Empirical models described in previous publications were developed and applied to estimate the probability of streamflow modification for every stream segment in the conterminous United States from 1980-2015. This metadata record documents 6 comma separated tables populated with predictions of streamflow modification (please see the Supplemental Element for citations or please refer to the cross-reference section). These data are based on watershed attributes computed for each NHDPlus v2.1 reach that were subsequently applied to previously published (and herein described) machine-learning models.