IDNR, ISWS, FEMA Collaborate on Development of Model Stormwater Ordinance for Illinois Communities

Chris Young
IDNR, ISWS, FEMA Collaborate on Development of Model Stormwater Ordinance for Illinois Communities
SPRINGFIELD – A model ordinance that Illinois communities can adopt to help manage flooding and combat flooding-related damages in urban areas has been developed by the Illinois Department of Natural Resources (IDNR) in collaboration with Illinois State Water Survey (ISWS), with the Federal Emergency Management Agency (FEMA) providing funding.

The model stormwater ordinance developed for use by Illinois communities was a key recommendation of the recently completed Illinois Urban Flooding Awareness Act Report. 

The report found that precipitation in Illinois has increased by 10% in the last century, with extreme precipitation events increasing by as much as 40%. With more and more developed land in Illinois, the report found 95% of all flood claims (private and federal flood insurance) were located within urban areas, with approximately 90% of those claims located outside of floodplains. The report recommended better coordination among state and local governments, and the model stormwater ordinance includes specific recommendations and regulations to better mitigate urban flooding damages.

The model ordinance suggests best practices, such as:

1. Incorporate green infrastructure into development regulations by recommending non-structural best management practices treat at least 25% of water quality requirements and volume controls;

2. Incorporate water quality controls wherever possible to protect the hydrology, hydraulics and beneficial functions of streams, lakes, wetlands, floodplains, and flood-prone areas;
3. Provide incentives to developers and property owners to decrease impervious areas and preserve natural areas to allow for evaporation/transpiration, infiltration, and stormwater storage;

4. Limit stormwater runoff from development sites to prevent flooding and excessive erosion;

5. Establish maintenance plans to ensure stormwater measures remain as originally intended.

“The model stormwater management ordinance should be a valuable resource for counties and municipalities when drafting or revising their own stormwater runoff requirements,” said IDNR Director Wayne Rosenthal. “Local governments should find this model ordinance helpful in supplementing their existing codes.”

Each local jurisdiction should review the components and tailor their ordinances in accordance with local conditions and development activities.

The model ordinance is available now for local officials and local citizens to review.  The model ordinance and the Urban Flooding Awareness Act Report are posted on the IDNR website at:

Local communities can also contact the IDNR Office of Water Resources for more information.
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