Water Under Weather: Time will heal what ails flood-plagued water

Kali Katerberg/Daily Mining Gazette Portage Lake took on an abnormal brown color due to flood-borne materials following the June 17 storm.

HOUGHTON — Despite a murky brown Portage Lake and beach closures immediately after June 17 flash flooding, the long-term ecological impacts to waterways aren’t expected to be substantial, but only time will tell.

The flooding released sewage, sediment and assorted contaminants into area waterways but the Department of Environmental Quality (DEQ) has received no reports of large amounts of oil spillage, and sewage losses were not major, said DEQ District Coordinator Steve Casey.

Another area of concern is sediment containing naturally occurring fecal matter from wildlife and livestock.

These contaminants are now in the waterways and will flow into Lake Superior, where they will be diluted.

“Unlike a lot of the other Great Lakes, it (Lake Superior) doesn’t have a lot of the cumulative impacts that say, you see in Lake Erie, or even Ontario or areas of Lake Huron. So we can absorb a little bit of this,” said Amy Marcarelli, ecologist for Michigan Tech Ecosystem.

Already Marcarelli is starting to see inland lakes and rivers clear up, as sediments move into Lake Superior, although Portage still has a ways to go. It was the deposit point for a significant amount of the materials.

In both lakes and rivers, the plants, algae and microbes will rebound quickly. Long term, the impact on organisms will vary, she pointed out, with river organisms more adapted to floods.

“If you’re a bacteria or a bug that’s living in a river, you can’t necessarily know how much water is going by. You can feel how fast the water is going, so for them this was a disturbance, but it’s not necessarily the end because they have all sorts of adaptations.”

According to sensors in the Pilgrim River, measuring the rate of oxygen production from algae and microbes, levels went down after the flood but these organisms will recover quickly, she explained.

“That’s not surprising, given the fact that probably all of the sand and rock and mud and everything on the bottom was moving, just like it was moving on Agate Street,” Marcarelli said.

Researchers have already seen some marked fish return to their typical locations in rivers. However, in lakes the recovery could be slower because the organisms aren’t as adapted to physical disturbances.

The impacts of disturbances and contaminants like E. coli and sewage might impact larger organisms like fish and insects, but she doesn’t expect to see the effects until next year.

If observed, the impacts wouldn’t be fish killed but lowered reproduction and altered movement.

At the moment, humans are the ones who need to watch out for contaminated water, with beach closures still in place and testing ongoing, fish are generally hardier.

“Right now the E. coli and the other microbial contaminants, they are a big concern for human health, and they are potentially also a concern for fish health but not as big,” she said. “Those guys are a little bit more resilient. They are adapted to living in the water with other microbes.”

Marcarelli isn’t sure when Portage Lake will return to its usual blue, but she has been surprised how long it has taken to clear. The lack of strong winds moving the water through could be the cause.

“Now that it’s (contaminants) there, there’s not much we can do other than wait. Please follow the Health Department advisories: don’t swim, don’t eat the fish,” she said, recommending locals and tourists wait for the Health Department’s OK.

“Don’t let it scare you away from the beaches forever but follow it,” she said.