Photo: CTV News

Communities across much of Eastern Canada are bracing for more flooding today, with rain in the forecast from central Ontario to northern New Brunswick.

Officials in Quebec are keeping a close eye on a hydroelectric dam west that's at risk of failing, while Ottawa's mayor has declared an emergency and part of the Trans-Canada Highway has been closed in New Brunswick.

The Chute-Bell dam west of Montreal has reached "millennial" water levels, meaning a flood that happens once every 1,000 years, but Hydro-Quebec says it's confident the structure is solid.

Simon Racicot, the utility's director of production and maintenance, told reporters yesterday that "we are entering into an unknown zone right now — completely unknown."

Meantime, Ottawa has joined several smaller Ontario communities in declaring a state of emergency, with Mayor Jim Watson requesting help from the Canadian Forces.

Farther east, New Brunswick's Department of Transportation said the Trans-Canada Highway was fully closed from Oromocto to River Glade, and could remain closed for several days.

And there's not much relief in sight, with Environment Canada predicting rain for a large swath of Eastern Canada, from Georgian Bay to the Gaspe Peninsula.