Heavy rainfall occurred in central and northern Illinois on April 18 and 19, 2013 causing major flooding along many rivers as well as widespread local drainage and urban flooding problems. During the two weeks preceding this event, the Chicago metropolitan area received 1 to nearly 3 inches of rain, increasing ground moisture and slightly elevating levels of area rivers and waterways. Beginning on April 18, 2013, rain gauges from Cook County and the U.S. Geological Survey (USGS) recorded 3.62 to 6.84 inches throughout a 24-hour period.
Within the U.S. Army Corps of Engineers (USACE) Chicago District boundary in Illinois, which includes Cook, DuPage, Kane, Lake, McHenry, and Will counties, riverine flooding impacts were the greatest on the Des Plaines, Fox, East Branch DuPage and North Branch Chicago rivers. Within the study area, identified as the “Chicago Area” for this study, the extreme rainfall resulted in major flood stages, and in some cases, record stages on the Des Plaines River, North Branch of the Chicago River, DuPage River, Fox River, and their respective tributaries.
The flooding impacted numerous homes, businesses, and roadways. A Federal Emergency Declaration (FEMA-4116-DR) was declared on May 10, 2013, allowing for federal assistance for 46 counties in the State of Illinois. Statewide, the Federal Emergency Management Agency (FEMA) dispersed approximately $169 million of individual assistance (IA) in 35 counties, and $31 million in public assistance (PA) to 39 counties. In the study area, nearly $152 million of IA and over $5 million of PA was distributed, representing nearly 90 percent and 17 percent of statewide disbursements, respectively. Additionally, U.S. Department of Housing and Urban Development awarded nearly $119 million of disaster recovery through their Community Development Block Grant program.
This post-flood survey and assessment report documents the meteorological conditions which led to flooding, documents the extent and impacts of flooding based on FEMA expenditures, and provides an analysis of post-flood survey responses. Documentation of this historic event can help local governments and municipal leaders have a better understanding of their risk to flooding and to better plan for and respond to future flood events.
In a USACE-administered post-flood public survey, "Post-Flood Survey Report: April 2013 Chicago Area Riverine & Basement Flooding," 1,829 riverine surveys were collected in six counties. Nearly 49 percent reported flooding in April 2013 and 6 percent reported receiving some sort of official warning to alert them of possible flooding. An additional 1,361 surveys were collected for the Cook County basement-specific survey. Nearly 88 percent of respondents reported having flooded at some point while at their residence. Almost 58 percent reported having experienced a sewer backup into their basement at some point when they owned or lived in their property, with an average time at their residence of 5 years.