How does a wellpoint operate to remove water from an excavation site?

A wellpoint operates to remove water from an excavation site primarily by bringing water to the surface using suction. This system employs a series of wellpoints—small-diameter wells installed around the excavation site. These wellpoints are connected to a vacuum pump that creates negative pressure, drawing water up from the surrounding soil and into the wellpoints.

The suction mechanism is effective because it allows for the extraction of groundwater from below the water table, ultimately lowering the groundwater level in the excavation area. This technique is particularly useful in maintaining a dry work environment during construction activities, which is essential for safety and stability.

The other methods mentioned, such as pressure drainage or gravity drainage, do not leverage the same suction principle that wellpoints utilize. Those methods may be effective in other contexts, but the key feature of wellpoint systems is their reliance on suction to manage groundwater effectively.