Output File Must Have Supporting Bed Mass/Volume Variables
If you want to use model results for a gradational hotsart, you must run it at Output 6 and Set the Mass/Volume option to Volume.
HEC-RAS will generate an error if the user requests a gradational hotstart from an output file that does not have all of the required bed layer results by grain class:
The gradational hotstart cannot use results files created with output level 1-3 (unless the user adds the layer masses by grain class). Run the model at output level 4 to generate a results file complete enough for a gradational hotsart.