Hydrofabric Integration
Routing requires a hydrofabric containing vector-based river network data that informs network connectivity from upstream to downstream. In addition to connectivity information, t-route ingests information/parameters from the hydrofabric that are used for various features, broadly categorized into the following components: Muskingum-Cunge routing, reservoir routing, data assimilation (streamflow and reservoirs), diffusive routing, and coastal coupling. Each of these components retrieves necessary info from different layers (NextGen) or files (NHD) as shown in Figure 1.
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| Figure 1. T-route features that require information from the hydrofabric. |
The information needed for each component are summarized as follows:
- Muskingum-Cunge (MC) Routing
- Parameters describing channel geometry from the hydrofabric
- Reservoir Routing
- Parameters describing waterbody geometry, including outlet geometries
- Crosswalk between waterbody IDs and underlying segment IDs (i.e., which segments are located within a given waterbody)
- Data Assimilation (Streamflow)
- Crosswalk between gage IDs and the segment IDs they are physically located in
- Data Assimilation (Reservoirs)
- Crosswalk between gage IDs and the waterbody IDs they are physically located in
- Delineation of "reservoir types" based on the observation source (USGS, USACE, RFC, glacially-dammed lakes)
- Diffusive Routing
- Segment cross-section topobathy parameters (e.g., geometries, manning's roughness)
- Coastal Coupling
- Nexus point latitude/longitude
- Points of interest (i.e., inland-coastal coupling nexus points)
More specific parameter information used by each component can be found in Table 1.
In the NextGen framework, all hydrofabric information is included in a single file (geopackage) for a given domain. Information within the geopackage is separated into relevant layers (e.g., flowpaths, lakes, nexus, etc.). T-route is updated to work with the latest release of the hydrofabric, assuming the layer naming conventions and contents are static.
If running on NHD networks used for previous versions of the NWM, t-route ingests hydrofabric information from multiple files. For instance, segment information is contained within RouteLink files, while waterbody parameters are contained in LAKEPARM files. Users must specify and provide multiple file paths in t-route's configuration file if specific routing features are desired.
| Table 1. Full list of t-route parameters/variables that are obtained from the hydrofabric. |
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