DECATUR - A teal-colored vessel called The Commodore continues its slow voyage through the waters of Lake Decatur.

But it's not on any shallow, leisurely cruise.

No, this barge has a deeper mission at hand - to remove the equivalent of more than 263,000 semitruck loads of sediment over the next decade or so.

"Day by day, we're making the lake a little deeper than it was yesterday," said Keith Alexander, director of water management.

An unusually dry summer that threatens water supplies across the state underscores the importance of the city's mammoth dredging project, water experts say.

"We are helping out the lake for situations like the drought we have started to encounter this summer," Alexander said. "But we won't realize the full benefits of this dredging operation until we're done."

The project's goal is to increase the lake's storage capacity by about 16 percent.

In the short term, plans already are under way to deal with this season's dry summer.

Until recently, the Lake Decatur water level stayed "exactly where we wanted it to be at this time of year," Alexander said.

But lake levels are expected to drop in coming weeks.

"It's just a matter of time," Alexander said.

The city already has been checking equipment at its well fields in DeWitt and Macon counties in case it needs to draw additional water supplies.

"We think there's a good chance we'll have to use it," Alexander said.

If water levels continue to fall, the city could encourage voluntary water conservation measures. The next step, if necessary, would be to enact mandatory conservation efforts.

"Typically, the community doesn't go to mandatory water conservation unless the drought really becomes long, and it looks like it's not going to come out of it quickly," Alexander said. "The last time we did mandatory conservation was in the drought of '88."

Forecasts call for near-normal temperatures and near-normal precipitation levels in July. But short-term forecasts call for below-normal precipitation.

"That does not look good long-term," Alexander said. "We're doing what most communities are doing. We're taking a conservative stance and being ready for what could be a long, hot, dry summer."

Gov. Rod Blagojevich on July 3 directed state agencies and all Illinois residents to conserve water.

"During this time of drought, we will all have to make sacrifices," Blagojevich said in a news release. "I convened the Drought Response Task Force to evaluate the state's water resources so that the appropriate water conservation efforts can be implemented."

The 10th driest June on record in Illinois has stressed water supplies statewide. Precipitation across the state has ranged from 4 to 10 inches below normal since March 1, a news release from the governor's office stated.

"Even if precipitation in July and August this year is near normal, recovering from current conditions will be difficult because those months are when crop demand for soil moisture peaks," said state climatologist Jim Ange in a news release. "For example, the most significant deterioration in corn and soybeans occurred in July 1988 as soil moisture reserves were depleted and temperatures routinely climbed into the 90s. We could have similar difficulties this year if dry weather continues."

Alexander said the city continues to monitor forecasts and water levels closely this summer.

In the meantime, the long-term project to dig out a deeper lake bottom continues.

Two three-man crews operate the dredging equipment from 6 a.m. to 10 p.m. five days a week from March through November.

"We run a lean, mean dredging machine," Alexander said.

So how does the dredge work?

Imagine a jumbo-sized drill bit that digs into the lake bottom. It's hooked up to a wet-dry vacuum floating on a barge in the lake.

Silt and water unearthed are piped nearly three miles to a storage site in Oakley Township. The silt someday could be used for agricultural, recreational, wildlife habitat or conservation projects.

And it's not just silt that the dredge crews encounter.

"We have a lot of tree stumps out here," said Stephen Yeager, water services manager. "We have a lot of debris that gets caught in the cutter head. The employees have to clean it out."

Dredge crew members have even started a collection of some of their more interesting finds, including soda and beer cans from decades past.

In all, the dredging project could cost up to about $31 million.

That's money well spent, city leaders say.

Major industries, in addition to residents, rely on a plentiful water supply, Mayor Paul Osborne said. Osborne applauded the foresight of previous city councils and community leaders who advocated dredging the lake.

"It's a project that kind of flies under the radar for a lot of people, but it's so important," Osborne said. "You're talking about a water supply. That's so critical to the city, especially during a dry summer."

Mike Frazier can be reached at mfrazier@;herald-review.com or 421-7985.