U.S. Dept. of the Interior, U.S. Geological Survey, Water Resources Division,
Water resources data. Pennsylvania
Water resources data. Pennsylvania (Online)
Pennsylvania
Water-data report
Annual water data reports
U.S. Geological Survey water-data report.
Geological Survey (U.S.)
Geological Survey (U.S.). Water Resources Division.
Pennsylvania. Department of Environmental Protection.
United States. Army. Corps of Engineers. Baltimore District.
United States. Army. Corps of Engineers. Pittsburgh District.
U.S. Department of the Interior, U.S. Geological Survey.
2005
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1981
Water resources data. Pennsylvania