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Risk Assessment Data Compilations Map Quick Road to Recovery during Iowa Floods

On June 9, 2008, Johnson County Emergency Management Director Dave Wilson anxiously watched as floodwaters rose to record levels of 28 feet upstream. Forecasts called for even more rain, painting a frightening picture for the County. Visualizing a repeat of the 1993 flood, Dave realized that using paper maps to plan response and recovery would not be a viable option.


Iowa City church surrounded by floodwaters

By the time the upstream City of Cedar Rapids crested on June 13, Dave had assembled a brain trust of agencies and individuals to help Johnson County face the imminent flood. Johnson County’s Emergency Management Agency (EMA) along with emergency support functions (ESFs) coordinated loss estimation analyses for use in planning initiatives throughout the County.

The Emergency Operations Center (EOC) was bursting at the seams 2 to 3 days before the flood with standing room only for 25 people. EMA officials urgently searched for tools that could help them model the expected impacts so they could plan to reduce losses from the impending disaster.

Plotting historical data on ink paper maps to plan response and recovery routes, and using simple Geographic Information Systems (GIS) analysis that intersects a flood boundary with building locations do not quantify a flood’s impact. The EMA found Hazus and turned to Shane Hubbard from the University of Iowa, Department of Geography (and a seasoned Hazus user), to assess potential impacts of the flood event.

Hazus is FEMA’s powerful GIS-based software methodology that estimates potential losses from earthquakes, hurricane wind and floods; calculating physical damage and functional loss in communities. Hazus’ ability to estimate the potential impacts of a flood provided the team with an unprecedented “crystal ball” into what would likely happen when the water reaches 28 feet.

Loss estimates of displaced households allowed the Red Cross and the Salvation Army to plan their response efforts and allocate resources based on need. For example, the Johnson County Administration Building was one of the critical facilities at risk, so the County decided to move evidence (i.e., police records, computer servers) from the building to alternate sites in order to speed law enforcement’s ability to recover from the flood.

According to Shane Hubbard, emergency managers are supposed to comply with the National Incident Management System to ensure that the various emergency support functions such as hospitals and universities are involved. “Rarely do people actually follow through with this to the extent Dave did,” declared Shane. “He led a consummate effort to proactively identify and rally community stakeholders during a critical time when coordination and cooperation was essential.”

Data Collection

Screenshot of HAZUS-generated map showing the amount of displaced personsThe EMA compiled data from National Flood Insurance Program (NFIP) floodplain maps, elevation data from the U.S Geological Survey (USGS), weather service updates, and forecasts into Hazus to estimate the flood extent. A countywide dataset of building locations created from local GIS data combined with the flood extent provided even more accurate Hazus outputs of estimated damage.

Hazus loss estimations became a part of every morning briefing in the EOC to quantify what this flood would mean to the community in terms of direct and indirect economic losses, including potential human casualties. ESFs including the Administration Building, Red Cross, Salvation Army, Homeland Security and FEMA community relations were briefed every morning at 10:00, and then consulted to verify fine-tune Hazus analyses based on updated data and flood criteria. View larger graphic (81 KB).

Protecting Critical Facilities at Risk

In addition to the Johnson County Administration Building, Hazus revealed that several MidAmerican Energy substations that serve as the primary power source for Johnson County would likely flood. MidAmerican erected portable substations to ensure a prompt failover could occur if conditions required. The National Guard provided additional protection by constructing sandbag bunkers around all equipment controls.

“Our local operations staff worked closely with City and County officials coordinating area by area assessments. The performance of our employees, the coordination and cooperation with local officials, and response from our customers allowed us to demonstrate our ability to respond to extraordinary challenges,” said Terry Smith, Director of System Control for MidAmerican Energy Company.

Expediting Response and Recovery Efforts

With 10 roads already closed, the EMA was able to use Hazus to create an estimate of upcoming road closures as the flood waters continued to rise. The analysis helped EMA and its partners to navigate major arteries by showing staff where to pre-position response teams and identify open routes to hospitals and operating bridges.

In 1993, nearly all Johnson County bridges were closed, so with floodwaters projected at similar or higher levels, the EMA was anticipating that every single bridge would be inoperable. The Iowa River cuts Iowa City in half, so the EMA was concerned they wouldn’t be able to get resources to the other side of the City.

Risk Mitigation Measures on the Horizon

Cover image of Iowa ReportUsing Hazus they estimated 1,110 households would be displaced. Actual results show 1,250 to 1,300 households displaced from the floods. Hazus didn’t take into account cabins and secondary homes in their General Building Stock run. Johnson County GIS Coordinator, Rick Havel was very satisfied with the accuracy of Hazus as a modeling tool.

After the Iowa floods, Johnson County was awarded a FEMA-funded Hazard Mitigation Grant Program (HMGP) Planning Grant to implement long-term hazard mitigation measures. The purpose of the grant is to reduce the loss of life and property due to natural disasters and to enable mitigation measures to be implemented during the immediate recovery from a disaster to protect citizens from future floods.

Johnson County is using Hazus in their mitigation plans to mitigate potential issues from sheltering, displaced households and estimated casualties in hopes of preparing communities for tomorrow.

Download the report Technology Helps Safeguard Citizens: Risk Assessment Data Compilations Map Quick Road to Recovery during Iowa Floods.

Last Updated: 
07/24/2014 - 16:00
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