Hydraulic Modeling
Supporting Flood Emergency Operations
Andy Yung

“It is now possible to turn real-time flood analysis into a flood forecasting system.”

Every year, flooding causes significant loss of life and property damage across the world. In the U.S., flood events account for about half of all federal disaster declarations. With this in mind, there is an increasing desire by flood-prone communities to identify where and how deep flooding is expected to occur so that first responders can mobilize to remove people from harm’s way and reduce the risk to life and property.

With current advances in technology, it is now possible to link readily available flood modeling programs together to produce useful data to assist in these efforts. Calibrated radar rainfall data can now be collected in real-time and easily ingested into a hydrologic model. This hydrologic model will produce flows at various points along a river system. In turn, these flows can be utilized as input to a hydraulic model (perhaps one familiar to the community to support National Flood Insurance Program efforts) to identify flood elevations along the river system. Lastly, these flood elevations can be converted to mapping data in GIS (Geographic Information System(s) to establish inundation maps to project expected flooding locations and depths.

All of these steps can be accomplished in a period of less than 15 minutes, and because there is a lag between the current time (when rainfall is collected) and actual flooding, estimates of flooding extent can be projected in advance to alert first responders. In addition, with the National Weather Service becoming more proficient at predicting location and amounts of rainfall a few hours ahead of a storm, it is now possible to turn real-time flood analysis into a flood forecasting system to provide for additional lead-time in emergency operations.

Andy Yung / P.E., CFM
Andy is a Principal and Chief Hydrologist in Walter P Moore’s Water Resources Engineering practice in The Woodlands, Texas.