Region
Colorado
234
United States
178
California
61
Colorado River Watershed (Colo.-Mexico)
57
West (U.S.)
42
Florida
29
New Mexico
26
Colorado River (Colo.-Mexico)
24
Nevada
24
Kansas
22
Washington (State)
21
Missouri River Watershed
20
Wyoming
20
Colorado River Valley (Colo.-Mexico)
19
Pennsylvania
18
Tennessee
18
Utah
18
Louisiana
17
South Dakota
17
Montana
16
New York (State)
16
Texas
16
Missouri River
14
Oklahoma
13
Arizona
12
Columbia River Watershed
12
Idaho
12
Illinois
12
Oregon
12
South Platte River Valley (Colo. and Neb.)
12
North Dakota
11
Missouri
10
Northwest, Pacific
10
Rhode Island
10
Ohio
9
Yampa River Watershed
9
Alaska
8
Arkansas
8
China
8
India
8
Nebraska
8
Southwest, New
8
Arkansas River Watershed
7
Developing countries
7
Dolores River (Colo. and Utah)
7
Georgia
7
Michigan
7
North Carolina
7
Puerto Rico
7
Massachusetts
6
more ...