By Sharon Hill, The Windsor Star, www.windsorstar.com
The construction of offshore wind turbines south of Kingsville could threaten the safety of drinking water for 60,000 people, says Union Water System advisory board manager John Kehoe.
Kehoe said the construction could cause weeks of turbidity in the water.
If the plant can’t filter the muddy water and be sure it is getting out pathogens such as E. coli, it could be shut down, Kehoe said.
“To consistently filter that out over a period of a long time … it would give me concern.
“Obviously, there’s more chance of failure of the treatment if we’re facing that situation.”
He said it is unclear what chemicals could be stirred up during construction.
“We don’t know what’s in that sediment, either,” Kehoe said.
SouthPoint Wind is proposing to build 15 offshore turbines south of Kingsville and Leamington, including five south of the system’s two intake pipes. SouthPoint Wind is also proposing 700 turbines in Lake Erie and Lake St. Clair meaning potentially another 50 turbines south of the system’s intake pipe.
The system, which serves Leamington and Kingsville and parts of Essex and Lakeshore, has two intake pipes at the end of Union Avenue, one about 500 metres offshore and one a kilometre out.
Kehoe said it appears the closest turbine is within 450 metres of one of the intake pipes in Lake Erie and four turbines are proposed within a kilometre of one of the intakes. “That concerns us obviously. That is actually quite close to the intakes.”
Kehoe said the system might be prevented from extending its intake pipe into the lake if five to 55 turbines are built south of the pipe. Another concern is maintenance of the turbines, which could increase boat traffic near the intake pipes, Kehoe said.
The system’s board is working with the Essex Region Conservation Authority on what to study and what to do. The board could discuss the issue at its April 21 meeting.
SouthPoint Wind has taken three core samples from Lake Erie and is waiting to hear the results, said Daniel Cherrin, a spokesman for SouthPoint Wind.
When asked what steps could be taken to protect water quality, Cherrin said the company isn’t at that stage yet but “will take every necessary precaution to insure environmental quality and safety of the water.”
Cherrin said the information in the draft application, such as where the turbines will be placed, is preliminary. The company is waiting for the provincial guidelines on offshore wind power, he said.
SouthPoint Wind’s draft proposal, which has been posted online, says the 15 turbines would be less than 1.5 kilometres from shore. Southpoint says it will maintain a setback from the intake pipe of at least 500 metres.
Construction could last 21/2 to almost five months. The draft document said the piles will be driven about 20 to 30 metres into the lakebed and will be hollow, open-ended steel pipe piles. “Use of open-ended driven pipe piles allows the lake bottom sediment to be encased inside the pipe, thus minimizing disturbance,” the document says.
Construction such as laying the cable, building the foundations and anchoring or propping up barges on the lakebed could disturb contaminated sediment, says the online information. It says turbid water could alter the taste and odour of water.
What could be in the sediment at the bottom of the lake? PCBs and mercury, but not enough research has been done in the areas where the wind turbines could go to give a definite answer, says Ken Drouillard, a researcher with the Great Lakes Institute for Environmental Research at the University of Windsor.
If the sediment contained PCBs or mercury and was stirred up, some of it could dissolve in the water and get into fish, Drouillard said. That could increase the number of advisories on how much fish to eat but Drouillard didn’t think it would contribute to poor drinking water.
“Will sediment disturbance affect water contamination? It might do so but I suspect marginally. It would probably be a bigger economic impact of the plants having to deal with higher suspended solids,” he said.
At the shore of Lake Erie is sand. About one kilometre out it becomes silt. Drouillard said the more turbines are built in deeper sediment, the higher the probability it could be contaminated.
In Lake Erie, contaminated sediment came from the Detroit River. Because of currents most of the contaminants from the U.S. side are deposited more on the Canadian side, he said. Amherstburg, however, has low levels of PCBs because that section is more influenced by what’s happening on the Canadian side of the river.
Drouillard said the contamination around Middle Sister Island in Lake Erie is equal to what’s found in the worst parts of the Detroit River. He said that closer to the Canadian shore of Lake Erie, the contamination levels drop.
Some surveys have found high contaminant levels three to four kilometres off Colchester that approach the levels at Middle Sister Island, he said.
In sandy Lake St. Clair, PCBs won’t be an issue but mercury could be thanks to chemical plants in Sarnia, Drouillard said.
What’s in the sediment and where it will end up needs to be studied, said Stan Taylor, source water protection program manager in Essex.
Taylor said studies are needed for intake pipes in Colchester, Kingsville and Wheatley in Lake Erie and Stoney Point and Belle River in Lake St. Clair.