Hydro excavation is a process that involves using pressurized water to expose underground utilities, dig trenches and holes, including digging in frozen ground. Hydro excavation helps remove soil with minimal damage to the environment. Sometimes called daylighting or noninvasive excavation, hydro excavation is a safe way to find underground utilities without the risk of breaking or destroying them. In addition, hydro excavation is a great way to dig precision holes without disturbing native plants and removing excess amounts of soil. Read on to learn more about the process of hydro excavation.
1. Bring the Hydro Evacuation Truck to the Site
The main workhorse of any hydro excavation project is the unit called the hydro excavation truck or hydrovac. This unit comes mounted on a truck or on a trailer and has a high-pressure water hose, a suction hose, a storage tank for water, and a tank to hold the loosened soil. Depending on the size of the hydrovac, the operator can use the high-pressure hose to inject the water and loosen the soil from as far away as 600 feet and can dig or excavate up to 60 or 70 feet deep.
2. Inject the Soil With Water
Whether daylighting or hydro-excavating a slot trench or a hole, water from the holding tank gets injected into the soil through the hose and then through a specialized wand that the operator uses to direct the water to a very specific location. If hydro-excavating in frozen ground, the hyrdrovac unit will need to have a boiler to send high-pressure hot water through the hose and wand to thaw the frozen ground.
3. Liquefy the Soil
Depending on the soil type — sand, clay, or silty loam — the water will begin to break up the soil. After a certain amount of time passes, the broken-up soil will begin to liquefy into a muddy, watered-down soil called a slurry.
4. Vacuum the Slurry
Once the soil becomes the right consistency, the heavy-duty vacuum mounted on the hydrovac system sucks it up. The slurry gets diverted into a holding tank located on the truck or trailer for later release. The hydro-excavating crew can choose between two types of vacuums, depending on the size and scope of the project.
For lighter duty excavating, like slot trenching or hole digging, the crew can use a fan system. If the project requires heavy-duty excavation, the operator can use a positive displacement blower. The latter system is a slower method but is ideal for breaking up hard soils or for hydro excavating at greater depths.
5. Responsibly Dump the Slurry
Once the hydro excavation process is complete, the crew will take the slurry to a designated off-site location where it gets pumped out. Some sites dewater the slurry to reuse the organic materials found in the soil.
If you need hydro excavation services, feel free to contact our team at PROS Services. We're available year-round so that you can complete any building or trenching project without interruption. Our team at PROS Services looks forward to helping you with your hydro excavation needs.
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