As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams or lakes at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area data for 45 selected stream-sampling stations in the Yellowstone River Basin are included in this data release. The drainage divides were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography. Drainage areas based on 1:100,000-scale hypsography data generally agree to within 5 percent with drainage areas measured at 1:24,000 scale, for areas larger than 50 km2.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams (or lakes) at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area data for 24 selected stream-sampling stations in the Yellowstone River Basin are included in this data release. The drainage divides were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography. Drainage areas based on 1:100,000-scale hypsography data generally agree to within 5 percent with drainage areas measured at 1:24,000 scale, for areas larger than 50 km2.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams or lakes at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area data for 45 selected stream-sampling stations in the Yellowstone River Basin are included in this data release. The drainage divides were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography. Drainage areas based on 1:100,000-scale hypsography data generally agree to within 5 percent with drainage areas measured at 1:24,000 scale, for areas larger than 50 km2.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams or lakes at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area data for 45 selected stream-sampling stations in the Yellowstone River Basin are included in this data release. The drainage divides were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography. Drainage areas based on 1:100,000-scale hypsography data generally agree to within 5 percent with drainage areas measured at 1:24,000 scale, for areas larger than 50 km2.

As part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment Program (NAWQA), an investigation of the Missouri River Basin is being conducted to document trends in surface-water quality, specifically for trends in nutrients and suspended sediment. Surface-water samples were collected from streams at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area boundary data for one stream-sampling station in the Missouri River Basin (MRB4) study area is included in this data release. The drainage divides were identified chiefly using 1:24,000-scale hypsography.

As part of the U.S. Geological Survey's (USGS) National Water-Quality Assessment Program (NAWQA), an investigation of the Missouri River Basin is being conducted to document trends in surface-water quality, specifically for trends in nutrients and suspended sediment. Surface-water samples were collected from streams at specific sampling stations. Water-quality characteristics at each station are influenced by the natural and cultural characteristics of the drainage area upstream from the sampling station. Efficient quantification of the drainage area characteristics requires a digital map of the drainage area boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital drainage-area boundary data for one stream-sampling station in the Missouri River Basin (MRB4) study area is included in this data release. The drainage divides were identified chiefly using 1:24,000-scale hypsography.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams or lakes at specific sampling stations. Efficient quantification of the site-specific geographic and environmental characteristics at sampling stations requires a geospatial data set composed of the site locations that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital data for 24 stream-sampling stations in the Yellowstone River Basin are included in this data release. The station locations were retrieved from the U.S. Geological Survey's National Water Information System where they are stored as latitude-longitude coordinate pairs referenced to the NAD27 datum. Selected station identifiers and geographic codes also were retrieved and are included in the data release.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Surface-water samples are collected from streams or lakes at specific sampling stations. Efficient quantification of the site-specific geographic and environmental characteristics at sampling stations requires a geospatial data set composed of the site locations that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital data for 24 stream-sampling stations in the Yellowstone River Basin are included in this data release. The station locations were retrieved from the U.S. Geological Survey's National Water Information System where they are stored as latitude-longitude coordinate pairs referenced to the NAD27 datum. Selected station identifiers and geographic codes also were retrieved and are included in the data release.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Efficient quantification of a variety of environmental and geographic characteristics of the study unit requires a digital map of the study-unit boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital boundary data for the Yellowstone River Basin study unit are included in this data release. The boundary follows drainage divides that were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography.

As part of the U.S. Geological Survey's National Water-Quality Assessment Program, an investigation of the Yellowstone River Basin study unit is being conducted to document status and trends in surface- and ground-water quality. Efficient quantification of a variety of environmental and geographic characteristics of the study unit requires a digital map of the study-unit boundary that may be processed, together with other digital thematic maps (such as geology or land use), in a geographic information system (GIS). Digital boundary data for the Yellowstone River Basin study unit are included in this data release. The boundary follows drainage divides that were identified chiefly using 1:100,000-scale (50 m accuracy) hypsography.