Assiniboine River levels are near their peak in the Portage la Prairie, Man., area tonight but provincial forecasters warn that a second river crest is expected to reach parts of the province's southwest soon.

Flows on the Assiniboine River at the Portage Reservoir "are nearing crest and early this evening the river was measured at 51,900 cfs [cubic feet per second]," government officials stated in a flood update issued Wednesday night.

That amount of water flowing is similar to about 35 Olympic-sized swimming pools per minute, according to the province.

The river is flowing through the Portage Diversion at a rate of about 33,900 cubic feet per second and the flow downstream from the diversion is at about 18,000 cubic feet per second, according to the province.

"The best time is for it to be as late as possible because that means you have more time to prepare … and get people ready, so every extra minute counts when you're up against a deadline like this," Manitoba Premier Greg Selinger told CBC News Network on Wednesday afternoon.

Selinger said the dikes are in better shape than in 2011, and officials hope they will continue to hold up against the mounting pressure of the river.

On Wednesday evening, officials said the work to prepare the area for the first crest is complete and the Portage Diversion, along with dikes along the lower Assiniboine River and temporary flood protection measures downstream, are being monitored.

However, officials warned that the Assiniboine is cresting a second time. It's expected to be smaller but sustained over a longer period of time than the first crest, according to the province.

The second crest is expected to reach the communities of St. Lazare and Miniota on Thursday, then reach the city of Brandon over the weekend.

More water headed to Portage Diversion

The provincial government is hoping to push much of the excess water through the Portage Diversion, a flood control structure just west of Portage la Prairie, which is already running at near capacity.

And all of that water is heading north, along a 29-kilometre channel to Lake Manitoba, where communities around the lake are fearing the increased lake levels.

Kam Blight, reeve of the Rural Municipality of Portage la Prairie, said the water going through the diversion is astounding, but he feels the communities along the river, just west of Winnipeg, are as prepared as possible.

"Oh, there's no doubt there's a large slug of water moving awfully fast through the Portage Diversion," he said.

"We have to be ready now because the flows are at such a high point that if we're not, we're in trouble [but] I feel we're in a good position.

In fact, Blight believes the crest won't be much higher than the levels already being seen.

"The crest is expected later today, however, basically we're almost in the crest right now. It's a minor change to what the actual crest will be from right now 'til tonight," he said.

Reeve Roger Poitras of the Regional Municipality of St. Francois Xavier, which is closer to Winnipeg, said sandbagging crews were working hard into the night.

Of the 93 properties identified earlier this week as being at risk, only four are left to sandbag and he's confident crews will get that done Wednesday morning.

He said you can see the water rising and Caron Drive in the municipality is now under water.

While he believes they will be ready, Poitras said it will take at least three weeks before they can relax.

Road dike at Hoop and Holler may not be cut

More than 700 Manitobans have been forced from their homes since torrential rainstorms caused overland flooding in parts of southeastern Saskatchewan and southwestern Manitoba in late June.

Officials are warning homeowners along the river to prepare for water levels about 30 centimetres higher than record flood levels the area saw in 2011.

However, a "dramatic mobilization" has helped prepare the province as much as possible for the crest of floodwater bearing down from the west, Emergency Measures Minister Steve Ashton said earlier this week.

Military and volunteer crews have been busy sandbagging homes in that area over the past several days.

Officials say it is now unlikely it will be necessary to cut through a road dike at the Hoop and Holler Bend in the Assiniboine to let the pressure off of the swollen river, as the other dikes are holding and there's no rain in the immediate forecast. They said the situation could change if the dikes become stressed.

Selinger reiterated on Wednesday that the Hoop and Holler cut would only be made as a "last resort."

The Assiniboine River crest is expected to reach the community of St. Francois Xavier 24 hours after the Portage Diversion crest, then the edge of Winnipeg just after that.

Forecasters said water levels are expected to drop quickly once the crest passes through the diversion.

Lake Manitoba residents on high alert

Meanwhile, people living near Lake Manitoba are preparing for the worst — rising lake levels, thanks to the Portage Diversion, combined with strong winds that could breach their dikes.

The Rural Municipality of St. Laurent, which has declared a state of local emergency, says about 750 properties are at risk.

Municipal officials say the provincial government has not helped them out to date, so they have hired private contractors to put sandbags in areas most at risk.

"The province is not giving us the courtesy of answering our phone calls, of letting us arrange a meeting with them," St. Laurent Coun. Mona Sedleski told CBC News late Tuesday.

Area resident Claude Noble said he fears that the sandbagging efforts won't help, as it took just one windstorm in 2011 to breach the dikes.

"Is this going to happen every three years?" he said. "They said that's a [once in a] 300 year flood. Well, it's been a short 300 years."

Second crest of the Assiniboine coming

The dikes in Brandon held when the Assiniboine River first crested in the western Manitoba city on Sunday.

The province expects the river to peak a second time for a day or two between July 12 and 14 in Brandon, with peak flows of 31,800 to 33,900 cfs expected.

Parts of the city have been under water since the rainstorms.

The city of Brandon says residents whose properties were damaged by the recent overland flooding can apply for disaster financial assistance starting Wednesday.

Information about how to apply can be found on the Manitoba government's emergency measures website.

The city says it's submitting its own claim for disaster financial assistance for damages to city property.