The short of it: The water is improving in certain urban and rural areas, but the valley still has quite a few water bodies on Wisconsin's and Minnesota's respective impaired water lists, which denote the water that fails to meet state standards for quality. St. Croix River, for instance, appears on both lists. A 2022 Minnesota Pollution Control Agency study found that while 31% of lakes with data were improving, 9% were degrading.
Hong prefaced her talk by saying, "I'll try to sandwich it so it's good, eh getting worried, good again. So you leave with a good feeling at the end of the meeting."
The good: the St. Croix Valley has improved its water quality in a few areas, like in Washington County, where 49% of the lakes have improving water quality, aided in part by over 5,500 water conservation projects in Washington County that help reduce pollution runoff.
Mercury levels are also starting to fall. With mercury affecting northern lakes more, given the way the chemical falls from the atmosphere, Minnesota still has 1,608 lakes with mercury advisories, while Wisconsin — due to fewer lakes farther north — has 446. But Minnesota delisted 12 lakes recently, which Hong attributes to shifts away from coal-burning power generation and changes in waste management.
"It's almost like a bathtub," Hong said. "Hey, the water is clear, but there's not really any fish in it, or there's not as many fish, not the variety of fish that we used to have."
The loss of shoreline leads to a loss of biodiversity in the region. That, high chloride levels, developments built too closely to water and other factors lead to scores of basins, streams, rivers and lakes in the St. Croix Valley landing a spot on one of the impaired waters lists.
There's more: Minnesota has 67 lakes and Wisconsin has 51 that are impaired due to rising levels of chloride alone.
"And the thing that is really challenging with chloride in comparison with some of these other issues, like phosphorus or the sentiment, is that we don't have anything we can do about it. We can't build a rain garden to get rid of it; we can't just plant a buffer strip to get rid of it. Once it's in the water, it's basically in the water, and we don't have a way to get it out."
Then, there's polyfluoroalkyl substances (PFAS), also called forever chemicals. On the Minnesota side, Hong mentioned that 3M's PFAS dumping to make teflon, firefighting foam and more has affected the water drinking supply — and it's extended to the St. Croix River.
"I fear that you might be seeing a fish consumption advisory on the St. Croix due to PFAS in the next couple years. Because it did already get a PFAS impairment on the Minnesota side at least," she said.
However, as promised, Hong ended her presentation with good news. She said that dams being taken down will help environment. Additionally, the South Washington Watershed district has worked with landowners, the DNR and others to re-meander Trout Brook, redirecting the water flow to a different river channel.
Despite the name, Trout Brook lost its trout population for around a decade. Then the fish returned, migrating from the Kinnickinnic River — "apparently lured by the cooler and cleaner water in recent years," Hong wrote in the Stillwater Gazette. The community also added 2,500 Heritage Brook Trout, a native species from the area. Hong attended the event and participated.
"Each of us got to put an entire bucket of fish in the stream," she said at the presentation Wednesday. "It was very fun."
The St. Croix River runs 169 miles with a surrounding watershed — the many lakes, streams and rivers that connect to it — covering 8,000 square miles. It's considered a National Park, one without an entrance fee for much of its scope (State Parks like Willow River require entrance fees typically, but the St. Croix National Scenic Riverway does not).