Multilevel water gauge in borehole - comprises pipes connected to filter layers at different levels and all housed in common vertical tube

摘要

Multi-level water gauge in a borehole is constructed by lowering into a borehole a pipe of smaller dia. contg. a number of side apertures at intervals throughout its height. Each aperture has attached to it a smaller dia. pipe leading up to the top of the main pipe and thus forming a watertight connection between the side aperture and the top of the pipe. Around the main pipe inside the borehole fill is then progressively introduced, comprising alternating filter layers and less permeable layers. Each filter layer is opposite one of the apertures.