SMALL DAMS PETITS BARRAGES

6.3 SURVEILLANCE PRACTICES
Safety surveillance of a dam is a program of regular visual inspection using simple
equipment and technique. It is the most economically efficient means of ensuring the longterm
safety and survival of the dam. Its primary purpose is to monitor the condition and
performance of the dam and its surroundings, and to ensure maintenance before the
development of potential hazards.
The procedure is unique to each dam but essentially it consists of:
� Regular and close examination of the entire dam surface and its immediate
surroundings;
� Appropriate measurements of cracks, surface erosion, soil transported by leakage,
etc.
� Keeping concise and accurate records of observations.
For continuity and consistency of approach, it is recommended that the same person
should normally carry out each type of inspection. When necessary, an experienced engineer
need to be brought in, to inspect or advice about particular problems.
To be effective, surveillance requires a good knowledge of the dam (data on
construction, reports on all work done and inspections, etc.), and the guarantee of good
maintenance and surveillance of any work already done. It is very important to gather all
known data about the dam concerning both its construction (surveys, design, construction, asbuilt
documents) and its later life (operation, reports on inspections, reports on maintenance
work, monitoring data, typical incidents, etc.).
The following items are useful when conducting an inspection:
� Notebook or diary and pencil to write down observations about the main points;
� Digital camera to provide photos of the particular anomalies and deteriorations;
� A tape to take some measurement allowing the location of wet areas, cracks and
slumps for future comparisons.
The quality of the visual observations, and therefore dam safety can only be achieved by
sufficient motivation and some technical training for the personnel involved.
6.3.1 Inspection Procedures
The procedure for dam safety surveillance is unique to each dam but consists essentially
of regular, close and systematic examination of the entire surface of the dam and it immediate
surroundings. In the case of small dams, especially those dams in which owner have not
sought appropriate advice, there may be a perception that above procedure are unnecessary,
or an unproductive use of time. There may also be a lack of knowledge of what needs to be
done.
For a small dam it is prudent to obtain professional engineering advice to set up the first
program, using a simple set of pro-forma check-list to record observations.
Smaller utility companies or municipal entities that own and operate small dams may not
have in-house engineering capability and staff to form their own performance program. In such
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