Authors: Anzy Lee – Utah State University
Title: Probabilistic quantification of within-reach hydraulic geometry variability to support probabilistic HAND FIM
Presentation Type: Poster
Abstract: Hydraulic geometry (HG) characterizes the at-a-station channel form and hydraulic conditions as a function of flow discharge. HG attributes including hydraulic radius, top-width, cross sectional area, and maximum depth vary within a river segment for a constant flow discharge. However, the shape of these within-reach HG distributions and how they scale with increasing discharge, downstream, and as a function of other larger-scale river attributes such as valley confinement has not been determined. This information could help calibrate height above nearest drainage (HAND) synthetic rating curves (SRC) to generate probabilistic SRCs and associated ensemble HAND flood inundation maps (FIM). Here we explore several benchmark reaches across the USA with diverse river morphology and calibrated 2D hydraulic models, we characterize the probability distributions of key HG attributes and investigate how their statistical properties change under different flow stages and river settings. A probabilistic approach to FIM has the potential to account for reach-scale variability and hydraulic attribute error and provide predictions in the absence of hydraulic models .