- Our researchers are reimagining urban ecosystems to recycle water for increased economic productivity and healthier water systems. Learn more.
- University of Minnesota research is helping farmers manage irrigation, runoff and drainage waters to reduce pollutant loss; keeping our economy pumping and our waterways healthy. Learn more.
- Minnesota’s rivers flow from the Hudson Bay to the Gulf of Mexico. Our research helps protect Minnesota’s 92,000 miles of rivers from habitat loss, pollution, and bank erosion. Learn more.
- Minnesota is home to over 17,400,000 acres of forests, which help to provide clean water for the state. Our researchers are developing new tools for forest and wetland management. Learn more.
- If you count all the lakes in Minnesota down to ¼ acre, we have 4.6 million, with shoreland that is worth $80 billion. Our scientists work to protect this strategic resource. Learn more.
- Lake Superior is one of five lakes on earth that contain more than half of the planet’s liquid surface freshwater. Through outreach, we share our expertise in large lake science with citizens across the state. Learn more.
- Minnesota’s 130-year legacy of iron mining continues to support the growth of the nation. We research opportunities for economic mineral development while preventing impact on freshwater resources. Learn more.
- Three out of four Minnesotans rely on groundwater for their drinking supply. Our scientists are researching the distribution and availability of groundwater to protect drinking water. Learn more.
- Water drives our climate and sustains the world’s people and ecosystems. Our scientists study global water and design water solutions for every continent. Learn more.
Lian Shen is the Director of the St. Anthony Falls Laboratory, the Director of the Fluid Mechanics Lab and is a Professor of Mechanical Engineering in the Department of Mechanical Engineering.
He primarily works on the computational and theoretical study of fluid dynamics in areas including turbulence, boundary layers, water waves, multiphase flows, and flow-structure interaction. The projects originate from a wide range of applications, including mechanical engineering, environmental fluid mechanics, geophysical fluid dynamics, renewable energy, and biofluids; however, basic research aiming at the fundamental mechanisms in fluid dynamics is always a major theme.
His research is supported by NSF, DOE, ONR, NOPP, NOAA, and private industry. He received his Doctorate of Science from the Massachusetts Institute of Technology.
Satellite Monitoring of Minnesota Lake Water Quality
Protecting the quality of lakes is a major concern of Minnesotans, but the expense and time required for ground-based sampling means that only a small fraction of this important resource can be monitored by conventional field methods. Satellite imagery now can measure key water quality constituents on virtually all Minnesota lakes at low cost and greatly supplement the information provided by ground monitoring programs. With support from a variety of state and federal agencies and the University of Minnesota we have measured lake clarity, a key indicator of water quality, on more than 10,000 lakes statewide using current and archived Landsat satellite imagery for seven time periods since 1975. It has proven to be an accurate, economical method to monitor lakes over large geographic areas and time.
Our past research documented a strong relationship between the spectral-radiometric responses of Landsat sensors and observations of water clarity by Secchi disk. The geographic coverage, spatial resolution and free availability of Landsat imagery make it particularly useful to assess inland lake clarity. Its coverage of 12,000 square miles per image allows simultaneous assessment of thousands of lakes in lake-rich areas. Its spatial resolution (30 meters) is suitable for lakes larger than ~10 acres, and it can be used to map in-lake variability. With an image archive dating to 1972, Landsat provides an unprecedented data repository. We have analyzed the water clarity data for temporal and geographic patterns/trends and relationships with land use and other factors that may affect lake quality. Mean water clarity at the state level remained relatively stable over the period 1975-2008, but strong geographic patterns are apparent, with lower clarity in the south and higher clarity in the north. Deep lakes tend to have higher clarity and are more stable than shallow lakes, and agricultural and urban land use are generally associated with lower clarity.
Water clarity of Minnesota lakes can be explored in the Lake Browser, a web-based mapping tool that enables searches and display of results for individual lakes. The data are used by state and local agencies for lake management and by citizens and educators.
Our current research is focused on using new enhanced satellite imagery to measure other key metrics of water quality, including chlorophyll (a measure of algal abundance), suspended solids, and colored dissolved organic matter (CDOM). Together, these three parameters control many important biological, chemical and physical features of lakes. We recently mapped CDOM levels in Minnesota lakes using 2015 imagery; with NSF funding we are expanding this mapping across ecoregions that span Minnesota, Wisconsin, and Michigan. With Legislative-Citizen Commission on Minnesota Resources funding, we are mapping chlorophyll and suspended solids concentrations in lakes across Minnesota. Our current work uses Landsat 8 and the new Sentinel-2 satellites, which have more spectral bands and other improvements compared to previous Landsat sensors. With increasingly sophisticated sensors and expanded availability of imagery, remote sensing of water quality will continue to develop over the next decade.
See more at water.rs.umn.edu.
At the Institute on the Environment (IonE), we envision a world in which sustainable agriculture feeds the world; renewable energy powers healthy homes, efficient transportation and flourishing businesses; every person has access to food, water and shelter; oceans, lakes and rivers are clean and healthy; communities have vibrant economies, neighborhoods and cultures; and thriving ecosystems support thriving economies and societies. At IonE, we go out of our way to collaborate with external partners while bringing different academic fields of expertise together within the University — all with an eye towards being responsive, agile and entrepreneurial in the face of a changing world.
MnDRIVE Advancing industry, conserving our environment is committed to researched based solutions to help protect our natural resources and drive economic innovation. At the core of that commitment is bioremediation, which presents new opportunities for researchers to partner with industry to develop solutions for increasingly complex and costly environmental and public health challenges. MnDRIVE Environment seeks to spur new research, as well as moving research out of the lab and into the field, through development of platform technologies.
At the Natural Resources Research Institute, we deliver integrated solutions for Minnesota’s natural resource-based economy. Minnesota’s economy has long depended on its natural resources — rocks, water and wood. Those resources are also the foundation of our environment. NRRI’s unique, multi-disciplinary expertise seeks practical solutions where economic growth meets environmental protection. NRRI begins with the understanding that a healthy environment with robust resources drives a strong economy to support a vibrant community which can then reinvest in the environment. NRRI funds and collaborates closely with UMD’s Center for Economic Development, housed in downtown Duluth. The result is a business focus that underlies all we do.
The University of Minnesota’s Remote Sensing and Geospatial Analysis Laboratory is conducting research on monitoring water quality of lakes and rivers and mapping land cover with digital mages from earth-observing satellites at local, state and regional scales. We have measured lake clarity, a key indicator of water quality, on more than 10,000 lakes statewide using Landsat imagery for seven time periods since 1975. Our current research is focused on using newly available enhanced satellite imagery to measure other key metrics of water quality, including chlorophyll, suspended solids, and colored dissolved organic matter. The satellite technology provides a cost effective way to acquire information, including temporal trends and geographic patterns, on lakes, rivers and wetlands.