Tõrva dam failures linked to decade's worth of rain

Two dams in Tõrva failed following exceptionally heavy rainfall, leading to flooding that impacted ten households. Scientists from the Estonian University of Life Sciences have conducted a rapid analysis, concluding that the rainfall preceding the event occurs, on average, only once every 11.6 years. This suggests the incident was not solely due to extraordinary weather.

Ottar Tamm, an associate professor at the university's hydroinformatics department, and Egle Saaremäe, a lecturer in water supply and sewerage, obtained precise rainfall data for the region. Fortunately, a hydrometric station is located very close to the affected dams, providing reliable measurements. The data revealed that 47.45 millimeters of rain fell over 490 minutes.

While such a volume of water could cause chaos in urban areas, it is not considered exceptional for water structures. The calculations indicated that similar rainfall events happen, on average, every 11.6 years. "Something else must have been at play," Saaremäe stated. "Either the water level was poorly regulated at the dams, or it was a maintenance issue. This accident cannot be solely blamed on the rainfall. Something else caused it – a confluence of unfortunate circumstances created a high risk and led to this disaster."

“

Something else must have been at play: Either the water level was poorly regulated at the dams, or it was a maintenance issue. This accident cannot be solely blamed on the rainfall. Something else caused it – a confluence of unfortunate circumstances created a high risk and led to this disaster.