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Error Assessment for Height Above the Nearest Drainage Inundation Mapping
Author(s) -
Godbout Lukas,
Zheng Jeff Y.,
Dey Sayan,
Eyelade Damilola,
Maidment David,
Passalacqua Paola
Publication year - 2019
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/1752-1688.12783
Subject(s) - terrain , scale (ratio) , range (aeronautics) , flood myth , drainage , drainage density , remote sensing , run out , hydrology (agriculture) , environmental science , geology , computer science , statistics , cartography , mathematics , drainage basin , geography , geotechnical engineering , ecology , biology , materials science , physics , archaeology , quantum mechanics , composite material
Real‐time flood inundation mapping is vital for emergency response to help protect life and property. Inundation mapping transforms rainfall forecasts into meaningful spatial information that can be utilized before, during, and after disasters. While inundation mapping has traditionally been conducted on a local scale, automated algorithms using topography data can be utilized to efficiently produce flood maps across the continental scale. The Height Above the Nearest Drainage method can be used in conjunction with synthetic rating curves (SRCs) to produce inundation maps, but the performance of these inundation maps needs to be assessed. Here we assess the accuracy of the SRCs and calculate statistics for comparing the SRCs to rating curves obtained from hydrodynamic models calibrated against observed stage heights. We find SRCs are accurate enough for large‐scale approximate inundation mapping while not as accurate when assessing individual reaches or cross sections. We investigate the effect of terrain and channel characteristics and observe reach length and slope predict divergence between the two types of rating curves, and SRCs perform poorly for short reaches with extreme slope values. We propose an approach to recalculate the slope in Manning’s equation as the weighted average over a minimum distance and assess accuracy for a range of moving window lengths.