Three-Dimensional Free-Surface Flow Model Verification and Validation: Assessment and Future Directions

The verification and validation of three-dimensional free-surface flow models continues to be an active area of research. Within the ASCE Committee on Computational Hydraulics, Wang et al. (2008) addressed terminology, presented analytical, laboratory, and field datasets, and recommended a systematic procedure for model verification and validation. Here, we first review these systematic procedures and associated skill metrics. In so doing, we assess the current state of the art and identify challenges. Particular attention is given to the grid convergence index (GCI) to determine grid uncertainty and challenges to its computation in NOS forecast systems. New approaches to determining grid uncertainty will be presented. A review of the present skill metrics for time series at a point as well as scalar and vector fields will be considered with additional skill metrics advanced. In addition, we discuss the role of recent new datasets, via advances in data acquisition, in providing new directions in: 1) data assimilation and 2) coupled hydrodynamic and biological models. A summary and conclusions section is included to provide further perspective and focus.