The girl, Becky Waldner, was found at about 10:30 a.m. Monday, approximately three kilometres east of where she was last seen on Saturday evening.
Searchers had been scouring the river since Becky disappeared near the Poplar Point Hutterite Colony, just east of Portage la Prairie, Man., while playing on a tire tube with friends.
Search groups from both the RCMP and area colonies had been involved in the search.
Relatives of Becky told CBC News on Monday that it was colony members who located the body.
Becky's uncle, Amos Waldner, said the girl's family is coping with the tragedy as best as possible.
Becky, who had two sisters and two brothers, was the youngest in the family.
"It is a sad day but we are grateful we could bring her home," he said. "It is the Lord's plan and we can't argue with that."
He described his niece as a happy girl who could always get his daughter out of the house to play.
"Life must go on. We will miss her," Waldner said. "We will stick together. It makes us stronger."
At least one woman in the tight-knit colony, which has approximately 100 members, said it is common for children to go swimming in the river, but she said the current has been higher than usual lately.
Colony members have been discouraging children from going into the river but given the extremely hot weather in recent days, more people have gone into waterways to cool down.
The Lifesaving Society of Manitoba has been working with Hutterite colonies in Manitoba for the past five years, teaching them about water safety.
Carl Shier, CEO of the society, said they go to colonies and give a day's session about dangers around water.
"But that's not enough. I mean, the reality is we're alerting them to it, the dangers around water. But I don't think just a day's visit over the course of the years that we've been going to any of them is going to be enough," he said.
People have to get into a pool or a supervised lake to learn about water safety but that's a challenge in rural areas, Shier said.
"[Go] five minutes in Winnipeg in any direction and [you can] find a place to get training in the water. Once you get into rural Manitoba, those realities are the drive is much further [and] the opportunities that much less."