Integrating Drone Images and Videos to Increase the Value of Observed Data and Model Forecasts for Flooding Events

Real time verification of river forecasts and the impact of stream and river flooding can make operational forecast much more useful for saving lives and mitigating property damage resulting from high water conditions.   Action plans based on high resolution mapped forecasts can be used by with greater confidence by Emergency Managers in very stressful, short-fuse situations when they can be validated visually as events unfold.  Because the landscape is constantly changing, sections of the map can quickly become inaccurate. 

Riverside Technology, inc. has developed an innovative real-time flood inundation mapping solution known as RiverTrak™, designed for streamlined deployment to rapidly produce dynamic maps of inundation depths and extents and customized to regional watersheds. Maps are created based on the latest available observed and forecasted gauge values from the National Weather Service or other public or private networks. RiverTrak provides historical, real-time, or scenario maps to integrate existing hazard mitigation efforts and information technology for areas affected by riverine flooding.  To address the issue of real-time flood map inaccuracy Riverside is developing a system that uses modern drone technology to easily and cost effectively update digital elevation models and flood inundation maps. 

Riverside worked with the city of Fort Collins over the summer of 2016 to beta test the RiverTrak flood inundation system.  As the inundation maps of the 2013 Fort Collins flood event were reviewed, some areas which had changed since 2013 were identified, which would cause flood extents and depths to be different if the same event occurred today.  The McMurry Natural Area was identified as an area with recent significant earth work changes.  This area is especially important because it is monitored as a threshold area to determine if action is required for emergency response.  Because the flood inundation maps were inaccurate at this critical location, the city was reluctant to use the maps in real-time events.  To re-fly the Lidar was not cost effective and would not happen any time soon.  So, Riverside proposed using drones to produce new data quickly and economically to update the maps. 

Photographs taken by the drone are processed using stereo photogrammetry software to develop new elevation points for the study area.  The new DEM data are integrated into the underlying model to produce updated inundation maps.  Riverside’s approach identifies the still accurate points of the existing Lidar derived DEM and updates the sections that have changed.  We can collect aerial photos of a study area and produce accurate results with high quality resolution in a single day.  

We will present the process and results of using drone technology to update the flood inundation maps for the City of Fort Collins McMurry Natural Area to demonstrate our solution.