Output Channel
Overview:
The OUTPUT_CHANNEL table is used by both HYDRO and QUAL to specify output requests inside of the channel. Output is HEC-DSS or text format. The variables that can be requested vary by model.
Tables:
OUTPUT_CHANNEL
The table specifies the name for output request, as well as the location, variable being output, time aggregation and destination file.
Field Descriptions
NAME
Name of the output request. This is part of the identifier of the table and will be used in the B_PART of the output if it is in DSS format. Generally, non-modelers will have an easier time understanding your output if this is a station name that is geographically fixed (e.g. "vernalis" or "RSAC075") than if it is a modeling construct ("ch101"). Similarly, avoid using avoid using VARIABLE inside this name -- this causes redundancy in the output DSS path and the layering won't work as well.
CHAN_NO
Channel number in which output is requested.
DISTANCE
Distance along channel (from upstream node to downstream), typically in feet. Results will be interpolated between Eulerian (HYDRO) or Lagrangian (QUAL) computational points.
VARIABLE
Model variable to be output. In HYDRO, you can request stage,flow,vel. In QUAL you can request stage,flow or the name of any constituent in the model. When no output request is made for a constituent that is not required for reaction kinetics, it is not calculted.
INTERVAL
Time Interval of the output. Can be any DSS-compliant interval with a unit that is not calendar dependent (MIN, HOUR, DAY). This is a departure from previous versions of DSM2, which offered monthly output.
PERIOD_OP
Period aggregation performed to convert the model time step into the time interval of the output. May be INST or AVE, which produce instantaneous
FILE
Name of the output file where the data will be stored. If the extension .txt is given, the output is automatically in text format. If a .dss extension is used, output is in HEC-DSS format.
Table Info
Identifier:
NAME, VARIABLE
Parent Table:
Table is parent
Include Block:
OUTPUT_TIME_SERIES
OUTPUT_CHANNEL_SOURCE_TRACK
This table is identical to OUTPUT_CHANNEL except it is only used in QUAL and it contains one additional field for tracking constituent sources.
Field Descriptions
NAME
Name of the output request. See comments above, and note that in this case you should also avoid using the SOURCE_NAME in the output name.
CHAN_NO
Channel number in which output is requested.DISTANCEDistance along channel (from upstream node to downstream), typically in feet. Results will be interpolated between Eulerian (HYDRO) or Lagrangian (QUAL) computational points.
VARIABLE
Model variable to be output. In HYDRO, you can request stage,flow,vel. In QUAL you can request stage,flow or the name of any constituent in the model. When no output request is made for a constituent that is not required for reaction kinetics, it is not calculted.
SOURCE_GROUP
Name of the source group that is being tracked in this output request. To learn how to define a group, see group reference. The group used must consist entirely of boundary or source locations -- not water bodies.
INTERVAL
Time Interval of the output. Can be any DSS-compliant interval with a unit that is not calendar dependent (MIN, HOUR, DAY). This is a departure from previous versions of DSM2, which offered monthly output.
PERIOD_OP
Period aggregation performed to convert the model time step into the time interval of the output. May be INST or AVE, which produce instantaneous
FILE
Name of the output file where the data will be stored. If the extension .txt is given, the output is automatically in text format. If a .dss extension is used, output is in HEC-DSS format.
Table Info
Identifier:
NAME, VARIABLE, SOURCE_GROUP
Parent Table:
Table is parent
Include Block:
OUTPUT_TIME_SERIES
- Finer output is preferred to daily. You can easily average to daily later outside the model using a script or time series application. Tidal data are poorly represented by daily aggregations, and numerous incorrect conclusions have arisen from aliasing (fluctuations over two weeks) when a 24 hour daily averaging operation is imposed on a naturally 25-hour phenomenon. Monthly output is no longer allowed.