The city of Ottawa has declared a state of emergency due to flooding.

Mayor Jim Watson made the announcement late Thursday afternoon. Watson said with significant rain in the forecast, the city has also formally requested the assistance of the Canadian Armed Forces.

Watson says 400 troops will be in key areas on Friday.

Ontario Premier Doug Ford says "I will be travelling to Ottawa first thing tomorrow morning to meet with the Mayor and city officials, tour the areas impacted by the flooding, and meet with residents to ensure they're getting the support they need from their provincial government."

Experts say the peak of the Ottawa River is now expected to surpass the devastating levels of 2017.

In Britannia, water levels peaked at 60.44 metres in 2017. This year, the Ottawa River Regulation Committee has forecasted the waters to peak in Britannia on Saturday at 60.55 metres.

"If we reached the forecasted levels, it would be a new historic record for this region from Ottawa to Pembroke," said Michael Sarich, the Ottawa River Regulation Secretariat.

"This is really in many ways just the beginning."

Sarich says although the committee is looking for promising signs, residents need to be prepared for the worst.

"These are very trying times for many people along the waterways," said Sarich.

"Peak levels are going to be higher than anticipated."

Pierre Grandbois was caught off guard in 2017.

"it was six inches along the wall all the way past the door," said Grandbois.

"The way we prepared in 2017 was pathetic."

Grandbois, whose grandparents live on the Ottawa River in Britannia, has taken extreme measures to prepare this year, building a sandbag wall around the entire perimeter of their home.

"We weren't prepared at all [in 2017] and it flooded pretty badly" said Grandbois.

"The basement had 5 feet of water."

Grandbois also has a sump pump working 24/7, along with back-up generators.

"Hopefully [the water] won't rise too fast in one day, but it's hard to know really."

Sarich is warning residents of weeks of flooding, saying the first peak of high water will come by Monday, but there will be another one coming from the North.

"We can still measure the snowpack in terms of metres, there's still a lot of water to come through the system," said Sarich.

"This is going to be an ongoing story for at least a couple of weeks."