Rain leaves suburbs soggy, rivers rising - could there be floods?
Several days of rain likely gave some suburban residents unpleasant flashbacks to July 2017 when countless streets, buildings and even entire neighborhoods were inundated with floodwater.
But while this week's storms have left much of the suburbs soggy, there is little danger of major flooding developing in the coming days, officials from the Illinois Department of Natural Resources and the National Weather Service said Thursday.
Up to 2 inches of rain fell overnight in some areas in southern Wisconsin and northern Illinois that has caused water levels on the Fox and Des Plaines rivers and the Chain O' Lakes to rise to near flood levels in Cook, Lake and McHenry counties. However, no rain is forecast through the weekend, and that means water levels on swollen rivers and lakes are expected to crest, then drop, officials said.
"According to the extended weather forecast, we are not expected to get any more rain in the near future, which is a good thing," said Munid Ahmad, an IDNR water resources engineer whose primary focus is to monitor water levels on the Fox River and Chain O' Lakes north of Algonquin.
Algonquin is likely to be among the harder-hit areas, as river water is expected to rise to moderate flood levels by Friday morning. Filip Street and Fox River Drive will be threatened by water, but buildings and roadways on Winaki and Onaway Trail will be underwater, weather service flood tables show.
Meanwhile, the Des Plaines River is expected to crest at minor flood levels in Gurnee, Lincolnshire and Des Plaines between Friday and Saturday, the National Weather Service is showing on its Advanced Hydraulic Prediction Service. That means flooding could close some roadways and forest preserves but isn't expected to cause any home or property damage. If the predictions hold, residences in Gurnee would face potential damage if the Des Plaines rises another 6 inches, and another foot in Lincolnshire.
Areas along the DuPage River, particularly in downtown Naperville, that saw flooding last week due to heavy rain have experienced no flooding this week.
Water levels on the Chain O' Lakes will continue to climb another 3 inches through Monday, then crest and start to drop as water is released through the Fox River downstream, Ahmad said. The Fox River is rising fast but will crest Friday or Saturday, he said.
The Fox Waterway Agency in Fox Lake announced Thursday afternoon the IDNR has closed the river to all boating. The Chain remains no-wake, and a debris advisory remains in effect.
To help reduce the flood risk in the northern part of the Fox River system, the large hinged crest gates are operating wide open at the Stratton Lock and Dam in McHenry and at the Algonquin Dam, IDNR officials said.
"The outflows are more than the inflows right now, and the gates are set as to not cause any unnecessary flooding," McHenry Dam Lockmaster John Palmieri explained.
The gates act as a relief valve for when the ground is saturated and rainwater runs into the rivers and streams that feed into the Fox River. Flooding occurs when more water flows into the system than the dam can release, as lakes and rivers overflow onto lands and water seeps into basements.
However, in releasing water, IDNR officials said they need to be aware of the amount sent downstream so as to not intentionally cause flooding south of Algonquin, like in South Elgin, Geneva and St. Charles.
The National Weather Service reports 2.1 inches of rain fell this week at O'Hare International Airport, but some areas, particularly in northern Lake County, received more.