Turbine Transmission Lines Revised due to Possible Groundwater Contamination

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Published on Friday, 31 October 2014 20:49

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Dufferin Wind Power Inc.’s remedial utility pole sealing plan got off to a sluggish start.

Faced with delays in sealing more than 300 utility pole foundations to guard against the possibility for groundwater contamination in Melancthon and Amaranth, Dufferin Wind missed the initial Sept. 15 deadline imposed by the Ministry of the Environment (MOE).

Although Dufferin Wind has been granted more time, a memo written to municipal officials by Gary Tomlinson, senior environmental officer with the MOE, stresses the need to get the work done as quickly as possible.

“Everybody recognizes the necessity of getting this project completed before the onset of the seriously rainy fall weather,” he wrote, expecting it will take until at least mid-October to complete the remedial work.

According to Dufferin Wind spokesperson Connie Roberts, more than 70 per cent of the work has been completed. The expectation is that it will be done by the end of the month, she added.  

“However, at this point, I have stressed to everyone involved that getting the process and required work done right is more important than meeting an arbitrary deadline,” Tomlinson added.

The Ontario Energy Board (OEB) approved Dufferin Wind’s plan to construct a 230 kV transmission line from its 49-turbine wind farm in Melancthon to Amaranth last year.

Earlier this summer, the MOE asked Dufferin Wind to revise those plans after a local resident argued some of its utility pole foundations could act as conduits for surface water pollutants to enter the groundwater supply.

“We’re at the headwaters and if there is a potential that we are going to pollute the water stream, then obviously that concerns me,” said Melancthon Mayor Bill Hill. “That affects an awful lot of people from a broader area beyond Melancthon.”

When asked to comment on the specifics of the sealing program, Dufferin Wind officials referred The Banner onto the MOE. While it considers the potential for water contamination to be low, the MOE has acknowledged it as a possibility.  

That’s because the retaining structures, or caissons, used by Dufferin Wind lend to the accumulation of surface water in and around the bases of the utility poles.

Dufferin Wind has agreed to address the possibility these caissons could transfer surface pollutants, such as fertilizers, into the bedrock in the event of heavy rain run-off or flooding.

“The ministry has found no evidence to suggest that negative impacts to the local potable water aquifer are occurring,” MOE spokesperson Kate Jordan said in an email. “The ministry believes the (sealing) program to be an effective mitigation method going forward.”

The work consists of installing a benonite clay seal both inside and outside of caissons. Getting the materials into Canada was difficult though, according to Tomlinson.

The only North American supplier of the type of clay required to provide a proper groundwater barrier is locared in Wyoming. There was an additional delay getting the benonite clay across the border as well.

“I can’t claim to understand what the holdup was with the Canadian Border Services Agency, but the crossing didn’t go smoothly or quickly,” Tomlinson noted.

Other factors contributing to delays included difficulties finding a contractor on short notice, as well as vandalism. Copper has been stripped from some of Dufferin Wind’s utility poles, Jordan explained.

“Based on what we’ve been told by the ministry, it was not an intention delay,” Hill said. “It was circumstances beyond their control.”

While the MOE is satisfied by the measures taken, Hill isn’t brimming with confidence. Since the transmission line runs through its abandoned rail lands, he said county officials are keeping a close eye on the situation.

“I’m not sure (the MOE) are keeping as close an eye on it as I’d like to see,” Hill said, who has written to the ministry several times. “I want some assurances that the ministry has the resources to monitor this.”

Another concern raised by local municipalities is Dufferin Wind’s use of pentachlorophenol (penta). The entire lengths, as opposed to only the bottom, of the poles have been treated with the wood preservative, Hill argued.

“The stuff is on the outside of the entire height of the pole, then obviously that can seep down,” he said. “It is an added concern for possible pollution.”

MOE officials aren’t worried though. Jordan said Health Canada and Environment Canada have both approved the use of penta as a wood preservative on utility poles.

“Penta treated poles stuck in the ground and exposed to groundwater ... do not present any particular hazard to the natural environment,” she said. “The ministry has no concerns with the entire length of the poles being treated with penta.”

By Chris Halliday

Published in the Orangeville Banner, Oct. 8, 2014

A major part of this transmission line is built on former rail lines, drilling through the aquifer of Brownfields.

Brownfields are vacant or underused sites with potential for redevelopment. They may be contaminated, often due to former industrial or commercial use. Brownfields are found in all types of communities across the province.

In the last century, many industries operated within the city core and along waterways. Some of these industries included mills, factories, railway yards and service stations. Many have since closed or moved away. The lands left behind – brownfields – lie idle and often are contaminated.

Excerpt from the Ministry of Municipal Affairs and Housing website

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