New England
New England
New England
(01)
(01)
(01)
Missouri
Missouri
Missouri
(10)
(10)
(10)
California
California
California
Mid-Atlantic
Mid-Atlantic
Mid-Atlantic
(02)
(02)
(02)
South Atlantic-Gulf
South Atlantic-Gulf
South Atlantic-Gulf
(03)
(03)
(03)
Caribbean
Caribbean
Caribbean
(includes
(includes
(includes
V
V
V
irgin Islands)
irgin Islands)
irgin Islands)
(21)
(21)
(21)
Great Lakes
Great Lakes
Great Lakes
(04)
(04)
(04)
Ohio
Ohio
Ohio
(05)
(05)
(05)
T
T
T
ennessee
ennessee
ennessee
(06)
(06)
(06)
Upper
Upper
Upper
Mississippi
Mississippi
Mississippi
(07)
(07)
(07)
Souris-Red-Rainy
Souris-Red-Rainy
Souris-Red-Rainy
(09)
(09)
(09)
Lower Mississippi
Lower Mississippi
Lower Mississippi
(08)
(08)
(08)
T
T
T
exas-Gulf
exas-Gulf
exas-Gulf
(12)
(12)
(12)
Arkansas-White-Red
Arkansas-White-Red
Arkansas-White-Red
(11)
(11)
(11)
Pacific Northwest
Pacific Northwest
Pacific Northwest
(17)
(17)
(17)
Rio Grande
Rio Grande
Rio Grande
(13)
(13)
(13)
Upper
Upper
Upper
Colorado
Colorado
Colorado
(14)
(14)
(14)
Lower
Lower
Lower
Colorado
Colorado
Colorado
(15)
(15)
(15)
(18)
(18)
(18)
Great Basin
Great Basin
Great Basin
(16)
(16)
(16)
Alaska
Alaska
Alaska
(19)
(19)
(19)
Hawaii
Hawaii
Hawaii
(20)
(20)
(20)
Hawaii
(20)
Water-resources region and region number (in parentheses)
EXPLANATION