SOMBA K'E/YELLOWKNIFE - The federal government has told the city to stop dumping the contents of storm sewers into a Kam Lake discharge site after fuel was found in the water and soil near the city's public works garage in June.

Blue fish mark the sewer grates in Yellowknife as a reminder to think before you dump. - Alyssa Smith/NNSL photo

In a letter addressed to Yellowknife Mayor Gord Van Tighem, Scott Stewart, a Water Resource Officer with Indian and Northern Affairs Canada, said the city's use of the Kam Lake discharge site "puts the water quality of Kam Lake at risk."

He wrote the city's current water licence does not allow the act of "discharging solids collected in the storm sewer into Kam Lake."

Marty Sanderson, acting district manager for Indian and Northern Affairs Canada, said the city has complied with its request and has chosen an alternate location to put debris from storm sewers.

He added the city is also required to update its stormwater management plan to include the deposit of materials from storm sewers by Aug. 31, 2011 as required by its water licence.

It is not known how long the city has been using the discharge site at Kam Lake.

On June 26, the pilot of a low-flying aircraft noticed a sheen on the surface of Kam Lake near the city's public works garage. The spill appeared to run from the shore into the water.

At the time, the contents and source of the spill were unknown.

On Aug. 19 the city's Public Works department and the Department of Environment and Natural Resources issued a press release stating the spill was likely caused by illegal dumping into one of the city's storm sewers.

An investigation by both departments showed the substances were diesel fuel and lubricating oil.

Public Works manager Chris Greencorn said his department uses vacuum trucks to clean debris out of the storm sewer catch basins. When these trucks get full, they are emptied into discharge sites.

One such site is located at the city's Public Works garage.

Greencorn said there is no way the lubricating oil and diesel fuel found in the soil and water around the public works garage came from Public Works.

"They just don't exist down in that neck of our city yard," he said. "Not a chance."

He said all oiling is done indoors in a controlled environment.

"We don't do any fuelling or anything down near the water," he said.

Greencorn said it was impossible to tell where the diesel and oil came from; and added the vacuum trucks could have picked them up at any of the city's 430 some catch basins.

Danielle Morin, an environmental protection officer with ENR told Yellowknifer the substance likely leached through the soil from the discharge site and into the lake.

She said the contamination in the area is "not excessive."

"You're not going to go there and see ducks covered in oil," she said.

Morin said she's concerned the public doesn't realize anything put into the storm sewers ends up in a lake.

"People tend not to think about it," she said. "They just think it's gone down the manhole and the sewer."

Morin suggested using the blue fishes painted next to sewer grates as a reminder not to dump.

She said the spill at Kam Lake is minor, but still requires clean up.

She said a private consultant has been hired to assess the level of contamination and come up with a plan for cleaning it up.

The city and ENR will then sit down and decide on the best option.

"The consultant will then present options as to how the area could be cleaned up," she said. "The final decision will be made by Public Works and the Department of Environment and Natural Resources."

She said the contractor has not indicated how long this process will take, but Morin said she guessed it will be a few weeks.

Morin said the presence of lubricating oil and diesel fuel in the soil and water can negatively impact both vegetation and animal life in the area.

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