Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Routed Upstream Watersheds for the Conterminous United States: Distribution of Phosphorus in Soil Horizons A and C and Geologic Mapping Units

This tabular data set represents the estimated distribution of Phosphorus (P) in the soil A and C horizons, milligrams per kilogram compiled for two spatial components of the NHDPlus version 2.1 data suite (hereto referred as 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 from the publication, Distribution of Phosphorus (P) in the soil A and C horizons, Terziotti, 2019). Units are milligrams per kilogram. 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, 2016).