01 New England Region

0101 St. John
0102 Penobscot
0103 Kennebec
0104 Androscoggin
0105 Maine Coastal
0106 Saco
0107 Merrimack
0108 Connecticut

010801 Upper Connecticut 010802 Lower Connecticut 0109 Massachusetts-Rhode Island Coastal
0110 Connecticut Coastal
0111 St. Francois

02 Mid-Atlantic Region

0201 Richelieu
0202 Upper Hudson
0203 Lower Hudson-Long Island

020301 Lower Hudson 020302 Long Island 0204 Delaware

020401 Upper Delaware 020402 Lower Delaware 020403 New Jersey Coastal 0205 Susquehanna

020501 Upper Susquehanna 020502 West Branch Susquehanna 020503 Lower Susquehanna 0206 Upper Chesapeake
0207 Potomac
0208 Lower Chesapeake

020801 Lower Chesapeake 020802 James

03 South Atlantic-Gulf Region

0301 Chowan-Roanoke

030101 Roanoke 030102 Albemarle-Chowan 0302 Neuse-Pamlico

030201 Pamlico 030202 Neuse 0303 Cape Fear
0304 Pee Dee

030401 Upper Pee Dee 030402 Lower Pee Dee 0305 Edisto-Santee

030501 Santee 030502 Edisto-South Carolina Coastal 0306 Ogeechee-Savannah

030601 Savannah 030602 Ogeechee 0307 Altamaha - St. Marys

030701 Altamaha 030702 St. Marys - Satilla 0308 St. Johns

030801 St. Johns 030802 East Florida Coastal 0309 Southern Florida

030901 Kissimmee 030902 Southern Florida 0310 Peace-Tampa Bay

031001 Peace 031002 Tampa Bay 0311 Suwannee

031101 Aucilla-Waccasassa 031102 Suwannee 0312 Ochlockonee
0313 Apalachicola
0314 Choctawhatchee - Escambia

031401 Florida Panhandle Coastal 031402 Choctawhatchee 031403 Escambia 0315 Alabama

031501 Coosa-Tallapoosa 031502 Alabama 0316 Mobile - Tombigbee

031601 Black Warrior - Tombigbee 031602 Mobile Bay- Tombigbee 0317 Pascagoula
0318 Pearl

04 Great Lakes Region

0401 Western Lake Superior

040101 Northwestern Lake Superior 040102 St. Louis 040103 Southwestern Lake Superior 0402 Southern Lake Superior-Lake Superior

040201 Southcentral Lake Superior 040202 Southeastern Lake Superior 040203 Lake Superior 0403 Northwestern Lake Michigan

040301 Northwestern Lake Michigan 040302 Fox 0404 Southwestern Lake Michigan
0405 Southeastern Lake Michigan
0406 Northeastern Lake Michigan

040601 Northeastern Lake Michigan 040602 Lake Michigan 0407 Northwestern Lake Huron
0408 Southwestern Lake Huron

040801 Southwestern Lake Huron 040802 Saginaw 040803 Lake Huron 0409 St. Clair-Detroit
0410 Western Lake Erie
0411 Southern Lake Erie
0412 Eastern Lake Erie-Lake Erie

041201 Eastern Lake Erie 041202 Lake Erie 0413 Southwestern Lake Ontario
0414 Southeastern Lake Ontario

041401 Southeastern Lake Ontario 041402 Oswego 0415 Northeastern Lake Ontario

041501 Northeastern Lake Ontario 041502 Lake Ontario 041503 St. Lawrence

05 Ohio Region

0501 Allegheny
0502 Monongahela
0503 Upper Ohio

050301 Upper Ohio-Beaver 050302 Upper Ohio-Little Kanawha 0504 Muskingum
0505 Kanawha
0506 Scioto
0507 Big Sandy-Guyandotte

050701 Guyandotte 050702 Big Sandy 0508 Great Miami
0509 Middle Ohio

050901 Middle Ohio-Raccoon 050902 Middle Ohio-Little Miami 0510 Kentucky-Licking

051001 Licking 051002 Kentucky 0511 Green
0512 Wabash

051201 Wabash 051202 Patoka-White 0513 Cumberland

051301 Upper Cumberland 051302 Lower Cumberland 0514 Lower Ohio

051401 Lower Ohio-Salt 051402 Lower Ohio

06 Tennessee Region

0601 Upper Tennessee

060101 French Broad-Holston 060102 Upper Tennessee 0602 Middle Tennessee-Hiwassee
0603 Middle Tennessee-Elk
0604 Lower Tennessee

