Hydrohistorian
The water itself
Flow says how much; these sensors say what. USGS runs continuous
temperature, conductance, dissolved-oxygen and turbidity probes at
201 Colorado sites. This is the latest reading at each,
provisional until USGS reviews it, refreshed every three hours.
Below the sensors: where sampled chemistry (nutrients, metals,
bacteria) has been collected, watershed by watershed, from the
Water Quality Portal. Drinking water is on each
provider's page.
201
sensor sites reporting
196
water temperature
127
specific conductance
57
dissolved oxygen
43
turbidity
Source: USGS National Water Information System instantaneous values, fetched 2026-09-09 18:23 UTC; public domain. A site with a Hydrohistorian gage page links to it; the rest link to USGS. Districts are assigned by location.
Where water has been sampled
Source Register of another agency · fetched 2026-09-09 · verify at Water Quality Portal ↗
The Water Quality Portal holds every sampling station USGS and the state, tribes and volunteer programmes have filed. Statewide it will not answer a dated query, so this is counted watershed by watershed: 66,737 stations across 88 HUC8 watersheds (39,135 USGS, 27,602 state and other), of which 3,363 reported a sample in the last 5 years on the state and tribal side. Results are not fetched here; each row links the portal's own file of its stations.
| Watershed (HUC8) | Districts | Stations | USGS | State, tribal, other | Sampled, last 5 y | Most active |
|---|---|---|---|---|---|---|
| Arkansas Headwaters 11020001 | Arkansas: Headwaters to Salida, Wet Mountain Valley, Arkansas: Salida to Portland | 6,859 | 1,062 | 5,797 | 176 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Middle South Platte-Cherry Creek 10190003 | South Platte: Denver Gage to Greeley, South Platte Cheesman to Denver Gage, South Platte: Greeley to Balzac | 6,611 | 5,718 | 893 | 203 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Animas 14080104 | Animas River Basin | 4,600 | 454 | 4,146 | 317 | Bonita Peak Mining |
| Upper South Platte 10190002 | North Fork of South Platte, Bear Creek, South Platte Cheesman to Denver Gage | 3,600 | 2,666 | 934 | 159 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| St. Vrain 10190005 | Boulder Creek, St. Vrain Creek, South Platte: Denver Gage to Greeley | 2,809 | 1,822 | 987 | 106 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Colorado Headwaters-Plateau 14010005 | Roan Creek Basin, Divide Creek, Rifle/Elk/Parachute Creeks, Lower Colorado River | 2,357 | 1,564 | 793 | 162 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Fountain 11020003 | Fountain Creek | 1,802 | 1,473 | 329 | 159 | USGS Colorado Water Science Center |
| Clear 10190004 | Clear Creek | 1,709 | 788 | 921 | 77 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Arkansas-John Martin Reservoir 11020009 | Arkansas: Las Animas to Stateline, Arkansas: Fowler to Las Animas | 1,641 | 1,326 | 315 | 71 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Yampa 14050001 | Middle Yampa River, Upper Yampa River, Lower Yampa River | 1,596 | 1,202 | 394 | 94 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Arkansas 11020002 | Saint Charles, Arkansas: Salida to Portland, Arkansas: Portland to Fowler, Fountain Creek | 1,561 | 1,190 | 371 | 65 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Gunnison 14020002 | Upper Gunnison River, East River Basin, North Fork/Tribs. | 1,459 | 302 | 1,157 | 117 | USGS Colorado Water Science Center |
| Cache La Poudre 10190007 | Cache La Poudre River, Laramie River, Sand Creek | 1,425 | 955 | 470 | 95 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Arkansas-Lake Meredith 11020005 | Arkansas: Portland to Fowler, Arkansas: Fowler to Las Animas, Fountain Creek | 1,342 | 1,176 | 166 | 40 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| San Luis 13010003 | San Luis Creek, Trinchera Creek, Carnero Creek, Rio Grande | 1,210 | 904 | 306 | 16 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Colorado Headwaters 14010001 | Upper Colorado/Fraser Rivers, Muddy/Troublesome Creeks, Tribs. North of Colorado River, Piney/Cottonwood Creeks | 1,156 | 525 | 631 | 124 | USGS Colorado Water Science Center |
