Utility potholing is also sometimes called utility daylighting, hydro-excavation, or air-excavation. The technique involves digging a series of non-intrusive, non-destructive test holes to garner as much information as possible about the layout of various utilities on or around a property. With potholing, you want to understand the locations, depths, lengths, and dimensions of different utilities on a piece of land before starting any major excavating.
The reasons for utility potholing are obvious: You don’t want to start digging the foundations for a new house, garage, or commercial project before being sure of where the utility lines are located. In addition, accidentally cutting into a gas line, water main, geothermal heating line, or electrical cables can be a materially costly disaster and hazardous to workers.
What is Potholing?
Utility potholing is a form of identifying unknown utilities below ground. You’re hoping to construct an accurate underground map of the different utility lines you might have on the property you’re working on, and potholing techniques will deliver it for you. In many jurisdictions, it’s even legally necessary to map area utilities before construction digging starts. Still, even if it’s not, you should do it unless you already have guaranteed accurate utility diagrams for the land you’ll be excavating.
Utility potholing either by hydro-excavation or air excavation involves using pressurized water or air to create narrow but deep test holes that reveal subsurface utility lines on your property. The hydro method uses water delivered in a narrow stream at high pressure to break through soil or clay, and the air excavation method does the same thing with pressurized air streams.
Both methods have drawbacks and benefits: With hydro-excavation, it’s possible to penetrate more rapidly and deeply into even densely packed soils, but the process creates subsurface traumas and waterlogging.
With the air method, excavated dirt can be reused, and there’s minor ground trauma, but the penetration rate and speed are lower. Air excavation also can’t penetrate certain dense types of ground. Then there is vacuum excavating, which works similarly to air excavation but with the addition of a vacuum nozzle for sucking out debris as it’s being broken up inside a hole.
Why use air or water? Well, older methods of potholing involved either digging by hand, which could be very slow and tedious, or backhoeing, which involves its own dangers. With pressurized air and water, you speed up the process enormously, with minimal ground damage while ensuring that you won’t accidentally cut into any utility lines with hard tools. In addition, the pressurized water or air jets themselves lack the force needed to cut into anything but soil, gravel, and clay.
Other Utility Scanning Techniques
Finally, newer, more advanced underground utility locating and ground-penetrating radar scanning techniques are being used to find specific types of utility lines without digging throughout a property. These are some of the fastest methods available, though they aren’t ideal for all contexts.
Regardless of the method used, locating utility lines precisely is extremely important if you’re not already entirely sure of where all these lines are located underground. As we referred to above, tearing open a gas line or water main is no joke. Here are some other benefits to consider.
The Many Benefits of Potholing
With utility potholing through pressurized water and air, vacuum methods, or scanning technologies, the benefits are evident whether you’re a contractor or property owner. Your existing utility lines should be mapped for any possible emergency context. Mapping them accurately before digging up the ground will dramatically reduce the chances of serious accidents.
Accident and Excess Cost Avoidance
Research has also shown that utility mapping reduces worker injury accidents by about 89%. You don’t want to be in the minority percentage of that statistic. Moreover, mapping utilities can save thousands or even hundreds of thousands of dollars in saved time, damage costs, and accident expenses.
Information and Visual Knowledge
By pinpointing where underground utility lines are located precisely, you can plan current and future construction projects much more quickly and efficiently. Single utility potholing or scanning projects can thus pay knowledge dividends that offer value for years or even decades. Furthermore, the same precise mapping of utility line layout, depth, range, and angles lets you access and probe these lines later for maintenance and replacement purposes as needed.
Legal and Insurance Advantages
In many places, construction contracting work is governed by laws that specify how excavation can be done. For example, mechanized equipment can’t be used within 18 to 36 inches of underground utilities in many states. By mapping your own site’s utility lines, you can keep on the good side of regulations that might lead to fines if ignored. In addition, because of the accident avoidance that utility mapping improves on excavation sites, you can also avoid certain worker compensation outlays.
Then, of course, there are your potential insurance benefits. These can include lower premiums and better workplace or property insurance policies if you can show that you’ve mapped your utilities correctly for existing or future construction work.
Finding the Right Potholing Service
Utility scanning and potholing services are available to handle your property’s complex probing and mapping project as accurately as possible. However, not all services offer the same options, benefits, and technologies.
A highly professional utility locating service, on the other hand, will provide a comprehensive menu of options that includes several different potholing and scanning techniques. They will also be able to incorporate visual mapping as part of their services. Additionally, they should be able to provide you with camera-based utility pipe inspection capacity as a further utility line care option. C Below Subsurface Imaging delivers all of the options described above and many others for your property or project needs. Contact us for more information or request an estimate.