The Millenium Project Inauguration ceremony was held on 2 April 2011 to mark the start of construction of Africa’s largest hydroelectric plant. In its final phase the plant will have an installed power of 5250 MW and produce over 15,130 GWh/year. The huge reservoir will store over 63 billion m3 of water making it twice the size of Ethiopia’s largest natural lake, Lake Tana.

 

The Gibe III hydroelectric project, the “Pride of Ethiopia”, will generate 1870 MW with an annual energy production of 6,400 GWh. This will boost the country’s output by 230% providing thousands of job opportunities for local communities.  Care has been take to mitigate any adverse effects on local populations and only 57 households will actually be displaced by this huge project: a negligible number when compared to the benefits this driving force will bring in terms of the Ethiopian economy.

 

The Gibe III dam is a classic gravity structure, about 240 m high, with a central overflow block where the spillway structure is located and a design discharge of about 10,600 m3/s.
In order to optimize the behavior of the spillway a physical model was built to scale 1:60 (according to the Froude similarity) in the LACTEC laboratory of Curitiba in Brazil. The hydraulic model has allowed optimization of the hydraulic layout of the spillway structure, minimizing the impact of the floods downstream.
The spillway structure and the hydraulic model include:
• an overflow crest, Creager – Scimemi profile, controlled by 9 radial gates,
• a chute on the downstream slope divided into 9 channels,
• each channel ends with a separate deflector bucket energy-dissipating device,
• the pre–excavated, unlined plunge pool on the river bed.
Each element of the hydraulic model is made using materials which reproduce the actual behavior of the spillway and optimize the modeling. For example, the crest, chutes and walls of the spillway are made with transparent plastic to allow monitoring and direct observation during the tests, while the plunge pool is made with three different types of material on which it will be possible to carry out the tests in order to reproduce as accurately as possible the actual state of the river bed.

 

 

Presentation of the key SP projects during the first fourty years of activity of the firm ( 1965-2005 ).