| North Fork Republican 10250002 | Arikaree River | 1,086 | 1,040 | 46 | 6 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Eagle 14010003 | Eagle River Basin | 1,053 | 364 | 689 | 115 | Eagle River Watershed Council (ERWC) (Volunteer) |
| South Platte Headwaters 10190001 | Upper South Platte | 1,047 | 426 | 621 | 31 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Big Thompson 10190006 | Big Thompson River, St. Vrain Creek | 973 | 329 | 644 | 91 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Uncompahgre 14020006 | Upper Uncompahgre River, Lower Uncompahgre River | 956 | 473 | 483 | 64 | Colorado River Watch |
| Middle South Platte-Sterling 10190012 | South Platte: Balzac to Stateline, South Platte: Greeley to Balzac | 933 | 772 | 161 | 50 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Piceance-Yellow 14050006 | White River Basin | 928 | 844 | 84 | 20 | USGS Colorado Water Science Center |
| Alamosa-Trinchera 13010002 | Alamosa La Jara, Culebra Creek, Trinchera Creek, Rio Grande +1 | 839 | 486 | 353 | 34 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Blue 14010002 | Blue River Basin | 835 | 339 | 496 | 62 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| South Fork Republican 10250003 | Republican River | 754 | 722 | 32 | 5 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Purgatoire 11020010 | Purgatoire River, Arkansas: Fowler to Las Animas | 749 | 583 | 166 | 45 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Roaring Fork 14010004 | Roaring Fork River Basin | 748 | 289 | 459 | 132 | Colorado River Watch |
| Lower Gunnison 14020005 | Lower Gunnison River, North Fork/Tribs., Lower Uncompahgre River | 681 | 444 | 237 | 77 | USGS Colorado Water Science Center |
| Upper San Juan 14080101 | Navajo River Basin, San Juan River Basin, Los Pinos River Basin, Navajo Reservoir +1 | 670 | 354 | 316 | 82 | Southern Ute Tribe |
| Bear 11040005 | Arkansas: Las Animas to Stateline | 668 | 655 | 13 | 3 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| East-Taylor 14020001 | East River Basin | 579 | 210 | 369 | 49 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper White 14050005 | White River Basin | 572 | 453 | 119 | 32 | USGS Colorado Water Science Center |
| San Miguel 14030003 | San Miguel River Basin | 569 | 316 | 253 | 36 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Mancos 14080107 | Mancos River Basin | 559 | 105 | 454 | 74 | Mountain Studies Institute (MSI) |
| Arikaree 10250001 | Arikaree River | 527 | 498 | 29 | 0 | |
| Chico 11020004 | Fountain Creek, Arkansas: Portland to Fowler | 509 | 484 | 25 | 59 | USGS Colorado Water Science Center |
| Lower Yampa 14050002 | Lower Yampa River, Little Snake River, Green River Basin | 505 | 260 | 245 | 5 | USGS Colorado Water Science Center |
| North Fork Gunnison 14020004 | North Fork/Tribs. | 429 | 270 | 159 | 24 | USGS Colorado Water Science Center |
| Upper Dolores 14030002 | Disappointment Creek Basin, Paradox Creek, West Dolores Creek/Tribs. | 421 | 119 | 302 | 34 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Bijou 10190011 | South Platte: Greeley to Balzac | 400 | 386 | 14 | 8 | USGS Colorado Water Science Center |
| Rio Grande Headwaters 13010001 | Rio Grande | 389 | 72 | 317 | 47 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| North Platte Headwaters 10180001 | North Platte River Basin | 383 | 162 | 221 | 12 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Frenchman 10250005 | Arikaree River | 370 | 366 | 4 | 3 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Huerfano 11020006 | Huerfano River, Cucharas River, Arkansas: Portland to Fowler | 339 | 167 | 172 | 25 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Lower White 14050007 | White River Basin | 339 | 210 | 129 | 7 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| McElmo 14080202 | McElmo Creek Basin | 332 | 59 | 273 | 15 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Big Sandy 11020011 | Arkansas: Las Animas to Stateline | 305 | 248 | 57 | 8 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Saguache 13010004 | Saguache Creek, Carnero Creek, San Luis Creek, Rio Grande | 290 | 227 | 63 | 10 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Crow 10190009 | South Platte: Greeley to Balzac | 278 | 261 | 17 | 2 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| North Fork Smoky Hill 10260002 | Republican River | 263 | 263 | 0 | 1 | USGS Colorado Water Science Center |
