UNIDATA
Unidata Manual 6293 - Precision Water Level Instruments Issue 2.1
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11 APPENDIX D – FLOATWELLS
11.1 The Need for Floatwells
If a float is located on open water, it can be affected by waves, wind and water
movement. If any of these influences are strong enough to interfere with the
position of the float, inaccurate measurements will result. A typical example is
where the float is washed out of position by a strong current. To ensure such
external influences do not affect the measurement, you will need to use a
floatwell (stilling well).
11.2 Floatwell Design
A floatwell must be designed to suit the conditions at the measurement site.
Small sites may only require a simple PVC cylinder one or two metres in length.
For larger sites, you may require steel or concrete structures to protect the float
from high water velocity and debris. More sophisticated structures may require
professional design.
Floatwells can stand in the water attached to a post or pier, or can be buried in a
concrete structure or a river bank. Water normally enters through holes in the
wall of the well or through inlet pipes.
