ONTARIO ENERGY MINISTER John Baird has said that Ontario Power Generation has instituted changes to flood warning procedures and computer systems at the province’s hydroelectric dams, after two deaths were attributed to sudden releases of water into the Madawaska river. The incident happened at the 28m high Barrett Chute dam and generating station near Calabogie in central Ontario, Canada, in June 2002.

There are seven large dams with heights ranging from 18-62m on the Madawaska river. Their optimum operation scenario to maximise income from power generation during the peak demand period requires careful and accurate timing. The computer system in use by the utility at the time of the accident was designed to react immediately to price and demand changes of the deregulated hydro market. The computers cause changes in energy generation by opening or shutting down equipment when necessary.

It is alleged that a generating station upstream on the Madawaska river responded to an increased demand for power in the province, by ramping up its generators, and sent a large flow of water downstream into the Barrett Chute dam. Under normal circumstances, Barrett Chute’s four turbines would have passed the inflow without any difficulty. But one of the turbines was undergoing maintenance at the time, forcing Ontario Power Generation to release excess flows through the spillway. However, according to reports appearing in the local press, the utility did not warn bathers downstream of the plant prior to the spillway opening.