SMALL DAMS

Chapter IV
CONSTRUCTION PRINCIPLES TO BE STIPULATED IN THE PARTICULAR TECHNICAL
CLAUSES
Protection of the construction site from water
This addresses the following problems:
!" collecting springs and infiltration, and release outside the various excavations;
temporary or permanent structures may be required;
!" protection of the fill and the borrow areas from runoff;
!"the particular technical clauses should stipulate up to what flow the construction site
should be protected, for example the 10-year flood calculated over the period of
construction, but for practical reasons, this flow will be translated into an elevation in
the tender documents and contract. That elevation will be referenced to a fixed point
downstream from the construction site. The contractor bears the sole liability for protection
of the construction site and his equipment as long as that elevation is not
exceeded.
Conditions for quarrying in borrow areas
The preliminary studies will have defined the various types of materials encountered
in the borrow areas and, according to their intrinsic and in situ characteristics, will
have assigned them a function and a place in the structure, or for some of them, will
have decided to eliminate them.
Additional site investigations and tests must be done to detail the results of the study
as soon as the test section is begun.
After stripping to eliminate and store topsoil and plant debris, a plan for operation of
the borrow area defining what part of the structure the various materials are destined
for should be set up.
Materials are extracted either in horizontal layers, which would permit some drying
by the sun and the wind, or in vertical layers, which would permit mixing of the
various layers.
The extracted materials can only be placed directly if their water content is within the
prescribed range. If not, drainage of the borrow areas or temporary storage for
drying or wetting can be necessary, and a cost for this work should be given in the
price schedule.
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Preparation of excavations
After examination of the base of the embankment and the cut-off, it may prove
necessary to excavate deeper.
Before placing any fill or concrete:
!" the surface of the excavation bottom must be cleaned and strengthened;
!" a detailed survey must be done;
!" the excavations must be formally accepted (see Chapter III, p. 62).