Characterizing powerboat hydrodynamics and their impacts on the water column and lakebed

Researchers from SAFL's Healthy Waters Initiative recently published a new report entitled "A Field Study of Recreational Powerboat Hydrodynamics and their Impacts on the Water Column and Lakebed." 

This study focused on characterizing the hydrodynamic phenomena produced by a moving powerboat and investigating the impacts on the water column beneath the boat and at the lakebed.

Join us for a presentation about the study, methods, and findings. There will be plenty of time for questions. 

About the work: The motivation for this field-based research study was the need to better understand the environmental impacts within the water column and at the lakebed as different types of recreational powerboats traverse under their typical modes of operation. The objectives of the study were to: 1) clarify and define the various hydrodynamic phenomena that are created by a recreational powerboat in motion, and how these phenomena vary with water depth and mode of operation, 2) investigate the depth of penetration and duration of emission gases (e.g., engine exhaust bubbles), 3) investigate the water column velocities and depth of penetration of the bow, stern, and transverse waves and their potential to resuspend lakebed sediment, 4) Investigate the propeller wash velocity and depth of penetration, and the potential to resuspend lakebed sediment, 5) investigate the effects of repeated boat passage on thermal stratification and mixing in the water column, 6) capture underwater and aerial video of the hydrodynamic phenomena and any subsequent impacts (e.g., sediment resuspension). 

This study generated a wealth of data that we used to developed recommendations on the minimum operational depth that recreational powerboats, under typical modes of operation, should maintain to minimize impacts to the lakebed.

About the presenters:

Jeff Marr is the Associate Director of Engineering and Facilities at the St. Anthony Falls Laboratory. Marr manages SAFL’s Applied Research and Engineering Team, which has ongoing work for public and private organizations in the fields of boat-generated waves, urban stormwater, hydraulic modeling, wind and water power, river engineering and restoration, and technology development for field monitoring. Marr is a licensed civil engineer specializing in hydraulics and sediment transport. His research interests include water hydraulics, river engineering and restoration, sediment transport dynamics, and hydropower. Marr is also an affiliated researcher with the University of Minnesota Center for Transportation Studies.

Andy Riesgraf joined the University of Minnesota in 2016 as a Research Scientist with the Minnesota Aquatic Invasive Species Center (MAISRC), where he studied deterrent methods to stop the upstream migration of invasive carp in the Mississippi River. In 2020, he joined SAFL’s Applied Research and Engineering team as a Research Scientist. Andy specializes in designing and conducting field studies on lakes and rivers, with technical expertise in the deployment of data acquisition systems. His research interests include lake and river water quality, boat-generated waves and propeller wash impacts, tracking fish and aquatic mammals, and aquatic invasive species prevention/management.