Potholing, a practice that is not new to the industry but not always in proper use, is an important part of installing underground assets. Before the commencement of excavation for the construction of underground infrastructure development, the existing infrastructure must be located and exposed for a visual. This is why potholing is commonly called daylighting. Potholing is one of the primary investigative construction techniques used to expose the horizontal and vertical location of utility lines. Potholing should be a crucial part of project planning. Regardless of the term you use, utility location is a crucial step that is necessary to ensure there is no potential or resulting conflict during construction. This also helps ensure the safety of the public and employees is top priority in each project.
Starting the Potholing Process:
Finding What is Below, Going Beyond the One Call Ticket
At the start of any project, always contact 811 through your state 811 website or by calling 8-1-1. Finding out what’s below takes some investigation and resources that may add on to your initial One Call ticket submission. Not every utility is in the One Call system in most states.
Most municipalities do not participate in 811. You must call and work with the local municipality to access maps and ask for their assistance in locating their assets.
Water and sewer mains are what most municipalities will mark and have mapped access to. This means all lateral lines or service lines will have to be marked privately.
There are companies that can come out and run sewers with closed-circuit television (CCTV) cameras to give you access to depths, footage, and give you an X marks the spot locate for your sewer mains and laterals/service lines. This is an added cost that will reduce your potholing time by over 75%, reducing the cost of labor drastically.
Any type of sprinkler system or any private system a homeowner or business has installed is typically not included in the One Call ticket. This is a simple door knock to inform the homeowner or business there will be digging around the property and allows for a quick question about utilities that may have been installed privately that excavators need to be aware of. This is a fantastic way to build a great rapport with the homeowner or business as well as prevent damages.
Pothole/Daylight Exposure
After investigating all underground facilities, including private facilities, exposure is key to potholing. Regardless of depth, it must be a requirement to expose all utilities, all the way around the lines. Often while potholing and once the asset is visible, it is viewed as a daylighted utility, and there are possibilities of striking that asset due to the asset not being fully visible.
Utilizing tools beyond hand digging is a major factor in potholing. When considering a potholing plan, having a good understanding of what type of assets are housed underground as well as depths can help identify what tools you will use in your potholing plans.
Know the options, tools, and what will work best in the project environment. Hand digging, Hydro-Excavation, Air Excavation, Vacuum Excavation, and outsourcing the potholing process are a few examples of different options and tools that can be used in this process. Being educated in all these options will drastically help improve the process of knowing what needs to be used on each project.
Knowing the tolerance zone in the state the project is occurring is key. A lot of contractors move from state-to-state working in new areas. Know before you go, set a standard in each potholing plan to educate all employees on the tolerance zone in the state where work is taking place.
At times, assets will be housed underground at depths greater than five feet. This will require a shoring/sloping/benching plan and process to visualize those assets while also being safe.
Always start with a strategic plan, investigate thoroughly, educate accordingly, and execute effectively and efficiently.