Dynamic rating model archive

Ratings are used for a variety of reasons in water-resources investigations. The simplest rating relates discharge to the stage of the river. From a pure hydrodynamics perspective, all rivers and streams have some form of hysteresis in the relation between stage and discharge because of unsteady flow as a flood wave passes. Simple ratings are unable to represent hysteresis in a stage/discharge relation. A dynamic rating method is capable of capturing hysteresis owing to the variable energy slope caused by unsteady momentum and pressure.

Using some simplifying assumptions, Fread (1973) developed what was termed a “dynamic loop” rating method to compute discharge from a time series of stage at a single streamgage for channels with compact geometry (no flood plain). Dynamic loop has specific meaning as it refers to a rating method that accounts for the variable energy slope "associated with the dynamic inertia and pressure forces of the unsteady flood discharge" (Fread, 1975) as opposed to rating loops imposed by alluvial bedform dynamics or scour and fill processes.

A dynamic rating method, which accommodates compound and compact channel geometry, referred to as DYNPOUND, has been developed using a numerical solution as the focal point of this study. The DYNPOUND method was implemented in the Python programming language and computes discharge from stage and stage from discharge. Stage and discharge time series computed with the dynamic rating method implementations were compared to the USGS published stage and discharge time series. The results from the DYNPOUND method were also compared to discrete stage and discharge measurements made at U.S. Geological Survey streamgage sites. Two sets of stage and discharge time series were created using one-dimensional unsteady simulation software with compound channel geometry to compare the results of the DYNPOUND method to results from the full one-dimensional shallow water equations.

This model archive accompanies the report by Domanski and others (2025) and the software release by Knight and others (2025). It contains the original source code and calibration parameters for the DYNPOUND rating method, along with the HEC-RAS project files, that were used to generate the results featured in the report (Domanski and others, 2025). The 'model' directory encompasses all input and output files required to run the model. The 'output' directory contains the expected output from DYNPOUND. The 'source' directory consists of the complete source code written in Python. The 'tables' directory contains all table data published in the accompanying report by Domanski and others (2025).