Site Preparation, Surveying, and Utility Locating
What the exam tests
This domain tests plan reading, grade calculation, site setup, and the ground-disturbance process that keeps machines away from buried services.
Core rules and concepts
- Plans and stationing: know the benchmark, the datum, station and offset notation, and the difference between existing and design grade. Cut or fill equals design elevation minus existing elevation; a negative result means cut.
- Level math: height of instrument (HI) equals benchmark elevation plus backsight; an unknown elevation equals HI minus foresight.
- Locate process: request a locate before any ground disturbance, respect the ticket expiry, and treat markings as approximate. Hand-expose or vacuum-excavate within the tolerance zone (commonly 1 m each side of the mark in Canadian jurisdictions; confirm your province).
- Colour code: red electric, yellow gas and oil, orange communications, blue water, green sewer and drain, white proposed excavation, pink survey marks.
- Site preparation: clear and grub, strip and stockpile topsoil separately, install silt fence downslope, stabilize the entrance, and set haul routes and traffic control.
- If you contact a utility: stop, shut down, move people back, and call the owner and the emergency number. Do not attempt a repair.
Worked example
Benchmark elevation 102.350 m; backsight reads 1.245 m, so HI equals 103.595 m. A foresight on existing ground reads 2.100 m, so existing elevation is 101.495 m. Design grade there is 101.000 m, so you must cut 0.495 m. Reasoning: keep the same HI for the whole setup, and re-check the benchmark before you trust a day of grade work.
Traps that cost marks
- Adding the foresight instead of subtracting it.
- Mixing feet and metres on a rod or plan.
- Treating a locate mark as the exact pipe location.
- Digging on an expired locate ticket or where markings have been destroyed.
- Stripping topsoil into an area you will need for fill.