Drainage-area boundaries for selected sampling stations, scale 1:100,000, Yellowstone River Basin, Montana, North Dakota, and Wyoming

Release Date

2001-01-01

Time Period

1996

Publication Date

2023-09-15

Zelt, R.B. and Hallberg, L.L., 2001, Drainage-area boundaries for selected sampling stations, scale 1:100,000, Yellowstone River Basin, Montana, North Dakota, and Wyoming: U.S. Geological Survey data release, https://doi.org/10.5066/P95RARCB.

The U.S. Geological Survey (USGS) began full implementation of the National Water-Quality Assessment (NAWQA) program in 1991. The program objectives are to describe current water-quality conditions and trends over time; and to improve our understanding of the natural and human factors that affect water quality. The Yellowstone River Basin (YRB) is one of more than 50 areas to be studied for this program. Among the principal program activities, water, bed-sediment, and tissue samples are collected from streams or lakes at specific sampling stations and analyzed for a large suite of chemical and physical constituents. 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 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). For NAWQA, sampling stations typically have drainage areas ranging from 50 to 500 km2 (indicator sites) or are located downstream of large river basins. 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. Therefore, the digital drainage-area data for 45 selected stream-sampling stations in the Yellowstone River Basin were based chiefly on 1:100,000-scale (50 m accuracy) hypsography.

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