IFC Releases New Flood Inundation Maps

By Mikael Mulugeta

The Iowa Flood Information System (IFIS) is an evolving web tool that is continually expanding the scope of its features. IFIS now offers Iowans access to flood inundation maps for 24 Iowa communities, up from 10 communities in 2013.

Flood inundation maps are particularly useful during flood events to help people visualize the potential extent of flooding at a range of river levels. This information can help individuals and communities plan and make sound mitigation decisions, and allows homeowners, business owners, and others to see how predicted flood levels might affect their property. Please Note: These are NOT regulatory floodplain maps that can affect insurance. Rather, they offer information people need to plan for and be ready for future flood events.

Clarksville inundation map

A flood inundation map of Clarksville.

IFIS includes a full set of flood inundation maps for the following communities:

How to Access Flood Inundation Maps on IFIS

From the IFIS homepage, select the button for “inundation maps.” Users can then select one of the highlighted communities listed above and use the flood map controller slider bar on the right to see the potential extent of flooding at any selected stage or discharge. IFIS uses a Google Maps interface, so users can zoom in and out, switch to different views (satellite and street view), and navigate around the map.

HAZUS

Also new on IFIS is the web tool Hazus, which allows users to estimate the cost of flood damages to buildings and other structures in various flooding scenarios. Hazus data is currently available for 12 Iowa communities, and IFC researchers are working to expand the tool to cover the entire state. Currently, IFIS provides flood loss and damage estimation for Cedar Rapids, Des Moines, Iowa City, Independence, Kalona, Rock Rapids, and Rock Valley.

Hazus, developed and distributed by the Federal Emergency Management Agency (FEMA), is a multi- natural hazard analysis tool. The web tool models the effects that natural hazards of various intensities can have on buildings and other structures in a given area, and then quantifies the total damage in dollars.

How to operate Hazus

Users can view flood damage for one of these communities by clicking on the “Damage Estimate” button and sliding the “Flood Map Controller” to model different scenarios.

For example, users can select Iowa City, simulate a 30-foot stage flood, and receive a total damage estimate of $19 million, which factors in the number of buildings damaged and the cost of the damage to their structure and content. Users can also click on individual buildings in the flooded area to access estimates of content and structural damage to those buildings. IFC researchers plan to add additional analysis layers that will include the number of schools, critical structures, and emergency centers affected in the damage estimate. The research team will add the additional layers after bringing the current level of analysis to all Iowa communities.