Analysis: Urban flooding not correlated with floodplains

CHICAGO — When it comes to flooding in cities, it makes little difference whether a property is located within a floodplain or not — damage happens, happens often, and can inflict significant costs. This stark lack of correlation between property damage claims and recognized floodplains is among the key findings of “The Prevalence and Cost of Urban Flooding,” a report released by the Center for Neighborhood Technology (CNT).

The report, the first of its kind to collectively analyze flood damage claims and sewer- and drain-backup claims data from multiple providers of insurance and other financial assistance, is part of a first phase of research at CNT on the prevalence and cost of flooding to property owners — such as homes and businesses — in urban and suburban areas. Urban flooding is caused by too much rain overwhelming drainage systems and waterways, and making its way into basements, backyards, and streets.

CNT researchers took the unprecedented step of combining insurance claims payout data for property damage in Cook County, Ill. (between 2007-2011, aggregated by zip code), with analysis of 115 responses to an online survey of property owners in Cook County that experienced property flooding in the last five years.

Key points emerging from the report:

Urban flooding in Cook County is chronic and systemic, resulting in damage that is widespread, repetitive, and costly — The analysis identified 177,000 claims made across 96 percent of Cook County zip codes, and in each of the five years. This is the equivalent of one in six properties in the county making a claim. Average payouts per claim were $3,733 across all types of claims, with total claims amounting to $660 million over the five years examined. Seventy percent of the online survey respondents estimate that they had flooded three or more times in the last five years, 20 percent have flooded 10 or more times.

There are multiple social and economic impacts on property owners — The online survey found that 84 percent suffered stress and 13 percent ill health. Forty-one percent lost the use of part of their property, 63 percent lost valuables, and 74 percent lost hours of work to clean up.

There is no correlation between damage payouts and the floodplains — When all types of claims are aggregated, some of the Cook County zip codes with the highest concentration of payouts (number and value) have no land area located within federally designated floodplains.

Claims were made across income groups, however 67 percent of the 27 zip codes with the highest concentrations of damage earn below the average median household income for Cook County.

Flood insurance is not carrying the burden of damage payouts — Claims via the National Flood Insurance Program — the only formal ‘flood’ insurance program — represent just 10 percent of total payouts.

No clear solutions for property owners — The vast majority — 76 percent of online survey respondents — had invested in measures to prevent future flooding, such as downspout disconnection and pumps, but only 6 percent believed that the investment had solved their flooding problem.

“In looking at the data we have, which is unique, we saw a somewhat shocking picture of the cost and frequency of urban flood damage,” said Harriet Festing, Water Program Director at CNT. “More shocking is that we know it represents a significant understatement of actual flood damage. There’s more data out there from insurers and property owners that will tell an even more disheartening story.”

Research conducted by CNT in 2012 (www.cnt.org/repository/Ready-for-Change.pdf) indicates that communities across the Great Lakes region are suffering from the impacts of urban flooding caused by moderate and heavy rain running off roofs, roads, and parking lots. The economic and social consequences can be considerable: Experts estimate that wet basements decrease property values by 10-25 percent, and that almost 40 percent of small businesses never reopen their doors following a flooding disaster.

“This report is further evidence of an increasingly persistent and prevalent problem, and one that cannot and should not be left to property owners to solve on their own,” said Kathryn Tholin, CEO of CNT. “There are steps that cities and counties can take now to protect properties and encourage smarter stormwater management.”

“The Prevalence and Cost of Urban Flooding” also finds that communities affected by urban flooding are not benefiting from state and federal programs and incentives designed to support them. For example, CNT research shows that only 19 of the 133 communities in Cook County are participating in FEMA’s Community Rating System, and that Cook County does not have a Multi-Hazard Mitigation Plan. This means that the majority of property owners in zip codes with high urban flood damage payouts are unable to benefit from reduced flood insurance rates and other protective measures that form part of the programs.

CNT is engaging a broad set of stakeholders in an expansion of this research, and is designing innovative and cost-effective solutions to protect homes and businesses in the future. This work includes the development and promotion of state legislation — the provisionally dubbed ‘Dry Basements Act’ — and the nation’s first wet weather Wetrofit service.

Download the CNT report, “The Prevalence and Cost of Urban Flooding,” at www.cnt.org/news/media/Prevalence-and-Cost-of-Urban-Flooding.pdf.