commonly in the 5–10 m height range. Earthfill embankments remain
dominant, but rockfill is to some extent displacing earthfill for larger struc-
tures as it offers several advantages.
It is also important to recognize that many major dams are now
necessarily built on less favourable and more difficult sites. For obvious
reasons, the most attractive sites have generally been among the first to be
exploited. A proportion of sites developed today would, in the past, have
been rejected as uneconomic or even as quite unsuitable for a dam. The
ability to build successfully on less desirable foundations is a reflection of
advances in geotechnical understanding and of confidence in modern
ground-improvement processes.
1.2.3 Historical perspectiveThe history of dam building dates back to antiquity, and is bound up with
the earlier civilizations of the Middle East and the Far East. Countless
small dams, invariably simple embankment structures, were constructed
for irrigation purposes in, for example, China, Japan, India and Sri Lanka.
Certain of these early dams remain in existence.
The dam built at Sadd-el-Kafara, Egypt, around 2600 BC, is gener-
ally accepted as the oldest known dam of real significance. Constructed
with an earthfill central zone flanked by rock shoulders and with rubble
masonry face protection, Sadd-el-Kafara was completed to a height of
14 m. The dam breached, probably in consequence of flood overtopping,
after a relatively short period of service.
Numerous other significant dams were constructed in the Middle
East by early civilizations, notably in modern Iraq, Iran and Saudi Arabia.
The Marib embankment dam, completed in the Yemen around 750 BC to
service a major irrigation project, was an example of particular note, as
this dam was raised to a final height of 20 m. The first significant masonry
dam, the 10 m high Kesis Gölü (North) dam in Turkey, dates from the
same period.
The Romans made a significant later contribution in the Middle East
and in countries bordering the Mediterranean. A number of Roman dams
remain in service, and to the Romans probably falls the credit for first
adopting the arch principle in dam construction. The 12 m high and 18 m
long Baume arch dam, in France, was completed by the Romans in the
second century AD.
In the Far East the construction of significant dams can be dated to
the period commencing c.380 BC. Activity initially centred upon Sri
Lanka, where a remarkable period of dam building commenced with the
10 m high Bassawak embankment and culminated in the Giritale and
Kantalai embankments (23 m and 20 m high respectively), completed in