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Colorado River near Grand Lake

River gage · COLGRACO · USGS 09011000 · Division 5 · Water District 51 · Grand County

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

The record

Period of record
1904-10-01 → 1986-09-30
Daily values
24,106
Latest cached reading
63.0 cfs (1986-09-30)
Trend
decreasing, -6.08 cfs/decade (-7.7% of median)
Pettitt changepoint
~1938

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 Colorado River near Grand Lake, water years 1904 to 1986. The measured record is decreasing at -6.08 cubic feet per second per decade. A Pettitt changepoint is detected around 1938. The underlying yearly values are available as a CSV download linked at the top of this page.

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Where it sits

Location as DWR records it (5.0).

Provenance

DWR station abbreviation COLGRACO; recorded station name “COLORADO RIVER NEAR GRAND LAKE, CO.”; 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.