SMALL DAMS PETITS BARRAGES

2.3 ZONED EARTHFILL DAMS
In arid parts of the world (e.g. Iraq, Iran etc.) zonal embankment small dams are usually
constructed with central clayey core stabilized by shell material embanked from coarse river
gravels, but this type of dam is possible also for not arid areas. These two basic materials are
separated by two sandy-gravel filter layers.
2.3.1 CENTRAL CLAY CORE DAMS
Where there are abundant pervious materials for dam shells but little amount of cohesive
materials, central core dams are more desirable. The central clay core may be thick or thin,
depending on the construction condition and on the availability of impervious soil. The shell
zones upstream and downstream of the central core may be filled with highly pervious
materials like sand, gravelly soil, weathering soils, etc.
Fig.2.3 – Itiquira embankment zoned dam, Brazil.
Fig.2.4 – Another cross section of the Itiquira dam, Brazil.
2.3.2 SLOPING CORE DAMS
Fig. 2.5 – Shadow Mountain Dam (1943 - 46), USA [2].
1- Clay Core
2- Sandy clay
3- Rip-rap
4- Alluvial gravel
and sand
1- Sandy clay
2- Rip-rap/Gravel
3- Coarse sandy
4- Gravel
5- Rockfill
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