New Flood Planning Map will help river communities prepare for seasonal flooding

This month we released the Flood Planning Map, the first in a series of maps and apps to help emergency managers and community leaders prepare for flooding events.

The Flood Planning Map provides flood planners with a set of tools and workflows to prepare for seasonal river flooding. These tools and workflows are based on real-world examples that have been used during previous flood events in the upper Midwest. Seasonal river flood planning is typically conducted weeks or months in advance of predicted crest in each community.  This advance notice gives community leaders time to plan for securing assets, protecting infrastructure, or evacuating citizens within the impact area.

The first version of the Flood Planning Map provides the ability to do the following:

To learn how to use the Flood Planning Map, watch the video How to Use the Flood Planning Map, which can be found in the local government resource center. If you have good flood inundation data with locations of infrastructure, facilities, and vulnerable citizens, you can begin planning for the next flood now. Then when flood warnings are issued, all you have to do is pull up the flood plan for the expected flood level and share the results with your community.

The Flood Planning Map depends on high-quality flood inundation polygons. There are several ways to create this data including hydrologic and hydraulic models with high-resolution LiDAR data using elevation cross sections and water depth grids. Many river communities hire engineering firms to create data for their communities or use a method prescribed by the US Geological Survey (USGS) Flood Inundation Mapping Science or the National Oceanic and Atmospheric Administration (NOAA) Advanced Hydrologic Prediction Service flood inundation mapping guidelines.

Whatever method you choose, you can load your inundation polygons into a feature class provided with the updated Local Government Information Model.

Identifying what public infrastructure, critical facilities, or citizens could be impacted is accomplished using two geoprocessing scripts provided in the Flood Planning toolbox. The first step is to create a series of potential impact areas using the inundation data with your community or jurisdictional boundaries. These impact areas are then intersected with your data to determine what assets and populations will be impacted at each potential flood level.

After you have determined what could be impacted in your community, you may want to see the effects of mitigation efforts such as temporary levees. If you have already created levees in another process or received data from an engineering firm about where levees should be built, you can load them into the levee feature class provided in the Local Government Information Model. If you don’t have any levees, you can use the editing process with a levee feature template to create your own. You can also use the Attribute Assistant add-on to calculate the budgetary cost estimate for your levees.