Dambreak


A number of large storage reservoirs are located on major river systems in Victoria and are owned, operated and maintained by various agencies.  These storages, including Dartmouth, Eildon, Hume and Thomson reservoirs, were constructed for the provision of water supply, although dams by their nature provide some degree of flood mitigation.

Dambreak flooding occurs when a dam fails by breaching or overtopping and a flood wave inundates downstream areas.

Dambreak flooding is a rare occurrence and is generally caused by poor design, construction or maintenance of the dam or exceptional severe rainfalls.  When dam failure does occur, the consequences to loss of life and flood damage can be catastrophic.  A catastrophic dam failure in Australia occurred in 1929 in Briesis, Tasmania, when a 24 metre high dam constructed for mining purposes failed after torrential inflow with the loss of 14 lives.

A dambreak also occurred in 1909 in Laanecoorie (located in northern Victoria) causing widespread flooding down the Loddon River affecting Laanecoorie, Bridgewater, Serpentine and Kerang. This flood currently represents the largest flood on record equivalent to the 100-year ARI flood.  The 1909 photograph below is a record of this dambreak.

Dambreak of Laanecoori Reservoir in 1909.  Courtesy Department of Sustaibility and Environment