Hydrohistorian
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Rio Grande Floodway at San Marcial, Nm
River gage · SMFRIONM · USGS 08358400 · Division 3 · Water District 20
Live gage at DWR ↗ · USGS monitoring location ↗ · Download daily record (CSV)
Source DWR administrative record · verify at DWR station ↗ Source Independent agency measurement · verify at USGS ↗ Source Our computation, no independent reference · computed here from the screened record
Two different numbers, deliberately: Flowing now is raw 15-minute telemetry, provisional and unreviewed. Latest cached reading is the end of the verified daily record. They are never merged, and the verified series is the one the trend is computed on.
The record
Readings come from the weekly-refreshed cache, never fetched live — the date beside the value says exactly how fresh it is. The live gage is one click up.
Annual flow & trend
Chart: annual mean flow at Rio Grande Floodway at San Marcial, Nm, water years 1949 to 2026. The measured record is no trend at 29.86 cubic feet per second per decade. A Pettitt changepoint is detected around 1974. The underlying yearly values are available as a CSV download linked at the top of this page.
Where it sits
Location as DWR records it (5.0).
Provenance
DWR station abbreviation SMFRIONM; recorded station name “RIO GRANDE FLOODWAY AT SAN MARCIAL, NM”; operated by USGS. Daily flows from the DWR HydroBase snapshot plus CDSS REST updates, refreshed on the weekly cycle. Trend statistics are Mann-Kendall (Hamed-Rao corrected) with Sen's slope in native cfs, the same numbers as the basin Trends tab.