UPDATE: 8:50 a.m.
Several sharp Castanet readers pointed out that the actual input of water into Okanagan Lake to cause a 2.5 centimetre rise must take into account outflow as well.
"Taking an average discharge over the last few days of about 65 cubic meters per second at Penticton and the outflow is about 5,600,000,000 litres," said Owen Scott, a geoscientist with TRAK International.
This puts the actual amount of water entering the lake, to cause a 2.5 cm rise, at about 14.3 billion litres, or an incredible 5,700 Olympic swimming pools.
That's a lot of water.
ORIGINAL: 5 a.m.
Okanagan Lake has been steadily rising for weeks now.
Every day, it is a couple of centimetres higher than the day before, but just how much water does it take to raise a 100-km long lake by a couple centimetres? A lot.
Craig Nichol of the Department of Earth, Environmental and Geographic Sciences at UBC Okanagan has done a rough calculation of how much water it takes to raise the large lake by 2.5 cm in 24 hours.
The numbers are staggering.
“The quick calculation would be to take the area of the lake - 348 to 351 km2 - depending on which handy Internet source gets used. Take the area of the lake 0.025 m to find the total volume of water being added per day in m3 = 8,700,000. Multiply by 1,000 to get litres = 8,700,000,000 litres per day,” Nichol told Castanet.
That's right, a staggering 8.7 billion litres of water flows into Okanagan Lake daily to raise the level by 2.5 cm.
“There seems to be a history of using Olympic-sized swimming pools as a visually recognizable amount of water – so that works out to be about 3,500 olympic sized pools per day,” said Nichol.
Each Olympic-sized pool holds 2,500,000 litres of water.
The lake rose another three centimetres between Wednesday and Thursday. It sits at 342.98 metres, just two centimetres below the forecast high mark of 343 metres.