Dewatering Services & Groundwater Control

Core Activities (tags): Dewatering Services in Dubai, Dewatering Pump Rental services in Dubai, Deep Well Systems, Well point Systems, Sumping Systems & Horizontal drainageCore Activities (tags): Dewatering Services in Dubai, Dewatering Pump Rental services in Dubai, Deep Well Systems, Well point Systems, Sumping Systems & Horizontal drainage

All of the technologies associated with Dewatering services, Vacuum filter installation, Wellpoint system or Deep wells, Horizontal drainage or Open dewatering are performed by our technically qualified and skilled workforce who have been catering for the UAE market for many years now . Be it civil engineering or infrastructure development, tunneling or when laying pipelines, HARCO world is your trusted partner. 

Consistent quality and time management are the forte of Harco. Our team is not only technical specialists in the Dewatering industry, but also qualified project managers adhering to project management principles of timely completion and quality control. Since we are a well-established contractor in this Industry, our process is already streamlined to the degree by which we can afford our client cost effective solutions, while delivering professional, high quality, Dewatering Services in Dubai and in areas around Dubai and UAE. Our research team constantly innovates to keep up with emerging technologies and consequently we do maintain a vast inventory of high quality tools and equipment to further our service objectives. When it comes to Dewatering Services, we provide turnkey solutions that are from A to Consultation,design, proposals, execution of the works, monitoring the results, generation of reports and documentation are the aspects of the work we undertake.

Deep wells system

The deep well system is pre drainage dewatering system 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. Deep well systems consist of one or more individual wells, each of which has its own submersible pump at the bottom of the well. Deep well systems are suitable for water-table or confined aquifers and will lower the water table 100 feet or more in a single lift without staging. Bothcasing drilling method or the rotary drilling method are used in accordance with the diameter, the geology and depth to make the boreholes. These wells are created by drilling a hole with a diameter of 324 mm to 2000 mm at a depth up to 300m.

The deep well system is pre drainage dewatering system 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. Deep well systems consist of one or more individual wells, each of which has its own submersible pump at the bottom of the well. Deep well systems are suitable for water-table or confined aquifers and will lower the water table 100 feet or more in a single lift without staging. Bothcasing drilling method or the rotary drilling method are used in accordance with the diameter, the geology and depth to make the boreholes. These wells are created by drilling a hole with a diameter of 324 mm to 2000 mm at a depth up to 300m.
When such a system is installed, a filter is placed around the screen. This arrangement helps to prevent the infiltration of the foundation materials into the well. The installation of filter also helps to improve the yield. The filter string may consist of a wire mesh filter, a slot filter or a slot bridge filter, all of which are available in different materials. Deepwells generally consists of an array of bored wells pumped by submersible pumps. The wells acts as a single unit and in concert, therefore the interaction between the cone of the drawdown results in ground water table lowering over a wide area. The ideal soil permeability value (k) for Deep Well System lay between 1x10-2 m/s and 1x10-5 m/s.

The method is more suitable where long term dewatering has to be carried out. This will thus work for large excavations for a variety of ground conditions. These systems can help provide under-drainage of the overlying soil that is less permeable into the permeable stratum that is pumped. This also helps to relieve the pressure below the confining layer of clay.

Harco takes these basic steps that are involved in relation with the design of deep well dewatering systems are:
1. The drawdown that is required for the well is initially determined. This will help to suit the geometry of excavation.
2. The inflow into the excavation is calculated. The inflow in large areas can be assessed using the flow nets. This can also check the potential during high inflow velocity that might cause piping or boiling.3. The yield and the wetted length of the trial well is calculated. 4. The number of wells and spacing is calculated. The zone interaction if any is found for those wells at less than 20m centers.
5. The filter pack and the screen slots are designed to make sure that the aquifer is not drawn into the well.6. The entry velocity to the well is checked
7. Pump size is checked so that it suits the screen or the liner.
8. Sufficient working space for side slopes and excavation have to be provided.
9. The calculations are repeated so that an optimum design is obtained.

 

Vacuum Deep Wells

Vacuum deep wells are utilized for underground water drainage and site decontamination with low permeable grade soils and low lying aquifers.
Vacuum deep wells are effective for operations with soil permea-pility values (k) between 1x10-5 m/s and 1x10-7 m/s.  

