A Publication of WTVP

Recommendations for the urban flooding problem in Illinois

The Office of Water Resources (OWR) is a part of the Illinois Department of Natural Resources and the lead state agency for water resources planning, navigation, floodplain management, the National Flood Insurance Program (NFIP), water supply, drought and interstate organizations on water resources. Its history dates back to 1823 with the formation of the Board of Canal Commissioners. The majority of OWR’s work on flood control projects has dealt with overbank river flooding in communities.

In 2014, the General Assembly directed OWR to write a report on the status of “urban flooding” in Illinois. Urban flooding was defined as any flooding in urban areas not related to overbank river flooding. In order to understand the magnitude of this issue, flood insurance and basement backup insurance claims were mapped statewide, and the scale and distribution were surprising. More than 90 percent of urban flooding damage claims from 2007 to 2014 were in areas that were not mapped as a floodplain. These claims, totaling $2.3 billion, were located in all but one of Illinois’ 102 counties.

The pre-study expectation was that older areas with combined sewers would be the main ones affected, but this study showed that urban flooding is prevalent everywhere there has been urban development. The recommendations contained in OWR’s Report for the Urban Flooding Awareness Act were grouped by the parties best able to implement them. The top recommendations for each group are as follows:

Local Stormwater Utilities
The top legislative recommendation is that all communities should have the authority to generate fees for stormwater management. One of the best ways is to create local stormwater utilities that would generate steady income for maintenance and operation of stormwater infrastructure. Property owners would generally pay based on the amount of runoff leaving their property, but because this is a usage fee, the amount paid could be reduced if runoff is reduced.

In addition, all counties should be given the authority to adopt stormwater management regulations like those of Peoria County. This is important because 86 of 101 counties in Illinois are not allowed to implement such regulations. Communities in those counties do not have a mechanism to block irresponsible development that occurs outside of their boundaries—even if it causes increased flooding inside their communities.

Recommendations for State Agencies
The top recommendations for state agencies include updating the state model local stormwater ordinance, collaborating on a stormwater revolving loan program, green infrastructure in state projects and flood insurance education.

The update to the state model local stormwater ordinance has been completed. This model provides communities with draft language for creating a new ordinance or updating their current ordinance with the best available stormwater ordinance language from around the state and the country.

The Illinois Environmental Protection Agency (IEPA) has the authority to distribute low-interest loans to communities for stormwater projects. The report recommends that the IEPA and OWR collaborate to improve the stormwater infrastructure in Illinois, and we hope to start those discussions later this year.

Along with recommending green infrastructure in state projects, other recommendations deal with flood insurance outreach and education. Everyone in or near a floodplain or with a basement should talk to their insurance agent to verify their flood coverage. The NFIP only covers damages from overland flow, with very limited basement coverage. Basement sewer backup and sump pump failures are only available as separate riders on a homeowner’s policy, and are usually limited to $5,000 coverage.

If water comes in through foundation cracks or joints, damage is not covered because that type of damage is treated as a maintenance problem. Relying on disaster assistance can be a mistake because most disaster assistance dollars from the Federal Emergency Management Agency (FEMA) come in the form of low-interest loans, which must be paid back. The report highlights the fact that there are only a few ways to cover flood damage losses, and it is important for homeowners to understand the different kinds of insurance and what types of flooding they cover.

Recommendations for Local Government
The top recommendations for local government include stormwater ordinance review, individual property evaluation, pre-disaster planning and an analysis of their stormwater system. The state model ordinance should be reviewed by communities to decide if there are sections in their own ordinance that should be updated.

Because property owners don’t always know the reason their basement is flooding, cost sharing to complete an engineering evaluation pinpoints what they can do to reduce their own flooding. These evaluations often recommend overhead sewer connections in basements, grading exterior land away from the house, and disconnecting downspouts from storm sewers and routing that water away from the foundation. When it is a known problem, some communities, like Peoria, cost-share with property owners for overhead sewer conversion to keep sanitary backup out of basements.

Pre-disaster planning should be completed before a disaster so valuable time after a disaster is not taken up by FEMA-required planning. For example, Peoria, Tazewell and Woodford counties have joined together in completing their pre-disaster plan.

Communities should also have a storm sewer atlas that is up to date with location, size and design data for the entire network. As more rainfall data is gathered, the statistics on which the designs of the stormwater networks are based are also updated. These statistics have trended upwards over the last 100 years, which means that if a storm sewer was designed to pass a 10-year storm 50 years ago, the current design statistics would identify it as less-than-10-year storm capacity today, even assuming it is in perfect condition. Comparing an entire stormwater network with equivalent design data would allow communities to prioritize upgrades to the system.

It is clear from these recommendations that no one sector can unilaterally fix the urban flood damages in Illinois. From state and local government to individual property owners, the recommendations in the report should be a guide to help each group decide what actions they can take now to start reducing the problem. iBi

Brad Winters, PE, CFM is a project engineer for the Office of Water Resources at the Illinois Department of Natural Resources in Springfield.