Attributes for NHDPlus Version 2.1 Catchments and Modified Routing of Upstream Watersheds for the Conterminous United States: Soller Surficial Materials, 2009

This tabular data set represents the percent of surficial materials compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data is the "Map database for surficial materials in the conterminous United States" produced by the United States Geological Survey (USGS, 2009). Units are percent. Surficial materials are defined as an unconsolidated blanket of sediments in which soils commonly are developed. These sediments generally were eroded from underlying rock, and then were transported and deposited (USGS, 2009). Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).