Laura Algeo, coordinator of Federal Emergency Management Agency’s National Cooperating Technical Partners Program, recently praised the Water Survey’s accomplishments as a Cooperating Technical Partner, including improving the flood mapping process in Illinois by streamlining the state process with the federal process to ensure there is maximum coordination with communities and developing accurate, easily accessible flood data for every county in Illinois.
Sally McConkey leads the Coordinated Hazard Assessment and Mapping Program (CHAMP) team that is responsible for these achievements. CHAMP’s more than 25 professional staff have expertise in engineering, GIS, hydrologic and hydraulic modeling, hazard mitigation planning, and community engagement. As part of the Illinois Association of Floodplain and Stormwater Management virtual conference earlier this month, McConkey described how her team assesses flood hazards, identifies high-risk areas, and engages community partners.
Identifying flood hazards in Illinois
FEMA’s flood insurance rate maps (FIRMs) and studies are the primary source for flood hazard information. FIRMs have the most comprehensive geographical coverage and are used by state agencies for regulatory purposes. Communities that participate in the National Flood Insurance Program adopt the FIRMs for floodplain management, and the maps are used to determine flood insurance requirements and insurance rates.
While there are national metrics, which flood hazard identification studies are undertaken is determined at the state and regional level. CHAMP and the Office of Water Resources (OWR) in the Illinois Department of Natural Resources, both FEMA Cooperating Technical Partners (CTPs), collaborate annually on a plan that prioritizes Illinois areas for flood studies and mapping. As a CTP, CHAMP receives FEMA funding to support community outreach, hydrologic and hydraulic studies, digital FIRM production, and various non-regulatory products.
Digital flood insurance rate maps for Illinois
Digital flood insurance rate maps (DFIRMs) are designed for use with digital mapping and analysis software. This provides users with the ability to determine the flood zone, base flood elevation, and the floodway status for a particular location.
The IllinoisFloodMaps.org website is the Water Survey's portal to county-level flood mapping data.
As shown in the map, most Illinois counties have FIRMs available in a geospatially registered digital format (green). Digital FIRMs will soon be effective for the red counties, Ford and Warren.
Studies to identify floodplains for mapping and preparation of digital FIRMs are underway in the 17 tan counties; CHAMP is working on 14 of those counties, but is not involved with the projects in Madison, Monroe, and St. Clair counties.
Six Illinois counties, shown in white, are still using paper FIRMs and no work has begun to update the maps. The hashed symbology means that updates to some of the FIRM panels are in progress.