Measurement of the vertical water velocities flowing through a bore-hole when the water is pumped out or injected will indicate the position of inlets or outlets in the hole.
Lowered into a bore-hole or into a suitable piezometric installation, Microflowmeter makes it possible to measure natural rates of flow and rates following pumping in and pumping out of water, and hence to deduce the petmeability of the strata which the bore-hole crosses.
The instrument we have used consists of a propellor and a photo cell detection system, and is particularly suitable for bore-hole measurements.
Some examples of the test show that the measurement of the vertical water velocities flowing through a bore-hole is useful not only to determine the permeability of strata, but also to estimate the behavior of ground water through the basement rock of dames and around tunnels.