The following changes to the NWS Chicago river forecast and flood warning program will take place on July 5, 2011:
Current river forecasts in the Algonquin area are issued for the U.S. Geological Survey (USGS) river gage located on the north side of the highway 62 (Algonquin Road) bridge immediately above the dam. Effective July 5th, forecasts and flood warnings will be issued based on data from the USGS gage located at the footbridge approximately 1/4 mile downstream below the dam. Forecasts for the old gage location will be discontinued. River levels at this gage are more representative during times of high water. This location will be referenced as Algonquin Tailwater (AFBI2). Flood stage for the new location is 9.5 feet and should be considered provisional.
Important: Users of river and forecast data for Algonquin should be aware that the new river gage is set at a different datum and therefore river stage values differ between the old Algonquin location and the new Algonquin Tailwater.
Action Stage at Lincolnshire will be raised from 10.5 to 11.5 feet and flood stage will change from 11.0 to 12.5 feet. If flooding is ongoing on July 5th, changes to these thresholds will occur after the water returns to normal levels.
River observations and forecasts are available on the NWS Chicago Advanced Hydrologic Prediction Service page.
The above changes are a result of cooperation with the USGS, Illinois Department of Natural Resources/Office of Water Resources, and the Village of Lincolnshire.
If you have questions or comments on these upcoming changes please contact:
333 W University Drive
Romeoville, IL 60446