Orlando Floodplains Study

RS&H is providing floodplain analysis and mapping services as part of a Continuing Stormwater and Engineering Design Contract with the City of Orlando, Florida. The primary objective is to convert areas with approximate flood zones and no Base Flood Elevations (Zone A) to detailed flood zones with established Base Flood Elevations (Zone AE). Converting the floodplains involves extensive hydrologic and hydraulic modeling of the city’s watersheds with Interconnected Pond Routing (ICPR).

RS&H is using Geographic Information Systems (GIS) and the city’s existing ICPR hydrologic models, which will be reviewed for accuracy and completeness prior to use. The team will then create new ICPR models for the areas not previously modeled based on GIS data, latest surveys, terrain data, and As-Built plans. The team will use the new models to assign Base Flood Elevations to the Zone A floodplains, therefore converting them to Zone AE floodplains. The team will also use the models to identify and resolve any inaccuracies in Base Flood Elevations currently being used in Zone AE floodplains.

After determining the floodplains and Base Flood Elevations from the hydrologic models, the team will use GIS to map the new Zone AE floodplain areas and elevations over the terrain data. The floodplain revisions will then be submitted to FEMA as Letters of Map Revision (LOMR).

The floodplain revisions will provide more accurate floodplain information for FEMA, city staff, and Orlando residents. For instance, using the more accurate floodplain information, homeowners whose land is located in an area where there is technical justification to revise a floodplain previously approved by FEMA could be provided insurance requirement relief.