A screenshot of the Great Lakes Water Level Dashboard. Clicking the picture will take readers to the tool.

Data on rain, snowfall, ice cover and evaporation will soon be incorporated into a new online tool that shows Great Lakes water level fluctuations over the past 150 years.

The Great Lakes Water Level Dashboard plots data on a graph that represents water levels of a lake the user designates. Users can even designate all of the Great Lakes at once to see their progression as a whole.

But enhancements expected in as soon as a month will show rain, snowfall, evaporation and ice cover, said Anne Clites, a scientist on the project at the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory.

The tool was released in June to help researchers and answer the public’s questions about lake levels, she said.

Users adjust the tool’s time span with a slider at the bottom of the page.

The average lake levels are lake-wide averages that are determined using gauges on each lake, said Clites.

They represent the elevation of lake surface water above a reference point that was most recently established in 1985, said Andrew Gronewold, another scientist at the research group. They must be recalculated every 25-35 years because of movements in the Earth’s crust.

“A major decline in water levels, especially for Michigan, Huron and Erie began about 1997,” Clites said. “Water resource scientists really can only speculate about the reasons for that at this point. One of the motivations behind this dashboard was to be able to explore questions such as that one.”

The data for the tool were gathered in recent years by the U.S. National Oceanic and Atmospheric Administration’s National Ocean Service and the Canadian Hydrographic Service, a part of the Department of Fisheries and Oceans.

The earlier data going back to the 1860s were gathered by the Lake Survey, a part of the U.S. Army Corps of Engineers.