Montreal Mayor Denis Coderre has given federal environment officials one week to approve the city's plan to dump eight billion litres of raw sewage into the St. Lawrence River, but Environment Minister Leona Aglukkaq has put the matter on hold until next month.
In a letter sent Friday to Aglukkaq, Coderre challenged the interpretation of federal laws the government invoked to suspend the sewage dump that was set to begin this weekend.
The mayor suggested the temporary bypass is legal under the Fisheries Act since it relates to construction or maintenance work.
A spokesman for Aglukkaq tweeted that Coderre was incorrect.
"The proposed sewage dump in the St. Lawrence can't be authorized under the Fisheries Act or regulations," Ted Laking wrote.
The city wants to close an interceptor - a large sewer used to feed wastewater to treatment plants - to do maintenance work and relocate a snow chute located underneath the Bonaventure Expressway, which is being converted into an urban boulevard.
This week, Ottawa put the project on hold pending further, independent scientific analysis, saying it could not conclude from the information it had as to whether the untreated wastewater to be released would be acutely toxic. An interim order issued Friday that no untreated wastewater should be dumped into the river until Nov. 3 to allow time to conduct a scientific review of the consquences.
Coderre described the federal actions as abusive and inappropriate and is calling on the federal government to give the go-ahead by next Friday.
Despite Monday's federal election, Coderre said bureaucrats and experts can complete the review quickly.
"For now it doesn't change anything because it's the same government that's there and we're working with bureaucrats," he said in Quebec City.
"I hope they weren't waiting for my letter to name an expert. In any case, they'll name an expert and it can be done quickly."
Coderre says the delay is in the interest of neither the public nor the environment and called the minister's intervention "unreasonable."
He noted the federal Environment Department has been aware of the city's plan since September 2014 and has been provided with all the documents detailing the repair and maintenance work that is necessary.
"If it is not possible to perform this work during the October-November 2015 window, we will have to delay it for one year," Coderre noted. "We consider it is not in the public interest or in the interest of the environment to delay such work for one year."
Delays could create serious problems: infrastructure failure, equipment breaks from large debris and risks of obstruction that will cause overflows during heavy rainstorms. Coderre also suggests it won't be possible to treat tens of thousands of tonnes of snow waste.
The mayor wrote that many other Canadian municipalities dump untreated sewage into waterways without any Environment Canada intervention.
Coderre replied in the letter the plan has been carefully crafted and a temporary diversion is necessary to allow workers to gain access to the tunnel.
"The bureaucrats in your department have never indicated any problems whatsoever with the information provided," he wrote.
Coderre says drinking water wouldn't be affected and, despite the optics, it is the most viable solution in terms of time and cost.
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