SMALL DAMS PETITS BARRAGES

FOREWORD
The ICOLD – International Committee on Large Dams decided to prepare a bulletin on small
dams in consideration to the great number of this type of dams, that represents generally more
than 90% of the total number of dams.
There are clear evidences of the construction of the first small dams about 5000 years ago in
Jordan, about 4600 years ago in Egypt and Baluchistan, and from 3250 to 3500 in Turkey,
Yemen and Greece. These data and other with a “Historical Review on Ancient Dams” are
presented at the ICOLD Bulletin N o 143, to be published in 2011 by ICOLD.
This bulletin was prepared as a guide for small dam owners, engineering, Government
agencies, developers and contractors who are in charge with the design, construction,
operation, maintenance and safety of small dams. This bulletin was developed mainly to the
embankment dams which represent the very large majority of small dam. It is however
important to point out that laws and regulations vary with different countries, and may even be
stricter than the guidelines in this bulletin.
In this bulletin “Small Dams” are defined as having the following characteristics:
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o 2,5 m < H < 15 m and H . V < 200
o H is height in meters above river bed level to maximum crest level
o V is storage volume in million m 3 at maximum operating level = full supply level.
Design criteria and typical features for small dams are generally different from those for high
dams, because the construction methods focus upon economy. So the risk may increase and
corresponding accidents may cause significant victims. The basic principle of design is to
produce a satisfactory functional structure at a minimum total cost. At the “Features of the
Design of Small Embankment Dams” are presented the important contributions from China,
United States, France, South Africa, Australia, Czech Republic and Japan, related to the
recommended embankment slopes for small dams based on the experience with the
construction of a large number of those small structures.
“Guidelines on Surveillance of Small Dams” presents the main recommendations in order to
assure that the dams will behave appropriately and with a minimum cost. The construction of a
dam can involve a significant investment and dam owners need to ensure that their money is
well spent and that their dam becomes an asset.
Ageing of embankment dams, updating of design standards and criteria and the deterioration
of conditions affecting the safety of small dams are analyzed in detail at the “Rehabilitation
Practices for Small Dams”, emphasizing the main remedial measures related to embankment
dams.
At the “Emergency Action Plan (EAP)” are emphasized the main points concerned the
application of such plan to minimize the consequences of a dam failure or malfunction,
regarding the population living downstream, presenting some recommendation about how to
develop an EAP, evaluating the possible dam risks and the management of the dam safety.
At the “Legislation & Decommissioning” chapter are pointed out the dam safety and security
of people, property and environment downstream of dams and the important responsibility of
the Government, who must legislate and enforce the rules through administrative agencies,
departments and offices.
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