07 Upper Mississippi Region

0701 Mississippi Headwaters

070101 Mississippi Headwaters 070102 Upper Mississippi-Crow-Rum 0702 Minnesota
0703 St. Croix
0704 Upper Mississippi-Black-Root
0705 Chippewa
0706 Upper Mississippi-Maquoketa-Plum
0707 Wisconsin
0708 Upper Mississippi-Iowa-Skunk-Wapsipinicon

070801 Upper Mississippi-Skunk-Wapsipinicon 070802 Iowa 0709 Rock
0710 Des Moines
0711 Upper Mississippi-Salt
0712 Upper Illinois
0713 Lower Illinois
0714 Upper Mississippi-Kaskaskia-Meramec

071401 Upper Mississippi-Meramec 071402 Kaskaskia

08 Lower Mississippi Region

0801 Lower Mississippi-Hatchie

080101 Lower Mississippi-Memphis 080102 Hatchie-Obion 0802 Lower Mississippi - St. Francis

080201 Lower Mississippi-Helena 080202 St. Francis 080203 Lower White 080204 Lower Arkansas 0803 Lower Mississippi - Yazoo

080301 Lower Mississippi-Greenville 080302 Yazoo 0804 Lower Red - Ouachita

080401 Upper Ouachita 080402 Lower Ouachita 080403 Lower Red 0805 Boeuf-Tensas
0806 Lower Mississippi - Big Black

080601 Lower Mississippi-Natchez 080602 Big Black - Homochitto 0807 Lower Mississippi-Lake Maurepas

080701 Lower Mississippi-Baton Rouge 080702 Lake Maurepas 080703 Lower Grand 0808 Louisiana Coastal

080801 Atchafalaya - Vermilion 080802 Calcasieu - Mermentau 0809 Lower Mississippi

080901 Lower Mississippi-New Orleans 080902 Lake Pontchartrain 080903 Central Louisiana Coastal

09 Souris-Red-Rainy Region

0901 Souris
0902 Red

090201 Upper Red 090202 Devils Lake-Sheyenne 090203 Lower Red 0903 Rainy

10 Missouri Region

1001 Saskatchewan
1002 Missouri Headwaters
1003 Missouri-Marias

100301 Upper Missouri 100302 Marias 1004 Missouri-Musselshell

100401 Fort Peck Lake 100402 Musselshell 1005 Milk
1006 Missouri-Poplar
1007 Upper Yellowstone
1008 Big Horn
1009 Powder-Tongue

100901 Tongue 100902 Powder 1010 Lower Yellowstone
1011 Missouri-Little Missouri

101101 Lake Sakakawea 101102 Little Missouri 1012 Cheyenne

101201 Cheyenne 101202 Belle Fourche 1013 Missouri-Oahe

101301 Lake Oahe 101302 Cannonball-Heart-Knife 101303 Grand-Moreau 1014 Missouri-White

101401 Fort Randall Reservoir 101402 White 1015 Niobrara
1016 James
1017 Missouri-Big Sioux

101701 Lewis and Clark Lake 101702 Big Sioux 1018 North Platte
1019 South Platte
1020 Platte

102001 Middle Platte 102002 Lower Platte 1021 Loup
1022 Elkhorn
1023 Missouri-Little Sioux
1024 Missouri-Nishnabotna
1025 Republican
1026 Smoky Hill
1027 Kansas

102701 Kansas 102702 Big Blue 1028 Chariton-Grand

102801 Grand 102802 Chariton 1029 Gasconade-Osage

102901 Osage 102902 Gasconade 1030 Lower Missouri

103001 Lower Missouri-Blackwater 103002 Lower Missouri

11 Arkansas-White-Red Region

1101 Upper White
1102 Upper Arkansas
1103 Middel Arkansas
1104 Upper Cimarron
1105 Lower Cimarron
1106 Arkansas - Keystone
1107 Neosho - Verdigris

