Check here for previously featured faculty
Featured Faculty: Nathan Johnson
Interests: Engineered management solutions to water quality problems in natural systems. Sediment biogeochemistry, contaminant transport and transformations
Courses Taught: CE 4237: Water Quality Engineering, CE 3025: Environmental Engineering, CE 3225: Hydrology & Hydraulics
Website: http://www.d.umn.edu/~nwjohnso/
Dr. Johnson received his PhD in Civil Engineering from the University of Texas at Austin in July, 2009. He joined the Civil Engineering Department at UMD in Fall 2009, teaching classes and performing research in the area of water resources and environmental engineering. He has developed three new courses at UMD with the intent of cultivating graduates capable of analyzing water quality problems in both engineered and natural systems. Dr. Johnson is currently designing a lab space to support environmental-related teaching and research efforts in Civil Engineering.
Dr. Johnson's research interests are environmental aquatic chemistry, sediment biogeochemistry, and biological and chemical processes related to contaminant transport and transformations. He is currently working on research related to the environmental impacts of mining on NE Minnesota water resources as well as legacy sediment contamination in the St. Louis River estuary.
Field sampling devices at
wild rice microcosms
Chemical and biological processes
involved in engineered sulfate
removal process
Dr. Johnson is involved with research seeking to help the Minnesota Pollution Control Agency (MPCA) and MN Department of Natural Resources (MnDNR) understand how to characterize and manage sulfate mobilized during ongoing, historic, and future mining activities. Sulfate is the topic of ongoing statewide water quality investigations into mercury accumulation in fish tissue, wild rice productivity, and accelerated eutrophication. One current project involves measuring chemical properties in pore fluids of sediment at wild rice beds using innovative sampling and analytical techniques. Another project is using laboratory-scale tests to investigate the feasibility of removing sulfate from the waters of mine pits. Natural materials are being used to stimulate microbial activity which could effectively remove both sulfate and hardness from mine pit waters prior to intentional or unintentional discharge.
Structure of microbial communities
in aquatic sediment and
implications for mercury.
Dr. Johnson's research group
collecting sediment cores
in storm water ponds
In the St. Louis River Estuary, Dr. Johnson's research group is currently investigating the extent to which inorganic mercury is transformed into the organic, bioaccumulative form of mercury in sediments. Both in-situ field measurements as well as controlled laboratory experiments are being used to understand the mercury-related chemical and biological processes occurring in different portions of the estuary. Dr. Johnson is also working on research seeking to find beneficial uses for dredged material. Partnering with the Army Corp's Engineering Research Development Center (ERDC), this project will characterize the water quality implications of combining fine dredged material and biosolids from the Western Lake Superior Sanitary District (WLSSD) for beneficial reuse