Distance matrices and river-network crosswalks for the Geospatial Fabric v1.1 to support data-driven models of water quality in U.S. rivers

This data release contains hydrologic network information to support national modeling of water quality in streams and rivers, including distance matrices that represent the spatial relationships among modeled river reaches. These data can be used as inputs to data-driven models that leverage information about spatial proximity to make predictions of water quantity or quality. The modeling network is represented by the flowline segments in the Geospatial Fabric for National Hydrologic Modeling, v1.1 (GFv1.1, Bock et al. 2020).

This data release contains four files:
1. linear_distance_matrix.zip: File includes a matrix indicating the linear distances between river outlets in the GFv1.1 network.
2. river_distance_matrix.zip: File includes a matrix indicating the bidirectional (i.e., upstream and downstream) distances among flow-connected reaches in the GFv1.1 network.
3. nhdv2_gfv11_crosswalk.parquet File includes a crosswalk table that maps NHDPlusv2.1 flowlines to GFv1.1 flowline segments. The crosswalk table contains the best-match NHDPlusv2.1 COMIDs that intersect a given GFv1.1 segment. Multiple quality control checks were conducted; however, we expect some data quality issues remain, especially in areas where NHDPlusv2.1 deviates considerably from the GFv1.1 source data (either NHDPlus v1 or NHDPlus HR). See metadata for more details.
4. source_code.zip: File includes R code used to generate the distance matrices and crosswalk dataset.