From extreme weather to abandoned coal mines, natural and manmade hazards can cause life-threatening emergencies and severe economic losses. Experts from PRI’s Illinois State Water Survey and Illinois State Geological Survey study these hazards, producing the long-term databases, maps, and other tools needed to reduce loss of life and financial burdens for victims.
Hazard Mitigation Planning
No Illinois community should be left unprepared in the face of a natural disaster — flood, blizzard, tornado, or earthquake. PRI’s Coordinated Hazard Assessment and Mapping Program works with Illinois counties, regional planning commissions, and the University of Illinois Extension to build comprehensive Natural Hazard Mitigation Plans. These plans reduce or eliminate risks to Illinoisans’ lives and property from natural hazards and are also the basis for Federal Emergency Management Agency funding for community projects that reduce exposure to these losses. However, not every county has the resources to complete a grant application. PRI works with these counties, helping them better assess and understand their unique risk factors and gain access to more federal funding.
Severe Storms and Flooding
As the state’s climate changes, severe storms have become more frequent. PRI scientists provide the necessary rainfall data to develop adequate stormwater systems for communities. PRI also assesses flooding hazards, identifies high-risk areas, and engages communities to help them act to prevent losses from flooding.
Severe storm data
PRI scientists collected decades of data and updated climate models to produce Bulletin 75, the publication that provides Illinois’ standards for expected extreme storms. Results revealed that the number of storms in Illinois producing more than 2 inches of rain has nearly doubled over the past century. During that time, the statewide average annual precipitation has increased 11 percent and temperatures have risen by 1.2 degrees.
These increases are significant when building adequate stormwater systems, assessing flood risk, and making other infrastructure decisions. Effective January 2020, the Illinois Department of Natural Resources Office of Water Resources and District 1 of the Illinois Department of Transportation began requiring Bulletin 75 rainfall data for newly initiated projects. The Federal Emergency Management Agency also accepts Bulletin 75 rainfall data for projects and map revisions. Illinois counties and communities are expected to update ordinances that will adopt the new Bulletin 75 standards for building structures based on predefined projected magnitude and duration of storms.
Flood insurance rate maps
Federal Emergency Management Agency flood insurance rate maps (FIRMs) and studies are used by state agencies for regulatory purposes, adopted for floodplain management by communities that participate in the National Flood Insurance Program and are used to determine flood insurance requirements and insurance rates. As a FEMA Cooperating Technical Partner, PRI’s Coordinated Hazard Assessment and Mapping Program conducts community outreach, performs hydrologic and hydraulic studies, and produces digital FIRMs for Illinois counties.
Effective digital FIRMs are now available online for most Illinois counties at FEMA’s Flood Map Service Center. CHAMP provides its preliminary and pending digital FIRMs, studies, and database products on illinoisfloodmaps.org.
Building footprints to assess flood risk
Using digital elevation aerial maps derived from lidar data, PRI researchers have marked and identified building footprints to help communities in 36 Illinois counties better mitigate flood damage in local areas.
A building footprint is the perimeter outline of each structure marked as seen from above, with a description of its size, shape, and the location of its foundation. These footprints assist in testing the building location and footprint against floods and other hazards, allowing people to accurately locate, analyze, and visualize risk exposure. The data are also used to count the number of structures in special flood hazard areas.
Coastal Erosion
Erosion can consume hundreds of acres of coastal land in Illinois, costing tens of thousands of dollars for municipalities working to conserve valuable infrastructure and recreational spaces. PRI geologists study the complex processes affecting the beach, dune, wetland, and estuarine systems on the Lake Michigan coastline. PRI research helps inform management decisions and supports the work of state agencies aimed at preserving the last remaining natural shorelines in Illinois, rare coastal wetland habitats, and several threatened and endangered plant and animal species.
Mine Subsidence
About 201,000 acres of residential and other developed land lie close to Illinois’ approximately 5,500 underground coal mines. PRI offers an online Coal Mines in Illinois Viewer (ILMINES) to help home and business owners determine the proximity of coal mines and underground industrial mines to their properties. Although subsidence — the sinking of ground at the surface due to the collapse of mined areas below — is uncommon, this tool helps landowners understand their risk.
Sinkholes
PRI provides statewide data on the location of cover-collapse sinkholes, which pose a serious hazard to the construction of buildings, roads, and other infrastructure. Sinkholes can also make groundwater more vulnerable to contamination. This is of particular importance in the Illinois “sinkhole plain” — principally within Monroe, Randolph, and St. Clair counties — where sinkholes tend to be larger and more numerous than in other parts of the state.
Earthquakes
PRI geologists have been involved in mitigating earthquake hazards in Illinois for decades, taking measurements and providing information on soil characteristics that affect the amplification of earthquake ground motion, such as type and properties of underlying materials, depth to bedrock, slope of the land, and depth to groundwater. These data are used to produce soil amplification and liquefaction susceptibility maps for federal and state governments as they develop earthquake hazard computer applications to assess damage levels. These applications are used for state and national earthquake exercises and state and county hazard assessment and mitigation efforts.
PRI’s Illinois State Geological Survey serves as a liaison with the Illinois Emergency Management Agency in developing earthquake exercises and response plans. PRI geologists also coordinate earthquake efforts and products through the Central United States Earthquake Consortium, which is a partnership of the federal government and the eight states affected by earthquakes in the central U.S. region.
Landslides
Landslides in Illinois are usually non-life-threatening, with only two known deaths, but they pose a significant economic risk due to property damage. PRI geologists maintain a landslide database using reports from various government entities, data from staff landslide inventories, and a photograph and slide collection. Staff have also produced maps useful to developers, businesses, and local government agencies.