Sediment Modeling Panel Discussion (part 1): Pre-Modeling Practices

Successful sediment transport models begin before modelers ever open modeling software…or even select a software package. Strong modeling practices begin with several pre-modeling practices. This panel discussion will bring together four morphological model developers (representing HEC-RAS 1D&2D, ADH, and SRH-1D) to discuss their pre-modeling principles and practices.

Pre-modeling practices begin with clarifying the modeling objective and the client question. Often the manger or decision maker requesting a morphological model does not have a clear question at the outset, and it’s up to the modeler to help them clarify their question. After the questions have been defined, the numerical modeler must determine if a numerical model can reduce the risk surrounding the design or morphological management decision with the data available, or if the question is more suited to qualitative, geomorphic, assessment, or physical modeling.

After the team clearly identifies the modeling question, the modeler must collect and assess the available flow, sediment, and calibration data. Input data are important, but project success often depends on calibration data. The team should take the data analysis to the stage of a rough sediment budget before modeling, because if the sediment data do not generate a balanced budget on a note pad, it will not magically balance in the model.

Finally, with a clear modeling question and a complete understanding of the data availability and a rough sediment budget, the modeler should select their software and construct a model with the end in mind from the beginning. The model should be constructed to answer the specific modeling question, scale to the available data, and generate clear evaluation metrics that are easily compared to the available calibration data.

The panel will discuss these principles and practices, addressing the following topics:

• When to invest in a numerical sediment model. • Clarifying and refining the modeling objective(s) • Designing the model to the model objective. • Scaling the model to the available data. • Pre-modeling data analysis. • Developing a conceptual sediment budget before building a model.