Construction Dewatering Methods - Sulzer

Main dewatering techniques

Construction dewatering methods refer to techniques such as wellpoints, deepwells, bypass and flood control. In wellpoint and deepwells submersible pumps are installed in a drilled well shaft, while in bypass and flood control pumps are placed in the area that needs to be dewatered. Let's review these common techniques.

Wellpoints

In Wellpoint, wells are drilled around the excavation area with submersible pumps installed in the well shaft. These pumps are connected to a header pipe allowing the groundwater to be drawn up by the pumps into the Wellpoints and then discharged.

Deepwells

In Deepwell, one or several individual wells are drilled, and submersible pumps are placed in each shaft. The Deepwell technique is best suited for deep excavations where large water volumes need to be discharged.

Bypass dewatering

When sewer lines need maintenance, the sewage flow is pumped around the damaged pipe section using dewatering pumps. The pumps are installed upstream of the maintained pipe section. Bypass technique is also common in irrigation and construction projects.

Flood control

Flood control refers to all methods used to reduce or prevent harmful effects of flooding from for example storm water and heavy rainfall. Be it construction, tunneling or mine work, site managers need to be prepared for potential site flooding, keeping pumps that can move high volumes of water against low head pressure nearby. The same applies to elevated water levels in channels, that could have a major impact on local communities when roads and houses get flooded. It is important that municipalities have good flood protection and are prepared to act quickly on these occasions.

Tunneling dewatering

Tunnel constructions are complex worksites where many variables need to be taken into consideration. Significant volumes of water from the construction site need to be removed in order to stabilize the ground or prevent flooding of the work area. Tunnel boring machines and drilling equipment require a reliable supply of cooling water, which must be recovered, extracted and treated after use. Tunneling projects require many dewatering pumps on site, ranging from small submersible pumps to very large units for large volume dewatering applications. For more detailed information, we recommend reading the article Keeping the water where you want it in tunnel construction