Know Your Flood Hazard – Nearly 12,000 square miles of drainage converge where the Fox and Illinois Rivers meet in downtown Ottawa. Let’s not forget that three of the top five highest recorded floods have occurred in the last 5 years in Ottawa. And the highest on record was only 11 years ago. To find out if your property is in a regulated floodplain or if there is historic flooding on your property, please contact the City at 815-433-0161 ext. 230.