What is water excavation and when do you use it? How does it work? What can you expect when a hydrovac truck shows up at your Calgary property?
By understanding the process, excavation day will go much smoother. It will also give you peace of mind knowing why water excavation is safer and more precise than traditional digging.
At Mr. Trenchless, we provide water excavation services in Calgary every day. Today, we’re going to give you a behind the scenes look at how it’s done.
What Equipment is Used for Water Excavation?
Water excavation in Calgary uses specialized equipment. Here’s a breakdown:
- Hydrovac Truck: This main vehicle holds the water tank, debris tank, vacuum system and all the controls. Truck sizes vary based on the job, but larger units that can hold more water and debris are better for bigger projects.
- Water Tank: Used to store fresh water used to break up soil, tank sizes range from 200 to 1,500 gallons. For cold weather work, this truck has a heating system to warm the water.
- Debris Tank: This collects slurry (a mixture of water and soil removed from the excavation site). Debris tanks are 4 to 15 cubic yards depending on the truck size.
- High-Pressure Water System: Water is delivered through handheld wand with pressures between 1,000 and 3,000 PSI. The operator controls the pressure based on soil and conditions and proximity to utilities.
- Vacuum System: A powerful blower creates suction that pulls slurry through a large hose into the debris tank. Industrial hydrovac systems generate thousands of CFM (cubic feet per minute) of airflow.
- Excavation Wand: This handheld tool combines the water nozzle with the vacuum hose. The operator directs water at the soil while simultaneously vacuuming up the loosened material.
- Hoses and Extensions: Flexible hoses connect the truck to the dig site and extensions let operators reach excavation points further than where the truck is parked.
How is Water Excavation Done Step-by-Step?
How does a water excavation job work? Let us provide an overview:
Step 1: Site Assessment
Before digging, the crew assesses the site. This is time to confirm utility locate markings, identify access points and determine the best position for the hydrovac truck. A truck parked closer to the excavation area is more efficient.
Step 2: Utility Locates Verification
Even with locate markings on the surface, the crew proceeds with caution. Water excavation is non-destructive, but knowing approximate utility locations helps operators work safely and efficiently.
Step 3: Equipment Setup
The operator positions the truck, deploys outriggers for stability and extends hoses to the dig site. Water and vacuum systems are tested before excavation day.
Step 4: Initial Water Application
The operator directs pressurized water at the soil surface. The water jet cuts into the ground, loosening and breaking apart the soil. Pressure is adjusted to suit the soil type. Lighter pressure is used near utilities and higher pressure is used in open areas.
Step 5: Simultaneous Vacuuming
As water loosens the soil, the vacuum begins pulling the resulting slurry into the debris tank. This is a continuous cycle of water breaking up the soil and vacuum removing it. The systems are constantly working together in real time.
Step 6: Progressive Excavation
The operator methodically excavates layer by layer. As for deeper digs, they work downward gradually instead of trying to blast straight to the bottom, while maintaining control and visibility in the process.
Step 7: Utility Exposure (If Applicable)
When an operator comes across utilities, it’s time to reduce the water pressure and carefully work around them. This exposes the utility without damaging it so the location and depth can be documented.
Step 8: Final Inspection
After the excavation reaches the required depth and the utility is fully exposed, the crew inspects the hole. Measurements are taken, photos are captured and any findings are recorded.
Step 9: Debris Disposal
The slurry in the debris tank is transported to an approved disposal facility. Depending on the material, it will go to a landfill, soil recycling site or another designated location.
Step 10: Site Cleanup
The crew cleans up the work area, removes equipment and leaves the site in good condition. Depending on the project, backfilling can either happen right away or after the other work is done.
How Does the Water Break Up Soil?
Essentially, the water does the digging. A pressurized water jet exits the wand at 1,000 to 3,000 PSI, cutting through the soil and breaking the bonds between particles, turning solid ground into loose slurry.
Operators adjust pressure to suit conditions. For example, loose sandy soil needs less pressure, while dense clay needs more. Near utilities, pressure drops to prevent damage. In winter heated water melts through frozen ground so excavation can be done year-round.
How Does the Vacuum System Work?
Water loosens the soil and the vacuum removes it. These systems run at the same time, making water excavation feel nearly effortless.
Industrial vacuums generate massive suction, pulling the slurry through 6-to-8 inch hoses and into the debris tank. There’s no need to pause to shovel or haul because when the material loosens, it’s gone. This is why water excavation is so much faster than hand digging.
What Happens After Excavation?
When the job is done, slurry is transported to an approved disposal facility. Depending on the material, it will go to a landfill, soil recycling site or dewatering facility.
The excavation site is backfilled in layers, compacted to prevent settling and restored to its original condition. Grass gets re-seeded, gravel gets raked smooth and hard surfaces are patched as needed. Water excavation is precise so restoration is limited to a small area and causes less disruption than traditional digging.
Book Your Water Excavation in Calgary Today
How is water excavation done? Pressurized water breaks up the soil, which is removed by a vacuum. It’s fast, precise and safe around buried utilities. At Mr. Trenchless, we take care of water excavation projects across Calgary. We get the job done right, while protecting your property.
Ready to get started? Contact us to book your water excavation project!
