A new report on the condition of northwest Minnesota waterways shows local rivers filled with mercury-contaminated fish, and streams and ponds loaded with soil erosion sediments and farm chemicals, making for an official local water quality rating of “poor.”
That’s the depressing conclusion of the Thief River Watershed Monitoring and Assessment Report just released by the Minnesota Pollution Control Agency.
The report also describes a dismal structural scenario in which local rivers and streams are prone to flash flooding in times of heavy rainfall and spring melting, and the opposite problem -- an inability to hold much-needed moisture during times of drought.
It’s all the result of our modern way of life, and mostly farming practices. The report says:
“Soil erosion coming from agricultural fields and/or stream banks appears to be the likely cause.”
The report also says:
“While not all streams in this region are capable to providing certain habitats ... channel alterations throughout the watershed have led to channel instability, which is increasing sediment load and deteriorating habitat quality and quantity.”
The reports states that “poor land use management and nutrients input” is choking off natural life in local streams and rivers -- two of the primary culprits names are the nitrogen and phosphorus which can be blamed primarily on agriculture.
“Overall, rivers and streams in the Thief River Watershed are in poor condition,” the report ultimately concludes.
The Thief River Watershed begins with the Thief River which begins its course in Marshall County at Thief Lake. The river flows south to southeasterly to the city of Thief River Falls where it joins the Red Lake River. This watershed covers an area of 624,422 acres in northwest Minnesota.
More Mercury Next Door
The findings of elevated levels of mercury in the fish of Thief River Watershed comes on the heels of another recent MPCA study which found “alarming rates” of mercury in Roseau River fish. This river is just north of Thief River in the Roseau Watershed District.
The landscape surrounding the Roseau River is also heavily farmed with chemical-intensive, heavy tillage agriculture. But as for the actual mercury getting into the fish, farming is not the likely source, but rather a variety of other environmental offenders, such as the burning of coal.
Coal is a known producer of acid rain in Minnesota. This combines with the soil to leach out naturally occurring mercury in the landscape and sends concentrated forms of the heavy metal into the water where it is absorbed by fish and stored in their fat.
To find how much fish you can safely eat, see Page 83 in the 2014 Minnesota Fishing Regulation manual, which you will find online HERE
The dismal results of these intensive studies of waterways in northwest Minnesota should give local residents pause. Hunting, fishing and water-related activities are the most often cited benefits of living in this region, but the science suggests that current farming, industrial and dwelling practices are sending this local landscape creeping toward a dead zone.