Michael Schmidt is the Water Quality Program Associate at the Minnesota Center for Environmental Advocacy, a nonprofit organization using law, science, and research to protect Minnesota's natural resources, wildlife and the health of its people.
Have you ever seen a lake that’s green? The iconic photos of Minnesota’s lakes always show clear blue water, but in reality we aren’t so lucky. Even here, where everyone loves their local lake (or several lakes!) and rivers, we experience water quality problems. The most visible is often algae.
Algal blooms on lakes are always a nuisance, but it can have some serious consequences. With high enough levels, kids and pets can get sick. Right now Minnesota has a cleanup plan for Lake Volney out for public review, which has had algae blooms so bad that children have been sickened by swimming in it. Algae can also be high in rivers and streams, leading to green waterfalls like Minneopa.
One kind of algae, commonly called blue-green algae, produces neurotoxins. These can be potentially harmful to people, and blooms of this type of algae have been found across the country and have been appearing in Minnesota.
Minnesota is working to stop algae in a few ways. The Minnesota Pollution Control Agency recently issued a strategy calling for a 45 percent reduction of the nutrients (nitrogen and phosphorus) that encourage algal blooms. Unfortunately, the strategy doesn’t lay out a clear path to achieve the reductions. Environment Minnesota and other groups sent a letter requesting improvements to the strategy. The state is also in the process of adopting water quality standards that set a limit on the nutrients in healthy rivers and streams. If nutrients are found to be too high, a cleanup plan (like the one for Lake Volney) will be required.
Unfortunately, state cleanup plans do not require the biggest pollution source to clean up its pollution. The state’s strategy found that agriculture is the largest source of nutrients in the state, but there are no requirements in place for most farmers to take action in response to a cleanup plan. As a result, the state has hundreds of lakes that don’t meet state standards. Once the new river standards are finalized, Minnesota will have dozens of rivers that fail to meet those. The rivers and streams that don’t meet standards are a little greener, but that’s nothing to envy.
If you see a lake or river that looks less picturesque and a little more grotesque, be careful! A good rule is to avoid swimming in lakes if the water has floating scum or looks especially green. If you do swim where there is algae, don’t drink any and be sure to wash off afterwards.