Lake Corpus Christi & Choke Canyon Water Levels

Live reservoir storage & Nueces Basin river flows · independent, unofficial

Last updated: Jul 30, 3:58 AM CT

1 of 11 gauges has not reported a new reading in over 2 hours. Affected values are marked stale below and may not reflect current conditions.

Corpus Christi water restrictions and drought stage rules

Corpus Christi sets its drought restrictions on combined storage across Choke Canyon Reservoir and Lake Corpus Christi, not on the level of either lake by itself. This page shows the stage that combined storage currently implies, the thresholds that start each stage, and the rule that decides when one ends. The official stage is declared by the City of Corpus Christi.

Current drought stage

Derived from combined storage across Choke Canyon and Lake Corpus Christi.

27.3%

Stage 3

Critical Shortage

As of Jul 30, 3:00 AM CT (Choke Canyon Reservoir 3:00 AM, Lake Corpus Christi 3:00 AM)

Stage 3 (Critical Shortage). About +25,200 af to reach the 30% clearance level.

Clears only after combined storage stays above 30% for 15 consecutive days. Not yet met.

The stage shown here is tracked by applying the City's initiation and clearance rules, day by day, to the TWDB daily storage history, so it can stay at a more severe stage even after the percentage climbs back over an initiation line. It is not an official declaration.

This is a storage-based estimate. The official drought stage is declared by the City of Corpus Christi.

Where each stage starts and what clears it

Every trigger below is a percentage of combined conservation storage across both reservoirs, not the level of either lake on its own.

StageStarts when storage falls belowClears after 15 days above
Stage 3Critical ShortageCurrent stage20%30%
Stage 2Moderate Shortage30%40%
Stage 1Mild Shortage40%50%
WatchWater Shortage Watch50%50%
NormalNo Active Shortagen/an/a

Why a stage can outlast the number

Drought stages initiate when combined storage falls below one of the threshold lines marked on the storage bar (20, 30, 40, and 50 percent). Clearing a stage takes more than climbing back over the line it started at. Storage must rise above the stage's clearance level, which is 30 percent for Stage 3, 40 percent for Stage 2, and 50 percent for Stage 1 and the Watch, and it must stay there for 15 consecutive days. That gap between the initiation line and the clearance level is deliberate. It keeps a single rainstorm from lifting the restrictions that a long dry spell put in place, and it is the reason the stage on this page can read more severe than today's percentage alone would suggest.

Each clearance step moves down one level at a time. When a stage clears, the count starts over against the next stage's clearance level, so working back to Normal from a deep drought takes several consecutive runs, not one.

Water Emergency levels (Level 1 and Level 2) sit outside this ladder entirely. They are triggered by supply versus demand analysis or by infrastructure and contamination events rather than by a storage percentage, and they are determined by the City Manager. Because they have no storage trigger, they do not appear as bands on the storage gauge.

This page shows where combined storage sits relative to published thresholds. It does not declare the current official drought stage, and it is not a substitute for the City's own notices.

Nueces Estuary freshwater inflow

The same combined storage percentage that drives drought stages also sets the freshwater inflow target for the Nueces Estuary under the TCEQ 2001 Nueces Estuary Agreed Order. As storage falls, the targeted inflow that must be passed downstream steps down with it.

Nueces Estuary inflow: passage of targeted inflows suspended (return flows continue), at storage below 30%, under the TCEQ 2001 Agreed Order.

Not an official compliance determination.

The Agreed Order matters to reservoir levels because it is one of the demands on the system that does not come from a tap. Water passed for the estuary leaves conservation storage the same way municipal supply does, which is why the tiers are keyed to the same storage percentage the drought stages use.

About This Dashboard

Corpus Water Levels tracks Lake Corpus Christi and Choke Canyon water levels, the two reservoirs that supply drinking water to Corpus Christi and the Coastal Bend. The dashboard combines live USGS gauge readings into a single view: combined reservoir storage against system capacity, the current drought stage, and Nueces Basin river flows measured along the Nueces and Frio rivers, updated about every 15 minutes.

Data Source & Disclaimer

Data: USGS Water Data, provisional and subject to revision. Independent and unofficial, not affiliated with the City of Corpus Christi, the Nueces River Authority, TWDB, or any agency. For flood forecasts and warnings, see the National Weather Service.

af
: acre-feet; the standard unit for reservoir storage. One acre-foot ≈ 325,851 gallons, which is water one foot deep over one acre.
cfs
: cubic feet per second; a river's flow rate.
gage height
: a river's water-surface height in feet above the gauge's local datum (a stage reading; not water depth and not sea-level elevation).
elevation
: a reservoir's water-surface height in feet above sea level.
% full
: conservation storage as a percentage of conservation capacity.
combined storage
: Choke Canyon plus Lake Corpus Christi conservation storage added together; this is the system that supplies Corpus Christi.
conservation capacity / pool
: the normal usable storage, meaning water below the top of the conservation pool.
drought stages
: City of Corpus Christi Drought Contingency Plan stages, triggered by combined storage: Watch below 50%, Stage 1 below 40%, Stage 2 below 30%, Stage 3 below 20%. A stage clears only after storage stays above its clearance level for 15 consecutive days.
Nueces Estuary inflow tier
: freshwater-inflow targets to Nueces Bay, set by storage level under the TCEQ 2001 Nueces Estuary Agreed Order.
OWC
: Outlet Works Channel; the gauge measuring water released from Choke Canyon dam.
USGS
: U.S. Geological Survey; source of the live 15-minute gauge data.
TWDB
: Texas Water Development Board; source of the daily reservoir history.
14-day volume (est.)
: an estimate of the total water past a river gauge over the trailing 14 days, from integrating the 15-minute flow readings.

Page last updated: Jul 30, 3:58 AM CT