Boaters on Lake St. Croix have seen the river turn the color of antifreeze this month. Bright green algae has been spotted in the last several miles of the river above its confluence with the Mississippi.
Such algae can be harmful to people and animals. While most people wouldn’t get in water looking like that, it’s important to make sure pets stay away.
The algae is the result of too many nutrients in runoff from fields, streets, lawns, and wastewater treatment plants. Water like this is why the St. Croix has been designated as an impaired river. Deb Ryun, executive director of the St. Croix River Association, said the algae is an issue which must be addressed.
“Green water in August is not ‘normal,’ as some have come to think,” Ryun said. “We can and should do better, which is why it’s so important we work collaboratively to improve the water in Lake St. Croix. The floating algae matts are a risk to human health and recreation like boating and fishing, and businesses in the area, suffer along with the health of our beloved river.”
Those collaborative efforts to reduce the runoff are picking up steam. For example, conservation districts and land-owners are working together to fix gullies eroding farm fields, cities are upgrading or building new wastewater treatment plants, and communities are installing rain gardens.
But as the photo above illustrates, we still have work to do.