Deep Well Dewatering

Sky Deep Well dewatering system is recognised as a cost effective and efficient way for medium to long term dewatering of large projects where the excavation is greater than 5 metres or when Wellpoint dewatering is deemed inefficient. Our Deep Well dewatering system offers many advantages including:

 

 

Deepwells can be located within the plot strtegically or along the periphery of the plot without obstructing the construction.

  • Clean single time installation wth minimal noise and easy to install
  • The deep well system relies on the gravity flow of ground water and hence does not rely on vacuum assisted self priming pumps, typically associated with Wellpoint dewatering
  • Relatively low maintenance free as the submersible pumpsets are housed in the Deep Well and cooled by the flowing groundwater
  • Ability to penetrate hard fractured substrata impervious to the jetting method of Wellpoint systems
  • Installation of up to 40m deep or more in a single stage
  • Capable of pumping high flow rates of ground water per Deep Well


Deep Well groundwater control systems are employed to lower groundwater levels to provide stable working conditions in excavations. A Deep Well dewatering system consists of an array of widely spaced bored wells fitted with multi-stage electric submersible pumps.

Deep Well dewatering systems are effective in a range of soil conditions from gravel to fine sands. The technique is particularly suited to deeper excavations or where artesian groundwater pressures threaten base stability. Deep Well dewatering systems can also be used where small amounts of drawdown are required over large areas.

Deep Well dewatering typically consists of vertical or inclined bore holes, usually in the order of 150mm to 400mm diameter casings placed through the strata requiring dewatering. A suitable uPVC deep well casing will be placed in the borehole, consisting of screened and cased sections. An adequate filter pack is installed to both maximise well yield and inhibit the movement of fines. After deep well development, airlifting within the deep well casing is carried out before a suitable electric submersible borehole pump is installed.

Deep Well Dewatering Systems

When the water table needs lowering below 10 metres, conventional vertical Wellpoint dewatering isn't feasible or economical. We can offer a Deep Well system as an alternative. A Deep Well system consists of an array of widely spaced bored deep wells fitted with multi-stage electric submersible pumps. Pumps typically used for deep well gravity drainage include multi-stage bore hole pumps electric submersible units: these pumps permit excavation down to any required depth in a single stage.

Deep Bored Pumping Well

When the water table needs lowering below 5 metres, conventional vertical wellpointing in stages isn’t feasible or economical. We provide an alternative the tube or bored well. A hole is bored to the required depth a mesh screen lining then allows water to accumulate at the bottom, which is removed by a pump installed in the well.

Pumps typically used for deep well gravity drainage include electric submersible units: these pumps permit excavation down to 24m in a single stage.

Deep Well dewatering systems can be installed in a ring around an excavation to lower the water level and maintain a safe, dry site. Several equations can be used to design Deep Well dewatering systems, however many of these are based on empirical data and occasionally fail. Practice and experience, along with a firm understanding of the underlying principles of dewatering, are the best tools for designing a successful system. This is where you can rely on the experience and technical dewatering expertise of Sky Dewatering team.

Deep Well dewatering systems are effective in a range of soil conditions from gravel to fine sands. The technique is particularly suited to deeper excavations or where artesian groundwater pressures threaten base stability. (Because the pump is installed at depth in the well there is no physical limit on drawdown other than the aquifer response and the performance characteristics of the pump in use. Well yields can be improved by specialist development techniques such as airlift in granular soils and acid development in chalk.)

A filter pack is placed around the Deep Well liner to prevent suspended solids from entering the Deep Well. The pumps are powered from a central control cabin and discharge water is normally collected in an HDPE or GI ring main.

Our Deep Well dewatering system is also a versatile pre-drainage solution which can pump high and low volumes of groundwater. This method is best suited to homogeneous aquifers that extend well below the bottom of the excavation.