Bc. Hankin et Kj. Beven, Modelling dispersion in complex open channel flows: Equifinality of model structure (1), STOCH HYDRO, 12(6), 1998, pp. 377-396
In a special opportunity, detailed measurements of the flow in an overbank
flow in the Flood Channel Facility at HR Wallingford were used in conjuncti
on with tracer test data to assess the effectiveness of dispersion models b
ased around random particle tracking (RPT). Ten different RPT models based
on different assumptions and levels of information about the nature of the
Lagrangian velocity field were investigated. Multiple simulations were used
to calibrate variable parameters controlling the average magnitude of the
perturbations for each model by comparison with observed concentrations at
one cross-section. The calibrated models were then used to predict concentr
ation distributions further downstream. Several of the calibrated models sh
owed close agreement between observed and predicted concentration distribut
ions. The most complex models using the most information about the velocity
distributions were no better (and in some cases worse) in prediction than
the simplest models investigated. It would appear that our knowledge of the
system, despite the quality of the experiments, is too uncertain to infer
a precise model structure.