Lake Vermilion benefited from early rains
DANVILLE - Like many other parts of central Illinois, Danville has had no significant rainfall in weeks. Despite that, Lake Vermilion is only a couple inches below its normal level, according to Aqua Illinois officials.
The lake is not dependent on Danville precipitation alone and has benefited from some timely rains earlier this summer and spring in the northern part of the county, according to Bob Ervin, area manager for Aqua Illinois.
The level of the lake, which supplies drinking water to Danville, Tilton, Catlin and Belgium, was much lower at the end of last summer and into early fall — down more than a foot. Even then, it wasn't at a critical point requiring any water use restrictions, Ervin said.
Some communities, like Decatur, are at that point this year, considering some voluntary water-use restrictions. Lake Decatur, which is that city's water supply, is down about a foot. According to the Illinois State Water Survey's Drought Update released last week, water levels at most community reservoirs in the state started dropping from their nearly-full levels in late spring, and several are already 1 foot to 2.5 feet below full pool.
The difference this year for Lake Vermilion, according to Ervin, has been timely precipitation in the Hoopeston and Bismarck areas and other parts of the lake's approximately 298-square-mile watershed that's mostly north of Danville and stretches into Indiana, specifically Benton County, Ind., site of the headwaters of the North Fork River that flows about 60 miles into Lake Vermilion.
Ervin said Aqua has equipment along the North Fork in the Bismarck area that measures flow, so the water company knows how much water is heading toward the lake, allowing the water company to react ahead of it.
David Cronk, production manager at Aqua, said Hoopeston got a big rain about a month ago and as that flow came down the river, Aqua made adjustments at the dam on the south end of the lake, raising the level in anticipation of drought conditions, because the Danville area was already running short on precipitation.
Ervin said that was about one month ago and brought the lake a couple inches above its normal level.
"In hindsight, it was a wise thing to do. That's helped us," said Ervin, who explained that Aqua officials are monitoring the situation closely but don't foresee any water use restrictions in the near future. "We are not to that point."
Rick Harper, severe weather manager with the Vermilion County Emergency Management Association, said the northern part of the county generally has received more rainfall than Danville. The last significant rainfall Danville received was in mid-June when less than an inch fell, according to local weather records. As of mid-June, the Danville area had received 10.76 inches of rainfall for the year, according to local weather records. The historical average up to the end of June is 20.24 inches, which is a shortfall of nearly 9.48 inches so far this year.
Farther north, it's also very dry with scorched lawns and withering crops, but rain has fallen at times. In early May, Harper said, a storm moved through and dumped 2.5 to 3 inches of rain in the Hoopeston area, causing flooding. More recently, in Bismarck, more than an inch fell a couple weeks ago, and Hoopeston got more than an inch last weekend. Some in the Hoopeston area reported as much as two inches, said Harper, adding that rain has been very spotty, moderate to heavy rain in an isolated area of the county and nothing anywhere else.
Ervin said rain in the watershed is just as beneficial for Lake Vermilion as rain in Danville.
But, he said, Aqua is being prudent, because there is still a lot of hot weather ahead. Cronk said Aqua is in water conservation mode, which means not letting any water out of the dam except what the water company uses. The lake's in good shape now, he said, but if it doesn't rain for another two months, then Aqua will have to re-evaluate.
This drought could have had a much more serious impact on the lake and the city's water supply if Aqua hadn't taken measures years ago to raise the level of the lake by 5 feet. Ervin said the lake level was raised in 1991. Before those measures, Cronk remembers a completely dry north end of the lake one summer.
Ervin said the other concern in drought conditions is possible algae bloom as the lake experienced last year when there was very little rainfall at the end of the summer into early fall and the lake water wasn't circulating much with no rain and lower river flows. An algae bloom doesn't pose any health risks to the water supply, he said, but it's a nuisance causing odor and taste issues in the water that must be addressed.
So far, Aqua is not seeing any significant growth of algae, he said, but the conditions are prime for it.
"It would be nice to get some much needed rain," Ervin said.