SMALL DAMS

L ife of the dam
ORGANISATION OF SURVEILLANCE BY THE OWNER
Dam surveillance is carried out by the owner or operator on the basis of inspections.
VISUAL INSPECTION
Systematic inspections
Inspections should be done once a month if H² V > 50 and once every two months
for smaller dams. They should be more frequent during first reservoir filling: weekly
inspections may be recommended, or possibly fewer if the reservoir water level varies
little. The contents of these inspections must be defined according to the structures
being inspected, and the itinerary is determined to ensure regular inspection of all
parts of the dam. For structures with instrumentation, the most simple measurements
will be made on these occasions such as reservoir water level, leakage flows,
piezometer readings, pore pressure cell readings, Vinchon vibrating wire readings,
pendulum readings, etc.
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Special inspections
This is the case when the reservoir is lowered or emptied exceptionally. The contents
of such inspections must be adapted to the special points to be inspected (structures
that are usually under water, river banks, upstream face, etc.).
Exceptional inspections
After a high flood, a storm or an earthquake, the owner or operator must examine
any damage and make certain decisions.
If incidents or anomalies are noted on the dam:
!"all anomalies should be marked out in order to determine the "starting point" with
quantifiable data that can be compared to later data;
!"if the anomaly is confirmed, the appropriate conduct should be defined according
to levels of urgency;
!" where necessary, the frequency of inspections and instrument readings should be
modified, as should their contents.
Means required
It is not necessary that the people doing visual inspections be specialists in Civil
Engineering. It is more important that they possess qualities of rigour and precision,
as well as appropriate motivation.
However, it is important to specify that:
!"the person in charge of inspections must have received sufficient information on the
dam;