Water collecting at the bottom of an open excavation can be dangerous and deadly:
- Water depth poses a drowning hazard; especially if the water is so dirty that a drowning victim cannot be seen.
- Reinforcing steel, wire ties, plumbing and electrical items create unseen mechanical entanglements in muddy water that may contribute to injuries or drownings.
- Stored water undermines soil at the perimeter, causing soil collapse at the perimeter that could result in serious injury, impalement on rebar, or death.
Water collecting at the bottom of an open excavation can cause expensive repairs and project delays:
- Although corrosion is acceptable on reinforcing steel, debris and mud from submergence in dirty water must be cleaned prior to placing concrete.
- Reinforcing steel supported by dobies in submerged soil might sink into the mud, reducing the required clearance to less than 3-inches (75 mm) from the soil.
- Saturated soil at the perimeter walls is subject to collapse, damaging steel, and requiring additional soil removal, shoring, and forming prior to rebuilding steel and placing concrete.
- Walls originally engineered and built to be supported by the soil might need to be reengineered and rebuilt with additional steel and concrete as freestanding walls.
The solution is a robust bed of crushed rock below the pool shell drained by a submersible pump located in a bucket in a sump at the deepest part of the excavation. Use a 5-gallon bucket with perforated holes that will allow water to enter at a high flow rate without allowing debris large enough to jam or damage the pump.
The hose should be secured in multiple locations and it should discharge at least 40 feet away from the excavation and the discharge water must flow away from the excavation. The pump's power cord needs to be secured and the plug should be set as high as possible. If a severe storm is anticipated, a generator should be considered to ensure that the excavation can stay relatively dry.
