SMALL DAMS

S mall concrete dams
Here we give four examples of medium-size dams (21 to 25 metres) and one small
dam (16 metres) that illustrate the various paths that may be followed. Design of small
or medium height RCC dams is not fundamentally different, and these case studies
could serve as examples for smaller dams with no major changes.
RIOU DAM (SEE PHOTO 23 P. VIII)
Riou dam (figure 3) was built by EDF; the dam is 21 metres high and involves
42 000 m 3 of RCC. It was extensively analysed within the framework of the French
national research project on RCC entitled BaCaRa. The selected cross-section was a
trapezoidal shape with a vertical upstream face, a downstream face sloped at
0.6H/1V and a crest width of 5.40 metres. The dam's watertightness was provided
by a PVC geomembrane fastened on the upstream face with steel anchors, while the
foundation was treated with a grout curtain. The dam body and its foundation were
drained from a gallery in the lower part of the cross-section. The downstream face
was free overflow for a width of 65 metres, and used as a stepped spillway chute.
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Fig. 3 - Typical cross-section of the Riou RCC dam - Faced with impervious geomembrane