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Hydrology Metering

Blue Mesa Dam · Gunnison River · CO

Blue Mesa Reservoir

Colorado's largest reservoir, drawn down repeatedly to feed the lower Colorado system.

Water surface elevation

7,422.1 ft

Bureau of Reclamation, daily · daily value, Aug 31

Water in storage

177,561 acre-feet

Bureau of Reclamation, daily · daily value, Aug 31

Share of capacity

18.9% full

against the 2019 survey capacity figure (USBR 2019 sedimentation survey)

Below full pool

97.3 ft

full pool at 7,519.4 ft

This month in the record

the lowest September in 57 years of record

monthly mean storage; record low 227,847 acre-feet (1977), record high 808,751 acre-feet (1970)

30-day trend

-1,870 af/day

storage, 2026-07-302026-08-29; over the year -779 af/day. Measured change, not a forecast.

Drought at the dam

D2 — Severe drought

US Drought Monitor at the dam's coordinates, released 2026-08-27; the feeding basin can differ.

full pool 7,519 ftcolumn continues below7,422

18.9% full

of capacity, by storage (2019 survey figure, USBR 2019 sedimentation survey). Sedimentation slowly shrinks real capacity.

The water line is elevation (USBR project datum); the percentage is storage ÷ capacity. They are different measures — a reservoir's volume is not linear in its depth, so the line's height in this column is not the percentage.

Snowpack in the feeding basin

Measured across the Gunnison headwaters.

Snow season

typically Oct 28 – May 27

0 in on the ground, 2026-09-01; median peak 14.8 in around Apr 15

Last winter's verdict

57% of median peak

water year 2026 — the snow that fed this year's pool

5 highest active SNOTEL stations in the basin (Slumgullion, Wager Gulch, Porphyry Creek, …), NRCS AWDB REST (SNOTEL), station set pinned 2026-08-31. Daily snow-water equivalent against the stations' own 30-year medians; off season the percent is withheld rather than divided by zero.

The last 120 days

Daily water-surface elevation in feet. The axis hugs the data — it does not start at zero. Source: committed snapshot (USBR RISE, retrieved 2026-08-31).

7418.87440.87462.8May 2Jul 1Aug 297423.1
See the numbers as a table
DateElevation (ft)
Aug 297423.08
Aug 287423.57
Aug 277424.08
Aug 267424.56
Aug 257425.05
Aug 247426.15
Aug 237426.15
Aug 227426.55
Aug 217427.00
Aug 207427.39
Aug 197427.86
Aug 187428.31
Aug 177428.79
Aug 167429.26
Aug 157429.72
Aug 147430.16
Aug 137430.62
Aug 127430.97
Aug 117431.39
Aug 107431.83
Aug 97432.25
Aug 87432.68
Aug 77433.04
Aug 67433.44
Aug 57433.84
Aug 47434.18
Aug 37434.53
Aug 27434.87
Aug 17435.20
Jul 317435.56

Most recent 30 days shown.

The whole record

Monthly mean elevation, Jan 1967 to Aug 2026. The axis spans the pools, not zero; elevations in USBR project datum. Months with fewer than 15 gaged days are dropped, and gaps in the record break the line. Source: USBR RISE, retrieved 2026-08-31.

monthly mean elevationpool reference lines
7,4247,4747,525Jan 1967Nov 1996Aug 2026full pool7,430
See the numbers as a table
MonthMean elevation (ft)Days gaged
Aug 20267429.529
Jul 20267440.531
Jun 20267451.930
May 20267457.331
Apr 20267463.830
Mar 20267467.731
Feb 20267467.428
Jan 20267467.631
Dec 20257466.531
Nov 20257465.230
Oct 20257465.131
Sep 20257470.630
Aug 20257478.331
Jul 20257486.031
Jun 20257487.730
May 20257482.631
Apr 20257480.230
Mar 20257480.431
Feb 20257481.428
Jan 20257482.731
Dec 20247483.031
Nov 20247482.530
Oct 20247484.731
Sep 20247489.330

Most recent 24 months shown; the full monthly series is in the page's API response.

Storage against capacity

Monthly mean storage in acre-feet, zero baseline. The dashed line is the 2019 survey capacity figure (USBR 2019 sedimentation survey) — sedimentation slowly shrinks real capacity. Storage can legitimately rise past a conservation-pool line when the flood pool is in use.

monthly mean storagecapacity
0492,524985,048Dec 1968Oct 1997Aug 2026capacity209,273
See the numbers as a table
MonthMean storage (acre-feet)Days gaged
Aug 2026209,27329
Jul 2026260,21331
Jun 2026320,12530
May 2026351,15531
Apr 2026390,71130
Mar 2026416,02431
Feb 2026414,07928
Jan 2026415,62731
Dec 2025408,54631
Nov 2025399,81130
Oct 2025399,35131
Sep 2025435,95630
Aug 2025489,78031
Jul 2025546,83031
Jun 2025560,31930
May 2025521,10031
Apr 2025503,18330
Mar 2025505,31331
Feb 2025512,67128
Jan 2025521,92231
Dec 2024524,34031
Nov 2024520,37130
Oct 2024537,22231
Sep 2024572,19330

Most recent 24 months shown.

Where these numbers come from

Readings at Blue Mesa Reservoir are the measuring agencies' own: each value above names its source (USGS gage, Bureau of Reclamation daily record, Army Corps project data, or this desk's committed copy) and its observation time in the reservoir's own time zone. The capacity figure is the 2019 survey USBR 2019 sedimentation survey number; sedimentation slowly shrinks real capacity, so the vintage travels with the percent.