Wellpoint dewatering is one of the most effective methods for lowering groundwater levels in shallow excavations. By installing a series of small-diameter wells connected to a header pipe and vacuum pump, water is removed from the soil, creating stable and dry working conditions for construction projects.
Depth Limit
Single-stage wellpoint systems can lower water approximately 5-6m. For deeper excavations, multi-stage systems or deep wells are required.
Why Wellpoint Dewatering Is Used
Safe Excavations
Prevents trench collapses and soil instability during construction
Improved Productivity
Allows dry conditions for foundation, pipeline, or utility works
Cost-Effective
Economical solution for shallow and medium-depth dewatering projects
Flexible & Scalable
Systems can be extended or relocated as the project progresses
How Wellpoint Systems Work
Wellpoint Installation
A series of wellpoints (small-diameter perforated tubes) are installed in the ground, usually 1-2 metres apart
Header Connection
Wellpoints are connected via a header main (pipe or hose) to a vacuum pump
Suction & Discharge
The pump creates suction, drawing groundwater through the wellpoints and discharging it away from the excavation
Continuous Operation
Continuous operation maintains a lowered water table, ensuring dry conditions in the work zone
Typical Applications
Pipeline & Utility Trenches
Lowering groundwater along narrow, linear excavations
Building Foundations
Keeping shallow basements and footings dry
Road & Rail Projects
Stabilising soils for subgrade preparation
Marine & Dock Works
Temporary groundwater control near shorelines
Pump Types for Wellpoint Systems
Vacuum-Assisted Auto-Prime Pumps
Specifically designed for wellpoint applications, capable of handling air and water mixtures.
Diesel Trailer Pumps
Mobile and ideal for large construction projects or remote sites without power.
Electric Pumps
Quieter and cost-effective where power supply is available. Lower running costs.
High-Capacity Units
Required for sandy soils or projects with high inflows. Handle large volumes efficiently.
Best Practices
Design the system based on soil permeability and excavation depth
Install wellpoints at consistent spacing and depth for even drawdown
Use filters or screens to prevent sand and fines from entering the system
Monitor water levels regularly to confirm drawdown effectiveness
Maintain standby pumps for continuous operation in case of breakdown
Ensure proper discharge management to avoid erosion or environmental damage
Environmental & Safety Considerations
Settlement Tanks
Discharge water may require settlement tanks or silt control before release
Ground Settlement
Avoid over-pumping which may lead to ground settlement and damage to nearby structures
Spill Containment
Ensure pumps are installed with spill containment for diesel-driven units
Noise Attenuation
May be required in residential or urban areas for 24/7 operation
Summary
Key Takeaways
- Proven and cost-effective – ideal for groundwater control in shallow excavations
- Right pump selection – vacuum-assisted auto-prime pumps designed for wellpoint applications
- Careful system design – based on soil permeability, spacing, and excavation depth
- Proper discharge management – maintain compliance and minimise environmental impact