Hydraulics of Wetlands: Monitoring and Modeling Emily Spargo University of Wisconsin-Platteville REU Advisors: Drs. Kolar, Nairn, & Strevett

Report Overview Wetland Hydrology Tracer Test Modeling Conclusions

The Big Question What is the hydraulic residence time of the water moving through the wetland, and how can I most effectively model the flow?

Wetland Hydrology ? ? ? ? ? Complex Systems Few Models Inputs Surface & below ground flow Few Models First in 1970’s Vary for specific type of wetland ? ? ? ? ?

Tracer Test Mechanics of a Tracer Test Bromide Input Sample Break-through curve Bromide conservative easy to measure non-toxic

Site Map

Data Collection & Analysis 8-day sampling period Hand and ISCO samples Bromide Ion Selective Electrode Analysis

Modeling Zero Order Model INPUT OUTPUT BLACK BOX

Modeling First Order Model Second Order Model INPUT OUTPUT INPUT

Our Model BLACK BOX Groundwater model Step Injection Parameters: Velocity Dispersion Tracer concentration after mixing

Site 1 velocity = 0.35 m/min. dispersion coefficient = 0.2 m2/min Field data Model velocity = 0.35 m/min. dispersion coefficient = 0.2 m2/min

Site 2 velocity = 0.01 m/min. dispersion coefficient = 0.5 m2/min Field data Model velocity = 0.01 m/min. dispersion coefficient = 0.5 m2/min

Site 3 velocity = 0.001 m/min. dispersion = 3 m2/min. Field data velocity = 0.001 m/min. dispersion = 3 m2/min. Model Field data Model velocity = 0.001 m/min. dispersion1 = 13 m2/min. dispersion2 = 2.5 m2/min.

Conclusions ????? Trends: Residence Times: Average velocity decreases Dispersion increases Reasonable trends Residence Times: Site 1 = 25.7 minutes Site 2 = 3.8 days Site 3 = 131.9 days ?????

Future Research MORE TIME MORE MONEY Complete tracer study Increase model complexity MORE MONEY Purchase reliable equipment Increase pay for REU students

Acknowledgements Dr. Kolar Dr. Nairn Dr. Strevett Denae, Danette, Jake, Jessica, Kim, & Todd NSF Grant # EEC-9912319