This research was supported by the Undergraduate Research Opportunities Program (UROP)

Alexander, E Calvin

Alexander, Scott C

Pencak, Edward S

University of Minnesota Digital Conservancy

From spring to stream: water quality analysis in Trout Brook, Dakota County, MN
The nitrate levels in Trout Brook springs and streams 
remain high, and appear to trend upwards. However, 
Trout Brook stream and springs are very variable 
systems. The water quality parameters vary greatly on a 
day to day time scale. Year-on-year trends cannot be 
documented with the certainty needed for effective 
environmental management without continuous 
monitoring of critical parameters. Relative depletion in 
2H and 18O from the upstream sample shows that 
meltwater had a higher contribution there than the 
springs, and stream samples were a mix of both ratios.
Edward Pencak, Scott C. Alexander, and E. Calvin Alexander, Jr. - University of Minnesota, Twin Cities
Similar Data Variance Observed In Springs
Isotope Ratios Show Mixing of
Meltwater & Baseflow
Low Data Collection Frequency Inhibits
Actionable Results
Discussion
• Use dataloggers to understand spring responses to    
     environmental conditions
• Determine age of water in samples to understand 
     response time for changing practices & policies
• Use observation based hydrogeologic knowledge of 
     the surface/groundwater dynamics to guide 
     environmental management and remediation effort to 
     improve the water quality in the Trout Brook surface 
     and groundwater sheds.
Recommendations
Elizabeth Lundstrom ran ion analyses.
Dakota County provided historical data.
Spatial data is courtesy of the MDNR and Dakota County. 
Funding was provided by UMN UROP.
Acknowledgements
Trout Brook has some of the highest recorded nitrate 
levels from southeast Minnesota springs. The springs are 
in karst and fed by the Prairie du Chien aquifer. Spring 
water is a relatively constant temperature when it enters 
the stream, creating a favorable environment for trout. 
The spring contributions are supplemented by flushes of 
snowmelt and precipitation events on surrounding 
agricultural an undeveloped land.
Introduction
15
9.36
27.01
14.91
20.01
13.76
17.64
13.74
Nitrate Levels are Highest
in West Branch
• Collect in-situ measurements and field samples
• Analyze cations, anions, isotopes, alkalinity
• Compare results to historical data
• Interpret trends
Figure 1: Nitrate-nitrogen concentrations in the springs and streams of Trout Brook. 
The numbers next to the symbols are the nitrate levels in the 3/17/18 sample event. 
The green shaded area is the Miesville Ravine Regional Park.
Methods
0 500 1,000 1,500 2,000250
Meters
Legend
Springs
Streams
Figure 2: Nitrate-nitrogen concentrations in the East Branch (TB1), West 
Branch (TB2) and Downstream end (TB3) of Trout Brook - including the 
2/13/17 and 2/23/18 Dakota Co. data sets.
Figure 3: Nitrate-nitrogen concentrations in the East Branch (TB1), West 
Branch (TB2) and Downstream end (TB3) of Trout Brook - excluding the 
2/13/17 and 2/23/18 Dakota Co. data sets. 
Figure 4:  Nitrate-nitrogen concentrations in four Trout Brook Springs - 
including Ron Spong's measurements from the 1980s and 1990s and all 
more recent measurements.
Figure 5. Stable isotope data from Trout Brook Springs and Streams. 
Sampled 3/17/18 during melting snow pack conditions.


From spring to stream: water quality analysis in Trout Brook, Dakota County, MN

https://conservancy.umn.edu/bitstream/handle/11299/196199/Poster_troutbrook.pdf?sequence=1&isAllowed=y

From spring to stream: water quality analysis in Trout Brook, Dakota County, MN

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