East Fork San Juan River
Streamflow, conditions and background by watershed segment. Data through November 1, 2026.
Data gaps and disparities
Found automatically in the gauge records behind this river, and notes from a reviewer who checked them against other sources. Gauges need at least 26 weeks of daily data to appear on the Flow tab.
Warnings (1)
- warning: gap Ef San Juan R Ab Sand Creek, Nr Pagosa Spgs, CO: 1 gap of 60+ days inside the record (730 days in all). Longest: Oct 1, 1996 to Sep 30, 1998 (730 days).
Context (4)
Show 4 notes
- ended Discontinued gauges: 2 gauges have stopped reporting: East Fork San Juan River Nr Pagosa Springs, CO (last 1980); Ef San Juan R Ab Sand Creek, Nr Pagosa Spgs, CO (last 2003). Their segments rest on fewer gauges after those years.
- flatline East Fork San Juan River Nr Pagosa Springs, CO: 4 runs of 30+ days at exactly the same flow: 15.0 cfs for 72 days from Dec 20, 1935; 22.0 cfs for 31 days from Dec 1, 1942; 21.0 cfs for 31 days from Jan 1, 1943. Usually an estimated period (ice, a broken gauge) rather than measured daily flow.
- flatline Ef San Juan R Ab Sand Creek, Nr Pagosa Spgs, CO: 17 runs of 30+ days at exactly the same flow: 15.0 cfs for 62 days from Dec 1, 1961; 20.0 cfs for 53 days from Feb 1, 1962; 11.0 cfs for 48 days from Feb 1, 1963. Usually an estimated period (ice, a broken gauge) rather than measured daily flow.
- single gauge Upper San Juan: 64% of this segment's weeks rest on a single gauge; the segment value is that gauge in those weeks, and jumps when other gauges join or drop out.
Values removed (0)
A reading is removed automatically only when it is impossible (for example, a daily mean above the highest flow USGS recorded that water year). Low and zero flows are never removed: rivers here really do dry up.
None.
Gauges
Each row is one physical gauge; "published by" lists every agency copy that was merged into it.
| Gauge | Segment | Published by | First | Last | Weeks |
|---|---|---|---|---|---|
| Ef San Juan R Ab Sand Creek, Nr Pagosa Spgs, CO | Upper San Juan | codwr, usgs | 1956-10-01 | 2003-09-22 | 2348 |
| East Fork San Juan River Nr Pagosa Springs, CO | Upper San Juan | codwr, usbr_hydrodata, usgs | 1935-09-30 | 1980-09-22 | 2348 |