Standpipe piezometers are used to monitor piezometric water levels. Water level readings are typically obtained with a water level indicator. Typical applications include:

-Monitoring pore-water pressure to determine slope stability.

-Monitoring seepage and ground water movement.

The standpipe piezometer, which consists of a filter tip and a riser pipe, is installed in a borehole. The zone around the filter tip is backfilled with sand and a bentonite seal is place above that to isolate the intake zone. The remainder of the borehole is backfilled with bentonite-cement grout. Pore water flows into the standpipe until a pressure equilibrium is reached. The water level in the pipe then represents the pore-water pressure in the soil around the intake zone. Readings are taken with a water level indicator.

Source: http://www.slopeindicator.com/instruments/piezo-standpipe.php

Link to report of this instrument: SP