ANN ARBOR (AP) - Great Lakes levels will continue rising and falling in often unpredictable ways and people should learn to deal with the changes instead of trying to tame nature with costly engineering projects, experts said Thursday.
Donald Scavia, director of the University of Michigan's Graham Sustainability Institute, announced a wide-ranging study of ways to adapt to up-and-down water levels during a seminar at which about 50 Great Lakes policymakers, scientists and advocates debated whether further efforts to control the inland seas would be worth the trouble.
"Lake levels are varying and they're going to continue to vary," Scavia said. "The question we should be focusing on is, how do you live with the variability instead of where do you put the next dam."
The five lakes are in constant flux, rising during spring and summer, then dropping in fall and winter. Levels also experience periods above and below their long-term averages that can last for years or decades. They were unusually low during the 1960s, but by the 1980s were so high that shoreline cottages were swept away.
One of the lengthiest sustained slumps began in the late 1990s and bottomed out in January 2013, when Lakes Huron and Michigan hit their lowest point on record. Since then, heavy snow and abundant rainfall have fueled such a rapid comeback that Lakes Superior, Erie and Ontario are forecast to return to normal this year.
Even Huron and Michigan, which suffered most, have risen substantially.
But the recovery was produced by a 15-month wet period and winter's bitter cold, which froze most of the lakes' surface area and blocked evaporation. Whether the improvement will continue or is a momentary blip in a downward spiral resulting from climate change remains to be seen, analysts said at the conference.
Dams, electric power plants and other infrastructure regulate the levels of Lakes Ontario and Superior to a limited extent. Some advocates want to build up Huron and Michigan, which are linked, by installing structures in the St. Clair River at the south end of Lake Huron to slow the outflow of water toward Lake Erie. That would compensate for water lost from deepening the channel over the years for navigation and gravel mining.
Roger Gauthier, chairman of a group called Restore our Water International, favors that option and said there's room for more engineering projects as well as adapting to nature's swings.
"The lakes have been modified by human intervention since European colonization," Gauthier said.
Others said such a project would cost hundreds of millions of dollars and might have negative consequences such as damaging fish spawning areas or causing flooding elsewhere. More scientific evidence is needed to judge whether it's a good idea, said Andy Buschsbaum of the National Wildlife Federation.
In the meantime, it's clear that levels will remain largely beyond human control, said Lana Pollack, U.S. chairwoman of the International Joint Commission, a U.S.-Canadian agency that advises both nations on boundary water issues. That means adaptability should be the watchword for the region's businesses, governments and shoreline property owners, she said.
Among many options could be using zoning ordinances or financial incentives such insurance eligibility to discourage unwise shoreline development, while marinas could install adjustable docks, speakers said at the conference.
The University of Michigan study will assemble experts from a range of disciplines to develop options for dealing effectively with rising and falling levels, Scavia said. The Graham institute used a similar method last year for an analysis of how "fracking," the controversial method of extracting natural gas from deep underground, is likely to affect the state.
"We can come up with better solutions if we better understand the science," said Howard Learner of the Environmental Law and Policy Center, co-sponsor of the seminar.