Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Routed Upstream Watersheds for the Conterminous United States: Watershed Potential to Contribute Phosphorus from Geologic Materials to Receiving Streams

This tabular data set represents the contribution of phosphorus (P) to streams from weathering and erosion of surficial geologic materials compiled for two spatial components of the NHDPlus version 2.1 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 from the publication, Watershed Potential to Contribute Phosphorus from Geologic Materials to Receiving Streams, Conterminous United States, (Nardi, 2014). Units are Mean bed sediment phosphorus value in parts per million (ppm). 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).