction and utility projects everywhere. Historically, excavation processes have posed major risks to the people and companies employing them, but with the inception and evolution of hydro excavation, these enterprises can be conducted in a much safer and more effective way.

Given this reality, it’s in the best interest of construction companies to work safely with the environment and their workers, looking to specialized services like hydro excavation to move them into the future.

Interested in learning about the range of our hydro excavation capabilities? Download our 2021 free brochure.