Stormwater: From Questions to Applications
The wet summer of 2019 led many to ponder, just what happens with so much stormwater runoff? Professor John Gulliver has been investigating such questions for years.
Gulliver conducts his research at the Saint Anthony Falls Laboratory (SAFL). His major research interests are preventing pollution caused by stormwater runoff and understanding mass transport in environmental systems, that is, the change in physical location or state of chemical elements or pollutants as they move within a system.
Gulliver’s current research projects involve development of technologies to treat stormwater runoff, assessment of stormwater infiltration practices including capturing and temporarily storing stormwater and allowing it to infiltrate into the soil, prediction of runoff from small urban watersheds, and remediation of phosphorus that is released into the water from sediment in lakes.
Gulliver enjoys teaching and conducting research with students, both undergraduate and graduate students. He has mentored many students to success and is most happy when his students are recognized for their work. That this recognition happens with a steady frequency helps to explain Gulliver’s cheerful disposition.
One shining example is current Ph.D. student Vinicus (Vini) Taguchi. He received a National Science Foundation Presidential Fellowship, a Diversity of View and Experience (DOVE) Fellowship from the University of Minnesota, and the 2018 Nels Nelson Fellowship from SAFL. Taguchi placed first for the Jody Conner Student Award for presentations at the 2018 North American Lake Management Society (NALMS) Symposium, was awarded the 2019 Matthew J. Huber Award for Excellence in Transportation Research and Education from the UMN Center for Transportation Studies, and received the 2019 Alvin G. Anderson Award from SAFL.
Taguchi presented at three conferences in 2019: the World Environmental and Water Resources Congress (Pittsburgh), “Low Dissolved Oxygen in Stratified Stormwater Ponds Causes Release of Phosphorus;” the Operation and Maintenance of Stormwater Control Measures Conference (Minneapolis), “How to Stop Ponds from Releasing Phosphorus;” and the American Chemical Society Fall National Meeting and Exposition (San Diego), “Sediment Phosphorus Release in Stormwater Ponds.”
Vini Taguchi, a graduate student advised by Professor Gulliver, appreciates his support: “At every opportunity, John has made every effort to support me and his other students, including writing impassioned letters of recommendation, looking for additional funding through project grants, encouraging us to present at conferences (seven for me so far), and nominating us for fellowships (I have received four). Despite expecting a lot of us with respect to research, he gives us flexibility and allows us to maintain a healthy work-life balance. John has gone out of his way to make me and my fiancée feel welcome. He hosted us for a St. Paul Saints baseball game, various gatherings at his home, and even took us ice fishing!”
Some other recent student accomplishments include Maria Garcia-Serrana (Ph.D., 2017) who won the Matthew J. Huber Award in 2016; Tyler Olsen (MS, 2017) who won the 2016 Nels Nelson Award; and Andrew Erickson (Ph.D., 2017) who won the 2011 Matthew J. Huber Award. Gulliver is currently working with five undergraduate and three graduate students in addition to two full-time Research Associates, and he is expecting more great work to come from these students.
Gulliver’s research has always been relatively close to its application. Several new technologies have been developed and put into use as a result of his innovations.
Iron-enhanced Sand Filter
Over the last 16 years, Gulliver has been working to improve management of stormwater runoff. His research in this area has been applied locally and internationally. In 2005 Gulliver, along with Peter Weiss (Professor, Valparaiso University) and former graduate student Andy Erickson (Ph.D., 2017), developed the concept of the Iron-Enhanced Sand Filter (IESF), which removes dissolved phosphorus from stormwater runoff through adsorption of phosphorous to iron corrosion products. Most lakes and ponds contain nutrients to foster algae growth. The addition of phosphorus from runoff allows that growth to really take off and causes algal and duckweed blooms. The IESF helps keep phosphorus out of the water, resulting in cleaner lakes. Over 100 Iron-Enhanced Sand Filters have been installed across the US, including several in Minnesota.
The SAFL Baffle is a simple device that improves the retention of suspended solids in manhole sumps and decreases washout that can occur in large storms. Gulliver developed The SAFL Baffle in 2010, with Omid Mohseni (SAFL and Barr Engineering) and former graduate student Adam Howard (MS 2011, co-advised with Heinz Stefan and Omid Mohseni). The SAFL Baffle is a perforated plate with approximately 45% porosity. It works as effectively as competing products while beating them on price by a factor of 2 to 3. The University of Minnesota patented the SAFL Baffle and licensed it to Upstream Technologies. Over 1,200 SAFL Baffles have been sold.
The Modified Philip Dunne (MPD) Infiltrometer is used to measure saturated hydraulic conductivity of soil while requiring less water than competing products. This improvement is important because measurements of hydraulic conductivity must often be made relatively far from water sources. Minimizing water requirements makes more measurements possible. The MPD Infiltrometer was developed by Gulliver in 2014 with John Nieber (Bioproducts and Biosystems Engineering, UMN) and former graduate students Rebecca Nestingen (MS, 2007), Brooke Asleson (MS, 2007), and Farzana Ahmed (Ph.D., 2014).
Phosphorus Release From Stormwater Ponds
Currently, Gulliver is working on phosphorus release from stormwater ponds with Jacques Finlay (Ecology, Evolution, and Behavior, UMN), Research Associates Poornima Natarajan and Ben Janke, current doctoral student Vini Taguchi and Emeritus Professor Heinz Stefan. In discussions with watershed districts, it was discovered that many stormwater ponds, which are designed to reduce phosphorus concentration, showed unusually high concentrations of phosphorus. Ponds with high concentrations could pollute rather than protect downstream water bodies. Subsequent measurements raised concern. The problematic ponds were temperature stratified beginning at only one meter of depth. Water below the stratification depth was not exposed to the atmosphere and had zero dissolved oxygen concentration. Thus, the iron oxides were releasing phosphate from the highly organic sediments that had collected over the years. This could be one reason that overall lake quality seems to continue to degrade. The researchers are determining how often this situation occurs, how to easily assess the occurrence, and how to mitigate it when it does occur. This research has generated a lot of interest. The researchers are exploring various effective and cost efficient solutions.
Fall 2019 marks Gulliver’s 38th year on the faculty at the University of Minnesota. In that time he served four years as Director of Graduate Studies and ten years as Department Head. He says, “That time passed like an inverse geometric progression, in that my 38th year seemed to go by 38 times faster than my first.” Gulliver has cut back on his teaching and plans to enter emeritus status in 2021 but will continue his avocation of urban hydrology and water quality research. Gulliver’s contributions and the many scholars he has trained portend a good supply of solutions for whatever stormwater issues arise in the near future.