From the US Census Bureau: "The linear hydrography shapefile contains all linear
features with "H" (Hydrography) type MTFCCs in the
MAF/TIGER database by county. The shapefiles are provided at a county geographic extent and in linear
elemental feature geometry. The linear hydrography shapefile includes streams/rivers, braided streams,
canals, ditches, artificial paths, and aqueducts. A linear hydrography feature may include edges with both
perennial and intermittent persistence."