Acknowledgement

The 1D sediment transport approach and algorithms in HEC-RAS were based on the approach originally developed in HEC 6 and HEC 6T by Tony Thomas.

Tony Thomas was the Corps of Engineer's original, numerical, sediment modeler, developing the first mobile-bed transport model at the Little Rock District before moving to HEC to develop HEC 6, which was the industry-standard, numerical, sediment-transport model for decades.

After developing HEC 6 at HEC, Mr. Thomas continued to develop 1D and 2D sediment models at the Waterways Experiment Station (now ERDC) and then worked for many years developing and applying HEC 6T in the private sector, advancing the technology he developed while with the Corps.

In the early stages of HEC-RAS sediment development (circa 2000) Tony came to HEC as a visiting scholar, and spent several months helping the RAS sediment team understand the HEC 6 code, providing insight into HEC 6T innovations, and helping us develop and test initial alpha version of the 1D, mobile-bed model in HEC-RAS.

 In the last 20 years HEC has added some new approaches and technology to 1D Sediment in RAS, but the framework and approach remain deeply in the HEC6 tradition.

Much of the technology in the 1D, HEC-RAS sediment model comes from HEC6 and reflects Tony Thomas' algorithm development and mentorship.