They are created by drilling a hole  with a diameter of 324 mm to 700mm at a depth up to 50m. The borehole is produced using the casing drilling method or the rotary drilling method in accordance with the diameter. The geology and depth.  

After the borehole is drilled the well is equipped with filter screen and surrounding space is refilled with filter gravel. In additions, the surrounding space is seated up to the top with clay blocker. The completed well is equipped with a multistage underwater pump for pumping the underground water. The pump pumps the water into a runoff ditch thereby lowering the underground wa-ter level to the required depth.
Vacuum deep wells are also placed under additional vacuum pressure from the top of the well. The vacuum is produced with a vacuum air aggregate. The vacuumed that is created maybe high as 0.9 bar.

The vacuum provides quick and more extensive drainage effort low permeability grade soils and also stabilizes the other sur-rounding layer of soil. 

Wellpoint system

Well Point Systems in Dubai Well Point Systems in Dubai

Wellpoint dewatering is the process of removing groundwater temporarily from soils in a localized area to complete the construction of a foundation, pipeline or other below-ground structure or to perform soil remediation. Wellpoint method of dewatering is used for: -Wellpoint dewatering is the process of removing groundwater temporarily from soils in a localized area to complete the construction of a foundation, pipeline or other below-ground structure or to perform soil remediation. Wellpoint method of dewatering is used for: -
Land remediation;
Pollutant reclamation;
Laying deep sewer, water or utility lines;
Excavation and lining work for canals and channels;
Excavations for basements, structures and foundations of buildings; and
Foundations of dams, bridges, powerhouses and underground tanks.

A series of shallow wells, usually 40 to 50mm in diameter and from 6 to 8 meters in length, known as wellpoints are installed at a predetermined depth and appropriately spaced along a trench or around an excavation site. Harco’s Dewatering experts employ several installation techniques, including installing or jetting by high pressure water, installing wellpoints by hand, using a casing or punch as well as drilling methods such as augers and drill rigs.

The installed wellpoint reaches the surface via a riser pipe, which is in turn connected to a common header pipe main through a clear, flexible swing joint that incorporates an adjustable header valve. The swing joint provides a clear view of what is being pumped, and the valve allows control of the air entering the system. Lastly, the header pipe is connected to a wellpoint pump. The vacuum produced by the pump draws water through notches in the wellpoints. The water then travels from the wellpoints through the swing joints into the header pipe to the pump. It is then discharged away from the site or to other processes to remove unwanted properties such as contaminants. These systems can be used to lower and control groundwater levels in excavations, in order to create a dry and stable working environment, and are also suitable for shallow foundations and trench works. Harco’s Wellpoint Dewatering Systems have the ability to deal with very low flows in silty sands to much larger flows in coarse sands and gravel.

Our streamlined processes and experience in the MENA regional market affords us the understanding of subsoil conditions locally. We are thus able to recommend the right equipment to our clients, resulting in cost and time benefits, besides the assured quality of work. After installation of the system, our team constantly monitors, improves and services the system from our vast network of depots.

Well Point Fluid Discharge Best Practices

It is a best practice to minimize the dewatering discharge velocity to avoid scouring the receiving area, and design structural controls such as basins or sumps that receive discharge water to handle the anticipated discharge flow. Harco takes 100% effort to ensure that all stakeholders, including the environment and surrounding society is taken into consideration while discharging wellpoint dewatering fluids.

Micro well system

This system has proven to be well suited for the drainage of law permeable grade soils and trenches with depths up to approx. 5.0m.

Installation requires a borehole of approx. 110mm which can be rotary– drilled or drilled with a casing up to a depth of 10 meter.

A plastic pipe with a 50mm diameter is inserted and cen-tered in the borehole sink. The lower 1.0m section of the pipe is installed the surrounding space is refilled with filter gravel and with clay blocker.

Several Micro Wells are connected to a circular pipeline via PVC suction hoses. Powerful vacuum pumps are used to create a vacuum in the circular pipeline up to – 0.9 bar. Part of the vacuum present on the pump’s inlet side is used to raise the water being pumped out of the wells. The remaining vacuum drains and stabilizes the surrounding layers of soil. After the construction project is completed the plastic pipe is withdrawn and the bore-hole is refilled with gravel.

The special design of micro wells makes them effective   in all soil layers since the entire length of the filter ele-ments is assembled to ensure it remain stable in the soil   

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