Region
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Michigan, Lake
10
North Dakota
10
Puerto Rico
10
Virginia
10
West Virginia
10
Death Valley (Calif. and Nev.)
9
Earth (Planet)
9
Illinois
9
Mexico, Gulf of
9
Asia
8
Iowa
8
Maryland
8
Oklahoma
8
Alabama
7
Canada
7
Colorado River (Colo.-Mexico)
7
Developing countries
7
Great Plains
7
Nebraska
7
New Hampshire
7
Australia
6
Chesapeake Bay (Md. and Va.)
6
England
6
Southern States
6
Yucca Mountain
6
Cape Cod
5
Columbia Glacier (Alaska)
5
Delaware
5
Delaware River (N.Y.-Del. and N.J.)
5
Great Lakes Region (North America)
5
Long Island
5
Maine
5
Poland
5
Rocky Mountains
5
San Joaquin Valley
5
Willamette River Watershed
5
Willamette River Watershed (Or.)
5
Africa
4
Albuquerque
4
Albuquerque Region
4
Alpine County
4
Atlantic Coast
4
Broome County
4
Columbia Plateau
4
Denver Basin
4
Erie, Lake
4
High Plains Aquifer
4
Latin America
4
Milford
4
Pacific Coast
4
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