U.S. Geological Survey scientist to address lake rehabilitation

The successful rehabilitation of Delevan Lake in Wisconsin will be addressed by a guest speaker at Ripon College on Oct. 3.

Dr. Dale Robertson, a research hydrologist with the U.S. Geological Survey, Wisconsin Water Science Center, in Middleton, Wisconsin, will present “The Importance of Biological Interactions in the Long-term Rehabilitation of Delavan Lake, Wisconsin” for the biology department from 2:30 to 3:30 p.m. in Farr Hall (room 130) on the campus. Members of the public are welcome to attend.

Because of excessive input of nutrients, Delavan Lake underwent eutrophication, a process that results in severe blue-green algae blooms and a fishery dominated by rough fish. Similar situations have occurred in many other lakes throughout the world, including Lake Erie, which recently has been in the news because of the potentially dangerous blue-green algae blooms.

In Delevan Lake, however, an extensive rehabilitation effort was implemented from 1990 to 1993 that successfully improved the lake’s water quality and dominance by game fish.

This success was short-lived because nutrient loading could not be adequately reduced. Changes in water quality continue to occur because of changes in nutrient loading, the invasion of zebra mussels, and a continually changing food web. Efforts continue to try to improve the water quality of the lake based on scientifically guided efforts.

Robertson was a post-doctoral research fellow at the University of Western Australia, where he worked on modeling the physical dynamics of lakes and reservoirs. His current research with the U.S. Geological Survey deals with modeling eutrophication and mixing in lakes, estimating loads and concentrations of nutrients and sediment in streams over large geographic areas, such as the Great Lakes and Mississippi River Basins, developing nutrient criteria for streams and rivers, and examining the effects of climate change on the physical dynamics, ice cover and productivity of lakes.

He has more than 110 professional publications in the fields of water quality, lake management and climate change.