Deep Well Dewatering
Deep well dewatering differs from wellpoint dewatering systems in that deep wells contain submersible pumps placed strategically inside the site boundaries to provide a dry site for excavation and construction.
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 200mm to 300mm 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.
Our deep well dewatering system offers many advantages including:
- Minimal noise
- Easy to install
- Does not rely on vacuum inducement, typically associated with Wellpoint dewatering
- Relatively maintenance free as the submersible pump sets are housed in the Deep Well and cooled by the flowing groundwater
- Ability to penetrate strata impervious to the jetting method of Wellpoint systems
- Installation of up to 100 feet deep or more in a single stage
- Capable of pumping tens to thousands of gallons per minute per Deep Well
Khansaheb Sykes creates unobtrusive Deep Well systems that cause a minimum of access restrictions by using relatively widely spaced wells and designing perimeter systems that rarely call for the use of internal wells, thus providing excavation interiors free from dewatering wells.
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.
Through our depots and offices, we provide a local hands-on service nationwide. Our dewatering products and ground water control services are just a phone call away. To get further information or advice call us on 00971 800 79537.
Khansaheb Sykes offer a full installation service for deep well applications, our highly experienced engineers will visit your site and by using soil analysis will advise you on the best solution for your dewatering requirement.
We will advise on the depth of each well and the quantity and positioning to ensure that the excavation remains dry through the project cycle. Once the system design has been approved, our specialist drilling rigs will bore the holes in readiness for the well screen to be installed. The well screens are typically 200mm or 300mm in diameter and are joined together to provide the required length. The wells are often surrounded with additional filter media to aid drainage and prevent fines from entering the system. Once the well has been flushed, it is ready to have the borehole installed. The type and size of pump used will match each application. The pump is carefully lowered into the well where it is safely installed. Once again, the depth at which the pump is installed will depend on the final depth of excavation, although the pump will always be installed away from the base of the well.
The electric cable that is fitted into the pump motor is taken up the well, where it is connected to a power supply via one of our control panels. Each control panel is normally fed from a mains distribution unit, which is supplied from a mains supply or generator. Khansaheb Sykes can also provide the distribution unit generator, fuel tank and even provide a fuel management service throughout the project cycle.
Each pump discharge is connected to a common discharge main by means of individual flexible hoses, non-return and isolating valves. When the system is commissioned a Khansaheb Sykes technician will balance each well to ensure optimum performance.
Once the system is up and running our service continues, some of the larger sites will have a permanent Khansaheb Sykes Operator on site 24/7 to ensure that the system is well maintained and operating at peak efficiency. Others may prefer periodic visits. Either way our emergency service is available 24/7 to provide an instant response to any unforeseen problems.
The Khansaheb Sykes 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 6 metres or when wellpoint dewatering is deemed inefficient. Our deep well dewatering system offers many advantages including:
- Cost-effective dewatering
- Low noise
- Problem free pumping
- Easy to install
- Does not rely on vacuum systems, typically associated with wellpoint dewatering
- Relatively maintenance free
- Ability to penetrate strata impervious to the jetting method of wellpoint systems
- Installation of up to 40 metres deep or more in a single stage
- Capable of pumping high volumes of water from each well
In addition to groundwater lowering for construction site excavations, Khansaheb Sykes are often called upon to devise many other types of deep well schemes for a variety of applications. Such applications include the use of deep wells as bore holes where water abstracted from the water table is used for industrial or commercial requirements. We can also use wells to help drain water in low lying areas or areas where drainage is a problem. Whatever the application, Khansaheb Sykes can provide the specialist skills and equipment for the installation of deep bored pumping wells. Our specialists will happily carry out a free site survey before offering you a detailed quotation.