Quasi-unsteady sediment analysis does not generate DSS data by default. Users can request limited DSS time series at any cross section(s). HEC-RAS will write out a DSS file named (project name).PXX.sed.dss (where XX is the plan number). This feature only works for quasi-unsteady analyses. Users can choose one or more cross sections to write DSS output. To add additional cross sections press the Set RS to Write DSS Sediment Output… button. To delete or clear a node from the DSS list double click on list. Double clicking removes nodes. Users can also select five different DSS results (or all five) These DSS output options were expanded in version 6.0. Earlier versions had much more limited DSS output.. Different result options generate different DSS formats, and some of them trigger HEC-RAS to write multiple Results. All DSS results are written by grain size. HEC-RAS can write Concentration as an instantaneous value at for each computational increment (INST-VAL, IR-Month) or average the Concentration over each day, which it writes as a regular daily time series (PER-AVE, 1Day). The mass flux leaving the cross-section control volume has three options instantaneous flux for each Computational Increment (INST-VAL, IR-Month), daily period cumulative data (PER-AVE, 1Day) that accumulates mass over time, and an instantaneous cumulative mass flux (INST-VAL, IR-Month). The time series written to DSS are equivalent to the MASS Out Cum variable in HEC-RAS, computing the cumulative total sediment mass leaving the control volume over time by grain class. Cumulative mass time series are stored by grain class (part C indicates that they are sediment data, the grain class number and the grain class name) and stored as irregular monthly (IR-Month) data.
