After decades of debate, the gates of the Petitcodiac River are now permanently open, allowing the silt-clogged river to flow freely.

The controversy between the two sides is not ending with the opening of the gates as some are celebrating the event as a victory for the river, while others are contesting the provincial government's action in court.

For Tim Van Hinte, the spokesperson for the Petitcodiac Riverkeeper, the opening of the causeway gates is a day that he said he's been waiting for for a long time.

But Van Hinte said it's an even better day for the people who live up and down the river.

"You know for 42 years the gates have been closed and this is the first time the Bay of Fundy is going to be united with its headwaters in the Petitcodiac," he said.

'If they aren't prepared to do that then we'll ask a court to issue a temporary injunction to close those gates until those conditions are met.'— Kevin Campbell

The causeway was built in 1968 between Moncton and Riverview.

When the gates opened on Wednesday at 2:15 p.m., a chorus of cheers and boos erupted from the roughly 500 people who gathered on the river's banks to watch the historic event.

Now that the river is flowing again, it will be studied for the next two years. The gates can be closed if necessary in the future.

Legal challenge launched

On Tuesday night, the Lake Petitcodiac Preservation Association and the Alma Fishermen's Association announced they were heading to court to ask a judge to shut the gates.

Ann Rodgers tried to rally the more than 100 people who showed up in Riverview to see what they could do to stop the province from opening the causeway gates.

"A lot of people are throwing up their hands saying it's a done deal," Rodgers said.

"Well it ain't a done deal because the fat lady didn't sing yet."

Kevin Campbell drove to Fredericton on Tuesday to launch the association's lawsuit against the provincial government.

Campbell said the province has not lived up to 17 conditions that must be followed before the gates can open, such as finishing work on the dykes, preparing aboiteaus to protect land from flooding and providing better protection to prevent the old Moncton dump from leaking into the water.

"If they aren't prepared to do that then we'll ask a court to issue a temporary injunction to close those gates until those conditions are met," Campbell said.

Jim Wood, a representative from the Alma Fishermen's Association, said his group wants to protect their fishing grounds from silt and pollution caused by opening the gates.

And the group was told that some homeowners around the lake will launch another lawsuit for damages once the gates are opened.

Tidal bore will be dramatic

Jacques Paynter, the communications director with AMEC Earth and Environmental, which has worked on the Petitcodiac causeway project for the province, said when the gates open on Tuesday there won't be much to see at first.

That's because the water on either side of the gates will be at about the same when the button is pressed and they open for good.

But when the tidal bore comes in at 11:15 p.m., Paynter predicts it'll be more dramatic.

"I would certainly say that this is an event that people have been waiting for," Paynter said.

"I know there's some opposition obviously but for 40 years I think it's been widely acknowledged that construction of the causeway was a mistake."

Paynter said once the gates are opened fish will be able to ride the tide and the infilling of sediment will be reversed thanks to an increase in the volume of water.

The next step is to remove the causeway altogether and replace it with a bridge.

He said if all goes according to plan construction of a bridge could begin next year.

In 2003, the river was ranked second on a list prepared by B.C. environmentalists of the most endangered rivers in Canada.

In 2008, the New Brunswick government committed $20 million to the first stage of a restoration project for the 3,000 square-kilometre watershed.

The province plans to replace the causeway gates with a four-lane bridge from Riverview to Moncton.

The total cost of the project has been pegged at $68 million.