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The Okanagan watershed is known as the most arid basin in Canada. Starting in Armstrong and running south past the U.S. border, the Okanagan Basin stretches almost 200 kilometres in length and 8,000 kilometres squared in area. It's about two thirds the size of Vancouver Island. Six main lakes make up the Okanagan watershed, or basin, including Okanagan, Kalamalka, Wood, Skaha, Vaseux and Osoyoos.
Even though the Central Okanagan was experiencing drought last year, the heavy water and recent flooding is starting to fill up the lakes in the basin.
With a massive water system like the Okanagan basin, and multiple gates controlling water levels all the way into the Columbia River, it takes a lot of water to upset the system.
A year ago at this time, the high waters and snow melt would have been absorbed into the ground, but three months of heavy rain is unusual in the Okanagan and has tipped the scales when it comes to ground absorption.
"Usually now the hills are like a sponge," said Shaun Reimer, section head for public safety and protection with the Ministry of Forests, Lands and Natural Resources.
"After a drought year, the sponge is dry and a lot of the snow will infiltrate into the soil, but right now the conditions are so saturated that the sponge is just sopping wet and everything that melts runs off," said Reimer.
Reimer controls the water gates for the Okanagan dam. He decides how much water stays in Okanagan Lake. Water levels are constantly fluctuating in a controlled manner in order to provide water for Vernon, Kelowna, Penticton and Osoyoos.
When unprecedented rainfall enters the picture, though, the balancing act becomes more difficult.
"In fact, it's one of the problems that we had in terms of managing the lake is that March 1st our snow index for the Okanagan Valley was 86% of normal," he said.
"There wasn't that much snow till later on, till again, once we saw March, April and May - they've been dramatically wet," he said.
As the gate keeper of the Okanagan Lake dam, Reimer said still there are limits as to how much water he can let out per day.
In fact, the past week's water inflow has filled up to more than the daily release allowance.
"Right now we have maximized our outflow. The design outflow at that dam in the channel below the dam is 60 cubic metres per second but right now we're running it at 68 cubic metres per second," said Reimer.
"When I'm releasing 65 to 68 cubic metres per second, I can basically take a centimetre and a half, or a centimetre and three quarters from the lake per day. And yet I got 36 centimetres inflow in a week."
With a daily limit release of 1.75 centimetres, that leaves an extra 23.75 centimetres currently pooling in the lake.
These targets and limits are based on the Okangan Basin Implementation Agreement that dates back to the seventies.
Based on these targets Reimer says the lake is currently holding a lot more than it usually would at this time of year.
"We're saying that we got 20% of our average inflow in one week," said Reimer.
Reimer said there will be some erosion and channel damage after the flooding ends.
Having said that, however, the Mayor of Osoyoos, Sue McKortoff, says things are looking good.
"I see that the Zosel Dam is still at the same level, so it has been about the last three days it's been pretty much the same level," said Sue McKortoff, Mayor of Osyoos.
The Zosel Dam is the dam in Washington that controls the water levels running from Osoyoos Lake to the Okanogan River near Oroville, Washington.
"Apparently Manfred Bauer who's the Mayor of Keremeos has a rock in the middle of the river somewhere over on the Similkameen and when the water gets over the rock, he worries and it's not over the rock yet. So that's terribly scientific," said Mayor McKortoff.
"I'm also on the Osoyoos Lake Water Quality Society, Okanagan Basin Water Board and the International Osoyoos Lake Board of Control. So I get information from all these agencies and if the weather stays the same and it doesn't get too, too hot or we don't get any wild rain storms, I don't think we have too much of a concern down here," she said.
So as far as the high water levels in Okanagan Lake and how it's impacting the rest of the basin, there's less of a risk of flooding further south.
The issue will be keeping up with demand of releasing water as more pours into Okanagan Lake.
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