Simultaneous Generation of Topographic Models and Manning Roughness Coefficient Maps From Tri‐Stereoscopic Satellite Images: Application to the Huarmey River, Peru

ABSTRACT Hydraulic models require accurate topography and reliable Manning roughness coefficients to predict flow behaviour. This paper develops an integrated methodology to simultaneously generate high‐resolution topographic models and Manning roughness coefficient maps using tri‐stereoscopic images from the PeruSat‐1 satellite. The study was applied to the Huarmey River, Peru, covering 33.25 km 2 . The methodology employs tri‐stereoscopic photogrammetric processing using the Semi‐Global Matching algorithm to generate topographic models with a spatial resolution of 0.70 m. Object‐based image analysis was used to identify 10 land cover classes, assigning Manning coefficients between 0.013 and 0.050 according to standard values. The results show a vertical RMSE of 0.434 m validated with 21 independent checkpoints, meeting ASPRS 2024 standards. Successful integration into the Hydrologic Engineering Centre's River Analysis System (HEC‐RAS) confirms operational functionality through simulation of a flow rate of 302.10 m 3 /s with stable convergence. The final cartographic products include eight thematic maps validating the applicability for flood risk management and urban land‐use planning studies.