NHD-RC: Extension of NHDPlus Version 2.1 with high-resolution river corridor attributes

This hybrid medium-resolution national hydrography dataset with river corridor attributes (NHD-RC) for the conterminous United States (CONUS) was created by merging lentic and lotic attributes from the high-resolution NHDPlus (U.S. Geological Survey, 2020) into the medium-resolution NHDPlus Version 2.1 (U.S. Geological Survey, 2016). NHD-RC includes attributes from an additional 5.4 million small pond features and 5 million kilometers of small streams beyond the approximately 123,000 lentic waterbodies and 4 million kilometers of larger streams and rivers accounted for NHDPlus Version 2.1. This hybrid approach permitted the use of the many attributes that have been linked to NHD by others, including land cover and dam inventories, to provide four distinct classes of medium- and high-resolution lentic waterbodies: (1) lakes, (2) reservoirs, (3) historic small ponds that were not intensively managed during the past century, and (4) managed small ponds that were constructed for water supply, farm use, or another management purpose. Small ponds located in upland positions without a defined and mapped flowline are also included. This hybrid dataset further advances the basis for improved and more comprehensive integrated modeling and analyses of river corridors.