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Colorado River Bl Shadow Mountain Reservoir

Reservoir gage · COLSHACO · USGS 09015000 · 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
1947-10-01 → 2026-08-14
Daily values
8,718
Latest cached reading
42.5 cfs (2026-08-14)
Trend
no trend, -2.67 cfs/decade (-1.9% of median)

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 Bl Shadow Mountain Reservoir, water years 1947 to 2026. The measured record is no trend at -2.67 cubic feet per second per decade. 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 COLSHACO; recorded station name “COLORADO RIVER BL SHADOW MOUNTAIN RESERVOIR, 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.