| Lone Tree-Owl 10190008 | South Platte: Greeley to Balzac | 245 | 234 | 11 | 4 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| South Fork Beaver 10250012 | Republican River | 217 | 215 | 2 | 2 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Beaver 10190013 | South Platte: Greeley to Balzac | 211 | 193 | 18 | 8 | Ducks Unlimited (Volunteer) |
| Sand Arroyo 11040004 | Cimarron River Basin | 206 | 206 | 0 | 1 | USGS Colorado Water Science Center |
| North Fork Cimarron 11040003 | Cimarron River Basin | 185 | 185 | 0 | 0 | |
| Tomichi 14020003 | Tomichi Creek | 180 | 70 | 110 | 25 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Rush 11020012 | Arkansas: Las Animas to Stateline | 170 | 105 | 65 | 1 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Piedra 14080102 | Piedra River Basin, Navajo Reservoir | 160 | 93 | 67 | 6 | Southern Ute Tribe |
| Conejos 13010005 | Conejos Creek | 153 | 70 | 83 | 14 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Kiowa 10190010 | South Platte: Greeley to Balzac | 150 | 143 | 7 | 2 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Middle San Juan 14080105 | La Plata River Basin | 150 | 88 | 62 | 9 | Colorado River Watch |
| Horse 11020008 | Arkansas: Fowler to Las Animas | 149 | 104 | 45 | 0 | |
| Little Snake 14050003 | Slater/Timberlake Creeks, Little Snake River | 149 | 67 | 82 | 6 | Mountain Studies Institute (MSI) |
| Apishapa 11020007 | Apishapa River, Arkansas: Fowler to Las Animas | 111 | 80 | 31 | 2 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Two Butte 11020013 | Arkansas: Las Animas to Stateline | 110 | 98 | 12 | 2 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper Green-Flaming Gorge Reservoir 14040106 | Green River Basin | 109 | 10 | 99 | 1 | USGS Colorado Water Science Center |
| Lower Dolores 14030004 | Dolores River Basin | 103 | 66 | 37 | 11 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Little Beaver 10250013 | Republican River | 99 | 99 | 0 | 0 | |
| Pawnee 10190014 | South Platte: Balzac to Stateline | 95 | 92 | 3 | 1 | USGS Colorado Water Science Center |
| Ladder 10260004 | Republican River | 73 | 71 | 2 | 0 | |
| Upper Cimarron 11040002 | Cimarron River Basin | 73 | 71 | 2 | 0 | |
| Lower South Platte 10190018 | South Platte: Balzac to Stateline | 71 | 53 | 18 | 3 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Stinking Water 10250006 | Arikaree River | 71 | 69 | 2 | 0 | |
| Lower San Juan-Four Corners 14080201 | McElmo Creek Basin | 65 | 15 | 50 | 4 | USGS New Mexico Water Science Center |
| Smoky Hill Headwaters 10260001 | Republican River | 54 | 53 | 1 | 1 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Upper North Platte 10180002 | North Platte River Basin | 49 | 24 | 25 | 3 | USGS Colorado Water Science Center |
| Westwater Canyon 14030001 | Little Dolores River | 49 | 12 | 37 | 1 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Whitewoman 11030002 | Arkansas: Las Animas to Stateline | 47 | 39 | 8 | 0 | |
| Vermilion 14040109 | Green River Basin | 43 | 12 | 31 | 0 | |
| Upper Laramie 10180010 | Sand Creek, Laramie River | 40 | 5 | 35 | 3 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Cimarron Headwaters 11040001 | Cimarron River Basin | 39 | 27 | 12 | 3 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Montezuma 14080203 | McElmo Creek Basin | 37 | 31 | 6 | 0 | |
| Upper Rio Grande 13020101 | Culebra Creek | 27 | 27 | 0 | 0 | |
| Lower Lodgepole 10190016 | South Platte: Balzac to Stateline | 19 | 15 | 4 | 1 | Colorado Dept. of Public Health & Environment-WQCD (State) |
| Sidney Draw 10190017 | South Platte: Balzac to Stateline | 10 | 10 | 0 | 0 | |
| Rio Chama 13020102 | Conejos Creek | 3 | 0 | 3 | 0 | |
| Lower Green-Diamond 14060010 | Green River Basin | 0 | 0 | 0 | 0 |
Source: Water Quality Portal (USGS, EPA and the National Water Quality Monitoring Council), station search and the five-year summary profile, fetched 2026-09-09; public domain, citation requested by the portal. The five-year figure is the STORET/WQX side only, and legacy portal profiles stop carrying USGS samples added after March 2024. Watersheds join districts by area (data/district_huc8.json); a watershed that crosses the state line is counted for its Colorado stations only. Report a problem →