PVC Wellpoints

Wellpoints are small-diameter (about 50 mm) tubes with slots near the bottom that are inserted into the ground from which water is drawn by a vacuum generated by a dewatering pump.

Wellpoints are typically installed at close centers in a line along or around the edge of an excavation.As a vacuum is limited to 0 bar, the height to which water can be drawn is limited to about 6 meters (in practice). Wellpoints can be installed in stages, with the first reducing the water level by up to five meters, and a second stage, installed at a lower level, lowering it further. The water trickling between the deep wells may be collected by a single row of well point at the toe. This method ensures a much thicker width free from seepage forces.

Wellpoint spears are generally used to draw out groundwater in sandy soil conditions and are not as effective in clay or rock conditions. Open pumps are sometimes employed instead of spears if the ground conditions contain significant clay or rock content.