Hydrofabric data model

While the official vignette gives you a more formal definition of the term “hydrofabric”, if that doesn’t do it for you, the short(er) answer I’d give you is:

“The Hydrofabric data are the geometric features delineating channel flow and contributing drainage area, the topologic relationships linking the network together, and the attributes providing the critical landscape attributes needed for hydrologic and hydraulic model execution.”

While the term “hydrofabric” has been used to describe concepts as narrow in scope as “a set of cartographic lines” to the entire data model used in the NextGen water modeling framework all the way up to entire branches of teams and workstreams, the most succinct and appropriate way to use this term is in describing both 1) a conceptual standard as defined by the OGC, and 2) the flowline –> catchment discretization of the landscape (contra: Semantics are important, I just hate them)

This page deals with the first of those. If you have an immediate task in front of you you likely want to jump straight into the data so just note that the theoretical foundation lives here if you get confused about what you find.

Hydrofabric as an OGC standard

a class of data needed to represent the land surface using flowline/catchment topologies.

“Hydrofabric” is the term used to describe the data model and associated product of flow-path representations and catchments and is typically derrived from mapping applications at 1:24000 scale or greater (1 inch on the map is ~0.3 miles in the world). In the US, the authoritative source of that data stems from the NHD Flowlines (formally termed flownetwork) are not a part of NHD but have been added in as a derrived product id3dhp is unique to all hydrofabric and database and links to both flownetwork, catchments, and waterbodies. Mainstem and drainage basins are a self-similar tree that helps us cross scales. By doing this we have a backbone to work against.
HY_Features is a conceptual model of hydrogarphy, the hydrofabric is a realization of that that follows better current computational and implementation requirements Mainstems are catchment unique levelpaths

A tool we can use to cross production boundaries (HUC4’s)

It’s worth taking a quick detour to describe the history of the current implementation of the “reference” hydrofabric. In the 60’s, the us census beuro and the usgs created map scale topo maps for quadrants, and had field personnel verify them as accurate. From those, the blue line river representation was used as a starting geometry. Using those lines as a starting point, the nhd program spun off in the 90’s to modernize and digitize the waterways and was then improved for the nhdplushighres which goes through the usgs water mission areas.

References

Writing layers out into gpkg from a cloud store: [[20240831204113]] Hydrofabric manipulations [[20241014200531]] Differentiating Stream Order vs mainstem vs levelpath

Explainers

[[20241014200956]] What does incorrectly labeling a catchment mean physically?

Hydrofabric as datasets

Because everything is done in table space as opposed to geographic space, the operations tend to be lightning fast and more memory efficient and so you are able to scale your analysis much faster than you otherwise could on the same hardware, same timeframe, and therefore same cost. This enables applications like CONUS scale flood mapping, USGS water prediction, and associated hydrofabric operations to be executed on common hardware

Hydrofabric for hydralics

It’s occasionally inappropriate to use hydrofabric as a hydraulic modeling framework.  Hydraulics and flying water are incompatible. 

What is a HUC?

“3D” Hydrofab

This is where you lose me but using those more time-efficient [[20240818074751]]Hydraulicc geometries [[20240718223131]] Cross sectional representations of the river-scape [[20241016192617]] Hydrofabric3D Data Model