Aug. – Sept. 2018 Flood Event Maps
High water levels on Lake Monona and the Yahara River have caused flooding in areas of Madison. These maps show increased flood risks due to the August – September 2018 flood event.
Areas with an Increased Flood Risk due to Lake Monona and Yahara River Water Levels
||Areas that may experience flooding due to rising Lake Monona levels.|
||Areas that may experience flooding due to rising lake levels and flash flooding during rainstorms.|
||Streets that could experience flash flooding during rainstorms.|
What to Expect
If you are in the purple flood zone, your property is at risk of flooding quickly during rain:
- Water may enter the basement through windows
- Stormwater or sewage may enter the basement through floor drains
- Your street may become impassible
- Street flooding may damage your vehicle
- Water could rise as much as 1 to 2 feet from the curb, depending on rainfall totals
Potential Flood & Flash Flooding Depths
This map shows the estimated potential depth of flash flooding if an intense rain storm were to hit the isthmus while the lake levels are high. The depth is measured from the lowest point in the street. This map is an estimate of depth and is most useful to determine how the risk of flooding varies throughout the flood risk zone.
Some areas adjacent to Lake Monona and the Yahara River will experience flooding. Flooding may also occur in other low-lying areas farther away as the higher river level forces water back through storm sewers. Since much of the drainage system is full of water, it will not take much rain to trigger urban flash flooding.