Region
Oregon
5
Willamette River Watershed
4
Colorado
2
Green River Formation
2
Sandy River Watershed
2
United States
2
Wyoming
2
California
1
Columbia Aquifer
1
Columbia River
1
Culpeper Basin (Va. and Md.)
1
Delaware
1
Hatfield
1
Kansas
1
Los Angeles County
1
Louisiana
1
Massachusetts
1
Ozark Mountains
1
Portland
1
Potomac River
1
Prince William County
1
Running Gutter Brook
1
Virginia
1
Washington Region
1