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Hydrology Metering

Choke Canyon Dam · Frio River · TX

Choke Canyon Reservoir

The larger half of Corpus Christi's two-lake system, and the half that has nearly run out — its level sets the city's drought stages.

Water surface elevation

191.1 ft

Texas Water Development Board, daily · daily value, Sep 30

Water in storage

145,588 acre-feet

Texas Water Development Board, daily · daily value, Sep 30

Share of conservation capacity

22.0% full

against the live feed conservation capacity figure (TWDB Water Data for Texas, statewide conditions feed)

Below full pool

29.4 ft

full pool at 220.5 ft

This month in the record

lower than 93% of the 42 Octobers on record

monthly mean storage; record low 29,382 acre-feet (1984), record high 694,844 acre-feet (2002)

30-day trend

-338 af/day

storage, 2026-08-18 → 2026-09-17; over the year +201 af/day. Measured change, not a forecast.

Drought at the dam

D2 — Severe drought

US Drought Monitor at the dam's coordinates, released 2026-09-17; the feeding basin can differ.

full pool 221 ftdead pool 136 ft191

22.0% full

of conservation capacity, by storage (live feed figure, TWDB Water Data for Texas, statewide conditions feed). Sedimentation slowly shrinks real capacity.

The water line is elevation (TWDB feed 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.

The last 120 days

Daily water-surface elevation in feet. The axis hugs the data — it does not start at zero. Source: committed snapshot (TWDB, retrieved 2026-09-17).

176.8185.7194.6May 21Jul 20Sep 17191.4
See the numbers as a table
DateElevation (ft)
Sep 17191.41
Sep 16191.42
Sep 15191.45
Sep 14191.48
Sep 13191.52
Sep 12191.55
Sep 11191.59
Sep 10191.63
Sep 9191.65
Sep 8191.68
Sep 7191.71
Sep 6191.75
Sep 5191.77
Sep 4191.80
Sep 3191.83
Sep 2191.87
Sep 1191.90
Aug 31191.93
Aug 30191.96
Aug 29192.00
Aug 28192.03
Aug 27192.07
Aug 26192.09
Aug 25192.12
Aug 24192.16
Aug 23192.20
Aug 22192.23
Aug 21192.26
Aug 20192.29
Aug 19192.32

Most recent 30 days shown.

The whole record

Monthly mean elevation, Oct 1999 to Sep 2026. The axis spans the pools, not zero; elevations in TWDB feed datum. Months with fewer than 15 gaged days are dropped, and gaps in the record break the line. Source: TWDB, retrieved 2026-09-17.

monthly mean elevationpool reference lines
131179226Oct 1999Apr 2013Sep 2026full pooldead pool192
See the numbers as a table
MonthMean elevation (ft)Days gaged
Sep 2026191.717
Aug 2026192.431
Jul 2026182.831
Jun 2026179.830
May 2026178.631
Apr 2026178.719
Mar 2026179.431
Feb 2026180.228
Jan 2026180.831
Dec 2025181.324
Nov 2025182.018
Oct 2025182.631
Sep 2025183.230
Aug 2025183.930
Jul 2025184.431
Jun 2025184.930
May 2025185.531
Apr 2025186.130
Mar 2025186.531
Feb 2025187.028
Jan 2025187.331
Dec 2024187.631
Nov 2024188.130
Oct 2024188.731

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 live feed conservation capacity figure (TWDB Water Data for Texas, statewide conditions feed) — sedimentation slowly shrinks real capacity. Storage can legitimately rise past a conservation-pool line when the flood pool is in use.

monthly mean storageconservation capacity
0365,013730,025Oct 1984Oct 2005Sep 2026capacity151,847
See the numbers as a table
MonthMean storage (acre-feet)Days gaged
Sep 2026151,84717
Aug 2026160,33831
Jul 202680,75131
Jun 202655,68830
May 202649,31331
Apr 202649,47830
Mar 202653,52931
Feb 202657,59328
Jan 202661,15931
Dec 202564,56331
Nov 202568,20330
Oct 202573,20831
Sep 202576,79330
Aug 202582,54431
Jul 202586,06031
Jun 202589,69430
May 202594,56731
Apr 202599,15130
Mar 2025102,65731
Feb 2025106,77528
Jan 2025109,21831
Dec 2024112,13231
Nov 2024116,41230
Oct 2024122,56331

Most recent 24 months shown.

Where these numbers come from

Readings at Choke Canyon 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 conservation capacity figure is the live feed TWDB Water Data for Texas, statewide conditions feed number — its basis: conservation capacity (TWDB); sedimentation slowly shrinks real capacity, so the vintage travels with the percent.