USGS Streamgage 09371010
San Juan River at Four Corners, CO
San Juan River at Four Corners, CO is USGS streamgage 09371010 in Colorado, monitoring river discharge in hydrologic subbasin 14080201. It sits on the San Juan River, alongside 9 other gauges Rivermatics tracks on the same river. It drains a watershed of about 14,600 square miles. Discharge records at this site go back to 1977. Typical flow runs near 1,245.5 cfs in July and 1,490.7 cfs in April, with the higher of the two arriving in April. Rivermatics issues a daily machine-learned flow outlook for this gauge, reaching 14 days ahead.
View live conditions & forecast →
Gauge details
- State
- Colorado
- Drainage area
- 14,600 sq mi
- Gauge elevation
- 4,614 ft
- Subbasin (HUC-8)
- 14080201
- Coordinates
- 37.00114, -109.02958
- USGS site number
- 09371010
- Records begin
- 1977-10-01 (49 years)
- Rivermatics forecast
- 14-day flow outlook
14-day flow forecast
Based on observations through for San Juan River at Four Corners, CO. Each day carries a median estimate and the band the model expects the flow to fall within — not a single number to plan against. Forecasts are re-issued daily; see the live screen for the current outlook.
| Date | Low p10 | Expected p50 | High p90 | Range |
|---|---|---|---|---|
| 538 | 576 | 617 | ||
| 517 | 577 | 662 | ||
| 504 | 580 | 697 | ||
| 535 | 658 | 1,073 | ||
| 626 | 939 | 1,865 | ||
| 698 | 1,127 | 2,384 | ||
| 778 | 1,328 | 2,817 | ||
| 769 | 1,264 | 2,360 | ||
| 708 | 1,079 | 1,881 | ||
| 666 | 968 | 1,598 | ||
| 616 | 874 | 1,406 | ||
| 573 | 795 | 1,235 | ||
| 547 | 759 | 1,195 | ||
| 531 | 737 | 1,180 |
All values in cubic feet per second (cfs). Estimates only — do not use them for navigation or for any safety, rescue, or emergency decision.
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 46 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 527.8 | 870.8 | 2,233.5 | |
| February | 538.3 | 918 | 2,683.8 | |
| March | 575 | 1,072.1 | 3,476.5 | |
| April | 548.6 | 1,490.7 | 5,185.7 | |
| May | 918.5 | 2,985.5 | 7,476.1 | |
| June | 756.8 | 3,927 | 8,641.7 | |
| July | 448.5 | 1,245.5 | 4,280 | |
| August | 390.7 | 862.4 | 2,604.8 | |
| September | 455.6 | 865.5 | 2,671.3 | |
| October | 601.3 | 907.2 | 1,842.3 | |
| November | 598.4 | 907.9 | 1,712.3 | |
| December | 557.4 | 894 | 1,961.9 |
All values in cubic feet per second (cfs).
Common questions
- When does San Juan River at Four Corners, CO normally run highest?
- June, on the long-term record. The median daily flow that month is about 3,927 cfs, against 862.4 cfs in August, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for San Juan River at Four Corners, CO?
- It depends on the month. In January, half of days historically fall near 870.8 cfs, with the middle 80% of days between 527.8 and 2,233.5 cfs. The month-by-month table on this page gives the full range.
- How long has San Juan River at Four Corners, CO been measured?
- Discharge records at USGS site 09371010 begin in 1977, about 49 years, covering roughly 9,160 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Is there a flow forecast for San Juan River at Four Corners, CO?
- Yes. Rivermatics trains a machine-learned model — a temporal-fusion transformer — on this basin's observed flows, weather, and snowpack, and issues a daily flow outlook reaching 14 days ahead: a median estimate inside a confidence band, not a single number to bet on. Every forecast is scored against days the model never trained on, and that track record is published on the live gauge screen. Open live conditions to see the current outlook.
- Where is San Juan River at Four Corners, CO?
- The gauge sits at 37.00114, -109.02958, in Colorado, in hydrologic subbasin 14080201, at an elevation of about 4,614 feet, draining roughly 14,600 square miles.
- Can I use San Juan River at Four Corners, CO data for flood or safety decisions?
- No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.
Upstream and downstream on the San Juan River
Every gauge Rivermatics tracks on this river, ordered by drainage area — upstream first. See the San Juan River in full.
- San Juan River at Pagosa Springs, CO 281 sq mi
- San Juan River near Carracas, CO 1,250 sq mi
- San Juan River near Archuleta, NM 3,260 sq mi
- San Juan River at Bloomfield, NM 5,350 sq mi
- San Juan River at Farmington, NM 7,240 sq mi
- San Juan River at Shiprock, NM 12,900 sq mi
- San Juan River at Four Corners, CO this page
- San Juan River near Bluff, UT 23,000 sq mi
- San Juan River below Piute Farms Wash near Monument Vly, UT 24,000 sq mi
- San Juan River near Co Rd 119 at Pagosa Springs, CO