Rio San Antonio
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 San Antonio River At Ortiz, CO: 18 gaps of 60+ days inside the record (3,912 days in all). Longest: Nov 1, 1920 to Sep 30, 1924 (1,430 days); Oct 1, 1931 to Apr 30, 1932 (213 days); Nov 1, 1929 to Apr 30, 1930 (181 days).
Context (8)
Show 8 notes
- fallback San Antonio River At Mouth, Near Manassa, CO: 58% of days come from usgs; codwr 33%, usbr_hydrodata 9% fill days usgs does not cover, so the source changes within the record.
- flatline San Antonio River At Mouth, Near Manassa, CO: 61 runs of 30+ days at exactly the same flow: 12.0 cfs for 69 days from Nov 24, 1925; 4.0 cfs for 62 days from Dec 1, 1924; 1.0 cfs for 62 days from Dec 1, 1930. Usually an estimated period (ice, a broken gauge) rather than measured daily flow.
- zero run San Antonio River At Mouth, Near Manassa, CO: 62 runs of 60+ days at zero flow; longest 262 days from Jul 16, 1963; 254 days from Jul 14, 1954. Usually real (a dry channel or no release), not missing data.
- flatline San Antonio River At Ortiz: 47 runs of 30+ days at exactly the same flow: 1.0 cfs for 92 days from Nov 30, 1963; 2.0 cfs for 70 days from Jan 1, 1960; 2.0 cfs for 70 days from Dec 6, 2001. Usually an estimated period (ice, a broken gauge) rather than measured daily flow.
- gap San Antonio River At Ortiz: 1 gap of 60+ days inside the record (64 days in all). Longest: Jan 7, 2020 to Mar 10, 2020 (64 days).
- zero run San Antonio River At Ortiz: 13 runs of 60+ days at zero flow; longest 139 days from Jun 17, 1951; 114 days from May 28, 2002. Usually real (a dry channel or no release), not missing data.
- flatline San Antonio River At Ortiz, CO: 60 runs of 30+ days at exactly the same flow: 2.8 cfs for 60 days from Jan 1, 1956; 2.0 cfs for 38 days from Oct 24, 1933; 1.0 cfs for 34 days from Aug 25, 1926. Usually an estimated period (ice, a broken gauge) rather than measured daily flow.
- zero run San Antonio River At Ortiz, CO: 9 runs of 60+ days at zero flow; longest 136 days from Jun 20, 1951; 113 days from Jun 10, 2026. Usually real (a dry channel or no release), not missing data.
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 |
|---|---|---|---|---|---|
| San Antonio River At Mouth, Near Manassa, CO | Conejos | codwr, usbr_hydrodata, usgs | 1923-04-02 | 2026-10-26 | 5397 |
| San Antonio River At Ortiz | Conejos | usbr_hydrodata | 1950-01-02 | 2026-10-26 | 3997 |
| San Antonio River At Ortiz, CO | Conejos | codwr, usace_cwms, usgs | 1919-09-29 | 2026-10-26 | 5029 |