Bui Dam Hydroelectricity Project, Bui National Park, Ghana
Bui Dam is a gravity roller-compacted concrete dam which is being constructed at the Bui National Park, located in Ghana. Upon its completion in 2013, the dam will generate 400MW of power and facilitate irrigation of about 30,000ha of land.
The total cost of the dam's construction was initially estimated at $622m, but a cost review conducted in 2012 raised that amount by $168m.
The dam is being constructed by the Sinohydro Corporation as part of an Engineering, Procurement and Construction (EPC) Turnkey Project Contract. Bui Power Authority (BPA) will own and manage the dam.
The project is being realised in two phases. The first phase included the detailed field investigations and preparatory works. The ongoing second phase comprises of construction of the main dam, spillway, power house and transmission lines.
Purpose of Ghana's Bui Dam
Ghana currently has the Akosombo Dam and the Kpong Dam which were constructed primarily to serve the sole purpose of generating power.
The Bui Dam, on the other hand, is a multipurpose dam which, besides generating power, will provide water for irrigation and also improve tourism and fishing industries in Ghana. The dam will also provide protection from a flood with the force of one in 10,000 years. It is also expected to generate several jobs.
The construction of the dam is expected to resettle 1,216 people within the project area and inundate 444 square kilometres of land. The project is, however, facing revolts from environmentalists due to the resettlement of fishes and animals such as the hippopotamus.
Constructing the dam within Bui National Park
The diversion of the Black Volta River was completed in December 2008 and the construction of the main dam began in December 2009. As of September 2012, 90% of the construction work has been completed.
Details of the Ghanaian water project
Bui Dam will have a height of 108m above the foundation and 90m above the riverbed. The crest of the dam will be 492m long and 185m high. The overall structural volume of the dam will be one million cubic metres.
The project also includes construction of two saddle dams on the south-western part of the main dam. The two saddle dams will have a crest elevation of 187m. One of the saddle dams will be a rock-fill embankment dam where as the other one will be an earth-fill dam.
The reservoir created by the main dam and the two saddle dams will have a gross capacity of 12.57 billion cubic metres, of which about 61% will be utilised for power generation and irrigation. The Bui Reservoir will cover a total area of 444 square kilometres at a maximum elevation of 183m and an average length of 40km.
The spillway will comprise of five gates measuring 15m each in width, to regulate the flow of water. The spillway will comprise of a single outlet and will be located on the right bank with an elevation of 169m. The capacity of the spillway will be 10,450 cubic metres a second.
The project also involves the construction of a bridge across the Black Volta River downstream of Bui Dam. The bridge will connect Brong Ahofo and the Northern Regions.
Financial support from Chinese Ex-Im Bank
The project is being financed through a concessional loan of $270m, a commercial loan of $292m and a $60m funding from the Government of Ghana. The two loans were offered by China Ex-Im Bank, with a grace period of five years and an amortisation period of 20 years.
History of Ghana's Bui Dam project
The idea to construct the Bui Dam was first conceived by the British-Australian geologist Albert Ernest Kitson in 1925.
Planning for the dam began in 1960 with support from the World Bank and Australia. It, however, did not materialise.
The first promising activity was undertaken in 1992 when Coyne et Bellier (now Tractebel Engineering) carried out a feasibility study on the project. Ecological investigations were also carried out in 1997 by the University of Aberdeen.
The Volta River Authority authorised Halliburton and Brown and Root in 1999 to construct the dam. The project was, however, held back in 2001 by the Government of Ghana.
The project finally became a reality when Sinohydro submitted a bid with funding from the Chinese Ex-Im Bank in 2005. It was followed by an environmental impact assessment and a feasibility study. The creation of the Bui Power Authority in August 2007 gave further impetus to the project.
Field Investigations for the project began in October 2007, with preparatory works commencing in January 2008.
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