(AREA) -- Experts say there's no guarantee that placing structures in the St. Clair River would elevate Lakes Huron and Michigan to their normal levels because they might not offset the effects of a warming climate. During a meeting of the Great Lakes Commission in Milwaukee on Monday, a panel debated the merits of putting "speed bumps" in the river that carries water from Lake Huron toward Lake Erie. Advocates for property owners on Lake Huron's Georgian Bay say it's needed to compensate for water lost from dredging decades ago. But Scudder Mackey of the Ohio Department of Natural Resources says evaporation and precipitation will have the primary influence on levels. Deborah Lee of the Army Corps of Engineers says it could take many years for the structures to make any difference.