|Data on the structure|
|Height of the barrier structure :||18.5 m|
|Height above valley floor:||209.50 m|
|Height of the structure crown:||228.00 m|
|Crown length:||432 m|
|Crown width:||4 m|
|Slope slope on the air side :||1: 2.5|
|Slope slope on the water side :||1: 2|
|Power plant output:||1.12 MW|
|Data on the reservoir|
|Altitude (at congestion destination )||225.00 m|
|Storage space||12.5 million m³|
|Design flood :||800 m³ / s or 1,100 m³ / s|
The dam on the Tazlău River was designed by the Bucharest Energy Project Planning Institute (ISPE) and built between 1958 and 1962. The purpose of the construction was the water supply of a thermal power plant and the other local industry in the industrial center Borzesti with a withdrawal rate of 6 m³ / s.
The 432 m long dam consisted of an 18.5 m high earth dam with a clay core and a concrete casing on the storage area side, which, in addition to the 58 m long relief device (weir system), had a 234 m long left and 126 m long right wing.
In order to increase the storage volume, a 577 m long accompanying dam was built on the right-hand side in connection with the right wing, the crown of which was initially the same height as the main dam. The last 200 m of the accompanying dam were lowered by 1 m in order to act as a flood basin to ensure natural flood relief.
Flood protection facility
The flood protection was taken into account in the middle of the dam in the form of a 58 m long relief device. This included 4 flap weirs (2.50 m × 11.00 m) and 2 segment locks each 15 t heavy (2.50 m × 11.00 m), which acted as bottom outlet .
- 800 m³ / s with a hundred-year flood
- 1,100 m³ / s with a thousand year flood
According to the construction company Hidroconstructia SA, the maximum discharge rate of the relief device was 1400 m³ / s, but calculations in the course of a specialist article only resulted in a maximum discharge rate of approx. 850 m³ / s.
Reconstruction and partial break in 1972
In the course of the construction of a leisure center, the area ( flood basin) of the accompanying dam , which was lowered by 1 m, was raised by 1 m again without compensatory measures.
In the same year, in the course of a flood in the left area of the dam, there was an overflow including a partial break, which was repaired locally.
As a result of this event, the removal capacities required for flood protection including a longer observation period were recalculated. The following flow rates were forecast:
- 1,515 m³ / s with a hundred-year flood
- 2,415 m³ / s with a thousand year flood
Despite the newly gained knowledge of possible flood levels , the relief systems were not converted.
Power plant construction in 1983
In 1983, a small power plant with a withdrawal rate of 12 m³ / s and an output of 1.12 MW for the local power supply was built in the area of the right accompanying dam . In the course of this construction work there was no adaptation of the relief systems.
The Belci dam breach in 1991
On July 28, 1991 , heavy rain set in in the upper reaches of the river, the eastern Carpathians , which was not reported to the barrier keeper of the Belci Dam due to a failing flood information system.
When heavy rain set in in the area of the dam on the night of July 29, 1991 (36.2 l / m² were measured within 1.5 hours) and the level of the dam area rose, the bottom outlet of a weir field was opened. Because of a power failure that occurred afterwards, the doors could no longer be moved electrically. The attempt to move it using an emergency unit or manually failed because of a missing battery for the unit or because of blockages .
On July 29, 1991, at 2:15 a.m., the dam crest was flooded with an influx of 1,200 m³ / s, at around 6:15 a.m. at the site of the repaired dam damage from 1972, an initial break of 40 m length and 10 m depth occurred which ultimately m long elsewhere about 6:30 to 112 and up to 15 m deep Hauptbresche led. On the evening of the same day, the main breach was widened by another flood wave (1,100 m³ / s).
According to a geotechnical investigation of the accident, the initial fracture can be traced back to a settlement process and a resulting weak point, which occurred in the exact area that was repaired in 1972. The high fracture dynamics in the main breach that followed was caused by a cable crest that was situated on the dam crest and caused a vortex .
The dam burst claimed 25 lives and 250 houses were destroyed. Reports to the contrary, which cited far more fatalities, erroneously included those victims who were not directly damaged by the breach of the dam, but by the actual upstream flood disaster of the Tazlău River .
The dam was not rebuilt after the accident.
- A. Vogel, R. Klein: The rupture of the Belci dam in Romania, in: Fachzeitschrift Geotechnik 16 (1993) No. 1, pp. 12-17.
- A. Diacon, D. Stematiu, N. Mircea: An analysis of the Belci dam failure, in: International Water Power & Dam Construction 44 (1992) No. 9, pp. 67-72.
- Flooding and landslides cause three major failures in Romania, in: Water Power and Dam Construction, October 1991.
- Hidroconstructia SA installation company
- A. Vogel, R. Klein: The break of the Belci dam in Romania, in: Fachzeitschrift Geotechnik 16 (1993) No. 1, pp. 12-17.
- Construction illustration p. 237 see Fig. A) (PDF; 10.0 MB).
- Image of the dam breach at agerpres.ro, accessed on August 21, 2020.
- Illustration of the destruction on p. 237 see Fig. B) (PDF; 10.0 MB).
- Mihai Popescu: The tragic story in Romania, in which 250 houses disappeared and 25 people died . vice.com, February 15, 2018, accessed August 21, 2020 (Romanian).