Patterns of Difference between Physical and 1-D Calibrated Effective Roughness Parameters in Mountain Rivers

Due to the presence of boulders and different morphologies, mountain rivers contain various resistance sources. To correctly simulate river flow using 1-D hydrodynamic models, an accurate estimation is required. In this article, a comparison between physical roughness parameter (PRP) effective coefficient (ERC) presented for three most typical morphological configurations in rivers: cascade, step-pool, plane-bed. The PRP its variation were obtained through multiple measurements field variables uncertainty analysis, while ERC range was derived with GLUE procedure implemented HEC-RAS, model. experiments, two modes Representative Friction Slope Method (RFSM) cross-sections tested, including parameter. results revealed that RFSM effect limited low flows cascade step-pool. Moreover, when HEC-RAS selected RSFM, only acceptable difference depended on magnitude morphology, as shown study, increased, ranges approached each other even overlapped This research aimed improve value selection process model given importance predictability results. addition, numerical values calculated