Learn which option is right for your next excavation project.
There are a wide variety of methods used to control groundwater during an excavation. Selecting the right dewatering process is a critical step in almost any construction project. Each individual job brings with it a unique set of ground conditions, and therefore must be assessed carefully.
It’s also important to attempt to reduce any impact on groundwater resources when choosing a dewatering method.
There are four primary dewatering pumping techniques used in most construction products requiring excavation. These techniques are not necessarily interchangeable, as each one has a narrow range of applications.
Wellpoints
This dewatering method uses rings or lines of closely-spaced wells that are installed around the excavation area. The wells, or “wellpoints,” are then connected to a headerpipe and pumped by wellpoint pumps that can handle both water and air. This system primarily works using the suction principle, so drawdown using this method is limited to around five to six meters below the wellpoint pump level. If a deeper drawdown is required, multiple stages of wellpoints must be used.
Sump pumping
This process allows groundwater to seep into the excavation area, where it is collected in sumps and pumped away by high-powered, solids-handling pumps. This method is often used in shallow excavation areas.
Eductor wells
The eductor well method is a dewatering process used to control pore water pressures in materials with low permeability characteristics, such as fissured clays or silts. This method uses the venturi principle, where high pressure water is circulated through eductors in the base of each well to create a vacuum that helps promote drainage.
Deepwells
Deepwells use a bored well, which is pumped by submersible pumps that help lower the groundwater level below the level of excavation. With this method, wells are usually installed at wide centers around the outside perimeter of the excavation area. This process is best suited for deep excavations where large drawdowns of liquid are necessary.
Not sure which dewatering method is right for your project?
If you’re not sure which dewatering technique is right for your excavation project, feel free to reach out to the professionals at MWI Pumps, the experts in submersible pumps and wellpoint systems.
If you only need a dewatering system for a short time, we offer a variety of trash pumps, wellpoint pumps, and dewatering pumps for rent. This way you can reduce the capitol outlay required. For more information on renting one of our pumps, call us now at 954-427-2206 or reach out to us through our online contact form.
