When will Fox River recede to its banks? Not for many days – if it stays dry

A hydrologist with the National Weather Service’s Chicago bureau hedges his words when talking about when the flooding on the Fox River may recede.

If no more heavy rainfalls inundate the watershed, the river “may be within its banks by around the middle of next week,” said hydrologist Scott Lincoln on Tuesday. “It needs to stay dry to make that.”

While there is rain in the forecast, current models don’t indicate heavy rain events, he said.

But he also emphasized the “around” part. Lincoln’s making that forecast based on the current reading at the New Munster, Wisconsin, river gauge and historic data – while also recognizing it can take days for floodwaters to recede as the river heads south.

New Munster crested at 15 feet Sunday “and has been on a slow fall” since then, Lincoln said, adding that location “is the primary flow of water heading into the Chain O’ Lakes.”

It can take three to four days for downstream gauges to see floodwaters crest after New Munster does, he said.

That slow progression – along with mitigation efforts and changes to the riverbanks over time – are why the weather service needs residents to update them with changes on the ground, Lincoln said.

The Flood Impact information they use – what areas are likely to get flooded based on how high the river is – comes from a combination of places, Lincoln said, including county and town emergency managers and residents.

According to readings from gauges on the river, parts of the Chain O’ Lakes are in major flood state and are still slowly climbing.

Elsewhere, heading downriver, the tailwater at the Stratton Lock and Dam climbed to major flood stage overnight, Lincoln said.

On Tuesday afternoon, the McHenry County Division of Transportation closed about a mile of River Road from McHenry Dam Road to West Fernview Lane due to water over the road. The closed road is east of the Stratton Lock.

Rawson Bridge near Cary remains closed from Tuxedo Lane to the Broken Oar in Port Barrington. The McHenry County Sheriff’s Office reminded motorists not to cross the bridge or to drive around any barricades at flooded roads. Additional road closures are expected as the river continues to rise.

Nunda Township announced Tuesday that it was ending its call for volunteers to help fill and place sandbags.

Below the Algonquin dam, water is expected to continue to climb through Thursday and reach 12.2 feet – major flood stage, Lincoln said.

The weather service does not have a gauge at Elgin, but gets daily updates from the Elgin Water Treatment plant employees. Elgin is expected to stay at or below minor flood stage and remain there even as the water does rise, Lincoln said

The difference in whether flooding is considered major or minor is that stretches of the river have different bank heights, he said, adding that the weather service takes into consideration if homes – life and property – will be affected by floodwaters.

“There are trails and parkland that are flooding in Elgin ... but it s pretty difficult to have flooding in Elgin proper,” Lincoln said.

At the South Elgin dam, the water levels have remained steady over the last few days, rising less than one-tenth of a foot.

The next gauge isn’t until Montgomery, where the water is expected to remain at minor flood stage for the next several days.

To see flood predictions and the flood impacts, residents can to go water.noaa.gov.