More than 60% of the world’s original dam water storage is
likely to be lost within just three decades due to the growing
accumulation of mud, sand and fine silt pouring into dams
across the globe. That was the warning sounded by top
hydrologists during the recent National Siltation (NatSilt)
Symposium hosted by the WRC.
“We currently lose more storage than we build, and climate
change will reduce water yields further due to increased
sediment loads,” said World Bank independent consultant, Dr
Nikolaos Efthymiou, pointing to the threat of more severe storms

and hotter temperatures that are expected to accelerate the
erosion of soils in many parts of the world.
Efthymiou said the heyday of dam building was between 1960
and 1990, with most dams being built in the 1970s. This meant
that the majority of the world’s dams were about 50 years old,
and the building of new dams had slowed significantly because
of economic factors and a shortage of suitable locations.
Though siltation rates vary widely according to local conditions
and land care, dams silt up at the rate of about 0.8% per year at a