110701 Verdigris 110702 Neosho 1108 Upper Canadian
1109 Lower Canadian

110901 Middle Canadian 110902 Lower Canadian 1110 North Canadian

111001 Upper Beaver 111002 Lower Beaver 111003 Lower North Canadian 1111 Lower Arkansas

111101 Robert S 111102 Lower Arkansas-Fourche La Fave 1112 Red headwaters

111201 Prairie Dog Town Fork Red 111202 Salt Fork Red 111203 North Fork Red 1113 Red - Washita

111301 Red-Pease 111302 Red-Lake Texoma 111303 Washita 1114 Red-Sulphur

111401 Red-Little 111402 Red-Saline 111403 Big Cypress - Sulphur

12 Texas-Gulf Region

1201 Sabine
1202 Neches
1203 Trinity

120301 Upper Trinity 120302 Lower Trinity 1204 Galveston Bay-San Jacinto

120401 San Jacinto 120402 Galveston Bay-Sabine Lake 1205 Brazos headwaters
1206 Middle Brazos

120601 Middle Brazos-Clear Fork 120602 Middle Brazos-Bosque 1207 Lower Brazos

120701 Lower Brazos 120702 Little 1208 Upper Colorado
1209 Lower Colorado-San Bernard Coastal

120901 Middle Colorado-Concho 120902 Middle Colorado-Llano 120903 Lower Colorado 120904 San Bernard Coastal 1210 Central Texas Coastal

121001 Lavaca 121002 Guadalupe 121003 San Antonio 121004 Central Texas Coastal 1211 Nueces-Southwestern Texas Coastal

121101 Nueces 121102 Southwestern Texas Coastal

13 Rio Grande Region

1301 Rio Grande headwaters
1302 Rio Grande-Elephant Butte

130201 Upper Rio Grande 130202 Rio Grande-Elephant Butte 1303 Rio Grande-Mimbres

130301 Rio Grande-Caballo 130302 Mimbres 1304 Rio Grande-Amistad

130401 Rio Grande-Fort Quitman 130402 Rio Grande-Amistad 130403 Devils 1305 Rio Grande closed basins
1306 Upper Pecos
1307 Lower Pecos
1308 Rio Grande-Falcon
1309 Lower Rio Grande

14 Upper Colorado Region

1401 Colorado headwaters
1402 Gunnison
1403 Upper Colorado-Dolores
1404 Great Divide - Upper Green

140401 Upper Green 140402 Great Divide closed basin 1405 White-Yampa
1406 Lower Green
1407 Upper Colorado-Dirty Devil
1408 San Juan

140801 Upper San Juan 140802 Lower San Juan

15 Lower Colorado Region

1501 Lower Colorado-Lake Mead
1502 Little Colorado
1503 Lower Colorado

150301 Lower Colorado 150302 Bill Williams 1504 Upper Gila
1505 Middle Gila

150501 Middle Gila 150502 San Pedro-Willcox 150503 Santa Cruz 1506 Salt

150601 Salt 150602 Verde 1507 Lower Gila

150701 Lower Gila-Agua Fria 150702 Lower Gila 1508 Sonora

150801 Rio Sonoyta 150802 Rio De La Concepcion 150803 Rio De Bavispe

16 Great Basin Region

1601 Bear

160101 Upper Bear 160102 Lower Bear 1602 Great Salt Lake

160201 Weber 160202 Jordan 160203 Great Salt Lake 1603 Escalante Desert-Sevier Lake
1604 Black Rock Desert-Humboldt

160401 Humboldt 160402 Black Rock Desert 1605 Central Lahontan

160501 Truckee 160502 Carson 160503 Walker 1606 Central Nevada Desert Basins

17 Pacific Northwest Region

1701 Kootenai-Pend Oreille-Spokane

170101 Kootenai 170102 Pend Oreille 170103 Spokane 1702 Upper Columbia
1703 Yakima
1704 Upper Snake

170401 Snake headwaters 170402 Upper Snake 1705 Middle Snake

170501 Middle Snake-Boise 170502 Middle Snake-Powder 1706 Lower Snake

170601 Lower Snake 170602 Salmon 170603 Clearwater 1707 Middle Columbia

170701 Middle Columbia 170702 John Day 170703 Deschutes 1708 Lower Columbia
1709 Willamette
1710 Oregon-Washington Coastal

171001 Washington Coastal 171002 Northern Oregon Coastal 171003 Southern Oregon Coastal 1711 Puget Sound
1712 Oregon closed basins

18 California Region

1801 Klamath-Northern California Coastal

180101 Northern California Coastal 180102 Klamath 1802 Sacramento
180201 Lower Sacramento 1803 Tulare-Buena Vista Lakes
1804 San Joaquin
1805 San Francisco Bay
1806 Central California Coastal
1807 Southern California Coastal

180701 Ventura-San Gabriel Coastal 180702 Santa Ana 180703 Laguna-San Diego Coastal 1808 North Lahontan
1809 Northern Mojave-Mono Lake

180901 Mono-Owens Lakes 180902 Northern Mojave 1810 Southern Mojave-Salton Sea

181001 Southern Mojave 181002 Salton Sea
8 JUNE 1999, last updated on 9 AUG 2000 D.L. Gustafson
dlg@rapid.msu.montana.edu