Abstract
Many old dams in the world today may not be
safe enough and represent threats to the communities they serve. They have
reached the end of their technical and economic lives making upgrading them
questionable. This raises the question of decommissioning or removing them open
for further discussion. In this paper the issues related to keeping old dams
are discussed showing with one example that the soaring costs of upgrades make
it impossible to perform for countries with limited resources without outside
financial support. An explanation is also given to show how even in rich
countries this is met by budgeting obstacles. Other objections to the presence
of these dams, added to the safety question which support of dam’s removal are
discussed. They include the accumulated damage they have caused to the
ecosystems such as siltation and fish migration. An emphasis is put on the need
for intensive studies required before removing any such dam in order to
mitigate any negative impact subsequent to such removal; and many actual
examples are given to illustrate this.
Keywords: Upgrading, Decommissioning, Dam Safety, Ecosystem,
Siltation, Fish Migration.