Abstract
Determining Flood Return Periods using ArcGIS-based Hydraulic Modeling and Observation
Track: Disaster and Emergency Management
Authors: Zhihao Wang, Graham Hayes, Chris Renschler, Martin Minkowski
In August 2011, Hurricane Irene swept through eastern New York State. Heavy rains in the Schoharie watershed caused record setting flooding. One critical concern of citizens and emergency managers after any flood is "Was it a 100-yr, 500-yr, or 1,000-yr flood?
This research attempts to model the flood inundation and flood return period using an ArcGIS-based HEC-GeoRAS flood model. HEC-GeoRAS utilizes 10m USGS DEM, NLCD landuse data, and flow rate data from two nearby gauging stations as input parameters. In addition, aerial imagery taken two days after the peak flooding using an RIT/IPLER airborne multi-sensor platform was inspected visually to establish the flood extent. Model results were validated against field observations, and previous FEMA flood model results.
To inform residents and emergency responders of potential floods threats due to climate change or wildfires, GeoWEPP (an ArcGIS-based runoff/erosion model) was used to test BMPs and simulate flood scenarios.climate change or wildfires.