Ottawans who want to watch their town get flooded now can do so from their home computers — with no real damage involved.
A computer simulation of flooding by the Fox and Illinois rivers that can be controlled by the viewer has been launched by the National Weather Service in partnership with the Illinois State Water Survey, FEMA and city of Ottawa.
“It is remarkable just how darned accurate this is,” said Ottawa Building Official Mike Sutfin during a demonstration for The Times.
As he adjusted the water level control, the blue overlay of the rivers began to expand from their banks onto low lying property.
“Then all of a sudden we get to see the scary stuff,” he said.
Suddenly, as the river heights passed any past records, flood walls were overwhelmed, bridges disappeared and neighborhoods were submerged.
“This is pretty crazy to look at, but for us it’s a wonderful planning tool for dealing with floods,” Sutfin said. “We can see how deep the waters will be and where. I think we should be prepared even for the crazy flooding, because although it’s unlikely, we shouldn’t consider ourself immune to it.”
As an indication of the precision of the ground map, Sutfin pointed out the faint image of the abandoned railroad bed east of Ottawa that once was the route of the interurban streetcar line between Ottawa and Marseilles.
“That old railroad bed restricts the flow of water until it reaches a certain height,” he said. “This map is really accurate.”
The inundation mapping extends approximately 3 miles upstream and 2.5 miles downstream of the Illinois river gage at Ottawa High School, as well as 4 miles upstream on the Fox River from its confluence with the Illinois.
The web site for the NWS flooding prediction is water.weather.gov/ahps2/inundation/index.php?gage=otwi2.
It includes a link to a YouTube video explaining how the site works and how to use it.
More detailed information about the Web interface is available at water.weather.gov/ahps2/inundation/inundation_mapping_user_guide.pdf.