PEI

How a 'slick' P.E.I. invention is helping the environment — and the fish

A P.E.I. watershed group is testing out a new invention that sucks up silt from a river and uses it to build the base for a saltwater marsh. They're calling it, at least for now, the silt gator, and it has the potential to reduce greenhouse gases.

'Silt gator' blasts silt from river to form base for saltwater marsh

Fred Cheverie (right) and his crew show the jets on the bottom of the silt gator, which stir up the silt before it's sucked into the hose, here at the Gowan Brae causeway. (Randy McAndrew/CBC)

A P.E.I. watershed group is testing out a new invention that sucks up silt from a river and uses it to build the base for a saltwater marsh.

They're calling it, at least for now, the silt gator, and it has the potential to reduce greenhouse gases.

"The saltwater marsh ecosystem is one of the fastest disappearing in the world with climate change," said Fred Cheverie, co-ordinator of Souris and Area Branch of the P.E.I. Wildlife Federation.

The silt is sucked up from the river and sprayed on spruce boughs to create a base for the saltwater marsh. (Randy McAndrew/CBC)

Creating a saltwater marsh has a couple of benefits, Cheverie said.

"By creating a saltwater marsh and getting grasses to grow in that, what will happen is they will suck up nutrients which will lighten the nutrient load downstream," he explained. 

"Secondly, those saltwater marsh grasses have a wonderful capacity for sequestering carbon, so you're doing two wonderful things for the environment at the same time."

Besides creating the base for the saltwater marsh, the silt gator also clears the siltation in the river, creating a better habitat for the fish. (Randy McAndrew/CBC)

Cheverie's colleague, Keila Miller, says salt marsh plants can suck up 14 times more greenhouse gas emissions than trees, "which is incredible."

And given the global emphasis on reducing greenhouse gas emissions, the Souris group's project is timely, she said.

"A lot of our funders are very eager to get on board to fund these types of projects because it is important."

'Slick' operation

Cheverie got the idea for the silt gator from a friend with a commercial clamming licence, who used a similar type of system.

"The pump would blow water out into the sand and move the sand all away and he'd go pick up the clams like picking potatoes and so I always remembered that," Cheverie said.

Cheverie is calling it a silt gator "because the boat with all the hoses hanging out looks like something you'd see on TV." (Randy McAndrew/CBC)

"I said if I could do that, grab the silty water that is riled up and put it into the saltwater marsh, that would be slick."

Cheverie is calling it a silt gator "because the boat with all the hoses hanging out looks like something you'd see on TV."

There are jets that stir up the silt from the bottom, before it's pumped into a hose and sprayed onto a pile of spruce boughs, to create the new marsh.

Silt concerns

Cheverie had to convince DFO that the pumps wouldn't cause issues.

"They had concerns, any time you move silt out of a river, you may cause agitation especially that could affect the aquaculture industry down the stream," Cheverie said.

The crew works together to pump up the silt and spray it on top of the spruce boughs. (Randy McAndrew/CBC)

The crew takes water samples to make sure the silt was staying in place.

"It's clear down stream, within 15-20 metres, you can see the bottom clear as anything," he said.

"We're not causing any problems downstream, that was my biggest fear."

Creating habitat

In fact, a side benefit to the project is that the silt gator removes excess silt from the river bed, something that is an issue in many P.E.I. rivers.

"When you're taking the silt out, you're deepening the channel downwards and that's going to create a lot of good habitat for the fish that are in the river itself," Miller said.

"That's a problem in a lot of the watersheds is siltation — if there's too much silt, it just chokes everything out."

The water is filled with silt as it is sprayed on to the spruce boughs. The crew describes it as looking like chocolate milk. (Randy McAndrew/CBC)

The work is now complete for this season, but there will be a phase two next year.

"This is kind of a pilot project to see if we could pull it off and we had some people here looking at it and they were thoroughly impressed," Cheverie said.

About the Author

Nancy Russell

Nancy Russell has been a reporter with CBC since 1987, in Whitehorse, Winnipeg, Toronto and Charlottetown. When not on the job, she spends her time on the water rowing, travelling to Kenya or walking her dog. Nancy.Russell@cbc.ca