Buildup of algae in a lake signalled increased level of nutrients in the water. Cropping practices have followed best management practices yet lack of oxygen in water triggered by cloudy days in late summer resulted in fish dying. A study was set up to determine the interaction of watershed, impounded water and dairy management in an attempt to reduce algal growth. Team expertise included soil fertility, engineering, dairy nutrition, manure and crop management, limnology and water quality. This paper will present the process and findings of the study along with management options suggested to improve water quality.