Attributes for NHDPlus Version 2.1 Reach Catchments and Modified Routed Upstream Watersheds: 30 year (1981 - 2010) annual average of daily intensity of precipitation for a rain event for the Conterminous United States and District of Columbia

This tabular data describes the annual average of daily intensity of precipitation for a rain event during the 30-year period 1981 – 2010 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. A rain event is defined as a period when the number of consecutive days with precipitation equals or exceeds 1 millimeter. Daily precipitation intensity is defined as the amount of precipitation over the duration of a rain event divided by the number of days in a rain event. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data for 30 year (1981-2010) annual average of daily intensity of precipitation for a rain event was a 1-kilometer resolution GeoTIFF file that was produced and acquired from DAYMET (2018). 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).