Effects of uncertain topographic input data on two‐dimensional flow modeling in a gravel‐bed river

摘要: [1] Many applications in river research and management rely upon two-dimensional (2D) numerical models to characterize flow fields, assess habitat conditions, evaluate channel stability. Predictions from such are potentially highly uncertain due the uncertainty associated with topographic data provided as input. This study used a spatial stochastic simulation strategy examine effects of on modeling. Many, equally likely bed elevation realizations for simple meander bend were generated propagated through typical 2D model produce distributions water-surface elevation, depth, velocity, boundary shear stress at each node model's computational grid. Ensemble summary statistics these predictions structure this relation morphology. Simulations conditioned different configurations indicated that became increasingly spacing between surveyed cross sections increased. Model sensitivity was greater base conditions than higher, subbankfull (75% bankfull discharge). The degree also varied spatially throughout bend, greatest occurring over point bar where field influenced by steering effects. Uncertain topography can therefore introduce significant analyses suitability mobility based output. In presence uncertainty, results studies most appropriately represented probabilistic terms using derived series realizations.