Tsai Award Ceremony
We will be celebrating the winners of the 2025-2026 Frank and Julie Tsai Award!
Winner: Porraket Dechdacho (Advisor: Dr. Peter K. Kang)
Abstract: From Fracture Intersections to Aquifers: Understanding Transport in Fractured Sedimentary Systems
My research focuses on flow and solute transport in fractured sedimentary systems, where fracture structure and fluid properties strongly influence subsurface transport behavior across scales. To better understand these processes, I combine multiscale visualization experiments, field dye tracer tests, and 3D discrete fracture network (DFN) numerical simulations. I begin at the fracture-intersection scale, using pore-scale Hele-Shaw experiments and numerical simulations to examine the influence of fluid density and flow properties on local flow behavior and solute trapping. Next, I expand to fracture-network-scale DFN modeling to examine how network properties control solute distribution and transport behavior in fractured aquifers. Building on this mechanistic and network-scale understanding, I integrate field observations from a local fractured limestone aquifer with DFN-based modeling to identify the structural and hydraulic parameters that most strongly control breakthrough curve behavior and transport persistence under realistic site conditions. Together, this work connects process understanding across scales, from individual fracture intersections to field-scale aquifers, and aims to improve our understanding of transport in fractured-rock systems and support better predictions of subsurface flow and transport processes.
About: I am a 4th-year Ph.D. student in the Department of Earth & Environmental Sciences, advised by Dr. Peter K. Kang. I was born and raised in Nakhon Si Thammarat, Thailand. I earned my M.S. in hydrogeology from the University of Nevada, Reno, and my B.S. in geosciences from Penn State. My research focuses on flow and solute transport in fractured sedimentary systems, integrating multiscale visualization experiments (network-scale flume studies and pore-scale Hele-Shaw cells) with field dye tracer tests combined with 3D discrete fracture network (DFN) numerical simulations to reveal how fracture network properties control flow and transport behavior in fractured aquifers.
Winner: Denesh K (Dr. Ardeshir Ebtehaj and Dr. Miki Hondzo)
Abstract: Reading Between the Wavelengths: Decoding Indicators of Toxic Blooms Using Hyperspectral Satellite Observations
Cyanotoxins, such as microcystin, pose a major public health hazard during freshwater cyanobacterial blooms. However, the detection of these toxic blooms is challenging because the toxins themselves lack direct optical absorption features. We demonstrate that hyperspectral observations from NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Ocean Color Instrument (OCI) can indirectly detect elevated microcystin concentrations by identifying subtle signatures hidden within the gaps of traditional multispectral satellite sensors to exploit bloom-related optical signatures. Using two years of NOAA in situ microcystin measurements from the Western Lake Erie Basin, we performed bootstrapped Welch’s t-tests to identify OCI wavelengths sensitive to high-microcystin conditions. These bands and derived spectral-shape metrics are then used to train a nested cross-validated random forest classifier, achieving 89.5% accuracy despite limited training data. The results reproduce expected spatial and seasonal patterns of toxic blooms and highlight the dominant role of spectral-shape metrics in the pigment absorption and red-edge regions. These findings suggest that hyperspectral data may provide a nuanced pathway for monitoring toxic bloom occurrence in inland freshwater systems.
About: Denesh is a Ph.D. student in the Department of Civil, Environmental, and Geo Engineering, working with Prof. Ardeshir Ebtehaj and Prof. Miki Hondzo. His research focuses on the remote sensing of harmful algal blooms, particularly through the hyperspectral detection of cyanobacterial pigments and toxin dynamics in inland waters. His work combines laboratory experiments, field observations, and satellite data with statistical techniques to characterize how light interacts with and reflects from the water column, improving the monitoring and prediction of toxic blooms. He also holds a Master’s degree in Physics, during which he worked on remote sensing of planetary analogue environments at the Physical Research Laboratory, India.
Dr. John Anfinson will be the keynote speaker for the event
Presentation Abstract: "I was asked if I would give the keynote presentation for the new Frank and Julie Tsai Fellowship, to which I was honored to say yes. Frank and Julie are University of Minnesota alumni. Frank received his PhD in civil engineering in 1968, and Julie her Master’s Degree in library science in 1964. I was specifically asked if I would bridge their worlds by showing you how I have used libraries and archives to understand and explain to others how humans have engineered the Mississippi River. To do this, I will draw on my time with the U.S. Army Corps of Engineers and the National Park Service, and tell you how the worlds of Frank and Julie have shaped my work for the St. Anthony Falls Laboratory on the cutoff wall and Pool 1 modeling projects."
About: Dr. John O. Anfinson has been researching, writing and speaking about the Mississippi River for over 40 years. He spent the first half of his 40-year federal career with the St. Paul District, U.S. Army Corps of Engineers, as District Historian, Tribal Coordinator and Cultural Resources Program Manager. He joined the Mississippi National River and Recreation Area, a unit of the National Park Service, in 2000, from which he retired as Superintendent in 2021. John is the author of The River We Have Wrought and River of History and many articles about the Mississippi River. He has presented at regional, national, and
international meetings. He is a founding board member of Friends of the Mississippi River and the Minnesota Marine Art Museum. John is the Vice-Chair of Minnesota’s Mississippi River Parkway Commission (Great River Road) and Pilot (Chair) of the 10- state Commission. From 2022 to 2025, he worked as a part-time guest speaker on American Cruise Lines boats operating between St. Paul and New Orleans, giving presentations covering the whole river. John is currently on two Mississippi River study teams with the University of Minnesota’s St. Anthony Falls Laboratory.
He holds a Ph.D. in U.S. History from the University of Minnesota.