|Fig. 1: Location of Cahora Bassa Dam in Mozambique. (Source: Wikimedia Commons)|
The Cahora Bassa dam is an enormous dam on the Zambezi river in the Tete province of Mozambique, built in the early 1970s. The Zambezi River is the fourth largest river in Africa, and the largest of any flowing into the Indian Ocean. In the late 1960s, the Portuguese colonial government decided the Cahora Bassa gorge (Fig. 1) would be an ideal location for a hydroelectric project.  In slick brochures and public announcements, planners lauded the expected benefits of the $515 million dam: amongst other promises, the dam would bring an expansion of farming, European settlement, greater capacity for mining, improved communications and transportation throughout the valley, and reduced flooding. The dam has an installed capacity of 2,075 MW, and would generate a substantial return, since 82 percent of its electricity would go to South Africa, making it the largest dam in the world producing energy mainly for export (this 82 percent figure is guaranteed per a 1969 agreement between the Portuguese colonial government and South Africa. Both the exact amount and price of energy exports remains a tightly-held secret). 
The legacy of the dam however, is likely to be judged much more harshly. Political and economic forces combined to recast the project for the overarching purpose of the sale of electricity to South Africa, an alliance couched in national security interests of a colonial state preoccupied with maintaining power. Security concerns in the mists of the FRELIMO independence movement provided a convenient rationale to bury information regarding the dam's consequences, leading two scholars in 1984 to remark that "Cahora Bass has the dubious distinction of being the least studied and possibly the least environmentally acceptable major dam project in Africa." 
In the years since the completion of the dam, various studies have reported the deleterious effects of the project. The Zambezi prawn fishing industry, responsible for 15% of the country's exports, has shown a 50% decrease in prawn catches since the 1970s. Erosion of river deltas and shorelines have reduced fish habitat, harming the main protein source of riverine people.  Further, soil fertility has declined as large parts of the delta are no longer agriculturally useful. The effects of this reduction in agricultural potential are clear: 10% of the Tete district suffers from acute malnutrition, higher than the Mozambican average. 
Hydroelectric dams have a long and storied history inextricably entwined with politics and power. At the time of Cahora Bassa's conception in the late 1960s, Portuguese planners envisioned a transformed Zambezi. However, the rosy purported benefits of the dam contrast starkly with the life-threatening work conditions suffered by the labour force employed to build it, the murky colonialist motivations for its construction, and the resulting environmental damage. Indeed, the history of the project reveals a willingness of an embattled colonial state to flex its coercive strength to entrench its hold over southern Africa. As modern-day African states increasingly attract foreign investors and interest in renewable energy grows, it will be tempting to view hydroelectric projects as a sustainable way to power booming economies. The case of Cahora Bassa should act as a strong reminder that questions of sustainability and development, whether it concerns livelihoods or ecosystems, cannot be separated from questions of power and control.
© Charlie Walker. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 A. Isaacman and C. Sneddon, "Toward a Social and Environmental History of the Building of Cahora Bassa Dam," J. S. Afr. Stud. 26, 597 (2000).
 A. F. Isaacman and B. S. Isaacman, Dams, Displacement, and the Delusion of Development: Cahora Bassa and Its Legacies in Mozambique, 1965-2007 (Ohio University Press, 2013).
 G. Schreyögg and H. Steinmann, "Corporate Morality Called in Question: The Case of Cabora Bassa," J. Bus. Ethics 8, 677 (1989).
 R. Beilfuss and C. Brown, "Assessing Environmental Flow Requirements and Trade-offs for the Lower Zambezi River and Delta, Mozambique," Int. J. River Basin Manage. 8, 127 (2010).