Investigating blue-green algae harvesting: Lower Fox River, Wisconsin

Blue-green algae is alargeissue for the Lower Fox River in Brown County, Wisconsin. The Lower Fox River feeds into the bay of Green Bayandflowsthroughdensely populated areas.Excessive blue-green algae blooms have become increasingly prevalent in Brown County in recent years, largely due to nutrient runoff from local industry, lawn fertilizers and agricultural fertilizers. Excess nitrogen and phosphorous accumulateinwaterways,creating conditions that allow forexplosive blue-green algae growthduring the warmer months of the year. Blue-green algae is harmful to humans,animals,and reducesproperty values of residents nearaffected waterways. In humans, exposure tohigh levelsofblue-green algaecan result in skin irritationand flu like symptoms.Foranimals, high levels ofexposurecan lead to irritationof skin, damage to internal organs, and death. Blue-green algae grown can also have effectson people who don’t come intocontact with waterways.Waterways with high levels of blue-green algaeare often discolored and emit offensive odors that can be carried by wind to nearby communities. These effects, along with decreased tourism and on-water recreation, can reduce property valuesin communities near waterways with excessive blue-green algae.Ateam ofundergraduate mechanical engineeringstudents from the University of Wisconsin-MadisonCollege of Engineeringweretasked with developinga methodto cost effectively and efficientlyremove blue-green algae from the Lower Fox River.

In this report, the effects of blue-green algae are discussed, researchon possible harvesting solutions are laid out,andthe chosen method of removing algae using a boat towing a plankton net is analyzed andoptimizedto maximize cost effectiveness and overall harvesting efficiency.Due to limitations includingtime constraints, budget constraints, and breadth of expertise,the project was significantly narrowed tofocus onanalyzing an optimized boat-towed plankton net.The team focused ondetermining the drag force induced by the netto correlate net drag, on a per net basis, to boat fuel consumption in order to minimizeoperating cost.

UniverCity Year Contact Info
Gavin Luter
Managing Director
gavin@cows.org
608-261-1141