Welltech’s highly skilled personnel have many years’ experience in this difficult art of managing groundwater.  You can be assured that if you have Welltech on site your project is in good, capable hands.

Wellpoint Dewatering is used in all types of ground which are permeable because of porosity such as gravel, sand, silt and clay.

A wellpoint system consists of a series of small wells installed around the perimeter of the area in which the water table is to be lowered and connected to a high vacuum pump by means of a set of header pipes with couplings and fittings.

The system is based on the induced flow of water in the water bearing strata towards filters (wellpoints) kept under vacuum by a high vacuum pump.

The pressure difference created between the pressure of the ground water (atmospheric pressure) and the filters (wellpoints) directs the ground water flow towards the wellpoints at a velocity which depends on the permeability of the various types of ground.

When the wellpoint system in a given section pumps more water than filters through the voids, the water table begins to lower forming a conical surface.

As pumping continues, the dewatered area increases until the capacity removed by the wellpoint system is equal to the capacity due to filtration.  At this point the water table stabilises forming the “cone of influence”.

Naturally, the size of this cone is closely linked to the permeability of the ground and will therefore be larger in low permeability ground.

For more information on the suitability of dewatering for your site, contact David Henderson at any time.


With environmental constraints making traditional dewatering more and more difficult, ground freezing is now becoming a viable option. 

Welltech’s research and development department have been progressing towards this innovative method of excavating below the water table.

The advantages of ground freezing include no ground water leaves the excavation hence no environmental issues. The depth of the excavation has no effect on the freezing system, unlimited depth can be frozen from the surface.

To discuss the unlimited possibilities of the exciting new method talk to our Technical Director, Research & Development, Ben Campbell anytime.


3”   Utility Pump – Continuing commitment to technical excellence.

The Junior is perfect for open pumping, mop up operations, raw sewerage, tank filling.

In the presence of clay conditions either from the surface or close to invert of the excavation, open suction dewatering is the preferred method. 

This consists of establishing a clean sump area at the lowest point of the excavation and pumping the free flowing water. 

It is desirable to have a blue metal aggregate layer on top of the clay base to allow the free water to flow to the low point.  It is then pumped via a vacuum primed dewatering pump to the point of disposal.


  • Compact and Robust
  • Vandal Proof Silence Enclosure
  • Continuous Prime
  • 100% Duty Cycle
  • Max. Solids: 42mm
  • Max. Flow: 25l/sec


  • Open Suction
  • Sumping
  • Sewerage Bypass
  • Truck & Tank Filling
  • Pump out Lakes,
  • Dams, etc.

Welltech’s commitment to technical excellence means you can be assured that the  ’s performance, silencing and reliability far exceed industry standards.


  • Length: 1770 mm
  • Width: 900 mm
  • Height: 875 mm
  • Capacity: 25 L/sec
  • Head: 23 meters
  • Solids: 42 mm
  • Vacuum: 22 CFM 
  • Mechanical Seal: Tun / Tun
  • Drive: TF 140E Yanmar
  • Power: 10.4 kW
  • Fuel Capacity: 126 litres
  • Inlet: 3” camlock
  • Outlet: 3” Camlock