Region
Chesapeake Bay Watershed
2
High Plains Aquifer
2
Long Island
2
Long Island Sound (N.Y. and Conn.)
2
Mississippi River Valley
2
Nebraska
2
New York (State)
2
Susquehanna River Watershed
2
United States
2
Arkansas
1
Clallam County
1
Idaho
1
Middle Atlantic States
1
Mississippi River
1
New Jersey
1
Potomac River Watershed
1
Washington (State)
1
West Windsor (Township)
1
Wyoming
1