Community Corner

Water Quality in St. Croix River: Problems, but Fixable

At stcroix360.com, a St. Croix scientist says it's a little more complicated than 'Been better. Could be worse.'

"So, how is the water quality in the St. Croix basin?"

That's the question that Jim Almendinger, senior scientist at the St. Croix Watershed Research Station, tackles at the St. Croix 360 website

Here's an excerpt:

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The very question assumes that there is a standard against which water quality can be measured, a scale that goes from “nauseatingly slimy” to “crystalline pure,” with the St. Croix ranking “OK, all things considered.” This means, of course, that we have work to do. ... 

The Clean Water Act has been tremendously successful in reducing pollution from specific “point sources,” mostly industrial waste and municipal waste-water treatment plants. On both the Minnesota and Wisconsin side of the St. Croix River, improvements to waste-water treatment plant technology have drastically reduced waste loads during the 1990s and early 2000s.

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However, the major pollutant loads to the St. Croix have come from “nonpoint” sources, which are diffuse sources from urban and agricultural lands. Often carried in run-off, nonpoint-source pollution may include excess sediment that chokes waterways by siltation, and excess nutrients (phosphorus and nitrogen) that cause nuisance levels of algae. Nonpoint-source pollution from urban areas is gradually being addressed for larger municipalities. Still, the largest contributor to the St. Croix is agricultural land, because of the large areas of tilled, fertilized land exposed to erosion, which transfers topsoil and nutrients to receiving waters. Ironically, agricultural runoff is explicitly excluded from regulation under the Clean Water Act. ...

So, in summary, the St. Croix has some problems with phosphorus pollution, but these problems appear to be fixable. Looking back in time to the sediment-core record, we see that the river ecology could be much improved if we can just reduce phosphorus loads back to about what they were in the 1940s. Looking forward in time with the watershed model, we see that selected land-use changes and agricultural best-management practices could reduce loads enough to reach this goal. There are also meaningful steps that all residents of the watershed can take. Rural residents should make sure their septic systems are in compliance.  City dwellers should support stormwater infiltration projects and use rain barrels and rain gardens. Never put yard waste on streets, where it can wash into our lakes and rivers. All lawn fertilizer should be zero-phosphorus. Consider composting food waste for your gardens, rather than sending it down the drain to the treatment plant.

However, there is no magic bullet that will singlehandedly fix the problem. It will take the concerted effort of many individuals and many different methods in order to produce an aggregate, watershed-wide reduction in phosphorus loads. Like many other large Midwestern watersheds, the St. Croix has suffered impairment (not yet death) by a thousand cuts. We should not be surprised if it takes a thousand band-aids to help repair the problem. Let’s hope that all the enjoyment and values that people gain from this National Wild and Scenic Riverway will translate into action on the river’s behalf.

Read the full post at stcroix360.com


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