“…Enhanced computing power has enabled large‐scale flood modeling applications ranging from regional to national scales (Sampson et al, 2015; Wing et al, 2017; Wing et al, 2019). However, although higher‐resolution (i.e., 10 m or finer spatial resolution) flood modeling studies are being reported in the recent literature (Noh, Lee, Lee, & Seo, 2019; Nyaupane et al, 2018), there are various open challenges for large‐scale flood simulation. Some of the challenges in a large‐scale coupled hydrologic‐hydraulic modeling framework are (a) high computational cost for model tuning and calibration (model parameterization), even with the support of high‐performance computing (HPC) (Dung, Merz, Bárdossy, Thang, & Apel, 2011; Getirana et al, 2017; Peña & Nardi, 2018), (b) inaccuracy in digital elevation models (DEMs) (Bhuyian, Kalyanapu, & Nardi, 2014; Casas, Benito, Thorndycraft, & Rico, 2006; Cook & Merwade, 2009; McKean, Tonina, Bohn, & Wright, 2014), and (c) difficulty in addressing reservoir operation and regulation (Fleischmann, Collischonn, Paiva, & Tucci, 2019; Mateo et al, 2014; Shin, Pokhrel, & Miguez‐Macho, 2017).…”