Hydrological (including Stream Temperature, Intermittency and Conductivity logger) biological, geomorphological, and geospatial data and R code used to develop five regional Streamflow Duration Assessment Methods (SDAMs) for the Arid West, Western Mountains, Great Plains, Northeast, and Southeast regions of the contiguous United States. Data files include a unified dataset files from those used to develop the five regional SDAMs and the R code is organized into three separate subfolders containing scripts, data files, and metadata for the development of 1) Arid West and Western Mountain (Western Methods) SDAMs, 2) Great Plains SDAM, and 3) Northeast and Southeast (Eastern Methods) SDAMs. Citation information for this dataset can be found in Data.gov's References section.