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UNIDATA
Unidata Manual 6293 - Precision Water Level Instruments Issue 2.1
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flowing, the larger the slope will be. The measuring location will need to be the
point of interest as the varying slope will introduce different errors in different
conditions.
If the water velocity is too high, it can begin to affect the water level inside the
floatwell by causing a venturi effect on the inlet holes. This effect can be
minimised if the intake holes are located on the upstream and downstream sides.
It can be eliminated if a static tube is used on an inlet pipe.
11.4.2 Siltation
Silt and sediment can collect in floatwells. This happens when silty water enters
the well and the silt settles in the still water. If there are several entrances and
exits through which water can flow, lots of silt can be deposited. In such cases
there must be some way to clean out the well. Small wells can be washed out
with a pump once the float system has been removed. Special designs may be
required to enable larger wells to be cleaned easily.
Note that the atmosphere in deep float wells can be foul and dangerous and you
should not enter them without taking precautions.
11.4.3 Environmental
impact
Building structures in and near waterways can cause erosion and damage. Site
operation can introduce and concentrate activities that may affect the local
ecology. The site design, construction and operation should be planned to
minimise such effects. Where appropriate, installations should be designed to