Vials of murky water from the Rideau Canal are being tested in a lab tonight to find out why our prized UNESCO world heritage site is turning green.  The Ministry of the Environment did the testing at the Chateau Laurier Locks in downtown Ottawa.  It will take a couple of days to get those results back.

Bill Wylie has grown up in Ottawa, enjoying the beauty of the Rideau Canal.  But not this year.

“It's a shame to see it this way,” says Wylie, as he walks along the canal, “it's a shame after it's been such a great sight for so many years.”

The ducks may love it.  There is plenty to eat.  But, the concern is what they're feasting on.  If it is blue-green algae, in high levels in a waterway, it can cause problems, according to Jesse Vermaire, a professor of Environmental Science at the University of Carleton.

“When those algae die, it settles to bottom of lake or river,” explains Vermaire, “and the algae is consumed by other bacteria which uses up oxygen. That would be a worry for the fish if the oxygen levels got too low.”

Staff from the Ministry of the Environment and Climate Change was out testing the water in the Canal yesterday, after our story aired on the 6:00 news.  In an email, Gary Wheeler, with the ministry said it hopes to have the test results back by the end of this week, adding:

“The Rideau Canal is used recreationally by boaters, canoeists, kayakers and paddle-boats and is not a source of drinking water.”

These have been ideal conditions for that bloom of blue green algae, if indeed that is what it is.  It has been persistently hot, very little rain and the narrowness of the canal does not allow for very much water flow.  Couple that with some phosphorus and nitrogen and the algae weeds go crazy.

We had viewers all along the Rideau canal system reporting “green water.” 

Scott tweeted out a photograph taken near Kingston, showing a similar green hue. And Cathy Dunthorne said it was “emerald green” all the way from Kingston to Jones Falls.

Blue or green, the canal is still a draw to paddleboarders like Haley Emerson.

“Overall it's a good experience getting out on the water and we're just happy to be out.”

“I did dip my feet in,” adds her friend Alexandra Blaight, “So far no rashes or anything but we are just enjoying ourselves on top of the water.”