Among the Third World solidarity posters adorning the walls of the Valley Peace Center in Amherst, Massachusetts in the early 1970s was one particularly striking photo of a handsome, heroic Mozambican Frelimo guerilla. Above him the text read: Stop The Cabora Bassa Dam! I had no idea why we should stop it, but if the Frente de Libertação de Moçambique said so, that was good enough for me.

Fast forward to November 27, 2007. In the dam city of Songo on the Zambezi River, Mozambique took over complete control of Africa’s second-largest dam from Portugal. In a formal ceremony attended by neighboring heads of state – including Zimbabwe’s Robert Mugabe and Bingu wa Mutharika of Malawi – Mozambican President Armando Guebuza declared, “The last mark of 500 years of foreign domination in our country has finally been removed.”

Maybe. In the 1970s, Frelimo had made the Cahora Bassa (as it’s now spelled) a high-priority target. Not only was the dam a project of the Portuguese colonial government, but it linked the Zambezi River to white Rhodesia, and was supported by apartheid South Africa and financed by transnational firms like General Electric and Siemens.

In 1975, the Portuguese relinquished political control over Mozambique but not over the dam. Nominally, Hidroelectrica de Cahora Bassa owned the dam , but Portugal retained 82% of the equity of the company. Nevertheless, South Africa encouraged the right-wing U.S.-backed Renamo guerillas to continue attacking the dam in hopes of overthrowing the leftist Frelimo government. Now, in an ironic switch, Frelimo had to defend the dam.

According to researchers Allen Isaacman and Chris Sneddon, the revolutionary movement never wanted it, but “sought to domesticate the ‘white elephant’ of Cahora Bassa for its own developmental purposes.” Said Isaacman and Sneddon, “Stuck with the dam, the newly installed FRELIMO government had little alternative but to discard its long-term opposition to the hydroelectric project. In a radical departure from its previous stance, it hailed Cahora Bassa as a symbol of liberation which would help the people of Mozambique achieve economic prosperity, transform the strategic Zambezi valley and bring the impoverished nation a new source of hard currency by exporting energy to markets throughout the region, not just to South Africa.”

The Cahora Bassa does bring in money, but it’s extremely costly environmentally, and it’s uncertain whether the country will actually make money on the operation. According to Agence France Presse, “Control of the dam is expected to fetch the African nation more than $150 million annually.” But, noted Mozambican Energy Minister Salvador Namburete, “From these $150 million a year, we are going to pay over 15 years a loan of $700 million (471 million Euros) from a Franco-Portugal Calyon/BPI bank consortium taken to buy the part of capital held by Portugal.”

In any case, it may not be worth it. Right now, the East African country is, according to Reuters, being hit by “the worst flooding to hit the country since 2000-2001, when 700 people died and half a million were driven from their homes.” As the United Nations World Food Program begins airlifting emergency supplies to flood victims, the Cahora Bassa is providing little in the way of flood control.

The dam sits astride the fourth-largest floodplain in Africa, and dam officials must decide whether to hold back or release water. In either case, it’s not helping. “There are 250,000 people living downstream of the [Cahora Bassa] dam, “ said ActionAid’s Mozambique director Alberto Silva, “This is the second year they will lose everything.”

Mozambique’s control of the dam may eventually work out if purchasers like Zimbabwe are able to make payments – a very big if. Nevertheless Mozambique, one of the world’s poorest countries, has to figure out how to control not only the Zambezi, but also the Cahora Bassa and the volatile 500 million cubic meters of water churning behind it.

If only they had stuck to their original plan and stopped the dam.

, Alec Dubro, creator of The Washington Pox, is a contributor to Foreign Policy In Focus.