According to the Common Ground Alliance’s most recent analysis of the Damage Information Reporting Tool, 36% of annual underground utility damages (with a known cause) are the result of excavation issues, with failure to pothole highlighted as the largest of these. What’s more, the report indicates that estimated total damages in the U.S. have reached an all-time high, increasing by 16% over a one-year period.
In response to these climbing numbers, the report details eight specific recommendations for the industry, not the least of which is promoting potholing as a best practice. Even though potholing has existed as a construction practice for quite some time now, not all teams take care to execute it prior to digging. As the data shows, this is a major oversight—one that can result in significant risk to workers, projects and underground infrastructure.
Here, we’re taking a closer look at exactly what potholing involves and how properly implementing this method can offer serious advantages for utilities construction projects.
Understanding the Practice And Application Of Potholing
Potholing, also sometimes referred to as daylighting, is a technique to garner visual confirmation of underground utilities and obstructions before moving forward with excavation. It provides insight into the location, length and depth of utilities so that workers can safely excavate the area with minimized risk of damage to existing infrastructure and/or interference with new construction.
The potholing method involves digging a series of very small test holes, usually measuring approximately 6 to 12 inches deep, into the ground to explore and accurately identify subsurface pipes, lines and other obstructions. This practice often leverages a vacuum excavation approach and equipment to obtain the necessary verification of underground objects all along the project’s bore path.
The process of vacuum excavation is most commonly implemented using one of two sources: water or air. Hydrovac and air vacuum excavation apply highly pressurized streams of water and air, respectively, to soften the ground soil and displace it from the potholing bores through high-suction vacuum equipment. The benefit of these excavation techniques is their ability to move hard or rocky ground without accidentally puncturing or harming the features below.
Potholing via vacuum excavation uncovers underground lines while leaving them fully intact. Once workers have a clear view of all the subsurface features, they can mark them, replace the removed wet or dry soil as backfill (if necessary) and harness the gleaned visual insight to proceed with their project safely.
5 Major Benefits Of Utilizing Potholing
Why pothole first? Following are some of the most compelling reasons to prioritize the practice of potholing prior to carrying out the excavation and building processes for a utilities construction project.
1. Access To Information And Insight
There’s immense advantage to pinpointing precisely where underground service lines exist before beginning a project. Even armed with charts and utility maps (which may be incorrect or out of date), you still run the risk of striking critical underground infrastructure. Having visual verification is as accurate as it gets in terms of understanding the work area. Potholing offers distinct insight into the type, horizontal position and depth of buried utility lines, as well as any existing damage to them. It gives workers the opportunity to proceed with minimized risk of personal injury, property damage and service interruptions.
2. Hazard Mitigation For Work Crews
Speaking of personal injury, data shows that construction crews face digging-related deaths and injuries every year. Without a reliable way to locate and bypass crucial underground utility infrastructure, the wellbeing of excavation operators is seriously endangered, particularly with regard to strikes on natural gas lines. With potholing applied via vacuum excavation, however, teams are able to locate dangerous infrastructure and prevent these hazards much more definitively.
3. Accumulated Efficiencies
It’s common to assume that potholing is an extra step in the construction process that incurs even more time on the project clock. The truth, though, is that this method can actually save time in the long run. When laying underground infrastructure without a direct line of sight to the existing features, there’s the inherent possibility of mistakenly hitting a line and causing the kind of damage that sparks significant downtime. This is the type of misstep that precipitates unforeseen extensions to the project timeline. It’s also worth noting that potholing is a much faster method of identification than relying on charts and maps.
4. Overall Project Cost Savings
Let’s face it, project downtime is not the only contributor to unplanned expenses on a construction project. There’s also the massive cost to repair vital utility lines ranging from water, electrical and gas to telecommunications and fiber optic. That doesn’t even include the potential for wrecking your own excavation equipment or incurring noncompliance fines. To keep your project within budget, planning for the potholing stage to daylight and avoid underground lines is paramount.
5. Legal Compliance
As the industry has pushed for both safer working conditions and less risky digging methods, state and local regulations have evolved over time. State laws, for instance, generally prohibit the use of mechanized equipment within 18 to 36 inches around all sides of a marked utility, otherwise known as the tolerance zone. For projects to be fully compliant with these types of governing mandates, it’s necessary to employ the safest and most precise methods. The practice of potholing through the use of vacuum excavation is in full alignment with proper compliance and helps mitigate liability issues.
Ultimately, potholing should be a must-do on every utilities construction project list. It’s the best way to locate and mark the position of underground assets before moving forward with final excavation. From safety and compliance advantages to time and cost savings, there’s so much benefit to be derived from applying this practice before the digging begins.