Lake J.B. Thomas: 20.7% full as of 2024-05-19

The elevation-storage rating curve used to produce the storage hydrograph is made of two segments: (1) the segment up to the conservation pool top (below the red line) is based on measured data, and (2) the segment in the flood pool (above the red line) is an extrapolation from the first segment and shouldn't be relied upon for flood storage information.

Historical Data

Date Percent Full Mean Water Level
(ft)
Reservoir Storage
(acre-ft)
Conservation Storage
(acre-ft)
Conservation Capacity
(acre-ft)
Surface Area
(acres)
Today 2024-05-19 20.7 2,226.54 42,135 41,462 199,931 3,145
Yesterday 2024-05-18 20.8 2,226.56 42,198 41,525 199,931 3,147
2 days ago 2024-05-17 20.8 2,226.58 42,261 41,588 199,931 3,149
1 week ago 2024-05-12 20.9 2,226.62 42,387 41,714 199,931 3,153
1 month ago 2024-04-19 19.6 2,225.81 39,865 39,192 199,931 3,073
3 months ago 2024-02-19 21.5 2,227.01 43,623 42,950 199,931 3,187
6 months ago 2023-11-19 22.6 2,227.73 45,941 45,268 199,931 3,250
1 year ago 2023-05-19 21.3 2,226.90 43,273 42,600 199,931 3,178
*

Percent Full is based on Conservation Storage and Conservation Capacity and doesn't account for storage in flood pool.

**

   Values above, including today's are averaged conditions. For near real-time instantaneous water level, see table below or the interactive map viewer.

Most Recent Instantaneous Water Level

Date/time Water Level
(ft)
Conservation Pool Elevation
(ft)
Height Above Conservation Pool
(ft)
Most recent 2024-05-19 18:45 2,226.53 2,258.00 -31.47
1 hour prior 2024-05-19 17:45 2,226.53 2,258.00 -31.47
2 hours prior 2024-05-19 16:45 2,226.54 2,258.00 -31.46
6 hours prior 2024-05-19 12:45 2,226.55 2,258.00 -31.45
12 hours prior 2024-05-19 06:45 2,226.54 2,258.00 -31.46
24 hours prior 2024-05-18 18:45 2,226.56 2,258.00 -31.44
48 hours prior 2024-05-17 18:45 2,226.58 2,258.00 -31.42
*

Data is provisional and subject to revision.

Additional Information

Impoundment date 1952-01-01
Vertical datum NGVD29
Dead pool elevation 2,200.00 ft above NGVD29
Service spillway crest elevation 2,258.00 ft above NGVD29
Emergency spillway crest elevation 2,264.00 ft above NGVD29
Emergency spillway crest elevation 2,267.00 ft above NGVD29
Maximum design elevation 2,275.00 ft above NGVD29
Top of dam elevation 2,280.00 ft above NGVD29
Conservation pool elevation 2,258.00 ft above NGVD29
Data download (CSV) period of record, last one year, last 30 days

Elevation-Area-Capacity Curves

1952-01-01 (source: USGS)
1999-11-01 (source: TWDB) : GIS Data
Data Source USGS:08118000

Lake Location