The Saskatoon Fire Department is warning people about using the river after a dramatic river rescue Sunday evening.

Firefighters found four women in two inflatable rafts trapped against one of the pillars of Gordie Howe Bridge at about 6:30 p.m. CST.

Both of the department's water rescue boats were sent out. When they arrived, one of the women had fallen into the water and couldn't support herself.

All four people were rescued and weren't seriously injured.

However, the fire department said this situation could have ended tragically. None of them were wearing life jackets.

"Had they not been able to hold onto something, they would have been again swept away quite quickly with the currents," said Assistant Fire Chief Yvonne Raymer.

Right now, the South Saskatchewan River is flowing at about four to six times higher than normal. Heavy rainfall in Alberta has meant water needed to be released from Lake Diefenbaker, swelling the river.

The Meewasin Valley Authority said the river is always unpredictable, but is much worse right now.

"Caution is advisable all the time but with the extra release of water from the Diefenbaker Dam, the river level is noticeably higher and the water is moving much more quickly," said Mike Velonas, manager of planning and conservation at Meewasin.

"It can be unpredictable. Places where you think it might be shallow it might suddenly drop off into deep water with the quickly moving flows."

For years, Meewasin has cautioned people to be careful on the river, especially novice boaters. However, recent high water has made the situation even more dangerous.

"Enjoying the river is a big part of the reason why Meewasin exists," said Velonas.

"And so we encourage people to come to the water to enjoy the water but to do so responsibly and safely and follow reasonable guidelines."

While the river is still high and fast, the Water Security Agency said it's better than its original projections.

The agency originally predicted the river would see flows of 1,300 cubic metres per second, considerably higher than the average flow of 150 cubic metres per second seen on the river.

The agency now says the Saskatoon area will see flows of about 700 cubic metres per second.

However, that doesn't mean people near the river should be complacent.

"At all times, we should practice river safety and make sure that we are doing everything to stay safe," said agency spokesperson Rod Podbielski.

"We would certainly encourage a high degree of caution when people are doing those types of recreational activities."

The agency believes the river will remain at its current level for about a week before receding.