REGINA - A fifth day of rain brought more misery to flooded communities in southeastern Saskatchewan and threatened even bigger problems downstream on the swollen Souris River.

Grey clouds hovered over the City of Estevan, which was expected to get up to 30 millimetres of rain Tuesday. That's on top of the 287 millimetres that has fallen on the city since May 1 -- making this the wettest May-June period since records began in 1945.

"Every time you look out and it's raining, it's makes you a little bit sick," said Estevan Mayor Gary St. Onge.

Estevan was one of 24 communities under a state of emergency Tuesday -- up four from Monday.

To make matters worse, the Saskatchewan Watershed Authority said Tuesday that it has to release more water from dams in the region because the reservoirs are filled to the brim.

"Essentially, the system is just absolutely saturated from starting with spring runoff and then just rain event after rain event," said authority spokesman Dale Hjertaas.

"Everything is full. The river channels are full, the sloughs are full and now the reservoir capacity is full as well. Each time it rains more of the water is moving on downstream and producing flows that none of us has seen before."

The problem area starts about an hour and a half southeast of Regina. Estevan is of particular concern because it sits on the Souris close to two major dams -- Boundary and Rafferty.

Increased outflows from Boundary Dam are expected to raise water levels downstream by about 20 centimetres. The outflow is also being increased at Alameda Dam near Oxbow, Sask.

St. Onge said he understands there were no other options.

"They have to release what they've got. You can't have the water going over the top of the dam. They don't really have any choice so we just have to try and live with what they're sending down."

The mayor said so far, they've been able to protect the water treatment plant, although staff are getting to the site by boat.

Colin King, deputy commissioner of emergency management, said the increase outflow means there will be even more water in Roche Percee, near the U.S. border. Much of the village of about 160 people is already submerged.

In all, Emergency Social Services in Saskatchewan estimates that nearly 800 people have been forced from their homes across the region. Officials said the exact number is hard to pinpoint because many evacuees are staying with family or friends, not in shelters.

There were also problems east of Regina, where the Trans-Canada Highway remained closed for a second day Tuesday because it was submerged under several metres of water.

Saskatchewan Premier Brad Wall is hoping Ottawa will help bail out communities affected by flooding.

Wall spoke Tuesday with Prime Minister Stephen Harper about disaster aid and flood protection. The premier said there's been concern that some flood damage won't be covered because it's man-made -- such as when a rural municipality intentionally breaches a road to divert water away from property or people.

"I was able to raise that with the prime minister and say, well, clearly these RMs wouldn't be cutting the roads if there weren't a flood. The flood's the cause, the disaster's the cause," said Wall.

"And he said, well, you know we'll have a look at that. He's already committed to fund permanent works ... to mitigate against further damage."

Saskatchewan announced a $22 million program in February to help communities, rural municipalities and individuals prepare for spring flooding. That was after the watershed authority warned there was a high likelihood of flooding from the spring runoff, especially in the southern part of the province.

The provincial government topped up the program with another $30 million. Wall said Tuesday that figure could near $100 million.

The premier also spoke with Harper about help for Saskatchewan farmers. Flooding is expected to leave about two million hectares unseeded this year in Saskatchewan. Last year, the federal government and the three Prairie provinces pumped an additional $450 million into a program to cover farmland that couldn't be seeded or was washed out after seeding due to near non-stop rain.

Wall said there will be a review on how the flood was handled, including reservoir management, but he hoped people wouldn't look to lay blame.

"It's a dangerous thing to hindsight this thing," said Wall.

"How do you deal with five, seven inches in a weekend? What release back in March can predict that future event? So I would be loathe to second-guess the hydrologists and the experts too much at this point. Hindsight's pretty easy and people understandably are very stressed."

While the situation is bad in Saskatchewan, it is worse downstream in Minot, N.D.

The Souris River is set to overtop levees there, promising to swamp thousands of homes and businesses. Some 10,000 residents have been ordered to leave their homes -- about a quarter of the city's population.

There are international agreements in place to make sure water released from the dams don't harm anyone downstream, including in Manitoba, where the Souris River eventually loops around and joins the Assiniboine River. Wall said the dams have prevented flooding over the decades and the release is important now to protect the integrity of the dams.

Hjertaas said there's nothing Saskatchewan can do to hold back the flow.

"The storage capacity in the dams has been used and so there is not capacity to reduce the impact on Minot. Obviously they would like us to reduce flows as quickly as we can ... but what we can do we are doing and or have done," said Hjertaas.

"They understand the situation that when a dam is full, it's full."

Hjertaas said it's tough to know when water levels might go down.

"At least for a couple of days, the flows are going to stay high. If it would quit raining, then it could start going down," he said.

With files from Associated Press