06/18/2026
Today's Think Safe Thursday touches on proper dewatering. It is important to remove the groundwater from a job site to avoid trench cave-ins.
Water is one of the world’s most precious resources that we cannot live without. But when inside of a trench, it creates hazards that can make our work much more dangerous, and in some cases, deadly.
When soil is combined with water, whether ground water or water from a leaking main, it fills the small voids between the soil particles. This adds weight to the soil and can cause gravity to help bring the walls of a trench down quicker than usual. The water mixed in the soil particles also acts as a lubricant, which causes cracks and fissures in soil.
If water is allowed to run through the trench, it can cause undermining. The bottom of the trench walls can erode away, and the weight of the walls will collapse because of the newly created space. If water is allowed to pool in the bottom of the trench, it can create a soft spot or "zone." The soil in this zone is more easily compressible and will cause the soil mass above the zone to collapse.
Drowning is another hazard that is created by water in a trench. Deep water caused by flooding, damaged utility lines, or pump malfunctions can become dangerous very quickly.
To maintain safety in any of the situations above, it is important to rely on the Competent Person to evaluate the incident. You should NEVER enter a trench that has accumulated or is accumulating water without the approval from the Competent Person. Keep an eye out for water in or around trenches and alert the Competent Person if necessary.
Happy Thursday- Think Safe, Stay Safe!
