Hoelscher Dewatering Inc.
Dewatering Services
Our specialists know how to get groundwater and surface water away from your site, and keep it away permanently. Whether your construction project is a straightforward residential development or a complex industrial facility, our expertise in the areas of pipeline, sewer, tunnel and mass transit construction is invaluable. We offer a wide spectrum of services, including preliminary consultations and conception, drafting of special proposals, expert project execution, and computer-controlled monitoring and documentation.

Eductors
Eductors are drilled and installed like deep wells, but differ in the way they extract water. Unlike electric submersible pumps, which burn out quickly if run in dry boreholes, educators pump air and water mixtures without issue. Sealing the borehole on an educator well also creates a vacuum assisted drainage path towards the well.
To help, Hoelscher Dewatering provides double pipe or concentric pipe educator systems, depending on project requirements; and its 30-plus years of installation, monitoring, control, and maintenance experience with educator wells guarantees optimal performance every stage of site dewatering.

Deep Wells
Once drilled, boreholes are lined with a wellscreen / casing assembly. Gravel is then added to fill the annular void around the assembly, and a bentonite seal is placed to protect the borehole against surface water and/or contaminants. Finally, a multi-stage submersible pump is installed within the deep well to begin groundwater extraction, and discharge lines are used to carry the groundwater to a discharge point at the surface. Together, this system works to lower the water table to a project’s desired depth.

Vacuum Deep Wells
Once drilled, boreholes are lined with a wellscreen / casing assembly. Gravel is then added to fill the annular void around the assembly, and a bentonite seal is placed to protect the borehole against surface water and/or contaminants. Finally, a multi-stage submersible pump is installed within the deep well to begin groundwater extraction, and discharge lines are used to carry the groundwater to a discharge point at the surface. Together, this system works to lower the water table to a project’s desired depth.
The groundwater removal is also assisted by a partial vacuum drawn by a vacuum pump aggregate at the upper edge of the well. The vacuum achieved can range up to 0.9 bar (13 psi). The vacuum provides faster and more wide-ranging drainage even in soils with low permeability, therefore stabilizing the surrounding soil layers.

Well Point Systems
Installation requires drilling a borehole of approximately 110mm in diametre to a depth of 8m. After, a plastic pipe 50mm in diametre is inserted and centre into the borehole, the bottommost layer of which is perforated with slots measuring 0.3mm in width. The annular space around the pipe is backfilled with filter gravel and sealed with clay sealant.