Our View: Be vigilant in observing river
A lot of press has been dedicated to the recent sediment spill at a sand mine near Grantsburg. This mine is also near the St. Croix River, and there is a piece of the story that I have yet to see printed. The work of a few ordinary people prevented a bigger spill.
Thank you, Don, the citizen who was out on a park trail and noticed a stream that was heavy with silt. He cared enough to take a few pictures and seek help. When I got the pictures, I passed them on to Burnett County Land and Water Department. My late-in-the-day inquiry was answered long after normal business hours -- so much for government workers not being engaged or caring. Before noon the next day, there was an onsite visit to the stream by the county, and another agency had an airplane track the sediment plume to its source. They then followed the stream and did some ground-truthing, and met with managers of the mining operation. They made temporary recommendations and scheduled follow-up visits. The final thank-you goes to the mining company. While it isn't ideal that the spill happened, my understanding is that they took quick action to take care of the immediate problem.
I've overheard some interesting comments about the spill. Beyond the unsightliness and noise of the operation, is there good reason to worry? After all, as one unconcerned citizen put it, "what's the big deal, it's not like it's toxic or anything, it's just sand?"
Toxic or not, sediment is a pollutant. Rivers running brown with silt are not only ugly, but can be deadly for all the critters that call those rivers home. Covering the stream bottom with silt can smother the bugs and mussels that make up the base of the river's food chain. The 60-plus species of fish documented in the St. Croix River depend on those bottom dwellers for their food source. It is no coincidence that we have a higher number of lake sturgeon, smallmouth bass and muskies than most other rivers in the U.S. They all thrive in our clear, free-running river.
Sand will also carry along whatever else is in it. One common hitch-hiker is phosphorus. Phosphorus binds to soil particles, so as soil is washed into the river, phosphorus is too. Lake St. Croix is listed as impaired for phosphorus. Letting soil wash into the St. Croix increases the level of phosphorus, which leads to increased growth of algae. Those unnatural algal blooms upset the normal balance of aquatic vegetation, which again affects the food supply for everything that lives in the river.
I'm sure we aren't at the end of this story. Our hope, of course, is that the mining operation will have no additional spills and will operate within the limits of its permits. I also hope more people take an active role in caring for our river. People come to the St. Croix valley to boat, fish and swim because of our clean water. By contrast, sediment-choked waters aren't much of an attraction. Here in the Midwest, we don't have to travel far to see examples of rivers and lakes allowed to fill with sediment run-off. Let's not let that happen to the St. Croix.