Megadams

WE HUMAN BEINGS HAVE A REMARKABLE DESIRE AND ABILITY TO shape our surroundings for our convenience and comfort. And because we have the inventive and technological capacity to do it, any failure to exploit a natural “resource” is deemed a waste. Immense skyscrapers, bridges, and dams, drained swamps, and deep-sea oil rigs are a testimony to our engineering skills. But too often we fail to consider a project’s impact beyond its immediate locale or payoff, and we end up paying heavy ecological costs.

In the debates about the future of dams at Alcan’s Kemano Completion Project in British Columbia, Alberta’s Oldman River, Saskatchewan’s Rafferty and Alameda Rivers, and Phase II of Québec’s James Bay Hydroelectric Project at Great Whale, critics often cite disastrous examples like Egypt’s Aswan Dam on the Nile and Brazil’s Balbina Dam in the Amazon rain forest. Let’s look at northern British Columbia.

British Columbia’s great river systems generate enough energy to supply the province’s domestic needs and to allow it to export the excess. In the early 1960s, B.C. Hydro targeted the Peace River as an economic mother lode, and in 1967, the W.A.C. Bennett Dam (named after the longtime premier of British Columbia) was completed with great fanfare. Henceforth, the unpredictable water flow of the Peace could be “controlled” and regulated, subordinated to human needs. Few, if any, wondered about the dam’s effects on a unique ecosystem 1,200 kilometers (745 miles) away in Alberta’s Wood Buffalo National Park, famed for having the only known nesting sites of the near-extinct whooping cranes.

The heart of Wood Buffalo Park is the world’s largest freshwater delta, formed by silt deposits from the Peace and Athabasca Rivers. The wetlands and meadows of the 5,000-square-kilometer (1,930-square-mile) area support millions of muskrats, of which up to 600,000 a year were trapped by the people of Fort Chipewayan. Over a million waterfowl and other migratory birds also exploit the tremendous productivity of the delta. And the sedge grasses provide nutritious feed for the bison for whom the park is named.

Dams change river ecology downstream, because the normal seasonal fluctuations in water levels are completely altered. In nature, rivers are low in winter and summer and flow heavily in spring. But electrical demands require peak release of water during the winter and less in the spring and summer. Before completion of the Bennett Dam, every five to eight years, ice would pile up in the Peace and cause a massive backup of water that would flood the delta.

Humans don’t like floods, especially when they occur erratically, but for the delta ecosystem, those floods were vital. The flooding was completely dependable within the elastic cycle of time, and the plants and animals of the affected region were exquisitely adapted to and dependent on it. Floodwaters flushed out accumulated chemicals and drowned willows and other low shrubs that encroached when wet areas dried out. Silt left after the water receded fertilized the delta for the protein-rich sedge grasses that the bison herds depended on.

There hasn’t been a flood in the delta for sixteen years, a triumph of our flood control. But a comparison of satellite photos made in 1976 and 1989 reveals a shocking change—40 percent of the productive sedge meadow habitat has been seriously altered and invaded by less palatable (for the bison) willows and low shrubs. Without the flooding to recharge the delta, 75 percent of the entire meadow area will be lost in the coming years.

Wood Buffalo National Park is a global heritage. One of the largest parks in the world, it is larger than Switzerland. It provides nesting grounds for whooping cranes and range for the largest free-roaming herd of bison on the planet. But it is under assault from within and without. Suggestions have been made to “depopulate” (meaning kill) the bison because they are infected with diseases that are said to threaten cattle. Magnificent stands of the tallest white spruce in Alberta have been logged for years in the park. And soon immense pulp mills in northern Alberta will spew toxic effluents into the air and water of the north.

The catastrophic impact of the Bennett Dam should teach us how little we know about the complex interconnections between ecosystems. Canada has some of the richest wilderness treasures in the world. But we must have greater humility about what we know and look far beyond immediate benefits and local effects or else we’ll put it all in peril.

Update

Wood Buffalo National Park continues to be assaulted by human activity. In a study commissioned by the Canadian Park Service, the drying of the delta was reported to be continuing because of the prevention of floods by the Bennett Dam far upstream. At the rate of drying, the report predicted, the delta will disappear as a vibrant ecosystem in thirty years.

The bison herd was infected with bovine brucellosis and tuberculosis, causing cattle farmers in neighboring lands to fear the infection of their animals. They pressured the government to eliminate the threat from the bison, and a plan was devised to kill the entire free-roaming herd of more than three thousand animals and to replace them with uninfected animals from other parks. It was an astounding plan, considering the fact that the park is one of the largest in the world, encompassing 44,000 square kilometers (17,000 square miles). Public reaction to the proposal was swift and intense, forcing the government to back down and suggest an alternative scheme, namely, to round up the animals and cull only the infected bison. It’s one thing to propose shooting all animals, but the scheme to capture, pen, and test thousands of wild creatures boggles the mind. To date, the plan has not been implemented.

Meanwhile, clear-cut logging within the national park continues, and pulp mills are polluting the air and the water in the park v1