Attributes for NHDPlus Version 2.1 Catchments and Modified Routing of Upstream Watersheds for the Conterminous United States: National Atmospheric Deposition Program (NADP) National Trends Network (NTN) 1985-2014

This data set represents National Atmospheric Deposition Program (NADP) National Trends Network average of annual precipitation-weighted mean atmospheric deposition for seven select constituents from years 1985-2014 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. The seven constiuents presented here are: Calcium, Nitrate, Sulfate, Inorganic Nitrogen, Magnesium, Ammonium, and Chloride. Units are kilograms per hectare. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data was produced by the National Atmospheric Deposition Program NADP, 2017). 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).