Three Saskatchewan municipalities have declared states of emergency as rising floodwater threatens homes.

The town of Radisson and the village of Borden, which are both located just northwest of Saskatoon, declared emergencies Monday afternoon.

Radisson town councillor Dave Summers says people in the community have been sandbagging and putting up barriers since Saturday, but the water "is rising rapidly."

"There's a lot of water coming, there's more to come, but we went into a state of emergency because we're going to have homes flooded if we don't so we're trying to prevent that," said Summers.

"Some homes may still flood and we have some people on evacuation standby."

Summers said a dozen residents of a seniors villa were evacuated as a precaution -- all went to stay with relatives. More homes were on evacuations alert in case the water started to rise.

Volunteers were helping residents move things out of their basements to higher floors, Summers said.

"The water is coming. We know we're going to get more within this week and whenever it warms up again because the snow isn't all melted," he said.

Radisson and Borden join the town of Maidstone, located further northwest along Highway 16, which has also declared an emergency because of flooding.

The communities are in an area that the Water Security Agency had warned would likely see flooding due to very high spring run-off.

The agency has said the entire southern half of Saskatchewan will see water run-off levels above or well above normal. Run-off is expected to be very high and flooding is likely to occur from Moose Jaw to Indian Head, including Regina, and south past Weyburn to near the United States border. Saskatoon, Prince Albert and North Battleford are in the red zone as well.

Maidstone was the first municipality to declare an emergency.

"I think that's just a result of local run-off in that particular area and ... some of the water got into the town and affected their sewer system," said Duane McKay, Saskatchewan's commissioner of emergency management.

"We've moved some equipment there to help them mitigate the damage and perhaps assist in re-routing some of the water around the community."

Parts of Highway 16 leaving Maidstone were closed on the weekend because of flooding.

Earlier Monday, flood concerns led to the evacuation of a young offender facility in Regina.

The Saskatchewan government said 29 young people were being moved out of the Paul Dojack Youth Centre because of rising water levels. Two vacant units at the facility had already flooded and three more were in danger of flooding.

There were also concerns about a bridge over Wascana Creek leading into the young offender facility.

"If there is no access over the bridge, then it's very difficult to get in and out either for staff or for emergency vehicles," said Judy Orthner, executive director of corporate affairs with the Ministry of Corrections.

"What we were particularly concerned about ... was that with the rising creek water ... the bridge could be in danger of floating away," she said. "As a result, we were advised that measures would be taken to save the bridge, but that meant the bridge would be inaccessible as a road in and out of the Dojack youth centre."

Orthner says that's what prompted the decision to move to other young offender facilities in the province, for possibly three to five weeks.

On Sunday evening, a Via Rail train derailed in eastern Saskatchewan near the community of Togo after the train went over a section of track that had been washed out.

"That was caused by some wearing away of the bed along the tracks and (it) just couldn't take the extra pressure of the train there," said McKay.

The train was heading to Churchill, Man., from Winnipeg with seven passengers and four crew. No one was hurt.

The water is just beginning to flow in many areas because the snow melt has been delayed by colder-than-normal temperatures.

Patrick Boyle, with the Water Security Agency, said there has been some localized flooding, including roads that had been over-topped with the water in the Maidstone area. But he said the run-off was "really in the early stages," especially in Wascana Creek, which flows through Regina.

Boyle said cooler weather forecast for Tuesday and Wednesday could slow down the melt ahead of an anticipated big warm-up next weekend.

"In those areas where the run-off has started, it will allow flows to pass somewhat before any of the further snow melt happens, so that's going to help alleviate the peaks," said Boyle.

"Essentially what it's doing is helping what we've had melt right now move through the system."