Dewatering

Dewatering

Dewatering is the process of removing groundwater, which ensures construction work can occur without trenches collapsing.

When groundwater is present, dewatering costs are charged to you. If the costs are more than the final invoice, the extra charges are not passed on to our customer. If the work required to remove the groundwater is less we will refund any unused part of the invoice to you.

You will be invoiced for the estimated dewatering cost. Once we’ve received your full payment, site works will commence.

Controlling groundwater

There are many systems that can control groundwater. The method used will be determined by the level, size and depth of excavation. Geological conditions and characteristics of the soil are also considered.

The simplest and most cost effective form of dewatering is a trench pump. Groundwater entering the excavation can be collected in a sump and pumped away. This system is only effective where the excavation is on or just below the groundwater level.

A trench pump cannot always control groundwater inflow. In this case we use a vacuum truck or well point dewatering system. This requires specialist contractors and equipment to extract, pump and dispose of the groundwater. This also significantly increases the cost of dewatering.

A vacuum truck uses a heavy duty vacuum to load solids, liquids, sludge or slurry through a suction line. This may require more than one truck. Disposal of the collected material and groundwater must comply with environmental regulations.

Well point dewatering systems need a series of suction spears. These are installed near the excavation site.

The suction spears are driven into the ground below the groundwater level. These suction spears are connected to larger header pipes which are also connected to a pump. The pump draws the groundwater into the suction spears and through the header pipe. The water is discharged via an approved environmental treatment system.

Dewatering systems require installation before the planned excavation. They may need to run continuously for several days. This lowers the groundwater level so excavation can begin.

Is your suburb likely to need dewatering

The suburbs below may be subject to groundwater costs. Recent costs for well point dewatering work in these suburbs have averaged $16,500. However additional fees may be payable depending on the specific job requirements, to be confirmed when assessing the application.

Albert Park

Clearview

Glenelg East

Largs North

Port Adelaide

Woodville West

Alberton

Cowandilla

Glenelg North

Lockleys

Royal Park

 

Allenby Gardens

Dry Creek

Glenelg South

Mansfield Park

Seaton

 

Angle Park

Edinburgh

Glengowrie

Mawson Lakes

Semaphore

 

Athol Park

Edinburgh North

Globe Derby Park

Morphettville

Semaphore Park

 

Beverley

Ethelton

Grange

North Haven

Semaphore South

 

Birkenhead

Exeter

Greenacres

Northfield

St Kilda

 

Bolivar

Ferryden Park

Greenfields

Novar Gardens

St Clair

 

Brighton

Findon

Hendon

Osborne

Taperoo

 

Brighton South

Flinders Park

Henley Beach

Ottoway

Tennyson

 

Broadview

Fulham

Henley Beach South

Outer Harbor

West Beach

 

Brooklyn Park

Fulham Gardens

Hove

Pennington

West Lakes

 

Buckland Park

Gepps Cross

Kidman Park

Peterhead

West Lakes Shore

 

Camden Park

Gillman

Kilburn

Plympton Park

Wingfield

 

Cavan

Glanville

Largs Bay

Plympton South

Woodville Gardens

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  • 18/06/2020
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  • 18/06/2020 03:05 PM - We are attending to an incident in Arthurton with no interruption to the water supply. The safety of our crews and customers comes first, and we always aim to minimise inconvenience by restoring services as quickly as we can. Reference Number WO: 07505663.
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  • 01/11/2020
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    We’re improving your services and undertaking maintenance work in Green Fields. Sometimes our crews need to temporarily interrupt the water supply to our customers and/or manage traffic while they are working. Temporary traffic management may remain in place until reinstatement of the impacted road is complete. We always aim to minimise inconvenience by restoring services as safely and quickly as we can.


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