SMALL DAMS PETITS BARRAGES

Fig. 6.9 – Recommended standpipe piezometer location for small earthfill dams
according the PHC.
Potential Hazard Classification
PHC 1 PHC 2 PHC 3
Fig. 6.10 – Recommended piezometer location for small rockfill dams according to the
PHC.
In Figure 6.9, some piezometers have their chamber located in the horizontal drain. That
allows controlling efficiency of the drainage system and measuring hydraulic gradient inside
the horizontal drain. Another solution is to have piezometers not reaching the drain, with the
chamber inside the downstream embankment. That allows measuring piezometry in the
embankment and, indirectly, controlling the efficiency of the drainage system.
Recommendations for Leakage Measurements
During the design of the dam and the internal drained system it is important to consider
how the seepage water will be measured, because sometime it is important to incorporate
some especial details at the horizontal blanket, in order to allow a more precise monitoring
system. At the small dams it is usually recommendable installing a triangular weir gauge at the
downstream toe, at the central section of the dam, when possible, as illustrated in Fig. 6.11
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