The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

The U.S. Geological Survey’s Water Availability and Use Study Program (WAUSP) (https://water.usgs.gov/ogw/gwrp/activities/regional.html) supports quantitative assessments of groundwater availability in areas of critical importance. As part of a WAUSP study in the arid to semi-arid Northwest Volcanic Aquifer Study Area (NVASA), estimates of runoff and baseflow were determined for 312 streamflow-gaging stations from 1904 to 2015. Gages with complete water years (October to September) of continuous-streamflow record were used to partition streamflow into runoff and baseflow, which is that part of streamflow attributed to groundwater discharge. For each water year annual estimates of baseflow, runoff, and a base-flow index were determined using a series of automated hydrograph separation programs—PART, HYSEP, and BFI. These streamflow-hydrograph analysis methods are available in the U.S. Geological Survey Groundwater Toolbox (https://water.usgs.gov/ogw/gwtoolbox/), which is a graphical, mapping and analysis interface built within an open-source MapWindow geography information system in a Windows computing environment.

This dataset represents 19,031 basin boundaries and their streamgage locations for the U.S. Geological Survey's (USGS) active and historical streamgages from the published dataset of Stewart and others (2006) and its subsequent updates (D.W. Stewart, USGS, written commun., 2011). Only the basin boundaries that were delineated within 15 percent of the basin area reported in the National Water Information System (NWIS) were included in this dataset. This dataset only includes streamgage basins in the lower 48 states and not in Alaska, Hawaii, or Puerto Rico. The basin boundaries and streamgage locations are provided in 18 shapefiles separated by 2-digit Hydrologic Unit Code. The USGS streamgage station's identification number attached to each delineated polygon can be linked to the attribute data found in Stewart and others (2006). The delineated watersheds were made from digital elevation models found in the NHDPlus data suite (version 1, 2006) and based on gage locations provided by Stewart and others (2006). These basins have been used in several USGS studies such as James Falcone's "GAGES-II: Geospatial Attributes of Gages for Evaluating Streamflow" (2011) and Xiaodong Jian and others, "WaterWatch-Maps, Graphs, and Tables of Current, Recent, and Past Streamflow Conditions " (2008).