Authors: Jared Stieve, Jose Castejon, Belize Lane, Anzy Lee, Noelle Patterson, Colin Phillips – Utah State University
Title: How do adjusted rating curves improve flood inundation mapping following changes in hydraulic geometry?
Presentation Type: Poster Presentation
Abstract: In addition to immediate impacts, flood events can change channel morphology and hydraulic geometry. Since the Office of Water Prediction’s Height Above Nearest Drainage Flood Inundation Mapping (HAND-FIM) approach relies on reach-average rating curves derived from hydraulic geometry, large channel changes can impact the performance of subsequent HAND-FIM predictions. Additionally, the extent and type (e.g. bank erosion) of channel change can vary considerably between and within stream reaches. Since obtaining new high-resolution terrain is expensive and time-consuming, a rapid hydraulics-based approach to adjust rating curves is necessary to provide accurate flood extent predictions as channels change prior to obtaining updated terrain. Channel change can fall into three operational scenarios: (1) Little change where rating curve is still accurate, (2) moderate change where a rating curve adjustment improves FIM skill, and (3) large change where new terrain and rating curve are required. We provide examples of each scenario to demonstrate how rating curves can shift following channel change and test if rating curve adjustments based on remote sensing products (e.g. satellite imagery) can improve HAND-FIM performance.