Flood Plain Information
In Winnetka, there are two sources of flood plain: the Skokie River (Base Flood Elevation 625.3 NAVD 1988) and Lake Michigan (Base Flood Elevation 585 NAVD 1988). Most of the flooding that occurs in Winnetka is not related to river flooding or elevated lake levels, but from flash flooding due to severe storm events.
During heavy rain, the capacity of the storm sewers is exceeded, and once stormwater starts pooling on the street surface, the potential for that water to infiltrate into the sanitary sewer system increases. As a result, basement back-ups can occur for those homes with a gravity sanitary sewer. Water can also enter into homes through basement window wells, exterior stairwells, and garages.
Winnetka’s Flood Plain & Stormwater Management
As part of the Village’s efforts to minimize and mitigate the effects of flooding, the Village participates and promotes the following:
- The National Flood Insurance Program (NFIP), which makes federally guaranteed flood insurance available for all eligible buildings, whether they are in a floodplain or not;.
- The NFIP Community Rating System (CRS), which recognizes community efforts beyond Federal Emergency Management Agency’s (FEMA) minimum standards by reducing flood insurance premiums for the community’s property owners. The Village of Winnetka presently has a CRS Class 6 designation, allowing flood plain policy holders up to a 20% reduction in their flood insurance premiums, less additional non-policy fees associated with their premiums.
- A cost-sharing program for the Sanitary Sewer Backflow Prevention Program, designed to assist residents of older homes to install a backflow device to help prevent sanitary sewer back-up into basements.