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HEC-DSS Export

The Partitioned DSS Export for HEC workflow packages existing routed WEPP outputs into HEC-DSS files and supporting sidecar files for downstream HEC workflows. It is an export step, not a new model run.

What You Actually See In The UI

The DSS export control is titled Partitioned DSS Export for HEC. The user-facing inputs are:

  • Start date (optional)
  • End date (optional)
  • Export mode
    • Export select channels
    • Export based on channel order
  • when Export select channels is chosen:
    • Channel Topaz IDs to export
  • when Export based on channel order is chosen:
    • Exclude channel orders with checkboxes 1 through 5
  • Export DSS

The download link appears only after the job completes:

  • Download DSS Export Results (.zip)

What Each Export Option Means

UI control What it means When to use it
Start date (optional) Lower date bound for the exported series Use when you only need part of the modeled record
End date (optional) Upper date bound for the exported series Use when your HEC study window is shorter than the full WEPP run
Export select channels Export only the channels you name explicitly Use when you already know the exact Topaz channel IDs you need
Channel Topaz IDs to export Comma-separated list of channel IDs Use for tightly targeted exports
Export based on channel order Export every eligible channel except the orders you exclude Use when you want a broad export filtered by network size/order
Exclude channel orders Removes selected Strahler orders from the export set Use to omit small headwater channels or other orders you do not want in the package

For stochastic climates, the help text matters: use simulation year numbering in the DSS date fields rather than real calendar years.

What The Export Button Triggers

Clicking Export DSS posts the current export settings to:

/rq-engine/api/runs/<runid>/<config>/post-dss-export-rq

The controller normalizes the form before submitting:

  • channel lists are parsed into positive integer channel IDs,
  • excluded orders are collected into an order list,
  • dates are passed as optional strings,
  • mode 2 derives the actual channel list from watershed channel order rather than using a manual list.

The route validates:

  • dates must be MM/DD/YYYY,
  • start date must be on or before end date,
  • channel IDs must be positive integers.

If validation passes, WEPPcloud stores the DSS export settings on the run, queues the DSS export job, and publishes the finished zip under browse/export/dss.zip.

What You Get In The Zip Package

The package is centered on export/dss.zip. The export directory typically contains:

  • totalwatsed3_chan_<id>.dss daily DSS series for each exported channel
  • peak_chan_<id>.dss irregular peak-flow DSS series derived from channel output
  • sed_vol_conc_by_event_and_chn_id.csv per-channel tabular sidecar with sediment and ash concentration fields when available
  • dss_channels.geojson exported channel geometries plus DSS/HEC metadata
  • boundaries/bc_<id>.gml and boundary shapefile sidecars boundary-condition helper files for downstream HEC work
  • README.dss_export.md export-specific technical notes copied into the package

Some runs may also include channel-buffer products when that generation step succeeds.

What You Are Not Getting

This package does not give you a complete HEC-RAS or HEC-HMS project. In particular, the export is not:

  • a rerun of WEPP,
  • observed gage data,
  • surveyed geometry,
  • cross sections, terrain, or a finished hydraulic model,
  • a guarantee that channel names match your local naming convention.

It is a WEPP-derived time-series package plus helper geometry and boundary sidecars.

How To Choose An Export Mode

Use Export select channels when:

  • you already know the exact Topaz IDs you need,
  • you are handing off only a few locations,
  • you do not want small upstream channels included accidentally.

Use Export based on channel order when:

  • you want a systematic export for many channels,
  • order is a better filter than hand-entering IDs,
  • you want to exclude the smallest or least relevant channels quickly.

How To Interpret The Results

The DSS files contain modeled WEPP outputs. Treat them as scenario-based hydrologic inputs, not measurements.

Two series types matter:

  • totalwatsed3_chan_<id>.dss daily channel series suitable for continuous-style review
  • peak_chan_<id>.dss irregular peak-flow series derived from channel routing output

Before using the package downstream, verify:

  • the channel set is the one you intended,
  • the date range matches the study window,
  • your HEC workflow is using daily versus peak series for the right purpose.

Core Assumptions And Limits

  • The export is only as good as the underlying WEPP run.
  • Channel IDs follow the modeled watershed structure in WEPPcloud.
  • Filtering by channel order is based on modeled network order, not on local naming or management importance.
  • Missing or weak WEPP channel outputs will carry directly into the DSS package.
  • The package helps with HEC handoff, but it does not remove the need for downstream hydraulic setup and review.