This data release contains information to support water quality modeling in the Delaware River Basin (DRB). These data support both process-based and machine learning approaches to water quality modeling, including the prediction of stream temperature. Reservoirs in the DRB serve an important role as a source of drinking water, but also affect downstream water quality. Therefore, this data release includes data that characterize both rivers and a subset of reservoirs in the basin. This release provides an update to many of the files provided in a previous data release (Oliver et al., 2021). The data are stored in 3 child folders: 1) spatial information, 2) observations, and 3) model driver data. <li><a href="https://www.sciencebase.gov/catalog/item/623e54c4d34e915b67d83580"> 1) Spatial Information </a>- Spatial data used for modeling efforts in the Delaware River Basin</li> - a shapefile of polylines for the river segments, point data for observation locations, and polygons for the three (Pepacton, Cannonsville, and Neversink) reservoirs in this dataset. <li><a href="https://www.sciencebase.gov/catalog/item/623e550ad34e915b67d8366e"> 2) Observations </a>- Reservoir (surface levels, releases, diversions, water temperature) and river (water temperature and flow) observations that can be used to train and test water quality models. </li> <li><a href="https://www.sciencebase.gov/catalog/item/623e5587d34e915b67d83806"> 3) Model driver data </a>- Driver data used to force water quality models, including stream reach distance matrices and daily meteorology data from NOAA GEFS and gridMET. This child item also includes the inputs and outputs of an uncalibrated run of PRMS-SNTemp which predicts mean water temperature at all reaches in the DRB. This data compilation was funded by the USGS.