The Yellowstone River Basin (YELL) study-unit in Wyoming, Montana and North Dakota, is part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. The long-term goals of this program are to describe the status and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources, and to provide a sound, scientific understanding of the primary factors affecting the quality of these resources. This web site will provide a focus for people who are interested in obtaining information about the program and obtaining access to data and publications relevant to water quality in the Yellowstone River Basin.

For details about the overall NAWQA Program, including program design and implementation, and early study unit findings since 1991, visit the NAWQA Program home page.