Title
Updated LOMR Flood Maps by FEMA
History
The Federal Emergency Management Agency (FEMA) recently updated hydrologic models for the Spring Creek watershed and released proposed Letters of Map Revisions (LOMR’s) to the Flood Insurance Rate Maps (FIRM’s) for public review and comment. FEMA completed and adopted the maps for other watersheds in the Village on November 1, 2019. The adopted and proposed maps show the floodway and flood plains for the State of Illinois, specifically including the Village of Orland Park. The last complete map update was released on August 19, 2008. Previously adopted maps were based on old rainfall data (Bulletin 70). The new rainfall data (Bulletin 75) was adopted in 2020 and shows a 14% increase in rainfall. The proposed LOMRs will be used to update the FIRMs
The purpose of this report and presentation to the Committee of the Whole (CoW) is to share high level details of the LOMR/FIRM and its potential impact on future projects.
The updated FIRM maps show significant increase in floodway, but the overall floodplains remain largely the same with minor exceptions in some areas. As mentioned above, the 2019 and 2020 LOMRs are based old rain fall data (Bulletin 70). Therefore, it is expected that the future developments, roadways projects, and properties in the Village may have less buildable area and higher costs associated with addressing stormwater and flooding issues. Staff further recommends that the Village factor flood plain and floodway issues into account when considering future requests for annexation.
The Village already has significant proactive strategies in place to protect against flooding, , as well as safeguards in place to protect developments from flooding. These safeguards include a 50 foot buffer between flood plains and development boundaries, lower water release rates from our stormwater basins as compared to MWRD release rates, and restrictions which are more protective than surrounding communities.
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