The wellpoint system is one of the most versatile of pre-drainage methods which can pump a few gallons per minute in fine sandy silts or many thousands of gallons per minute in coarse sands and gravels.
A wellpoint system consists of a number of wellpoints spaced along a trench or around an excavation site, all connected to a common header, which is attached to one or more wellpoint pumps.
Wellpoint systems are most suitable in shallow aquifers where the water level needs to be lowered no more than 15 or 20 feet. Due to the vacuum limitation of the pump, excavations that are deeper will require multiple stages of wellpoint systems.
When designing a wellpoint system, it is necessary to give first consideration to the physical conditions of the site to be dewatered.
Things to consider include:
-The physical layout
-The amount of water to be pumped
-Depth to imperviousness
To select the proper components of the wellpoint system - the friction losses developed in the suction side system must be considered.